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August  1982  $2.49  Va 
Issue  #263 


ome-Brew 
ontest  Winner: 
Smart"  Squelch 

age  44 

'oor  Man's 

pectrum 

iialyzer 

age  10 

"he  Ultimate  Fuse 

age  52 

~rek  to  Tibet 

age  32 


onfessions 
Df  a  Counter 
Evolutionary 

'age  100 


74470 


65946 


Amateur  Radio's 
Technical  Journal 


A  Wayne  Green  Publication 


Poor  Man's 
Spectrum  Analyzer 

—  another  73  breakthrough 
WB5IPM 

The  AC4YN  Story 

—  a  Tibetan  adventure, 

circa  193M937  C5YN 

"Smart"  Squelch  for  SSB 

W9MKV,W9YAN 

The  Ultimate  Fuse 

—  ac  overload  protection 
W20LU 

Multi-Purpose 
Peak  Adapter 

—  don't  settle  for  being 
average K9EUI 


10 


32 


44 


52 


54 


Spectrum  Analyzer  — 10 

The  $100  TVRO  Receiver 

|ra  —Satellite  Central, 

part  VIII Gibson 


60 


VUM: 

Volume  Units  Meter 

—  makes  measuring  decibels 
easy W4MLE 

Analog  Isn't  Dead 

—don't  be  LED  astray  by  the 

digital  revolution    .    WB6AFN/9 

Line  Voltage  at  a  Glance 
—at  last,  a  useful  gadget 

W4RNL 

Confessions  of  a 
Counter  Evolutionary 

—  the  best  circuit  yet? 

WA2FPT 


72 


76 


84 


100 


TVRO  Receiver— 60 


Never  Say  Die— 6 
Social  Events— 92 
Ham  Help— 97,  122,139 
Reader  Service — 114 
Fun!— 116 
Letters— 117 
Contests— 119 
New  Products— 126 


DX-126 
Review— 130 
Awards— 133 
Corrections— 135 

Satellites— 138 
Dealer 
Directory— 162 

Propagation — 162 


2  Meter,  220  or  440 


ICOM's  reliable,  field  proven,  handhelds  have 
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provided  by  a  quality  speaker  and  an  electret 
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0-15  watt  low  power  Touchtone®  pad  is  included." 


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THE  SYSTEM,  Accessories  for  the  handheld 
series  are  interchangeable  among  transceivers. 
Slide  on  removable  battery  packs  allow  quick 
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IQDC1 

DC  Regulator 

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( comes  with  DC 
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power  from  BC30 ) 


IOBP4' 


OBP3T  Battery 

Battery  Pack 
I&BP2**  8.4VDC250  mAH 

Battery  Pack      1  5  hr  charge 
7.2  VDC  425  mAH  / 

1 .5  hr  charge  I 

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■fWtU  charge  from  iKJO>  B&5U.  CFl,  or  12 
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1        ft  Accept  6  AA  stie  batteries    Alkaline  or  NiCd 
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Uhrc1— *- 


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IOML1    12  VDC 
144  MHz  Booster 

10Wout/12VIX: 

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BNCtoPL259) 


IOBC25U 
AC  Wall  Charger 
1 17  VAC  in 
(for  charging 
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IOCP1 

Cigarette  Lighter 
Cotd  w/Fuse 

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INFO 


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The  loops  are  Utz-wire  wound  on  RF  fer- 
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4     73 Magazine  *  August.  1982 


Reaper  Service  for  facing  page  ^303-* 


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Store 

commands, 

as  well  as  text. 

for  automatic  execution 

The  Heathkit  /iMatic  Memory  Keyer's  sneak 
preview  caused  a  sensation  at  Dayton  in  1981, 
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— .  / ._  -  / 


h—       —        Hu! 


AM-422R1 


W2KSD/1 

NEVER  SAY  DIE 

ed/tor/a/  by  Wayne  Green 


THE  WORLD'S  FAIR— 
KNOXVILLE 

Yes,  there  is  a  ham  exhibit  at 

the  new  World's  Fair,  The  local 
hams  got  together  and  man- 
aged  to  get  some  space  in  the 
Knoxviile  exhibit  for  the  sta- 
tion. It's  a  good  looking  exhibit, 
packed  with  Ten-Tec  gear  for  the 
most  part.  That's  not  too  sur- 
prising since  Ten-Tee's  plant  is 
just  a  few  miles  from  Knoxviile. 
The  fair  isn't  large  by  World's 
Fair  standards.  I've  only  seen  a 
few  such  fairs,  so  perhaps  I  was 
expecting  too  much,  I  am  old 
enough  to  have  spent  a  good 
deal  of  time  wandering  the  New 


York  fair  in  1938,  watching  the 
early  television  programs  being 
produced.  They  had  iconoscope 
cameras  In  those  daysT  so  the 
lights  had  to  be  fierce  compared 
with  the  later  developed  image 
orthocons,  which  were  far  more 
sensitive  (and  expensive). 

They  had  a  lot  of  entertain* 
ment  exhibits  at  that  fair.  I  didn't 
see  much  of  that  at  Knoxviile, 
Here  the  exhibits  are  almost  en- 
tirely international  and  national, 
with  little  from  our  major  indus- 
trial corporations. 

At  the  Montreal  fair,  there  was 
a  good  deal  of  entertainment* 
but  the  lines  were  so  long  to 


watch  it  that  many  were  discour- 
aged. I  know  I  had  to  miss  most 
of  the  highly  touted  shows  be- 
cause I  didn't  have  a  day  apiece 
to  devote  to  line  standing.  For- 
tunately, most  of  the  ones  that  I 
had  to  miss  at  Montreal  turned 
up  when  San  Antonio  had  their 
World's  Fair,  so  I  eventually 
saw  them. 

I'm  beginning  to  recognize 
that  a  successful  fair  means  hot 
weather  and  long,  long  lines.  I 
think  the  line  tor  the  Chinese  ex- 
hibit is  almost  the  length  of  the 
whole  fair*  It  reminded  me  of  an 
illustration  by  Ripley  for  an  item 
which  said  that  there  were  so 


Three  of  the  landmark  structures  of  The  1982  World's  Fair  in  Knoxviile,  Tennessee,  form  around  the  three- 
acre  Waters  of  the  World  Lake.  At  left  is  the  Sunsphere,  266  feet  high  and  the  "theme  structure"  of  the ex- 
position.  The  five-level  sphere,  encased  in  glass  made  of  24-karat  gold  dust  houses  a  restaurant  and  two 
cocktail  lounges  and  observation  areas.  In  the  right  foreground  is  the  1,500-seat  Tennessee  State  Amphi- 
theatre. The  United  States  pavilion  (at  tar  right)  features  "talk-back  computers,"  a  "national  energy  debate" 
utilizing  teisvision  screens  and  a  new  IMAX  film,  to  be  shown  on  a  screen  seven  stones  high  and  90  feet 
wide.  Downtown  Knoxviile  forms  the  background  at  left.  (Photo  by  Mike  DuBose) 

6     73Magazine  •  August,  1982 


many  Chinese  that  a  column  of 
them  four  wide  could  parade  by 
night  and  day  forever,  with  the 
newly  born  keeping  up  with  the 
pace  of  the  line.  The  line  at  the 
fair  seemed  endless.  Most  of  the 
more  interesting  exhibits  had 
lines,  but  none  compared  with 
the  Chinese. 

It  appears  that  Knoxviile  has 
gotten  a  bum  rap  from  some  of 
the  media.  I  was  there  in  tate 
May  and  found  little  problem  in 
getting  hotel  accommodations. 
Even  when  I  went  on  Sunday  to 
the  fair,  I  was  able  to  park  within 
one  block  of  the  fair  gate.  They 
have  parking  lots  all  around  the 
outskirts  of  town  where  you  can 
leave  your  car  and  be  commuted 
by  a  bus. 

Of  course,  my  favorite  subject 
is  food.  That  was  one  of  my  big 
memories  of  the  New  York  fafr 
of  '38.  Montreal  was  a  bust,  with 
most  of  the  food  stands  selling 
only  buffalo  burgers — which  are 
okay,  but  not  exciting, 

At  San  Antonio,  I  had  a  great 
time  eating.  They  had  all  sorts  of 
fast  food  services.  Knoxviile  has 
done  the  same.  They  have  one  of 
the  widest  varieties  of  food  of 
any  fair  yet.  Have  you  ever  seen 
a  cobbler  stand?  Yep,  a  choice 
of  appte<  cherry,  blueberry,  or 
mixed  fruit  cobbler,  with  or 
without  soft  ice  cream.  You 
could  also  get  Belgian  waffles, 
nice  and  fresh  and  crisp,  with 
either  whipped  cream  or  soft  ice 
cream. 

There  are  plenty  of  repeaters 
around  Knoxviile,  so  if  you 
decide  to  drive  to  the  fair  you 
won't  have  any  problem  getting 
talked  in.  I  catted  in  on  146. 73 
and  got  route  instructions- 
first  to  the  Knoxviile  hamfest. 
then  to  the  fair.  No  problem 
getting  help. 

If  you're  within  driving 
distance  of  Knoxviile,  I'd  say  it's 
worth  your  while  to  plan  on  get- 
ting down  there  (or  up)  this  sum- 
mer. Be  sure  to  check  in  at  the 
ham  exhibit  and  log  in.  If  you 
flash  your  ham  license,  they'll 
let  you  sit  down  and  do  some 
contest-type  operating.  It  seems 
that  World's  Fair  stations  are 
reasonably  rare,  so  there  are 
pileups  for  everyone.  It's  a  lot 
easier  than  getting  down  to 
Swaziland  or  something.  And 
you  can  get  a  taste  of  quite  a 
bunch  of  foreign  countries  by 
visiting  their  exhibits. 

Speaking  of  the  Knoxviile 
hamfest,  while  I  didn't  see 
anyone  there  from  Ham  Radio 
magazine,  I  did  catch  a  glimpse 


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PUBLISHER/EDITOR 

Wayne  Green  W2MSD/1 

EXECUTIVE  VICE  PRESIDENT 

Sherry  Smythe 

ASSISTANT  PUBLISHER/EDITOR 
Jeff  DeTray  WB8BTH 

MANAGING  EDITOR 
John  Sgrnetl 

ASST.  MANAGING  EDITOR 

Susan  PhiLbrfck 

EDITORIAL  ASSISTANTS 

Nancy  Noyd 

RtChard  Pheni.x 

Steve  Jewett 

TECHNICAL  EDITOR 
Tim  Daniel  N8RK 

ASSISTANT 
TO  THE  PRESIDENT 

Matthew  Smith  KA1IEI 

ASSOCIATES 

Roberi  Baker  W62GFE 

John  Edwards  KI2U 

Bill  Gosney  KE7C 

Sanger  Green 

Chod  Harris  VP2ML 

Or  Marc  Leavey  WA3AJR 

J,  H,  NeJson 

Bill  Paslernafc  WA6ITF 

Peter  Stark  K20AW 

PRODUCTION  MANAGER/ 

PUBLICATIONS 

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ASST.  PRODUCTION 
MANAGER/PUailCATIONS 

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ADVERTISING  GRAPHICS 
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Deborah  Stone 

Irene  Vail 
Judl  Wlmberly 
David  Wozmak 

PHOTOGRAPH  I' 

Bryan  Hastings 

Jonn  R.  Schwejgert 

Robert  M,  Villeneuve 

Thomas  VIHeneuve 

TYPESETTING 

Sara  Bedell 

Melody  BedeM 

Marie  Barker 

DebtriE  Davidson 

M  i ch el e  Des Roch ei s 

.Jennifer  Fay 

Anne  Rocchlo 

EHen  Schwartz 

Karen  Stewart 

Lisa  Steiner 

GENERAL  MANAGER 

Da  bra  Wetherbee 

CONTROLLER 

Roger  J.  Murpny 

EXECUTIVE  ASSISTANT 

Leatrice  O'NeiP 

ACCOUNTING  MANAGER 
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8     73Magazme  *  August,  1982 


of  one  of  the  00  chaps.  Funny 
thing,  even  though  this  was  an 
official  ARRL  hamfest,  I  didn't 
see  any  of  their  officials. 
Hmmm.  Maybe  I  missed  'em. 

The  people  at  TenTec,  in  ad- 
dition to  supporting  the  ham  ex- 
hibit at  the  World's  Fair,  also 
had  the  most  elaborate  exhibit 
at  the  hamfest.  I  don't  know  how 
they  get  any  work  done! 

The  ham  station  at  the  fair 
was  not  of  enough  importance 
for  the  FCC  to  manage  a  special 
events  call,  but  the  Knoxville 
chaps  were  very  resourceful.  A 
local  club  had  the  call  WA4KFS, 
so  they  "borrowed"  the  call  for 
the  fair... it  representing  the 
Knoxville  Fair  Station. 

I  sat  down  for  a  few  minutes 
to  see  how  the  station  was  wor k- 
ing.  Aiming  the  beam  at  Europe, 
I  found  a  relatively  clear  spot 
(not  bad  for  Sunday  afternoon 
on  20m)  and  cafled  CCL  Wouldn't 
you  know  that  the  chap  who 
came  back  to  my  call  lives  a  few 


miles  from  Peterborough  and, 
when  he  found  out  who  was 
operating,  mentioned  that  he 
drives  past  my  place  every  day 
going  to  work! 

Having  been  on  the  ham  tour 
to  China  a  year  ago,  I  wasn't 
ready  to  face  the  three-hour  or 
more  line  to  see  their  exhibit. 
Then  I  found  out  that  our  press 
passes  not  only  got  us  in  the  fair 
free,  but  were  also  useful  for  go- 
ing to  the  head  of  lines.  Hmmm, 
It  makes  good  sense  since  one 
of  the  things  the  fair  needs  most 
desperately  is  some  good  press. 
So  Sherry  and  I  ambled  down  to 
the  China  exhibit,  flashed  our 
press  passes,  and  got  right  in. 

Sherry  was  disappointed,  I 
think.  Sure  enough,  China  had 
all  their  stuff  thereon  exhibit. . , 
with  a  lot  of  the  items  for  sale. 
But  it  was  pretty  much  the  same 
as  we'd  seen  at  the  Canton 
Trade  Fair.  We  did  come  close  to 
buying  one  of  their  gorgeous 
rugs,  Only  the  problems  of  ship- 


ping it  home  slowed  us  down  In 
Canton .  . .  now  we  had  no  such 
excuse.  The  rugs  are  spectacu- 
lar and  quite  reasonable  in 
price.  They're  not  as  inexpen- 
sive as  in  China,  of  course,  but 
they're  still  a  bargain. 

The  exhibit  was  interesting, 
but  wouid  have  been  a  bummer 
If  we'd  had  to  invest  much  line 
time.  That's  probab(y  one  of  the 
drawbacks  to  being  into  travel. 

The  worst  days  as  far  as  lines 
are  concerned  are  Friday  and 
Saturday.  Thursday  is  the  light- 
est attendance  day,  with  Sun- 
day being  second.  That's  Bap- 
tist country,  remember,  and 
Sunday  is  for  church.  The  lines 
for  food  were  small,  if  any,  Sure, 
if  you  really  had  to  have  a  ham- 
burger and  wanted  it  at  12:30, 
there  was  a  tine.  But  right  next 
to  that  stand  you  could  get 
something  more  Interesting 
with  no  wait.  The  Hungarian  ex- 
Con  tinued  on  page  139 


Well ...  I  Can  Dream,  Can't  I? 


by  Bandel  Linn  K4PP 


/ 


(WJtfKg1 


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"While  we  were  digging  you  a  deeper  ground,  we  struck  oil!" 


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Poor  Man's  Spectrum  Analyzer 

another  73  breakthrough 


Frank  H,  Perkins  WBStPM 
Box  13642 
Arlington  TX  76013 

Hams  enjoy  making  all 
types    ot    electrical 

measurements.  In  fact,  it's 
one  of  our  favorite  pas- 
times and  topics  of  conver- 
sation Fortunately,  good, 
low-cost  oscilloscopes, 
DVMs,  and  other  instru- 
ments are  available  to  us 
for  measuring  voltage,  cur- 
rent, power,  swr,  frequency, 
and  so  on. 

There  is  one  instrument, 
however,  that  has  been  be- 
yond the  reach  of  most  of 
our  budgets  — the  spectrum 


analyzer.  Commercial  ver- 
sions of  this  useful  rf  instru- 
ment start  at  $2500,  which 
is  a  little  steep  for  most  of 
us.  U  is  possible  for  you  to 
build  a  simple  spectrum  an- 
alyzer for  about  $150  that 
works  with  a  low-cost  oscil- 
loscope. The  analyzer  can 
be  used  to  check  HF  trans- 
mitting equipment,  among 
other  applications,  Its  use, 
theory  of  operation,  and 
construction  are  discussed 
in  this  article, 

Spectrum  Analyzer 
Operation 

A  spectrum  analyzer  is  a 
special  receiver  that  allows 


Photo  A.  High  frequency  spectrum  analyzer  covers  0  to  60 
MHz. 

10     73 Magazine  *  August,  1982 


you  to  view  the  frequency 
components  of  its  input  sig- 
nal on  an  oscilloscope  CRT. 
The  spectrum  analyzer  re- 
peatedly tunes  across  the 
frequency  band  you  have 
chosen  with  its  center-fre- 
quency and  frequency-span 
controls.  For  example,  if 
you  set  the  center-frequen- 
cy control  for  20  MHz  and 
adjust  the  frequency-span 
control  for  a  tuning  range 
from  10  MHz  below  to  10 
MHz  above  the  center  fre- 
quency, the  analyzer  will 
repeatedly  tune  the 
10-MHz-tf>30-MHz  band. 

As  the  analyzer  tunes 
from  the  low  end  to  the 
high  end  of  the  band,  it 
moves  the  CRT  trace  from 
left  to  right.  The  5-meter 
output  from  the  analyzer 
moves  the  CRT  trace  up- 
ward from  the  bottom  of 
the  CRT  screen  according 
to  signal  strength.  A  spec- 
trum analyzer  display  usu- 
ally looks  like  a  number  of 
spikes.  The  farther  to  the 
right  a  signal  (spike)  ap- 
pears on  the  CRT,  the  high- 
er its  frequency;  the 
strength  of  the  signal  is  indi- 
cated by  its  height.  There 
usually  appears  to  be  some 
"grass"  along  the  bottom  of 
the  CRT  display  This  is  due 
to  noise.  You  probably  have 
seen  spectrum  analyzer  dis- 
plays in  ham  gear  sales  liter- 


ature and  some  magazine 
articles. 

To  appreciate  how  useful 
a  spectrum  analyzer  can 
be,  let's  first  look  at  Photo 
Bf  an  rf  signal  on  a  normal 
oscilloscope.  To  me  it  looks 
like  a  clean  sine  wave 
What  do  you  think? 

Now  let's  look  at  Photo 
C,  the  same  rf  signal  on  our 
spectrum  analyzer.  The 
half-spike  on  the  left  is  our 
zero-frequency  reference. 
The  next  signal  to  the  right, 
which  is  the  tallest,  is  the 
fundamental  component  of 
our  rf  signal.  The  three  sig- 
nals to  the  right  of  the  fun- 
damental are  the  2nd,  3rd, 
and  4th  harmonics. 

!f  the  spectrum  of  our 
transceiver  or  linear  ampli- 
fier output  looked  the  same 
as  this  photo,  we  would  not 
be  complying  with  FCC 
Regulation  97  73,  even 
though  our  fundamental 
signal  was  properly  within 
an  HF  amateur  band. 

To  understand  what's 
wrong,  compare  the  height 
of  the  2nd  harmonic  signal 
to  the  fundamental.  The 
second  harmonic  is  about 
2  6  CRT  divisions  shorter 
than  the  fundamental.  With 
a  10-dB-per-division  vertical 
calibration,  the  second  har- 
monic is  26  dB  below  the 
fundamental. 

FCC  Regulation  97.73  re- 


Photo  B,  Rf  signal  as  viewed  on  an  ordinary  oscilloscope,  Is 
this  a  clean  signal? 


quires  low-power  transmit- 
ters up  to  5  Watts  to  sup- 
press afl  signal  frequency 
components  (spurs)  outside 
the  HF  band  of  operation  at 
least  30  dB  below  the  fun- 
damental. For  a  transmitter 
from  5  to  500  Watts,  this  fig- 
ure is  40  dB.  For  a  100O 
Watt  transmitter  or  linear 
amplifier,  the  figure  is  43 
dB  Checking  our  photo 
again,  we  notice  that  the 
3rd  harmonic  signal  is 
about  39  dB  below  the  fun- 
damental. We're  also  going 
to  have  a  problem  with  the 
3rd  harmonic  if  we  are  run- 
ning 5  Watts  or  more  pow- 
er. The  4th  harmonic  is  no 
problem  since  it's  about  55 
dB  below  the  fundamental. 

We  can  correct  the  prob- 
lem by  adding  a  filter  be- 
tween our  transceiver  or  lin- 
ear and  the  antenna.  How- 
ever, unless  we  are  able  to 
check  the  output  spectrum 
of  our  transmitting  equip- 
ment, we  may  never  know 
we  have  a  problem  — until 
our  neighbors  start  conv 
plaining  or  we  get  a  "friend- 
ly advisory"  from  the  local 
FCC  monitoring  station. 

There  are  many  uses  for  a 
spectrum  analyzer  besides 
monitoring  transmitter  out- 
puts, but  this  use  alone  can 
make  an  HF  spectrum  ana- 
lyzer construction  project 
worthwhile.  If  you  build 
one,  you'll  probably  be  the 
first  on  your  block  (or  in 


your  favorite  net  or  club)  to 
have  one  of  your  own! 

Spectrum  Analyzer  Hookup 

Fig.  1  shows  how  to  hook 
up  the  high  frequency  spec- 
trum analyzer  for  monitor- 
ing the  output  spectrum  of 
a  transmitter  or  linear  am- 
plifier. Remember,  the  ana- 
lyzer is  a  receiver.  It  re- 
quires a  very  small  sample 
of  power  for  operation.  This 
is  done  with  an  L-pad  sam- 
pler. The  sampler  will  not 
interfere  with  normal  trans- 
mitting or  transceiving  op- 
eration. The  output  from 
the  L-pad  is  further  reduced 
with  a  step  attenuator  to 
match  the  full-scale  input* 
power  requirements  of  the 
analyzer  (1/4  to  1/10  of  a 
milliwatt).  The  spectrum  is 
displayed  on  the  oscillo- 
scope being  used  with  the 
spectrum  analyzer. 

It  is  important  to  observe 
good  safety  practices  when 
using  the  L-pad,  attenuator, 
and  spectrum  analyzer.  Be 
sure  all  station  equipment. 
the  L-padt  attenuator,  ana- 
lyzer,  and  oscilloscope 
cases  are  properly  ground- 
ed. Use  the  proper  L-pad  for 
your  power  range,  Double- 
check  your  hookup  before 
applying  power.  If  the  out- 
put of  a  transmitter  was  di- 
rectly connected  to  the  an- 
alyzer by  accident  it  would 
instantly  be  damaged  when 
the  transmitter  was  keyed, 


V  W  Is 


Photo  C  Same  rf  signal  on  the  spectrum  analyzer.  Second 
harmonic  is  only  26  dB  below  the  fundamental.  Don't  put 
this  signal  on  the  air! 


Overall  Circuit  Operation 

Let's  first  discuss  Fig,  2, 
the    spectrum    analyzer 

block  diagram.  We  will 
then  look  at  the  circuits  in 
each  block  in  detail,  Notice 
that  the  analyzer  block  dia- 
gram looks  similar  to  that 
of  a  single-conversion  su- 
perheterodyne receiver 
The  i-f  frequency  of  the 
spectrum  analyzer  is  90 
MHz. 

The  sampled  input  signal 
from  the  L-pad  is  adjusted 
to  the  proper  power  level 
with  the  step  attenuator,  as 
we  discussed  before.  The 
signal  is  then  taken  through 
a  low-pass  filter  with  a 
60-MHz  cutoff  frequency 
The  low-pass  filter  prevents 
90-MHz  signals  from  leak- 
ing into  the  analyzer  and 
"confusing"  it.  The  input  is 


next  mixed  with  the  90-MHz 
to  150-MHz  voltage-con- 
trolled oscillator  (vco)  in 
the  double-balanced  mixer. 
The  difference  output  from 
the  mixer,  which  is  the  de- 
sired i-f  signal,  is  then  fil- 
tered by  the  90-MHz  band- 
pass filter.  The  bandpass  fil- 
ter provides  the  necessary 
selectivity  for  the  spectrum 
analyzer.  The  90-MHz  sig- 
nal from  the  bandpass  filter 
is  preamplified  and  applied 
to  the  log  amplifier.  The 
output  of  the  log  amplifier 
is  logarithmic  signal 
strength  video  for  the  oscil- 
loscope vertical  (Y)  axis 

The  voltage-controlled 
oscillator  frequency  is  con- 
trolled by  the  sweep  gener- 
ator, which  simultaneously 
controls  the  horizontal  (or  X 
axis)  of  the  oscilloscope. 
Note  that  when  the  vco  is 


TRANSMITTER 

OR 
LINEAR 


2Q-6QilCinv 


1_£ 


4D 


L-PA0 
SAMPLER 


DUMMY  LOAD 

OR 

ANTE M MA 


OSCILLOSCOPE 


I     JLII5 


T    AH  IS 


V 


HF  SPECTRUM 
ANALYZER 

ATTENUATOR 


O-SflUBm 


aODDD 

1    HO  20  Zfl 


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ttiDTH    CENTER 

o    © 


JJ  VIDEO 


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Note  7.  Never  hook  transmitter  or  linear  directly  to  step  attenuator  or 
analyzer  Always  use  L-pad  sampler  of  the  proper  power  rating. 
Note  2.  Be  sure  transmitter,  linear,  L-pad,  attenuator,  analyzer,  and 
scope  are  grounded. 

Fig,  7.  Typical  HF  spectrum  analyzer  hookup. 

73  Magazine  *  August  1982    11 


» 


Photo  D.  Bottom  view  of  spectrum  analyzer  chassis.  Log 
amplifier  is  at  the  top.  Power  supply  and  sweep  generator 
board  is  directly  below  the  log  amplifier  Vco  is  next  The 
mixer  is  directly  below  the  vco.  The  mixer  connects  to  the 
low-pass  filter  at  the  left  The  bandpass  filter  is  at  the  lower 
right.  Preamplifier  is  on  the  middle  right 


tuned  to  90  MHz,  the  ana- 
lyzer is  tuned  to  zero  MHz. 
When  the  vco  is  tuned  to 
120  MHz,  the  analyzer  is 
tuned  to  30  MHz.  With  the 
vco  at  1 50  MHz,  the  analyz- 
er is  tuned  to  60  MHz. 

The  tuning  range  of  the 
analyzer  is  adjusted  with 
the  center-frequency  and 
frequency-span  controls  on 
the  sweep  generator.  The 
sweep  generator  automati- 
cally tunes  the  analyzer 
across  its  tuning  range 
about  10  times  each  sec* 
ond  The  sweep  generator 
clamps  or  "shorts  out"  the 
video  during  the  retrace  be- 
tween each  sweep  to  avoid 
a  confusing  oscilloscope 
display.  This  eliminates  the 
for    an    oscilloscope 


INPUT 

FROM       _ 
L-PAD 

SAMPLER 


ATTENUATOR 


C-39  3* 


LOW 

PASS 

FILTER 


MIXER 


o-eowHt 


BAND 

PASS 

FILTER 


PREAMP 


LOG   AMP 


BBM 


K-!5GM«*i 


90Umz 


flQMMl 


MJUttl-*LOa  DC 


VCO 


Fftta  SPAN  ADJUST 


CENTER    FRE0    ADJUST 


f 


n 


3-i*. 


SWEEP  GENERATOR 

AND 

POWIR   SUPPL> 


•7 


HE-TRACE  CU*'1 


VIDEO   TO  SCOPE 
IT  AMES! 
Z.5VP-P 


( 


SWEEP  TO  SCOPE 
(X  AXIS) 
1\  P-P 
10-13  H* 


IZVAC 


Fig.  2.  Block  diagram, 


MINIBOX 


—I 


SO  1 39 


TO  ANTENNA  OR 
DUMMY  LOAQ 


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A-B 

SERIES 

ELEMENT 


^i/J! 


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U&-GZS  9'U  (BMC) 


TO  ATTENUATON   ANO 
HF   SPCCTHUM 

AMAL12.ER 


fft 


100    1000  WATT  SAMPLED 


A*- 


500  J* 
— vft *B 


A* 


2K.  fW 
— "tfV* — 


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25 -1  WATT  SERIES  CLEMENT 


I -Id  WATT  SERIES  ELEMENT 


10-100  WATT  SERIES  ELEMENT 


Note  f.  Carbon  composition  (noninductive)  resistors. 
Note  2.  "Fuse"  is  single,  hair-thin  copper  strand  from  ac  "zip"  cord. 
Note  3.  Connect  SO-239  connectors  with  RG-6  center  conductor  wire. 
Note  4,  Test-run  sampler  before  connecting  to  attenuator. 

Note  5,  Keep  BNC  connector  3Tt  away  from  SO~239s;  space  resistor  sets  3/8"  minimum;  "fuse"  is  1/2"  to 
3/4"  long. 


Fig.  3,  L-pad  power  samplers. 


12     73  Magazine  •  August,  1982 


with  a  Z-axis  (blanking)  in- 
put. The  power  supply  pro 
vides  +24Vdc  +12  V  do, 
and  —  6  V  dc  for  the  spec- 
trum  analyzer  circuitry.  The 
power  supply  operates 
from  12  V  ac  supplied  by  a 
wallplug  transformer 

L-Pad 

Fig.  3  shows  the  sche- 
matic of  a  100-to-1000-Watt 
L-pad  sampler,  with  alter- 
nate circuitry  for  a  10-to- 
100-Watt  sampler,  a  1-to-10- 
Watt  sampler,  and  a  0.25-to- 
1-Watt  sampler  Four  pairs 
of  4.7k,  1-Watt  resistors 
form  the  series  element  of 
the  100-to-1000-Watt  sam- 
pler. A  51 -Ohm,  1/2-Watt  re- 
sistor forms  the  shunt  ele- 
ment. The  L-pad  resistors 
are  rated  for  continuous  op- 
eration. A  single  hair-thin 
strand  from  an  old  "zip" 
cord  provides  some  fusing 
protection  in  the  event  of  a 
component  failure  or  cir- 
cuit fault.  The  series  ele- 
ments for  the  other  power 
ratings  are  shown  in  Fig.  3 

O-to-59-dB  Step  Attenuator 

Fig.  4  shows  the  step  at- 
tenuator schematic.  Five  pi- 
style  resistive  attenuators 
are  switched  in  or  out  as 
necessary  to  achieve  the 
proper  attenuation.  Switch- 
es are  double-pole,  double- 
throw.  Resistors  may  be  1/2 
Watt  or  1/4  Watt,  although 
1/4-Watt  resistors  are  easier 
to  work  with.  Note  the 
shielding  between  sections. 
Resistors  must  be  5%  toler- 
ance (The  resistor  values  for 
each  attenuator  came  from 
Reference  1 ,) 

Low-Pass  Filter, 
Mixer,  and  Vco 

Fig.  5  shows  the  details  of 
these  circuits  The  low-pass 
filter  consists  of  three  pi- 
sections,  separated  by 
shielding.  The  cutoff  fre- 
quency of  the  filter  is  about 
60  MHz  Three  sections  are 
used  to  give  a  high  attenua- 
tion at  the  90-MHz  if  fre- 
quency and  above. 

Each  port  of  the  double- 
balanced  mixer  is  padded 
with  50-Ohm  attenuators  to 


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IC-720A 

listen  to  signals  from 
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With  a  100  KHif  — 

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Talk  with  a  160  — 
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—  ready  to  go 
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dual  VFO's  —  split 
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DFM  (  Direct  Reed 
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tuning,  speech 
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RTTY  ( FSK  >. 
computer 
compatible  tuning, 
12  volt  operation,  all 
features  standard 

except  CW  &  AM 
narrow  filters.  ICQM 
system*  accessories 
are  available  for  a 
complete  station. 


ynamic  range. 
♦  ly.SdBm  interce 
point  receiver      1 
utilizing  ICOM*-* 
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dual  VFO's  —/ 


memory  pe/  band. 


*ICt)M  system,    n 

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nmftiifiir  it  VMt  tIr  At  td 
tmtfrs  fi  C\f5  fn/ut't  stm 
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itntitimt  li'-Nffi  ft*4*tbm 
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f  uiftW  llLLV&SStifil+S  ti*rti*  ittth  lift  HfTVtT  ttf 

VhiHit'-uif tittup  hrn»nffutmtiyt  timtur 
H  t ttttfthtfuhn *h t» ttfi  **utt 'ttt m *tx  tfntaffflW 
ft  tK  tUA  meittitn- fa*  toft  ft  \fi  » SEffenMf 
%.  U    it  ft  uulufHHutxuiUtxrix  nwtjth' 
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ICOM  America  Inc..  21 12-1 1 61b  Ave  NE.  Del 

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subject  to  change  wtiftour  nonce  <x  obfrgorton    All  KTOM  iowca  wgrnfitGrirty  exceed  FCC  regufaftons  hminng  vpunou*  r 


encourage  good  mixer  per- 
formance (low  mixer  spurs) 
at  the  expense  of  extra  con- 
version loss,  Mini-Circuits 
SRA-1  and  SBL-1  are  good 
commercial  mixers  It  is 
quite  possible  to  build  a 
suitable  double-balanced 
mixer  from  smalt  ferrite  tor- 
oids  and  hot  carrier  diodes, 
if  you  have  trouble  finding 
these  commercial  units. 
(Consult  Reference!  for  de- 
tails) 

The  vco  consists  of  an 
MRF901  Colpitts  oscillator 
coupled  to  a  wideband 
2N5179  amplifier.  The 
MRF901  was  eventually 
chosen  for  the  oscillator 
transistor  because  of  its 
well-behaved  phase-shift 
characteristics  between  90 
MHz  and  1 50  MHz  The  two 
MV109  hyper-abrupt  E pi- 
cap  diodes  act  as  tuning  ca- 
pacitors and  account  for 
the  oscillator's  wide  tuning 
range.  A  small  pick-up  loop 
near  the  oscillator  coil  pro- 
vides an  output  for  check- 
ing frequency  and  doing 
other  tests,  The  oscillator  is 
also  lightly  coupled  to  the 


2N5179  vco  amplifier.  The 
output  of  this  amplifier 
drives  the  local  oscillator 
port  of  the  mixer.  A  diode- 
capacitor  rf  detector  pro- 
vides a  dc  output  for  check- 
ing amplifier  output  power 
The  wideband  amplifier  de- 
sign is  based  on  data  from 
Reference  1.  The  oscillator 
design  is  based  on  third- 
attempt  desperation!  Note 
the  use  of  the  feedthrough 
capacitors  and  shielding. 
These  are  as  much  a  part  of 
the  circuit  as  the  MRF901. 

Bandpass  Filter 

The  bandpass  filter  is  de- 
tailed in  Fig.  6.  It  consists  of 
four  relatively  small  helical 


Job 


Photo  £.  Vco  layout.  Oscillator  is  near  the  feedthroughs, 


resonators.  The  input  and 
output  resonators  are  tap- 
coupled  to  the  input  and 
output  connectors,  The 
four    resonators    are   aper- 


ture-coupled to  each  other. 
The  two  center  resonators 
are  slightly  stagger-tuned  to 
give  the  filter  bandpass  a 
sharp     'nose/     The    3-dB 


6db 


[Qdb 


UG  625 ayu 


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EQUIPMENT 
UVDER  TEST 


m [*1  \P-* QPQT     ■     -r.     ■  W»BT    • ^   ftPOT  1 


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-\      j.  V— \      i  V — 

mr  * *  ESPfti    • •  qpdi 


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500 


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DfOI 

'  240 


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62 


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dpbi 

f  240 


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€2 


At 


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L 


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25&/U 


flO-56  COAX   TO 
LOW  PASS  FlLTIH 
r-64frm  TO  -iQdfrml 


Note  h  DPDT  toggle  switch— Radio  Shack  275-1546  or  equivalent, 

Note  2.  BNC  receptacle— Radio  Shack  278-105  or  AmphenoJ  31*236. 

Note  3.  Resistors  1/2  or  1/4  W,  5%  non inductive. 

Note  4.  Attenuator  box  made  from  single-  and  double-sided  G-lO  circuit  board  plus  copper  shim  stock. 

Fig.  4.  0-59-dfl  step  attenuator. 


UB-625  B/U 


KG   SB  COAX   TO 

ATTENUATOR 
[  C  TO  -IQdbml 


r 

3y^ 


f  turns  *ao 

ON    T37-* 


7    TURNS  #10  T  TURNS   #50 

ON    T37-G  ON   T37-G 


-*-ninr^^ == T^^~l ^ ^T^T-^ 

36  pF   5&pF       B6pF   56  pF       56pF   9€pF 

SM  BM  SM  ISM  M  BM 

I 


IB 


MIN^CIRCUlTS 

0B,M 


+IBV0C   FROM 
POWER  SUPPLY 


r 


UG  £25  B/Li 


VCO  TUNING  VOLTAGE 
FROM  S*CCP  CIRCUIT 


UG-625BAJ 

VCO  HF  TEST       ■■— 
AMD  ACCESS^ 


ftG  5B  COAX  TO 
BANC  PASS  FILTER 


A  VCO  OUTPUT 
LEVEL  (D  C) 


Note  1.  Resistors  are  1/4  Wt  5%;  unspecified  capacitors  are  50-V  ceramic. 

Note  2,  Capacitors  marked  "SM1'  are  ±  5%  silver  mica. 

Note  3.  1000-pF  feedthrough  capacitors  available  from  Alaska  Microwave. 

Note  4.  MV-209s  or  MV-309s  may  be  substituted  for  M\M09s  (contact  Motorola  distributor}. 

Note  5,  Box  built  from  single-  and  double-sided  G-10  circuit  board  plus  copper  shim  stock. 

Fig>  5+  Low-pass  fitter,  mixer,  and  vco. 


14     73 Magazine  •  August  1982 


SELECT  YOUR 
FAVORITE  FEATURE 


CTftM 


f*?I 


*"*> 


Yes,  the  CT2100  has  the  features  you  want  -  and  built-in,  too!  The  CT2100  has  been  designed 
by  the  RTTY  people  at  HAL  for  optimum  operator  convenience.  No  "hidden"  keyboard  con- 
trols to  remember  -  it's  all  on  the  front  panel,  arranged  for  serious  operators*  Why  settle  for  a 
compromise  or  imitation  when  you  can  have  the  CT2100?  Compare  feature  for  feature;  you'll 
find  that  the  CT2100  offers  the  most  performance  and  flexibility  for  your  dollar. 

•  Send  or  receive  ASCII,  Baudot,  or  Morse  code 

•  RTTY  and  Morse  demodulators  are  built-in 

•  RTTY  speeds  of  45,  50,  74,  100,  110,  300,  600,  and  1200  baud  - 
ASCII  or  Baudot 

•  Four  RTTY  modems:  "high  tones",  "low  tones", 
"103  Modem  tones",  and  w202  Modem  tones" 

•  Three  shifts  for  high  and  low  tones  (170,  425,  and  850  Hz) 

•  Crystal-synthesized  transmit  tones 

•  Send  and  receive  Morse  code  at  1  to  100  wpm 

•  Characters  displayed  on  24  line  screen 

•  Choose  either  36  or  72  characters  per  line 

•  2  pages  of  72  character  lines  or  4  pages  of  36  character  lines 

•  Split-screen  for  pretyping  transmit  text 

•  Audio,  current  loop,  or  RS232  data  I/O 

•  Printers  available  for  hard-copy  of  all  3  codes 

•  On-screen  RTTY  tuning  bar  plus  LED  indicators 

•  ALL  ASCII  control  characters;  half  or  full  duplex 

•  Brag-tape  storage  of  8-256  character  messages  in 
MSG2100  EPROM  option 

•  Two  programmable  HERE  IS  messages 

Write  or  call  for  more  details.  See  the  CT2100,  KB2100,  Printer,  and  Video  Monitor  at  your 
favorite  HAL  dealer. 


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Photo  F.  Bandpass  filter  layout 


bandwidth  of  the  filter  is 
about  220  kHz.  Insertion 
toss  is  somewhat  high,  but  is 
acceptable  for  this  applica- 
tion. 

Preamplifier 

and  log  Amplifier 

The  schematics  of  the 
preamplifier  and  log  ampli- 
fier are  shown  in  Fig,  7,  The 
preamplifier  consists  of  two 
wideband  2N5179  amplifi- 
ers The  log  amplifier  con- 
sists of  six  tuned  90-MHz  i-f 
stages.  Each  stage  uses  the 
friendly  40673  dual-gate 
FET,  The  input  stage  acts  as 
a  buffer  amplifier;  The  next 
five  stages  form  the  loga- 
rithmic signal-strength  vid- 
eo detector.  The  log  ampli- 
fier may  remind  you  of  an 
i-f  strip  in  an  FM  receiver  In 
fact,  it  uses  the  limiter  prin 
ciple  in  its  operation. 


Notice  that  each  stage  in 
the  log  amplifier  has  an  rf 
detector  across  its  output 
consisting  of  a  50-pF  capac- 
itor, a  1N914  diode,  and  a 
10k  resistor  The  rf  detector 
on  the  buffer  stage  is  just  a 
tuning  aid.  The  outputs  of 
the  rf  detectors  on  the  1st 
through  5th  log  amp  stages 
are  tied  to  a  common  Ik  re* 
sistor  (in  parallel  with  a 
150-pF  capacitor).  Because 
of  its  relatively  low  value, 
the  detector  outputs  are 
more  or  less  summed 
across  the  1  k  resistor. 

A  small  input  signal  is 
amplified  by  all  five  log 
amp  stages.  Only  the  5th 
stage  will  develop  enough 
signal  to  provide  an  output 
from  its  detector.  As  the  in- 
put signal  is  made  larger, 
the  4th  stage  detector  also 


will  begin  contributing  to 
the  output.  As  the  output  is 
made  still  larger,  the  5th 
stage  will  saturate  or  limit. 
From  this  point  it  will  con- 
tribute no  additional  volt- 
age across  the  Ik  output  re- 
sistor. At  about  this  same 
signal  level,  the  3rd  log  amp 
stage  will  begin  to  contrib- 
ute some  output,  and  so  on. 
Each  log  amp  stage  pro- 
vides a  gain  of  about  12  dB 
until  it  saturates.  The  gain 
of  the  i-f  strip,  from  the  1k 
resistor's  point  of  view,  then 
drops  12  dB.  It  is  this  suc- 
cessive limiting  and  drop- 
ping off  of  i-f  stages  that 
creates  the  logarithmic  vid- 
eo output  characteristic. 
Note  that  when  the  1st  log 
amp  stage  saturates,  the  log 
amplifier  reaches  its  full* 
scale  output. 

I  was  surprised  how  accu- 
rately the  logarithmic  am- 
plifier does  track  a  logarith- 
mic curve.  Using  my  com- 
mercial  step  attenuator  as  a 
reference,  the  calibration 
of  my  logarithmic  amplifier 
was  within  1  dB,  The  sensi- 
tive i-f  system  must  be 
shielded  to  prevent  interfer- 
ence from  commercial  FM 
stations. 

Power  Supply  and  Sweep 
Generator  Circuits 

These  circuits  are  shown 
in  Fig.  8  The  power  supply 
is  straightforward,  provid- 
ing +  12  V  dc,  +24  V  dc, 
and  -6  V  dc.  Note  the 
feed  thro  ugh  capacitors 
used    to   filter   out    any    rf 


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Note  7.  Coils  are  6  turns  of  #12,  1/2"  Inside  diameter,  5/8"  long,  taps  at  1/4  turn. 

Note  2.  10-pF  piston  trimmer,  SpragueGoodman  GGP8R500  or  equivalent;  alternate,  air-variable,  John* 

son  189-564-1. 

Note  3.  Filter  box  made  from  single-  and  double-sided  G-10  circuit  board  plus  copper  shim  stock. 

Note  4.  Filter  box  is  1-1/8"  deep. 

Note  5+  Mount  BNG  connectors  near  front  side. 

Note  6,  Coupling  apertures  are  3/8"  x3H6\  Drill  3/8 '-diameter  holes  in  compartment  wall  pieces  and 

then  solder  copper  shim  strips  across  tops  and  bottoms  to  narrow  apertures. 

Fig.  6.  Bandpass  filter 


picked   up  by  the  12-V-ac 
power  leads. 

The  heart  of  the  sweep 
generator  is  the  555  IC 
timer  The  two  2N2907s  act 
as  current  sources.  Each 
generates  linear  ramp  volt- 
ages across  !OuF  tantalum 
capacitors.  The  555  syn* 
chronizes  the  ramps.  The 
ramps  are  set  at  a  10-Hz-to- 
12-Hz  repetition  rate  One 
ramp  is  fed  through  a  dc-re- 
storing  capacitor-diode 
clamp  to  the  output  con- 
nector for  the  oscilloscope 
horizontal  (X)  axis.  The  sec- 
ond ramp  is  fed  to  the  5k 
frequency-span  potentiom- 
eter through  an  inverting 
operational  amplifier  buf- 
fer. The  output  from  the  fre- 
quency-span pot  is  summed 
with  the  output  of  the  5k 
center-frequency  pot  in  the 
vco-tuning  voltage  amplifi- 
er. The  output  of  this  ampli- 
fier is  fed  to  the  vco-tuning 
voitage  input. 

When  the  ramps  are  reset 
by  the  555,  pin  3  of  the  555 
also  trips  the  retrace  VMOS 
clamp  transistor  through 
the  retrace  comparator  am- 
plifier. This  shorts  the  loga- 
rithmic amplifier  video  out- 
put to  ground  during  re- 
trace. Otherwise,  the  video 
is  fed  to  the  output  connec- 
tor for  the  oscilloscope  ver- 
tical (Y)  axis.  The  4th  ampli- 
fier in  the  TL084C  quad-op- 
erational-amplifier IC  is 
used  simply  as  a  6-V-dc  ref- 
erence by  the  other  three 
amplifiers. 

Shielded  Enclosure 
Construction 

All  circuits  in  the  high 
frequency  spectrum  ana- 
lyzer except  the  sweep  gen- 
erator and  the  power  sup- 
ply must  be  installed  in 
shielded  enclosures  I  built 
each  enclosure  for  my  ana- 
lyzer using  1/16-inch,  C-10 
epoxy  circuit  board  stock. 
Enclosure  base  plates  are 
made  from  single-sided  or 
double-sided  stock.  Dou- 
ble-sided stock  must  be 
used  for  the  enclosure 
sides,  ends,  and  partitions. 
(See  Fig,  9  for  construction 
details.) 


16     73Magazme  •  August,  1982 


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Note  the  brass  "cap 
strips/'  These  provide  a 
base  for  soldering  on  the 

thin  copper  (shim  stock)  en- 
closure tops.  I  use  this 
method  for  mounting  the 
tops  so  that  they  can  be 
peeled  back  easily  when  I 
need  to  modify  or  repair  cir- 
cuitry. Use  a  40Watt  sol- 
dering iron  for  soldering  the 
enclosures  together.  Solder 
the  tops  on  with  a  25-Watt 
iron,  Be  sure  the  solder 
seams  have  no  gaps. 

Don't  let  the  need  for 
shielded  enclosures  dis- 
courage you.  There  are  sev- 
eral easy,  accurate  ways  to 
cut  circuit  board  material. 
Beg,  borrow,  or  buy  a  copy 
of  Printed  Circuits  Hand- 
book (Reference  4),  This 
book  does  a  good  job  of 
showing  how  to  cut  circuit 
board  stock.  Alternatively, 
make  friends  with  a  ham 
who  owns  or  works  at  a 
commercial  circuit  board 
shop!  Anyway,  making 
shielded  enclosures  is  easi- 
er than  it  first  appears. 

My  original  analyzer 
used  quite  a  few  BNC  con- 
nectors. The  number  of 
connectors  can  be  reduced 
by  building  the  low-pass  fil- 
ter, mixer,  and  vco  enclo- 
sures together  on  one  base 
plate.  Look  at  the  schemat- 
ic. Fig,  5,  for  shield  parti- 
tioning details.  Likewise, 
the  preamplifier  and  log 
amplifier  enclosures  can  be 
built  together  {Fig,  7\  The 
bandpass  fitter  should  be 
built  by  itself,  as  should  the 
attenuator.  This  arrange- 
ment allows  the  analyzer  to 
be  tuned  up  with  very  little 
test  equipment. 

Circuit  Board  Layout 
and  Construction 

There  are  a  lot  of  possi- 
ble component  substitu- 
tions for  the  spectrum  ana- 
lyzer Some  of  the  compo- 
nents you  use  in  your  ana- 
lyzer will  no  doubt  be  dif- 
ferent from  the  ones  I  used 
—at  least  in  physical  size. 
This  makes  standard  circuit 
boards  impractical  It  is 
easy  to  lay  out  your  circuit- 

18     73 Magazine  •  August,  1982 


Photo  G.  Preamplifier  layout  Note  that  the  brass    'cap 
strips"  have  been  installed. 


ry  for  construction  on  sin- 
gle-sided circuit  board 
stock.  The  copper  is  on  the 
top  side.  It  acts  as  a  ground 
plane  and  helps  stabilize 
the  circuitry.  All  analyzer 
circuitry  built  in  this  man- 
ner was  built  on  1.8-inch- 
wide  circuit  board  strips  — 
lengths  as  needed.  The  low- 
pass  filter,  bandpass  filter, 
and  attenuator  are  built  "in 
the  air"  inside  their  shielded 
enclosures.  They  don't  need 
a  circuit  board. 

Get  some  drafting  vel- 
lum with  a  light  blue,  1/10- 
inch  grid  on  it,  After  you 
have  all  the  parts  for  a  cir- 
cuit, you  can  begin  devel- 
oping its  circuit  board  lay- 
out After  mulling  over  the 
schematic,  lay  the  actual 
components  on  the  grid  pa* 
per  and  think  through  their 
interconnections  fuggle 
them  as  needed  into  a  neat 
arrangement.  Remember 
that  all  ground  connections 
are  going  to  be  made  on  the 
top. 

After  you  have  the  layout 
and  interconnections  visu- 
alized in  an  area,  pick  up 
each  component  and 
sketch  in  its  outline  on  the 
vellum  Show  its  connec- 
tion to  other  components 
(under  the  board)  with  dot- 
ted lines.  You  wilt  be  sur- 
prised how  fast  this  goes. 
Remember  to  keep  the  in- 
put and  output  compo- 
nents of  each  rf  stage  sepa- 


rated. This  is  aided  by  using 
circuit  board  strips  Check 
the  photos  of  my  layout  for 
ideas  (minor  circuit  changes 
were  made  after  some  of 
the  photos). 

Once  the  layout  is  com- 
plete, tape  it  to  your  circuit 
board  blank  Drill  through 
the  layout  into  the  circuit 
board  each  place  where  a 
component  or  wire  lead 
goes  through  the  board 
Use  a  #55  drill  bit,  After  all 
holes  are  drilled,  lightly 
countersink  with  a  1 /8-inch 
drill  bit  all  holes  that  are 
not  going  to  be  a  ground 
connection.  This  keeps  the 
leads  going  through  these 
holes  from  shorting  to  the 
ground  plane.  Drill  1/8-inch 
holes  in  each  corner  of  the 
board  4-40  x  1/2-inch 
screws  are  put  in  these 
holes  to  act  as  legs  for  the 
board.  Begin  installing  com- 
ponents. They  are  intercon- 
nected under  the  board  by 
their  leads  and/or  bus  wire. 
Remember  to  keep  connec- 
tions as  short  as  possible. 

The  vco  oscillator  circuit 
is  built  totally  on  top  of  the 
circuit  board  ground  plane 
so  that  leads  can  be  very 
short.  Follow  the  layout  in 
the  photo  carefully.  The 
vco  amplifier  is  built  in  the 
normal  way. 

I  used  brass  tubes 
(bought  at  a  hobby  shop) 
for  coil-winding  mandrels. 
Where  wiring  goes  through 


a  partition  on  the  schemat- 
ics, use  a  1/8-inch  hole 
drilled    in    the    partition 

wall. 

After  you  doublen:heck 
your  wiring,  install  the  cir- 
cuit boards  in  their  shielded 
enclosures.  Tack-solder  the 
ground  plane  of  the  circuit 
to  one  side  of  the  enclo- 
sure. Do  not  install  the  tops 
of  the  enclosures  yet—we 
have  testing  to  do! 

Because  of  the  power  in- 
volved, build  the  L-pad 
sampler  carefully.  The  cir- 
cuit board  used  to  mount 
the  resistors  has  no  copper 
on  either  side  except  at  the 
corner  on  the  far  side  of  the 
SO-239  connectors.  This 
small  piece  of  ground  plane 
is  covered  with  masking 
tape  before  the  copper  is 
etched  with  ferric  chloride. 
The  51-Ghm  resistor  is 
grounded  here,  A  ground 
wire  is  then  taken  from  here 
to  a  lug  at  the  BNC  connec- 
tor (make  the  lug  from  cop- 
per shim  stock), 

Mount  the  board  using 
4-40  x  3/4-inch  screws.  Use 
5/1 6-inc  h~d  ia  meter  X  1 /2- 
inch-long  aluminum  tubing 

slipped  over  each  4-40 
screw  to  stand  the  circuit 
board  off.  Be  sure  the  resis- 
tor pairs  are  separated  from 
each  other  by  3/8  of  an  inch. 
The  physical  layout  of  the 
resistors  should  look  like 
the  schematic  in  Fig.  3.  The 
"fuse"  wire,  which  is  a  sin- 
gle, hair-thin  strand  of  cop- 
per wire  from  an  old  "zip" 
cord,  must  be  at  least  1/2 
inch  long.  The  L-pad  is  built 
in  a  medium-size  minibox. 

I  mounted  the  shielded 
enclosures  and  the  sweep 
generator/power-supply 
board  in  a  3-inch-high  X12- 
inch-wide  x  18- inch-deep 
aluminum  chassis.  (Refer  to 
Photo  D  for  typical  mount- 
ing.) Individual  circuits  are 
tested  before  final  mount- 
ing and  installation  of  the 
enclosure  tops. 


Testing  and  Alignment 

The  minimum  test  equip- 
ment needed  to  align  and 
test  the  HF  spectrum  ana- 


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■n  d  n 

iflD  >r 


lyzer  includes  a  high-im- 
pedance volt  ohmmeter,  a 
350-MHz  frequency  count- 
er, and  a  5-MHz  bandwidth, 
single-channel,  dc-coupled 
oscilloscope  with  a  trig- 
gered sweep  A  grid-dtp  os- 
cillator also  is  useful.  You 
should  make  up  several 
2-foot  RC-58  cables  with 
BNC  connectors.  These  will 
be  used  during  testing.  For 
best  results,  testing  and 
alignment  should  be  done 
in  the  order  listed  below. 

Power  Supply  Testing. 
Check  the  resistance  be- 
tween the  primary  and  sec- 
ondary  of  the  wallplug 
transformer  before  use.  It 
should  show  an  open  cir- 
cuit. Check  the  secondary 
ac  voltage  It  should  be  12 
V  ac  to  15  V  ac  with  no 
load.  Hook  the  12  V  ac  to 
the  power  supply  and 
check  the  12  V  dc,  24  V  dc, 
and  —  6  V  dc  outputs  They 
should  be  within  1/2  volt. 

Sweep  Generator  Testing. 
Connect  the  power  supply 
to  the  sweep  generator  and 
turn  the  power  supply  on. 
Check  pin  2  of  the  555  IC 
with  your  oscilloscope  You 
should  find  a  TOHz-to-12- 
Hz  ramp  waveform.  The 
bottom  of  the  waveform 
should  be  at  4  volts  and  the 
top  of  the  waveform  at  8 
volts.  The  front  of  the  ramp 
(long  slope)  should  appear 
straight  You  should  find  a 
similar  ramp  at  the  X-axis 
output  connector.  This 
ramp  will  be  between  —06 
volts  and  3.4  volts. 

Check  pin  8  of  the 
TL084C  op  amp  You  should 
find  a  pulse  train  with  a 
1G-Hz-to-12-Hz  repetition 
rate  The  pulse  train  should 


Note  1.  Resistors  are  1/4  W,  5%; 
unspecified  capacitors  are  50-V 
ceramic. 

Note  2.  Capacitors  marked 
"SM"  are  ±  5%  silver  mica. 
Note  3,  L43  12  rf  transformers 
and  FT37-43  to  raids  are  avail- 
able from  Amidon 
Note  4,  Shielded  box  made  from 
single-  and  double-sided  G*10 
circuit  board  plus  copper  shim 


Fig.  7.  Preamp  and  log  amp. 


20     73  Magazine  •  August,  1962 


AUGUST  SPECIALS 


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JSMagazine  •  August,  1982     21 


be  high  (20  volts)  about 
20%  of  the  time  and  low 
(-3  volts)  about  80%  of 
the  time 

Turn  the  frequency-span 
pot  fully  clockwise  (no 
ramp)  and  set  the  center- 
frequency  pot  mid-range. 
Yousholildfind6Vdcto12 
V  dc  on  pin  seven  of  the 
TL084C  op  amp  (vccKuning 
voltage).  Vary  the  setting  of 
the  center-frequency  pot. 
The  vco-tuning  voltage 
should  vary  from  —3  volts 
to  21  volts  Set  the  center- 
frequency  pot  for  a  10-volt 
output.  Turn  the  frequency- 
span  pot  counterclockwise 
until  you  have  a  ramp 
waveform  from  2  volts  to  20 
volts  (readjust  the  center- 
frequency  pot  as  needed). 
This  completes  preliminary 
sweep  generator  testing. 

If  your  sweep  generator 
fails  to  act  as  above,  re- 
check  component  values 
and  circuit  hookup  for 
problems,  Refer  to  the 
theory  of  operation  for  ad- 
ditional hints. 

Vco  Testing.  Connect  the 
vo>tuning  voltage  from  the 
sweep  generator  to  the  vco. 
Ground  the  RG-58  shield  at 
the  vco  enclosure.  Connect 
12  V  dc  from  the  power  sup- 
ply to  the  vco  power  input. 
Disconnect  one  side  of  the 
oscillator  coil  for  a  mo- 
ment. Power  up  and  check 
the  MRF901  collector  volt- 
age. It  should  be  about  6  V 
dc  to  8  V  dc.  If  it  is  too  high, 
reduce  the  value  of  the 
100k  bias  resistor.  If  it  is  too 
low,  increase  the  value  of 
the  bias  resistor.  You  can't 
use  a  pot  here!  Once  the 
collector  voltage  is  verified, 
power  down  and  reconnect 
the  coil. 

Power  up  and  connect 
your  counter  to  the  vco  rf 
test  jack.  Turn  the  frequen- 
cy-span pot  fully  clockwise 
(no  ramp)  and  adjust  the 
center-frequency  pot  for  a 
3-volt  output.  Your  counter 
should  read  about  90  MHz. 
Adjust  the  vco  coil  spacing 
to  get  the  vco  in  the  89*5- 
MHz~to-90.5-MHz  range. 
Check  the  dc  output  from 
the  rf  detector  of  the  vco 

22     73 Magazine  *  August,  1982 


Photo  H.  Log  amplifier  layout.  Note  strip  design 


amplifier  output  for  a  0.8-V- 
dc-to-1.3-V-dc  level.  Adjust 
the  spacing  between  the 
vco  coil  and  the  amplifier 
pick-up  loop,  if  necessary, 
to  obtain  the  proper  detec- 
tor output 

Set  the  center-frequency 
pot  for  a  150-MHz  oscilla- 
tor output.  You  should  have 
a  tuning  voltage  of  about 
18Vdc  Check  the  rf-detec- 
tor  output  voltage  again  to 
be  sure  it's  still  between  0.8 
V  dc  and  1.3  V  dc.  Monitor- 
ing the  dc  voltage  from  the 
rf  detector  with  your  scope, 
tune  the  center-frequency 
pot  back  and  forth  between 
3  volts  and  18  volts,  The  de- 
tector output  voltage  may 
smoothly  vary  some  but 
should  not  "jump."  An 
abrupt  voltage  change  indi- 
cates a  parasitic  oscillation. 
If  this  should  occur,  work 
with  your  oscillator  layout 
(very  short  leads)  to  get  rid 
of  it 

A  tuning  voltage  of  less 
than  1  V  dc  may  cause  the 
oscillator  output  to  be  erra- 
tic in  frequency  and  ampli- 
tude This  is  not  a  problem. 
Once  the  vco  oscillator  and 
amplifier  are  operating 
properly,  install  the  vco  en- 
closure top. 

Preamplifier  and  Log  Am- 
plifier Testing.  Connect  12V 
dc  to  the  preamplifier  and 
log  amplifier  circuits  and 
power  up.  Turn  the  frequen- 
cy-span pot  fully  clockwise 
(ramp  off)  and  adjust  the 
center-frequency  pot  for  90 
MHz  at  the  vco  rf  test  jack. 
Disconnect   the   frequency 


counter.  Hook  the  attenua- 
tor box  to  the  vco  rf  test 
jack  with  a  two-foot  RC-58 
cable  Hook  the  output  of 
the  attenuator  to  the  input 
of  the  preamplifier  with  an- 
other two-foot  cable. 

Set  the  bias  pot  on  the 
log  amplifier  about  mid- 
range.  Monitor  the  dc  out- 
put of  the  rf  detector  on  the 
log  amplifier  buffer.  Tune 
the  buffer  transformer  slug 
for  peak  output.  Use  the  at- 
tenuator to  set  the  detector 
output  to  0.2  V  dc  Now  ad- 
just the  bias  pot  of  the  log 
amplifier  for  peak  output. 
Adjust  the  attenuator  for  a 
just-detectable  output  at 
the  log  amplifier  buffer.  If 
all  seems  well  with  the  pre- 
amplifier, install  the  top  on 
its  enclosure.  Prepare  the 
top  for  the  log  amplifier 
section.  Drill  1/8-inch-diam- 
eter  holes  in  the  top  over 
each  i-f  transformer  loca- 
tion and  over  the  bias  pot. 
(Use  drafting  vellum  as  a 
template.) 

Hook  the  oscilloscope  to 
the  video  output  of  the  log 
amplifier.  Adjust  the  slugs 
in  each  log  amplifier  stage 
for  peak  video  output.  The 
tuning  of  each  stage  should 
be  smooth,  and  the  tuning 
of  the  bias  pot  should  also 
be  smooth.  If  the  video  out- 
put from  the  log  amplifier 
jumps  suddenly  while  tun- 
ing, you  may  have  a  self-os- 
cillation in  the  log  amplifi- 
er. If  this  happens,  carefully 
work  with  your  layout-  Fer- 
rite  beads,  extra  bypass  ca- 
pacitors, and  small  copper 


shim  stock  shields  can  be 
used  to  eliminate  the  prob- 
lem. My  i-f  strip  was  quite 
stable,  so  I  do  not  think  you 
will  have  a  problem. 

If  you  live  near  a  com- 
mercial FM  station,  it  may 
interfere  with  your  tuning 
efforts.  Tape  the  shield  top 
on  the  log  amplifier  during 
initial  tuning  to  help  elimi- 
nate this  problem.  As  soon 
as  it  appears  that  the  log 
amplifier  is  working,  solder 
on  the  top.  Once  the  top  is 
soldered  on,  it  will  totally 
eliminate  the  interference. 

Bandpass  Filter  Tuning 

Set  the  vco  to  90  MHz. 
Hook  the  attenuator  be- 
tween the  vco  rf  test  jack 
and  the  bandpass  filter  in- 
put. Hook  the  bandpass  fil- 
ter output  to  the  preampli- 
fier and  log  amplifier.  Moni- 
tor the  video  output  of  the 
log  amplifier  on  your  oscil- 
loscope. With  the  tops  off 
the  bandpass  sections,  you 
should  get  some  signal-  If 
not,  temporarily  bridge  the 
input  and  output  sections 
with  a  1-pF  capacitor  tack- 
soldered  at  the  input  and 
output  tap  points.  Tune  the 
input  and  output  stages  for 
peak  response.  Remove  the 
1-pF  capacitor  if  used,  Now 
peak  the  two  middle  stages. 
You  probably  will  get  an 
overcoupled  response  (dou- 
ble-hump). Just  center  the 
tuning  between  the  humps. 

Now  install  the  shield 
tops,  one  at  a  time.  Tune  all 
bandpass  stages  after  each 
top  is  installed.  Tuning  will 
become  very  sharp,  espe- 
cially if  you  are  using  air- 
variable  tuning  capacitors 
instead  of  piston  trimmers. 
When  the  last  top  is  in- 
stalled, carefully  peak  all 
stages. 

Set  up  your  oscilloscope 
for  X-Y  operation,  using  the 
X-axis  output  of  the  sweep 
generator  for  the  oscillo- 
scope horizontal  input  and 
the  log  amplifier  video  out- 
put for  the  vertical  input. 
Gradually  turn  the  frequen- 
cy-span control  counter* 
clockwise  until  you  get  a 
sweep  display  of  the  filter 


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3871  S.  Valley  View,  Suite  12,  Dept.  7,  Las  Vegas,  IMV  89103 

In  Ntn/ati*  Call      /OaC'S/    I  "2892 

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OutnOe  Nevada  Call:  V-/  *-/  VJ 


AvEiilable  by  Mail  Order  Only 

Send  Check*  of  Mon«y  Order  Minimum 

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73 Magazine  •  August,  1982     23 


Photo  /.  L-pad  sampler. 


bandpass.  Make  fine  adjust- 
ments for  a  smooth  band- 
pass shape.  Stagger-tune 
the  two  middle  bandpass 
filter  sections  just  a  bit  to 
sharpen  the  nose  of  the  fil- 
ter. Be  sure  to  put  in  enough 
attenuation  to  keep  the  vid- 
eo output  from  the  log  am- 
plifier under  two  volts  dur- 
ing the  bandpass  filter  tun- 


ing  procedure. 

If  it  seems  that  you  have 
an  over-coupled  response 
in  your  filter,  narrow  the  ap- 
erture between  the  two 
middle  bandpass  filter  sec- 
tions. If  the  filter  tunes 
sharply  but  exhibits  high 
loss,  then  widen  the  aper- 
ture between  the  two  mid- 
dle sections. 


Final  Setup 

Install  all  circuitry  in 
your  chassis  and  complete 
all  wiring  and  coaxial  cable 
hookup.  Set  the  analyzer 
upside  down  in  front  of 
your  scope.  Connect  your 
oscilloscope  to  the  ana- 
lyzer X-  and  Y-axis  outputs. 
Set  up  the  oscilloscope 
again  for  X-Y  operation. 
Turn  the  analyzer  on  (no 
signal).  Turn  the  frequency- 
span  pot  fully  clockwise  (no 
ramp).  Using  your  frequen- 
cy counter  at  the  vco  rf  test 
jack,  set  the  vco  for 90  MHz 
operation  with  the  center- 
frequency  pot.  You  should 
see  two  horizontal  lines 
about  2  volts  apart.  Rotate 
the  frequency-span  pot 
counterclockwise  a  little. 
You  should  see  the  band- 
pass-filter response  again. 
This  is  due  to  mixer  leak- 
through  and  is  normal. 

Set  the  retrace  line  (lower 
straight  line)  under  the 
bandpass  response  curve  at 
the    bottom    of    the    CRT 


screen.  Widen  the  trace 
with  the  oscilloscope  con- 
trols to   reach   across  the 

screen.  Turn  the  frequency- 
span  pot  fully  clockwise 
again.  Set  the  vco  frequen- 
cy to  120  MHz.  Now  turn 
the  span  pot  counterclock- 
wise until  the  zero-frequen- 
cy half-spike  appears  on  the 
left  side  of  the  screen. 
There  should  also  be  some 
grass  above  the  retrace  line 
along  the  bottom  on  the 
screen.  The  analyzer  should 
now  be  scanning  0  to  60 
MHz 

Feed  a  small  30-MHz  sig- 
nal from  a  grid~dip  oscilla- 
tor (use  a  pick-up  loop  as 
shown  in  Photo  J)  or  a  low- 
power-signal  generator  to 
the  analyzer  through  the  at- 
tenuator. You  should  now 
see  the  30-MHz  signal  spike 
about  mid-screen.  You  may 
also  see  the  2nd  harmonic 
of  the  30-MHz  signal  on  the 
right  edge  of  the  screen.  Ad- 
just the  attenuator  so  that 
the  30-MHz  signal  is  about 


VfHOKM 

setwace 


ro  scope 

"*"  AXIS 


ftr 


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/L0£0  IN 
FROM 
LOG  AMP 


YiDCO  OUT 

TO  SCOPE 
V  AH  IS 


1 2  VAC,  SOPmfl 
WALL  TRANSFORMER 


(SH 


TO  VCO 


SW££P  CIRCUtTS 


(000^ 
50V 


X 


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300pF 

F.T. 
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IN4003 


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YfZm 


IM4003 

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REGULATOR 


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35V 
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Note  7-  Wall  transformer  available  from  Jameco. 

Note  2.  Other  devices  available  from  Radio  Shack, 

Note  3.  TLQ84C  is  quad  op  amp. 

Note  4.  500-pF  threaded  feedth  roughs  available  from  Alaska  Microwave, 


Fig.  S,  Power  supply  and  sweep  circuits. 


24     73  Magazine  •  August,  1982 


You  won't  find  as  much 
well  thought  out  program- 
ming, circuitry,  and  features 
anywhere,  at  any  price!  The 
ATR-6800  combines  the 
best  of  both  worlds,  an  easy 
to  use  video  system  for 
CW/RTTY/SSTV  with  auto- 
matic station  control  and  a 
stand-alone  computer  with 
expandable  memory  &  full 
instruction  set  in  Motorola 
assembly  language,  Add  the 
BASIC  language  option 
package  and  you'll  have  the 
unique  combination  of  an 
RFl  proof  computer  and 
ultimate  RTTYYCW  HAM  station.  And  don't  forget  "easy  to 
use."  All  of  us  at  Microlog  are  RADIO  ACTIVE  on  RTTY,  so 
there's  a  lot  of  personal  attention  to  detail  and  ease  of  opera- 
tion. ^Stick-on"  command  listing  and  video  status  display  will 
get  you  on  the  air  quick  and  sounding  like  a  pro. 


MICROLOG 

INNOVATORS  IN  DIGITAL  COMMUNICATION 

AMATEUR  RADIO 
COMMUNICATION 

AT  ITS 

FINEST 

Both  Systems  Provide 

•  SIMPLE  DIRECT  CONNECTION  to  your  Transceiver. 

•  COMPLETE  SYSTEM,  built-in  Demodulator  &  AFSK 
Modulator    with    keyboard    programmable    tone    pairs, 

•  SPLIT-SCREEN  operation  with  keyboard  selectable 
line    location.    •    LARGE,    TYPE    AHEAD    text    buffer. 

•  TEN,  programmable  message  memories,  plus  ID'S 
WRG  &  SELCALs.  •  RANDOM  CODE  generator  &  hand 
key    Input   for   practice,    •    Baudot    60   to    132    WPM. 

•  ASCII  UO  &  300  baud.  •  SYNC-LOCK  MODE  for 
improved  ASCII  operation.  •  RECORDER  INTERFACE 
FOR  "BRAG-TAPE"  or  recording  off-the-air.  •  CODE 
CONVERTED     Printer    output    in     Baudot    or    ASCIL 

•  SSTV/GRAPHICS  transmit.  •  FULL  63  KEY 
Computer  grade  keyboard. 


There's  a  certain  thrill  to 
using  efficient,  reliable 
digital  communications 
equipment  on  the  air.  That's 
the  fun  of  RTTY.  Spice  up 
your  Amateur  Radio  opera- 
tion with  the  silent  video 
system  that  does  it  all,  the 
Microlog  ACT-1.  Even  if 
you  own  a  home  computer 
and  are  considering  an  out- 
board i  nte  rf  ace/prog  ram , 
remember,  we've  put  it  all 
in  one  RFl  tight  enclosure 
that's  ready  to  go  ad  soon 
as  you  power  up.  And,  with 
the  "Battery-backed"  mem- 
ory option,  you  won't  even  lose  your  pre-programmed 
messages  if  there's  a  "blink"  in  the  AX*  The  ACT- 1  has 
features  that  the  competition  doesn't  even  have  on  the  draw- 
ing board!  Check  for  yourself,  you  could  spend  a  lot  more 
and  still  come  up  short. 


*  ^pn  ^  Qf\{\  A  /  ¥  ■  ■    1   ^he  most  often  asked  question  we  hear  is  "What's  the  difference  between  the  ATR 

A  I  K-DOUU  VS  PiK*  I  "  1  &  the  ACT-1?'"  The  ACT-1  is  a  dedicated  system  for  RTTY/CW/SSTV.  It  provides 
all  the  functions  and  features  you  need  for  a  multi-mode  station,  Along  with  this  superior  ^ON-the-AIR"  performance,  the 
ATR-6800  extends  your  operation  into  the  realm  of  automatic  station  control  and  computer  programming.  Plug-in 
applications  modules  expand  the  ATR's  memory  to  add  new  HAM  oriented  programs  which  are  enabled  by  simple 
keyboard  commands.  By  adding  the  BASIC  option  package,  you'll  have  pre-programmed  full  community  ma  i  I  box ,  contest 
dupe  sheet,  personal  station  log,  message  edttor.  BASIC  computer  language  and  16k  of  battery- backed  (non- volatile) 
memory.  We  also  provide  a  subroutine  list  so  that  you  can  write  programs  to  directly  control  the  ATR  6800  in  easy  to  use 
BASIC  language.  The  ATR-6800  then  is  the  expandable,  "do  everything"  system  where  your  imagination  is  the  only  limit! 
The  ACT-1  is  designed  for  the  HAM  who  needs  the  essentials  of  a  complete  video  system  for  digital  communications, 

TECHNICAL  SPECIFICATIONS  ATR-6800  &  ACT-1 


INPUTS 

Spuiikui  Audio 

Digital 

"RS232 


lOOmv  min, 

TTL  Keyer,  Hand  Key 

±  1ZV.  33Q  Ohm  Source 


OUTPUT  TO  TftAWSM  tHER  FOR  CWRTTVISSTIf 


*  Voltage  Keying 
-  Vortipe  Keying 
"Mercury  Re**? 


fcr  S  K  TdVKA, 

AFSK  Tone*,  L» 
Sla*  Scan 


+  40VDC  *  300ma  Max 
■  *5GVDC  m  50maM*j 

JO0VDC  Of  2  amp  O0VA  Me*  i  H  O  INC 

ATH  —  R*4Ay  *  30V  8  2  *mp  NO  4  H  C 

ACT  1  —  Tmftttor  *  <2VDC  O  30U™  G»Q  an 

XMT 

key  scan;  PtwrvmrBbt*  500  Hz  to  MOO  He 

MiC  Compalibie  XkSOttn  Audio 

MicCompeiitilt  Audio  Sync  imo  Hi  Blacfc-tSOOKr 

Whlle-2300  Hi 


MISCELLANEOUS  CONNECTIONS 
RS  232 
Primer  Driver 


Tap*  Recorder 
Brag  Tip« 


MMoc 


i  12VDC.  330  Ohm  Source  frr,pedanc&,  NomiIvb  Mant 
ATR  -  •  Hi-speed    R5'Z32    upto   2*00    fl&Lid 

-  Slo-apeed  Baudot  8.  ASCII  Flwiing 
Relay  le*  Currant  Loop  Switch  tng 
ACT-1  —       •  Sifrsoeeo  Baudot  &  ASCh  Tranalsbv 
Switch  *  aOVOC  «  too  ma 
-OptonaJ    HitoeeO   ASCII   *&222    6 
MiktSaud 
100  A*  Audio 

hot  KoniaJ  and  Vertical  Outputs  lo  Scop*  lor  HTTT 
Tufting  Aid 

MattM  Speed  Trackirvg    Aylomatlc  or  Speed  Lock 

VIDEO  OUTPUT 

1  Vu.li  Peak  lo  Peak  MagBtlve  Syrw  Composiw  Video  (Ameflnn  Standard) 
European  BtaDdard  available  upon  requesl. 

VIDEO  FORMAT 
normal 

Bate*  on  Mifte  or 
*htMo*«acfc. 

PUpMy  Sp"t  frJean 


SYNC:  TfanamHB  ■■BJanfc.Firi"  m  RTTY  and  BT  »n  Morae  *riort  Tex!  Buffer  ia 
Amply  and  unll  »*  In  Iran  am  It  Keyboard  com  mend  on/ofl 

UN-SHIFT  on  Space:  Automatically  splits  back  to  ■■LETTERS"  upon  recalpi 
or  iranamlssion  of  apace  Keyboard  command  orvnft 

REAL  Tl WE  CLOCK:   Keyboard   set,  always   em   screen   display    nn«fs, 
mmulesL  seconds  Cart  also  be  'needed  in  transmit  lert  buffet  py  keyiKsard 


■f  the  end  or  a  hne- Mayte 


CODE  PRACTICE:  Random  S  ctiar  generator  sends  at  any  f  peed  you  set  we 
lift*  keyboard.  Hand-Key  mou!  eJkrwt  u-s*  in  code  pnacttcs  oecillalar  thai  mil 
aittn  read  your  aendingl 

STATUS  DI5PLAV  cm  be  caiiod  up  to  sna*  irw  conditfon  and  control  com 

mands  (or  20  progremmable  pMmmeters,  auth  as  AFSK  tone  treqa.  UN  OS, 

?rl rtler ,  s-tc.  Use f ul  h.b  a  "  H ELP' '  o  ommand  in  caaa  you  m  I aplace  tn*  m&nu*l . 
here's  also  a  CLin&iani  "TOPUNE"  display  ol  Time,  Mode,  Spaed,  &  Code 
in  use 


WORD  WRAP  AROUND:  Proems  Bf^lbng 

in  tK#ne  ai  wen  a: 


TUNING  INDlCATOflS 

Audio  RrT    inr,P-  Ufll)  H;  Keyed  flaQfiri«ralad 

Visual  LED  on  Mark  (KaydowinJ 

Scope  TunJfio  ellipse  lor  RTTY 

PPOCRAMMABLE  MEMORIES 

tfjMO  cnarectef  mefUQee  t*00  leiaip  or 
Hem  ts  ■  1040  character  messages  <*»  lptat»  bailery 

10  jScrwracm  mejumym  in  atAApArd  10  and  '?  N 

RTTY  (O 
WW:  Upto  iScftaractetm 

SukxHwi  CiaL  ATR  —  a  memoriee,  up  to  IS  ctmcters  s»c 

ACT  t  —  2  iTnimonea  lor  onntaf  on  and  prmter  on 


DETECT10R  MODES 
Direcl 


delector  wrtn  AGC  controJlefl 
|100  HZ  nomineJ  w%om   ~   aOQ  Hj 


Hi 


firtd    e   2725I22S5 
rones  venafane  *  500  -  3000  Hz. 

RS233  cornpeLrble  tUtlF  duotex  of  fulk  duplex  up  lo 

woo  Baud 


"COMPUTER  CAPABILITY 

Memory  Standard  uriil  ftai  #000  oytes  ol  RAM  for  user  pro 

Br  am.  Baelc  pachaoe  adds  i©K. 
aalc  ar  Motorola  M6&Q0 
Command i>  Irirjuc,  Ouipul;  Load,  Go  wUh  Break  Point;  or  Normil 

Bailt 
Tape  Inierfaoe  Store  Programs  oe  Audio  Castalte 

POWER 

US  VAC  60  Hz  «  VA  Ma*  AjJt-1,  30  VA  M«i  030  VAC,  M  Ht  oprJonat) 

1J  fdl  version  aveilaole 

E»TgmAl  input  tpr  czufyMng  eapendad  battery  Decked  memory  6-15WOC  # 
iQ  ma.  maa- 


ie^  «  cftarectara  par 
nee,  20  cnaracwt  par  line 


KajuuarJ 
Any  location 


LMa  D  (Otf>  Mt  Lirk  20,   keyboant 

SSTV  3  linea  ft  ctiaracteni  per  Mne  *  graphiea 

TEST  MESSAGES:  Omck  Brawn  Fox  and  RYRY's  In  BailtfaJ.  U"  U'  In  ASCH 


**  Terminal 

DATA  RATES 

Mor^g 

Baudot 
ASC» 

S*ow  Scan 

OUTPUT  OPERATING  MOOES 

Symbol  Gftanctvr  ouputs  wtien  ryped 

Word  Words  sent  arter  "Space  Bar** 

Line  Line  sent  i  tier -Reium 

Buffer  Send  entire  content*  or  text  buffer 


5-199  VJFM   Keyboard   ne  loci  able   lh   1    WPM   Stepa 

Autp  spend  Iracklng  or  speed  on  receive 

Alt  standard  45,  50.  57    74-.  tOG  Baud  (00.  G6  75.  100 

end  IJ?  WPMI 

1 10  *  000  Baud  normal  A  synclock  u*ing  mtemar 

Modem  ATR  adds  speeds  up  ic  woo  Basal. 

8  s^condt  per  frame 


MECHANICAL 

ATR-6800 

Bta 

MH'Wi  12VJD*4"H 

waioni 
ACT-1; 

IS  ib. 

Slza 

17.8iNr.3H«M0 

Weight 

7  lb 

ATR-BB00  A  ACT-1: 

Color 

Seme  Top.  BlSi:k  Blae 
ALS0SJ  Aiummum  Alloy 

Material 

'Standard  on  ATR.  Opt  tonal  on  ACT-1 

•  "StBrdanj  on  ATR.  Not  available  on  ACT  T 


„5i        MICROLOG  CORPORATION  —18713  AAooney  Drive— Gaithersburg,  MD  20679  (30t)258B40U 


v$e&  List  of  Adve/users  o/i  page  H4 


73  Magazine  ■  Augusl+1982     25 


the  same  height  as  the  zero- 
frequency  half-spike  It 
things  have  gone  well  so 
far,  you  are  getting  a  signal 
through  the  low-pass  filter 
and  mixer,  so  you  can  now 
install  their  enclosure  tops. 

Set  the  frequency-span 
control  so  that  the  30-MHz 
signal  spike  is  about  two 
scope  divisions  wide.  Now 
fine-tune  the  bandpass  fil- 
ter again  and  re-peak  the 
log  amplifier  Switch  the 
10-dB  attenuator  section  in 
and  out  while  adjusting  the 
vertical  gain  of  the  oscillo- 
scope so  that  the  signal 
height  changes  one  CRT  di- 
vision. Now  switch  a  20-dB 
section  in  and  out  Signal 
height  should  change  two 
CRT  divisions  Readjust  the 
frequency  span  control  for 
a  O-to-60-MHz  analyzer  tun- 
ing range. 

Increase  signal  strength 
until  the  first  small  spike 
pops  out  of  the  grass  be- 
tween the  0-  and  30-MHz 
signals.  This  is  slightly 
above  the  overload  point  of 
the  analyzer  The  30-MHz 
signal  spike  should  be  near 
the  top  of  the  CRT  screen 
(8th  vertical  division).  Full- 
scale  inputs  should  be  the 
next  (7th)  CRT  division 
down.  Touch  up  the  oscillo- 
scope controls  if  necessary. 
The  zero-frequency  half- 
spike  will  be  about  six  divi- 
sions tall.  Switch  all  attenu- 
ation out  and  reduce  the 
signal  generator  output  so 
that  the  30-MHz  test  signal 
is  seven  divisions  talL 
Check  the  vertical  calibra- 
tion of  the  analyzer  over 
the  attenuator's  59-dB 
range. 

Using  your  signal  genera- 
tor and  frequency  counter, 
take  notes  on  the  horizon- 
tal calibration  of  your  ana 
lyzer  This  is  done  by  cen- 
tering a  signal  from  your 
signal  generator  on  each 
CRT  horizontal  division 
{vertical  line)  and  recording 
its  frequency.  Your  ana- 
lyzer is  now  ready  for  use. 
But  first,  test  the  L-pad  care- 
fully! 

Hook  up  your  L-pad  to 
your    transmitting    equip- 

26     73 Magazine  *  August.  1982 


Photo  /,  The  spectrum  analyzer  can  easily  be  tuned  up  with 
simple  test  equipment. 


ment   Be  sure  everything  is 

grounded  properly,  I  sug- 
gest mounting  the  L-pad 
and  attenuator  on  an  alumi- 
num plate  which  is  in  turn 
wall-mounted.  Ground  the 
plate!  Do  not  connect  the 
attenuator  to  the  L-pad  yet. 
Connect  your  transmitter  to 
an  swr  meter,  the  swr  meter 
to  the  L-pad,  and  the  L-pad 
to  your  dummy  load.  The 
L-pad  should  introduce  lit- 
tle, if  any,  swr.  Starting  with 
low  power  (100  Watts  or 
less),  key  down  for  30  sec- 
onds. Power  down  your 
transmitter  completely  and 
quickly  inspect  the  inside 
of  your  L-pad,  The  "fuse" 
should  be  OK  and  nothing 
should  be  hot.  Continue 
testing  to  full  station 
power. 


si&es  AM 

DOUBLE-SIDC& 
&iOr  l/lCin  THICK 


If  everything  has  gone 
well,  then  power  down  your 
transmitter  completely  and 
connect  the  attenuator  to 
the  L-pad.  Switch  in  all  at- 
tenuation and  connect  the 
attenuator  to  the  spectrum 
analyzer.  Remember  that 
the  analyzer  and  oscillo- 
scope cases  should  be  sol- 
idly grounded.  Starting 
again  with  low  power,  key 
down  and  adjust  the  attenu- 
ator for  a  full-scale  spec- 
trum analyzer  display.  How 
does  your  spectrum  look?! 
Always  switch  in  full  atten- 
uation before  increasing 
power,  Remember,  do  not 
go  over  one  kilowatt  con- 
tinuous output  (2  kW  p-p). 
Do  not  attempt  to  use  the 
spectrum  analyzer  system 
where  your  swr  is  greater 


cqpptB   SHI*  STOCK 


i/4  «n   tflDE 
3RAS5   STfilP 


SOLDER  FILLETS 


BASE- 

SINGLE  OF?  DOUBLE-SIDED 

G-IO  CIRCUIT  BOARD,  1/15 -r. 
THTCK 


Note  I.  Solder  G-10  circuit  board  and  brass  strips  with  40-W  iron. 
Note  2.  Solder  copper  shim  stock  with  25-W  iron. 

Fig,  9.  Shielded  box  construction  detail. 


than   2:1.   Always   be   sure 
you  are  using  an  L-sampler 

with  a  high  enough  power 
rating! 

Component  Sources 
and  Substitutions 

It  often  is  lamented  that 
home-brewing  projects  Is 
difficult  these  days  because 
of  poor  component  avail- 
ability. I  started  seriously 
experimenting  with  elec- 
tronics 20  years  ago  in  the 
good  old  days  of  compo- 
nent availability  The  differ- 
ence between  now  and  then 
is  that  we  have  about  a 
thousand  times  more  com- 
ponents to  experiment 
with! 

It's  simply  a  matter  of 
motivation  and  tenacity 
You  can  get  any  component 
that  you  need  True,  Mom 
and  Pop's  local  TV  compo- 
nent place  doesn't  carry 
everything,  but  they  may  be 
able  to  order  it  for  you. 
Don't  be  afraid  to  contact  a 
manufacturer  or  a  big  dis- 
tributor like  Hall-Mark,  Ar- 
row, Allied,  etc  They  are 
usually  glad  to  work  with 
you  (although  order  mini- 
mums  can  be  an  occasional 
problem).  Best  of  all,  look 
at  the  ads  in  this  magazine- 
There  are  several  dozen 
mail-order  distributors 
which  market  primarily  to 
the  experimenter 

On  specifics:  You  can  get 
circuit  board  stock,  chemi- 
cals, drill  and  router  bits, 
etc  ,  from  Kepro  in  Fenton, 
Missouri.  You  can  get 
MRF90K  40673s,  500-pF 
and  1000-pF  feedthrough 
capacitors  from  Alaska  Mi- 
crowave Labs  in  Anchor- 
age, Alaska.  You  can  get 
ferrite  beads,  toroids,  and 
i-f  transformers  from  Ami- 
don  Associates  in  N,  Holly- 
wood, California  Small  air- 
variable  capacitors  for  the 
bandpass  filter  are  avail- 
able from  Radiokit  in 
Greenville,  New  Hamp- 
shire. You  can  get  resistors, 
capacitors,  555  ICs,  TL084C 
quad  op  amps,  VMOS  tran- 
sistors, and  many  of  the 
parts  discussed  above  from 
Radio  Shack    You  can  get 


I 


A 


It  sounds  ridiculous,. doesn't  It?  Amateur 
Radio  advertising  is  not  exempt  from  exag- 
geration. When  facts  are  distorted  by  fabrica- 
tion you  may  be  induced  to  buy  a  product  thai 
ultimately  is  incapable  of  meeting  the  per  for* 
mance  claimed  by  the  manufacturer,  Caveat 
Emptor  (buyer  beware)? 

TM 

The  AEA  IsoPole  antenna  has  3  db  gain 
over  a  dipole  in  free  space.  This  is  an  honest 
and  supportable  claim.  Yet  other  manufac- 
turers claim  as  much  as  a  7  db  gain  for  their 
antennas  using  no  reference  standard  or  a 
1/4  wave  antenna  as  reference  The  1/4  wave 
is  no!  a  recogni2ed  reference  used  by 
reputable  antenna  engineers  because  it  is 
most  difficult  to  property  decouple  in  a 
repeatabie  fashion 

The  IsoPole  antennas  offer  the  maximum 
gain  attainable  for  the  length  of  antenna. 
This  is  a  bold  statement  and  one  we  know  we 
can  stand  behind! 

For  any  linear  array  antenna  to  outperform 
the  IsoPole  by  3  db  or  more  on-the-honzon 
gam.  it  would  have  to  be  a!  least  20  feet  long' 
Anything  less  and  you  can  bet  that  advertis- 
ing deception  is  being  used. 

Before  you  buy  a  VHF  or  UHF  base  station 
antenna,  get  some  good  honest  facts  aboui 
VHF  antenna  design    Send  for  your  FREE 


copy  of  "Facts  About  Proper  VHF  Vertical 
Antenna  Design'  by  Professor  D,K, 
Reynolds,  K7DBA.  You'll  be  glad  you  did 

In  the  meantime  we  would  like  to  expose 
you  to  some  of  the  comments  we  have 
received  frum  customers  thai  are  using  the 
IsoPole 

Seattle,  WA  —  Compact  &  easy  to  install. 
quality  &  keeps  XYL  happy  -looks  good! ! 

Half  Moon  Bay,  CA  —  Found  repeaters  I  on- 
\y  heard  about  before  from  my  OTH  —  Ex- 
cellent Amazed  at  light  weight  and  low  cost... 

Sturgis.  SO  —  The  Isopole  Antenna  has  ex- 
ceeded my  expeciafions- 

Lumberton,  NC  —  You  really  do  what  you 
say1  The  best  2  mtr.  antenna  t  have  ever  own- 
ed! 

La  Habra,  CA  —  Hooked  up  today,  and  it  was 
a  perfect  match  throughout  the  entire  band, 
For  the  money,  you  can  not  go  wrong 

Tokt  AK  —  Truly  a  fine  antenna,  working  bet- 
ter than  the  five  etemenl  yagi  it  replaced 

Sacramento,  CA  —  Assembly  was 
remarkably  easy.  I  needed  an  efficient,  low 
profile  antenna  &  your  product  fit  the  bill  to  a 

Warsaw,  IND  —  AMAZED!!!  Antenna 
ground  mounted  on  required  mast  &  outper- 
forming a  (Ft.FU  at  55'  on  top  of  tower. 


Lorls,  SC  —  I'm  a  commercial  radio 
salesman,  and  the  Isopole  is  THE  antenna  I 
recommend. 

Seattle.  WA  —  Works  well  —  excellent  Had 
(R  R  )  at  80  With  the  Isopole  a!  20  ft  I  now 
hear  repeaters  and  simplex  I  never  heard 
with  (RR.)  The  Isopole  will  soon  be  at  80 

Freehold.  NJ  —  Jus  everything  your  ad  says 
and  more 

Great  Neck,  NY  —  Amazing  difference  bet- 
ween (R.FL)f  1 0  db  or  better,  raise  rept.  never 
heard  before  —  SUPER,  73  and  thanks. 

Richfield,  OH  —  Works  extremely  well, 
broke  a  repeater  at  100  mi  using  150  rrrw  1 

Vernon,  TX  —  (The  dealer)  said  the  antenna 
WAS  THE  BEST  ON  MARKET  and  1  AGREE!  It 
IS  AN  EXCELLENT  antenna  &  works  to  specs 
-Thanks. 

Prices  and  Specifications  subject  to 
change  without  notice  or  obligation, 


Brings  you  the 
Breakthrough! 


*>2 


Advanced  Electronic  Applications,  Inc   ■  P.O.  Box  2160  •  Lynnwood,  WA  98036  *  (206)  775  7373  ■  Telex:  152571  AEA  INTL 


**See  List  of  Advertisers  on  page  1 U 


73  Magazine  •  August,  1982     27 


^   ^W    ■*  TWI».'I*T  YHMBBM  TO5TTXW  BOH  THJ*  « 

Photo  K.  O-io-60-MHz  spectrum  on  longwire  antenna,  using      Photo  L  O-to-SQ-MH?  spectrum  on  /ongwjre  antenna  with 
accessory  preamplifier,  my  trusty  hut  noisy  computer  on. 


accessory  preamplifier, 

wall  transformers  and  tan- 
talum capacitors  from 
Jameco  in  Belmont,  Califor- 
nia. 2N5179s  are  carried  by 
most  TV  parts  houses.  The 
double-balanced  mixers 
can  be  ordered  directly 
from  Mini-Circuits  in  Brook- 
lyn, New  York.  See,  you 
have  no  excuse! 

OK,  the  MV109s  might 
be  a  slight  problem.  An 
MV209  or  MV309  should 
also  work  I  got  my  stock 
from  Hall-Mark,  If  you  run 
into  a  problem  getting 
these  diodes,  pick  up  the 
phone  and  call  Motorola 
Semiconductor  in  Phoenix, 
Arizona,  for  help. 

The  high  frequency  spec- 
trum analyzer  should  be 
fairly  tolerant  of  compo- 
nent substitutions  except  in 
the  vco  oscillator  circuit 
and  the  L-pad.  For  example, 


the  "hotter"  3N211  could 
substitute  for  the  40673  if 
you  crank  its  gain  down  a 
bit  with  the  log  amplifier 
bias  pot.  You  could  use 
MRF901s  in  place  of  the 
2N51 79s  (don't  try  to  go  the 
other  way!).  Solid  copper 
conductors  (#12)  stripped 
from  house  wiring  can  be 
used  for  coil  stock  in  the 
vco  and  bandpass  filter 
Any  decent  electrolytics  of 
the  proper  capacitance  and 
voltage  rating  can  be  used 
in  the  power  supply  and 
sweep  generator  circuits. 
Electrolytics  could  also  be 
used  in  place  of  the  tanta- 
lum capacitors  in  a  pinch. 
Try  to  get  close-tolerance 
parts  in  this  case 

Useful  Accessories 

You    can    duplicate    the 
2-stage  wideband-preampli- 


Specifications  for  HF  Spectrum  Analyzer 

Frequency  range 

0  to  60  MHz 

3-dB  bandwidth 

220  kHz 

3f>dB  bandwidth 

1.100  kHz 

3;30-dB  shape  factor 

1:5 

Dynamic  range 

60  dB 

Spurious  responses 

60  dB  below  full-scale 

Nofse  floor 

65  dB  below  full-scale 

Full-scale  input 

-8dBm  ±2dBm 

Y-axis  output 

0  to  2.5  volts 

X-axis  output 

-0.5  to  +  3.5  volts 

Y-axis  calibration 

lOdBj'division 

X-axis  calibration 

6  MHz/division  (approximate) 

0  to  8  MHz 

4  MHz  ±075  MHz/division 

8  to  24  MHz 

8MHz±1  MHz/division 

24  to  60  MHz 

6MHz±!  MHz/division 

fier  circuit  to  use  as  an  ac- 
cessory ahead  of  the  atten- 
uator This  will  allow  you  to 
view  the  0-to-6OMHz  radio 
spectrum  on  a  longwire  an- 
tenna and  quickly  judge  the 
band  conditions  through  six 
meters,  Vco  frequency-tun- 
ing is  somewhat  nonlinear, 
which  is  typical  of  simple 
wideband  oscillators.  A 
6-MHz  crystal  oscillator 
driving  a  TTL  Schmitt  trig- 
ger makes  a  useful  calibra- 
tor The  output  of  the  TTL 
gate  contains  every  har- 
monic through  60  MHz. 
Lightly  couple  the  TTL  gate 
to  the  spectrum  analyzer  in- 
put with  an  insulated  wire 
antenna  placed  near  the  an- 
alyzer input  connector.  A 
momentary-on  push-button 
can  be  used  to  activate  the 
calibrator. 

Analyzer  Applications 

We  have  talked  about  us- 
ing the  HF  spectrum  ana- 
lyzer to  monitor  transmit- 
ting equipment  This  was 
the  primary  application  I 
had  in  mind  when  I  de- 
signed the  analyzer.  It  is  es- 
pecially useful  to  hams  who 
are  home-brewing  their  own 
HF  transmitters  or  linears.  It 
is  also  useful  for  checking 
low-pass  filter  performance 
and  band  conditions.  I'm 
sure  you  will  find  other  ap- 
plications. 

The  analyzer  has  a  50- 
Ohm  input  impedance  and 


is  dc-coupled.  Be  sure  to 
add  a  blocking  capacitor 
ahead  of  the  attenuator  if 
you  are  going  to  look  at  an 
rf  signal  that  is  riding  on  a 
dc  level.  Stay  away  from 
high-voltage  dc  circuits, 
The  bandpass  of  this  ana- 
lyzer is  too  wide  for  looking 
at  S5B  modulation  linear- 
ity. However,  this  can  be 
judged  adequately  from  a 
two-tone  pattern  on  a  nor- 
mal oscilloscope 

From  Here 

This  project  demon- 
strates that  a  useful  spec- 
trum analyzer  can  easily  be 
built  from  relatively  com- 
mon and  inexpensive  com- 
ponents. Avid  experiment- 
ers should  treat  this  design 
as  a  starting-off  point. 
Meanwhile,  let's  get  those 
transmitter  spectrums 
cleaned  up!  ff  you  would 
like  to  ask  me  a  question 
about  the  analyzer  project, 
please  send  an  SASE  73!  ■ 

References 

1*  Solid  State  Design  for  the  Ra- 
dio Amateur,  by  Wes  Hay  ward 
and  Doug  DeMaw,  ABRL  Publi- 
cations. 

2.  Hewlett-Packard  Electronic 
instruments  and  Systems,  by 
Hewlett-Packard,  Palo  Alto,  Cal- 
ifornia, 1981. 

3.  "High  Performance  Spectrum 
Analyzer,"  Wayne  Ryder,  Ham 
Radio,  June,  1977. 

4.  Printed  Circuits  Handbook, 
2nd  Edition,  by  Clyde  F. 
Coombs,  McGraw-HilL 


28     73 Magazine  •  August.  1982 


r. 


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73  Magazine  *  August,  1982    29 


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CM-U  TUNED  INPUT  ACCESSORY;  Tuned  input  ac- 
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MIX  Mini  Transceiver:  25  Watt  PS»  SSB/CW 
Transceiver  for  any  one  Amateur  Band,  160  to  6 
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STATION  ONE  CW  Radio  Station:  A  complete 
3- band,  25  watt,  CW  transceiver  and  accessaries 
station  for  new  and  experienced  hams.  This  kit 
comes  complete  wfth  transceiver,  code  key.  3 
band  dipoie.  headset  logbook.  ARRL  License 
Monual.  radio  and  code  course  on  cassette.  5*W 
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GLMOOO  Antenna  Tuner:  1.8-30  MHz  con- 
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MLX-2500  Transceiver:  (NDT  Hiner  Optional) 
160-80-40-30-20-1 7-15-1 2-IO  Meter  amateur 
bands:  USB.  LSB,  CW:  SOO  watts  PEP  SSB.  400  watts 
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Supply  built  in;  All  Silicon  Solid  State  Receiver, 
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The  AC4YN  Story 

a  Tibetan  adventure,  circa  1936-1937 


In  1936,  it  was  decided  to 
send  a  political  mission 
to  Lhasa  in  Tibet.  I  was  then 
a  subaltern  in  Peshawar  Dis- 
trict Signals  on  the  north- 
west frontier  of  India, 

At  that  time,  Tibet  was  in 
a  politically  weak  position. 
The  Dalai  Lama  had  died 
and  his  reincarnation  had 
not  yet  been  found.  The  Ta- 
shi  Lama  was  on  a  visit  to 
China,  and  the  Chinese, 
who  had  always  considered 
Tibet  to  be  a  province  of 


China,  wished  to  bring  him 
back  to  Tibet  with  an  escort 
of  their  army.  A  regent  had 
been  appointed  to  cover 
this  period. 

The  Tibetan  government, 
therefore,  invited  the  mis- 
sion to  Lhasa  with  two  ob- 
jectives. The  primary  one 
was  to  persuade  the  Tashi 
Lama  to  return  to  Lhasa,  to 
march  out  beyond  Lhasa, 
meet  him,  and  bring  him 
back  to  Lhasa  in  triumph 
without   an   escort   of   the 


BRITISH   MISSION  TO  LHASA   1936*37. 
[Oprmtcm:  tiffrtl    I!  V.  >->p**n  *  S,J.  Da-t;.  Royil  Signal*,  *nd  Mr.  K-W.  FoJ 


TO  RADIO 


PHONE 
UR  CW* 


MC/S 


UR  SIGS.     WERE  RST 

TX 

PUSH-PULL 
COLPITIS 
AERIAL 
HALF-WAVE. 

TKS  FOR  OSO     OM 

I  HOPE     C     U     AGN     SN.     735  FROM 
B.E.RH  A.  R.RL. 


SIGS   WORKED  HEREON 
AT  HRST  GMT-  ON 

QRM  QRN  QSB 

RX. 

SG-DETLF 

AERIAL. 

40 

MARCONI 


o 


CwretptwdeuM  to  i  Qr.itim&i  Tiiieiv  vvi  Calcutta, 


C5YN  (ex-AC4YN,  VUQ  VU2YNf  LA9YC,  VS1YN,  DL2YN)at 
home. 

32     73 Magazine  •  August,  1982 


Chinese  army,  The  second 
objective  was  for  us  to  re- 
view the  Tibetan  army  and 
advise  on  its  improvement 
with  a  view  to  making  Tibet 
a  more  effective  buffer 
state  between  the  northeast 
frontier  of  India  and  China. 

The  political  side  of  the 
mission  was  handled  by  the 
leader,  the  late  Sir  Basil 
Gould,  who,  at  that  time, 
was  B.  J.  Could,  Esq.,  politi- 
cal officer,  Sikkimf  and  by 
H.  E.  Richardson,  Esq.,  Brit- 
ish trade  agent.  Gyantse, 
the  late  CoL  Freddy  Spen- 
cer  Chapman,  personal  as- 
sistant to  Gould,  and  Rai 
Bahardur  Norbhu,  a  high- 
ranking  English-speaking  Ti- 
betan, 

The  health  of  the  mission 
was  in  the  hands  of  Captain 
W.  S,  Morgan  of  the  Indian 
Medical  Service.  While  the 
mission  was  in  Lhasa,  he 
also  did  a  great  deal  of 
work  for  the  Tibetans.  He 
held  many  clinics  and  car- 
ried out  many  successful 
operations  for  cataracts  un- 
der what,  by  modern  stan- 
dards, would  have  been 
considered  very  primitive 
conditions, 

Military  matters  were  in 
the  hands  of  Brigadier  Phil- 
ip Neame  VC  DSO,  and 
communications  were 
looked  after  by  Lieut. 
Sidney  Dagg  and  myself. 

Communications  in  Tibet 
were  rudimentary.  The  Indi- 
an Posts  and  Telegraphs  op- 
erated as  far  as  Cyantse, 
where  the  British  trade 
agent  had  his  post  support- 


ed by  a  squadron  of  Indian 
mounted  infantry.  Beyond 
Gyantse,  the  mail  was  car- 
ried by  mounted  runners.  A 
telegraph  line  operated  as 
far  as  Lhasa.  It  was  a  single 
strand  of  galvanized  iron 
wire  supported  on  light 
wooden  poles  with  no  spe- 
cial insulation.  It  operated 
single-current  simplex  earth 
return.  One  could  tap  in  not 
only  at  Gyantse,  but  also  at 
each  rest  house  along  the 
route.  Mounted  linemen  pa- 
trolled the  route  re-erectrng 
any  poles  that  were  blown 
down  and  repairing  breaks 
in  the  line. 

If  we  went  beyond  Lhasa, 
we  would  no  longer  have 
access  to  this  circuit.  It 
would  therefore  be  neces- 
sary for  us  to  take  transport- 
able wireless  with  which  we 
could  send  back  our  diplo- 
matic traffic.  Another  im- 
portant reason  for  taking 
wireless  on  the  mission  was 
to  outface  the  Chinese 
They  had  a  transmitter  at 
Lhasa  although  I  never 
heard  it.  As  it  happened,  we 
never  went  beyond  Lhasa. 
The  Tashi  Lama  died  before 
we  succeeded  in  persuad- 
ing the  Chinese  not  to  send 
an  escort  of  their  army. 

The  responsibility  for 
producing  radio  equipment 
was  given  to  Northern  Com- 
mand Signals;  Lieut.  Sidney 
Dagg  of  that  regiment  was 
given  the  task  As  no  suit- 
able service  equipment  was 
available,  he  had  a  trans- 
mitter and  receiver  built  in 
the    regimental    workshops 


at  Rawalpindi,  ft  must  be  re- 
membered that  everything 
was  carried  on  pack  ani- 
mals—ponies or  yaks  — in 
panniers  two  to  an  animal, 
each  one  not  weighing 
more  than  one  maud  (80 
lbs). 

Dagg  produced  the  fol- 
lowing equipment: 

•  The  main  transmitter, 
consisting  of  a  self-excited 
push-pull  Colpitts  oscillator 
using  two  AT-50  triodes 
with  an  input  of  100  Watts. 

•  A  balanced  Collins  cou- 
pler to  couple  the  transmit- 
ter to  the  open*wire  aerial 
feeders. 

•  An  Eddystone  "All  World 
Four"  (1-V-2)  battery  receiv- 
er, 

•  A  rotary  transformer  to 
convert  12  volts  dc  to  1000 
volts  dc  at  up  to  100  mill i- 
amps. 

•  A  Phillips  record  player 
—  turntable,  pick-up,  and 
amplifier  — operating  on 
230  volts  ac. 

•  Two  twelve-inch  movrng- 
coil  loudspeakers.  (We  had 
baffles  made  locally  on  ar- 
rival.) 

•  One  transverse-current 
carbon  microphone. 

•  One  12-volt  dc  to 
230-volt  ac  rotary  convert- 
er. 

•  One  550-Watt  Stuart 
Turner  charging  engine, 

•  Four  six-volt,  120-Am- 
pere-hour  batteries. 

•  Two  36-foot  steel  sec- 
tional masts. 

•  Lots  of  aerial  wire,  insula- 
tors, and  Eddystone  4-inch 
feeder  separators. 

I  brought  a  few  things  of 
my  own  from  Peshawar: 

•  A  1-V-1  receiver  which  1 
had  built  myself.  This  cov- 
ered 10  to  550  meters  using 
Eddystone  plug-in  coils. 
The  tuning  control  was  a 
Utility  100:1  slow-motion 
dial.  The  receiver  proved 
much  more  efficient  than 
the  All  World  Four.  The  tun- 
ing and  reaction  controls 
were  much  smoother  and 
the  signal/noise  ratio  very 
much  better;  Much  to  my 
sorrow,  I  was  made  to  leave 
it  behind  when  I  left  the 
mission. 


COLLI  MS  COUPLE  P 


SOOpF 


BOOpF 


QP£N   WIRE   FEEDERS 
TO  30  METRE  DIP0LE 


RHEOSTAT 


Fig.  7.  AC4YN  transmitter 


Fig.  2.  AC4YN  receiver. 


•  A  simple  audio  amplifier 

ending  in  two  PX-4  triodes 
in  push-pull  to  enable  my 
receiver  to  operate  a  loud 
speaker   for    broadcast   re- 
ception, 

•  45  feet  of  duralumin  tu- 
bular mast  in  5-foot  sec- 
tions, the  property  of  Pesha- 
war District  Signals  I  had  to 
leave  this  behind  also, 
much  to  the  fury  of  my 
commanding  officer. 

•  My  own  key,  a  pair  of 
headphones,  and  a  small 
box  of  bits  and  pieces.  Un- 
fortunately, I  no  longer 
have  this  key  as  the  Post  Of- 


View  from  roof  of  rest  house  at  Phari  Village  and  jong  in 
middle  distance.  Himalayas  in  background. 

73Magazine  *  August,  1982     33 


f  ice  "lost"  it  when  they  had 
my  equipment  in  custody 
during  the  last  war. 

Before  joining  the  mis- 
sion, I  was  sent  to  Simla,  the 
summer  hill  station  of  army 
headquarters,  There  I 
gained  experience  in  oper- 
ating the  control  station  of 
the  army  group  with  which 
we  would  be  communicat- 
ing from  Lhasa,  It  was 
known  as  the  VV  group  as 
all  stations  had  a  three-let- 
ter callsign,  of  which  the 
first  two  were  VV  The  mis- 
sion call  was  VUQ  I  also 
was  briefed  to  check  the  ac- 
curacy of  The  Army  Route 
Book  of  Tibet  and  look  out 
for  any  possible  landing 
grounds. 

From  Simla,  1  travelled 
across  India  to  Calcutta 
where  I  joined  Dagg.  We 
did  some  shopping  and 
then  went  on  to  join  the  rest 
of  the  mission.  We  first  trav- 
eled by  train  across  the 
Plain  of  Bengal  to  Siliguri, 
the  railhead  in  the  foothills 
of  the  Himalayas,  I  chiefly 
remember  the  flatness  of 
the  country  and  the  paddy 
fields. 

At  Siliguri,  we  transferred 
to  a  taxi  and  had  a  hair-rais- 
ing and  spectacular  drive 
up  the  beautiful  valley  of 
the  river  Teesta.  At  one 
point,  we  crossed  the  river 
by  a  bridge  which  spanned 
a  gorge  in  one  magnificent 
archr  with  the  river  racing 
far  below.  The  Teesta  is  a 
tributary  of  the  Brahmapu- 
tra, 


BURMA 


The  route  from  Calcutta  to  Lhasa.  [Map  from  1930s  sources 

by  Alan  R,  PhenixJ 


We  arrived  safely  at 
Cangtok,  the  capital  of  Sik- 
kim,  where  Sir  Basil  Could 
had  his  residency.  Already 
at  Cangtok  were  Freddy 
Chapman  and  Brigadier 
Philip  Neame.  Chapman 
not  only  acted  as  PA  [per- 
sonal assistant]  to  Sir  Basil 
but  was  also  in  charge  of 
cinematography,  botany, 
ornithology,  and  zoology, 
Here,  Dagg  and  I  took  the 
opportunity   to  check   our 


radio  equipment  The  trans- 
mitter worked  well,  and  we 
called  in  on  the  VV  group. 
We  also  checked  that  the 
receivers  would  bring  in  the 
BBC  overseas  service  for 
news,  etc,  We  did  not  have 
time  to  try  out  the  amateur 
bands  at  that  time. 

We  then  divided  the 
equipment  into  80-pound 
loads  for  back  transport. 
The  most  awkward  load 
was  the  charging  engine, 
which  weighed  120  lbs.  In 


the  Army,  this  was  carried 
as  a  top  toad  on  a  Class  I 
mule.  However,  we  had  no 
proper  pack  saddles  and 
the  ponies  would  not  have 
been  strong  enough.  Final- 
ly, it  was  t  ashed  to  two 
stout  bamboo  poles  and 
carried  by  four  coolies. 

When  we  set  off,  our  en- 
tourage down  to  the  last 
servant  and  sweeper  was  50 
strong,  including  25  pack 
animals  and  their  drivers 
These  were  ponies  at  first 
and  yaks  later.  In  those 
days,  the  motor  road  ended 
at  Cangtok,  so  from  then  on 
we  either  walked  or  rode. 

As  far  as  the  halfway 
point,  Gyantse,  there  were 
good  rest  houses  at  each 
stage  in  which  we  could 
spend  the  night  in  comfort. 
The  first  day's  journey  was 
through  rain  forest,  where 
rhododendrons  grew  in  thir- 
ty-foot trees  and  leeches 
abounded  The  first  halt 
was  at  Karponang  at  9,500 
feet,  just  short  of  the  Tibet- 
an border.  I  remember  suf- 
fering from  mountain  sick- 
ness here,  but  it  passed  off 
in  about  half  an  hour. 

Next  day,  we  crossed  into 
Tibet  by  the  Natu  La  Pass  at 
14,600  feet  and  dropped 
down  into  the  Chumbi  Val- 
ley, Over  the  pass  it  was 
much  dryer  as  the  monsoon 
drops  most  of  its  moisture 
on  the  southern  slopes  of 
the  Himalayas,  leaving  Ti- 
bet a  comparatively  dry 
country  with  only  a  few 
inches  of  snow  despite  a 
very  hard  winter. 


Lieut  Dagg  unpacks  and  tests  record  player  at  an  intermedi- 
ate halt.  Freddy  Chapman  at  right, 

34     73  Magazine  ■  August,  1982 


How  the  charging  engine  traveled  to  Lhasa. 


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In  the  valley,  we  spent 
three  nights,  one  at  Champi- 
tung,  1 3,350  feet,  another  at 
Yatung,  9,950  feet,  and  a 
third  at  Gautsa,  12,600  feet 
At  Yatung  there  was  a  de- 
tachment of  Indian  mount- 
ed infantry.  The  next  day 
we  climbed  up  out  of  the 
valley  on  to  the  main  Tibet- 
an plain  at  14,300  feet  We 
stopped  the  night  at  Phari, 
which  was  a  small  town 
with  a  fort  or  jong,  and  a 
good  rest  house. 

At  each  of  these  halts, 
Dagg  and  I  set  up  a  receiver 
to  check  on  the  VV  group 
and  take  down  news  broad- 
casts from  the  BBC  It  was  a 
year  after  sunspot  maxima, 
so  HF  propagation  was 
good  and  there  was  nothing 
unexpected  about  what  we 
heard.  The  only  embarrass- 
ment was  the  charging  en~ 
gine.  Dagg  had  been  given 
no  chance  to  test  it  at  high 
altitude,  and  as  we  gained 
height,  it  developed  less 
and  less  power  due  to  short- 
age of  oxygen  At  6,000  feet 
it  would  just  work.  At 
10,000  feet  it  would  start 
and  run  when  cold.  As  soon 
as  it  warmed  up  it  stalled, 
and  that  was  that. 

We  sent  a  signal  home  to 
Stuart  Turners  who,  in  due 
course,  sent  out  a  pair  of 
variable-jet  carburetors. 
They  did  not  arrive  until  af- 
ter I  had  left  the  mission, 
but  I  was  told  that  when 
they  were  fitted  the  engine 
ran  very  well,  developing 
more  than  its  rated  power. 


Tibetans  working  the  hand  charger. 


The  transmitter,  receiver,  and  Collins  coupler  installed  in 
the  barracks  at  Cyantse. 


While  Dagg  and  t  were 
dealing  with  radio  matters. 

Chapman  was  studying  the 
local  fauna  and  flora.  In 
due  course,  he  sent  back  a 
magnificent  collection  of 
seeds  and  pressed  flowers 
to  Kew  Gardens. 

There  were  six  more  night 
halts  before  reaching  our 
major  intermediate  halt  at 


Cyantse:  Tuna,  15,000  feet, 
Dochen,  14,900  feet,  Kala, 
14,850  feet,  Samada,  14,100 
feet  Kangmar,  13,900  feet 
and  Saugang  at  1 3.000  feet 
Cyantse  itself  was  at  13,100 
feet.  The  way  was  mainly 
over  a  stony  plain  with 
mountains  rising  to  20,000 
feet  in  the  distance.  Some- 
times  we   passed    through 


rocky  gorges  and  occasion- 
ally by  streams.  We  passed 
close  under  Mt  Chomol- 
hari,  a  beautiful  snow-cov- 
ered cone  rising  to  24,000 
feet 

Gyantse  is  a  fair-sized 
town  with  monasteries,  a 
jong,  the  headquarters  of 
the  British  trade  agent,  and 
barracks  for  a  company  of 
Indian  mounted  infantry,  at 
that  time  the  2/7  Rajputana 
Rifles,  Here  several  official 
receptions  took  place-  For 
instance,  we  had  to  time 
our  arrival  carefully  so  as  to 
be  three  miles  from  the 
town  at  1 1  00  am  We  were 
met  here  by  Ra|a  Teringr  a 
cousin  of  the  Maharajah  of 
Sikkirn.  Half  a  mile  further 
on,  we  were  met  by  Mr. 
Richardson  (the  British 
trade  agent),  Capt  Salo 
mons,  an  escort  of  mounted 
infantry,  and  Capts.  Guthrie 
and  Morgan  of  the  IMS,  the 
Army  surgeons  Captain 
Morgan  accompanied  us 
for  the  rest  of  the  mission.  A 
mile  further  on,  the  eastern 
,ind  western  jongpens  met 
us,  and  finally  the  Tibetan 
trade  agent  and  the  Abbot 
of  Gyantse  Gompa,  This  or- 
der of  precedence  is  very 
strict  The  most  senior  offi- 
cial meets  you  nearest  your 
destination  and  the  most 
junior  farthest  out.  On  each 
occasion,  ceremonial 
scarves  of  white  natural  silk 
are  exchanged. 

Here,  Dagg  and  I  were 
able  to  have  a  thorough 
sort-out  of  our  gear.  We  cut 


View  of  my  tent,  home  of  AC4YN,  in  the  garden  of  the  Dekiy 
Langka  at  Lhasa. 


The  transmitter  and  receiver,  VUQ/AC4YN,  m  my  tent  at 
Lhasa. 


36     73 Magazine  *  August,  1962 


5  MODES:  CW,  Baudot  ASCII,  memory  keyer, 
Morse  code  practice.  TWO  MODELS:  MFJ-496, 
$339.95.  256  character  buffer,  256  character  mes- 
sage memory,  automatic  messages,  serial  numbering, 
repeat/delay:  MFJ-494,  $279.95.  50  character  buffer, 
30  character  memory,  automatic  messages. 


MFJ  brings  you  a  pair  of  5  Mode  Super  Key- 
boards thai  gives  you  more  features  per  dollar 
than  any  other  keyboard  available.  You  can  send 
CW,  Baudot,  ASCII,  Use  It  as  a  memory  keyer 
and  for  MORSE  code  practice. 

You  get  text  buffer,  programmable  and  auto 
matic  rnessaoe  memories,  error  deletion,  buffer 
preload,  buffer  hold,  plus  much  more. 

MODE  1:  CW 

The  256  character  (50  for  494)  text  buffer 
makes  sending  perfect  CW  effortless  even  if  you 
"hunt  and  peck." 

You  can  preload  a  message  into  the  buffer  and 
transmit  when  ready.  For  break-in.  you  can  stop 
the  buffer,  send  comments  on  key  paddles  and 
then  resume  sending  the  buffer  content. 

Delete  errors  by  backspacing. 

A  meter  gives  buffer  remaining  or  speed.  Two 
characters  before  buffer  full  the  meter  lights  up 
red  and  the  sidetone  changes  pitch. 

Four  programmable  message  memories  (2  for 
494)  give  a  total  of  256  characters  (30  tor  494V 
Each  message  starts  after  one  ends  for  no 
wasted  memory.  Delete  errors  by  backspacing. 

To  use  the  automatic  messages,  type  your  call 
into  message  A.  Then  by  pressing  the  CO  button 
you  send  CO  CO  DE  (message  A). 

The  other  automatic  messages  work  the  same 
way:  CO  TEST  DE.  DF,  QRZ 

Special  keys  for  KN.  SK,  BT,  AS,  AA  and  AR. 

A  lot  of  thought  has  gone  into  huma::  engineer 
ing  these  MFJ  Super  Keyboards. 

For  example,  you  press  only  a  one  or  two  key 
sequence  to  execute  any  command. 

All  controls  and  keys  am  positioned  togicaJty 
and  labeled  clearly  tor  instant  recognition. 

Pots  are  used  for  speed,  volume,  tone,  and 


weight  because  Ihey  are  more  human  oriented 
than  keystroke  sequences  and  they  remember 
your  settings  when  power  is  off. 

Weight  control  makes  your  signal  distinctive 
to  penetrate  ORM, 

MODE  2  4  3  (RTTY):  BAUDOT  &  ASCII 

5  level  Baudot  is  transmitted  at  60  WPM 
Both  RTTY  and  CW  10  are  provided. 

Carriage  return,  line  feed,  and  "LIBS"  are  sent 
automatically  on  the  first  space  alter  63  charac- 
ters on  a  line.  This  gives  unbroken  words  at  the 
receiving  end  and  trees  you  from  sending  the 
carriage  return.  After  70  characters  the  function 
is  initiated  without  a  space. 

All  up  and  down  shift  Is  done  automatically. 
A  downshift  occurs  on  every  space  to  quickly 
clear  garbled  reception. 

The  buffer,  programmable  and  automatic  mes- 
sages,  backspace  delete  and  PTT  control  (keys 
your  rig)  are  included. 

The  ASCII  mode  includes  all  the  features  of 
Baudot.  Transmission  speed  is  110  baud,  Both 
upper  and  lower  case  are  generated. 

MODE  41  MEMORY  KEYER 

Plug  m  a  paddle  to  use  it  as  a  deluxe  full 
feature  memory  keyer  with  automatic  and  pro- 
grammable memories,  iambic  operation,  dot  dash 
memories,  and  all  trie  features  of  the  CW  mode. 

MODE  5:  MORSE  CODE  PRACTICE 

There  are  two  Morse  code  practice  modes. 
Mode  1 :  random  length  groups  of  random  charac- 
ters, Mode  2;  pseudo  random  5  character  groups 
in  8  separate  repeatable  lists  (with  answers). 

Insert  space  between  characters  and  groups  to 
form  high  speed  characters  at  slower  speed  tor 
easy  character  recognition. 


Select  alphabetic  or  alphanumeric  plus  punc- 
tuation. You  can  even  pause  and  then  resume. 

MORE  FEATURES 

Automatic  incrementing  serial  number  from  0 
to  999  can  be  inserted  into  buffer  or  message 
memory  for  contests. 

Repeat  function  allows  repetition  of  any  mes- 
sage memory  with  1  to  99  seconds  delay.  Lets 
you  call  CO  and  repeat  until  answered. 

Two  key  lockout  operation  prevents  lost  charac- 
ters during  typing  speed  bursts. 

Clock  option  (496  only)  send  time  in  CW.  Bau 
dot,  ASCII,  24  hour  format. 

Set  CW  sending  speed  before  or  while  sending. 

Tune  switch  with  LED  keys  transmitter  for  tun- 
ing. Tune  key  provides  continuous  dots  to  save 
finals.  Built  in  sidetone  and  speaker. 

PTT  (push'to-talk)  output  keys  transmitter  for 
Baudot  and  ASCII  modes. 

Reliable  solid  state  keying  for  CW:  grid  block, 
caihode.  solid  stale  transmitters  (-300V.  10  ma 
Max.  +  300V,  1 00  ma  Max).  TTL  and  open  col* 
lector  outputs  for  RTTY  and  ASCII 

Fully  shielded.  RF  proof.  All  aluminum  cabinet. 
Black  bottom,  eggshell  white  top.  IS'WWxIVTH 
(front)  x3vrH  (back).  Red  LED  indicates  on, 

9-12  VDC  or  110  VAC  with  optional  adapter 

MFJ  494  is  like  Mf  J-496  less  sequential  num- 
bering, repeat/delay  functions.  Has  50  character 
butter,  30  character  message  memory.  Clock  op- 
tion not  available  for  MFJ-494. 

Every  single  unit  is  tested  for  performance  and 
inspected  for  quality    Sofid  American  construction. 

OPTIONS 
MFJ-53  AFSK  PLUG-IN  MODULE.  1 70  and  850 

Hz  shift.  Output  plugs  into  mic  or  phone  patch 
jack  for  FSK  with  SSB  rigs  and  AFSK  with  FM  or 
AM  rigs.  $39.95  { +  S3). 

MFJ-54  LOOP  KEYING  PLU6-.N  MODULE.  300V, 
60  ma  loop  keying  circuit  drives  your  RTTY  print 
er.  Opto  isolated.  TTL  input  tor  your  computer  to 
drive  your  printer,  $29.95  ( +  $3). 

MFJ  61  CLOCK  MODULE  {MFJ  496  only)  Press 
key  to  send  tome  in  CW,  Baudot  or  ASCII,  24  hour 
format.  $29  95  (  +  $3). 

110  VAC  ADAPTER.  $7.95  (+  $3). 

BENCHER  IAMBIC  PADDLE.  $42.95  (  +  $4), 

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$39,95  lor  MFJS3  AFSK  module.  $29.95  for 
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Clock  module,  $7,95  tor  the  110  VAC  adapter 
and  $42.95  for  Bencher  Paddie.  Include  $5,00 
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73Magazine  *  August.  1982     37 


Using  the  PA  equipment.  The  monk  who  enjoyed  singing. 


The  Regent  inspects  the  record  piayer/PA  equipment 


a  dipole  for  the  Army  HQ 
group  wavelength  of  30  me- 
ters. Each  half  of  the  dipole 
was  25  feet  long,  and  the 
open-wire  feeders  were  40 
feet  long  We  set  up  the 
transmitter  and  receiver  in 
a  room  in  the  barracks.  We 
were  lucky  enough  to  find 
here  a  home-made  charging 
machine  which  had  been 
built  to  charge  the  battery 
of  a  broadcast  receiver.  It 
was  built  around  a  six-volt 
car  dynamo  driven  by  a 
wondrous  contrivance  of 
wooden  pulleys  and  flap- 
ping leather  belts.  Cranked 
by  coolies,  it  managed  to 
produce  enough  charge  to 
enable  us  to  maintain  short 
schedules  with  the  VV 
group,  but  not  enough  to 
spare  to  enable  us  to  make 
any  transmission  on  the  am- 
ateur bands. 

It  was  now  decided  that 
Dagg  should  go  back  to  Cal- 

3fl     73  Magazine  *  August,  1982 


cutta  and  have  a  new  hand- 
charger  built.  It  had  been 
hoped  that  a  charging  en- 
gine used  by  a  recent  Ever- 
est expedition  might  still  be 
available  at  Katmandu,  but 
enquiries  showed  that  it 
had  been  disposed  of.  Dagg 
eventually  rejoined  us  in 
Lhasa  with  a  most  efficient 
gear-driven  device  It  used 
a  Ford  12-volt  dynamo  and 
had  two  large  crank  han- 
dles. Four  coolies  managed 
to  produce  6  Amps  through 
12  volts  of  batteries.  This 
rate  of  work  is  only  about 
1/1 0th  HP,  so  they  can't 
have  been  working  very 
hard! 

The  political  part  of  the 
mission  went  ahead  to  Lha- 
sa, leaving  me  behind  with 
the  radio  gear  and  the  Bell 
and  Howell  35mm  projec- 
tor. There  was  no  point  in 
taking  these  on  up  to  Lhasa 
until  power  was  available. 


Ringang. 


In  due  course,  I  was  sum- 
moned to  join  the  main  par- 
ty. 

Now,  Lhasa  had  an  elec- 
tric light  plant.  It  worked  on 
the  dc  three-wire  system 
with  440  volts  of  batteries 
having  the  center  tap 
earthed.  The  supply  was, 
therefore,  220  volts  Those 
on  one  wire  had  positive 
earth,  those  on  the  other 
had  negative  earth.  The 
cells  were  charged  by  a  mo- 
tor generator.  The  motor 
ran  at  3  kV  ac.  The  ac  was 
generated  by  a  small  hydro- 
electric plant  in  the  foot- 
hills  of  the  20,000-foot 
mountains  which  rose  from 
the  12,000-foot  Lhasa  plain 
about  three  miles  away. 

The  insulation  of  the 
transmission  line  was  a  bit 
rudimentary,  and  on  damp 
evenings  there  were  impres- 
sive brush  discharges,  The 
stream  driving  the  turbine 
froze  at  night  during  the 
winter  so  that  charging 
could  be  carried  out  only 
by  day. 

You  will  realize  that  this 
was  a  considerable  engi- 
neering achievement  when 
you  remember  that  every 
item  had  to  be  carried  up 
from  the  road  head  by  coo- 
lies  and  pack  animals. 
Great  credit  also  is  due  to 
the  Tibetan  official  who  as- 
sembled and  commissioned 
it  with  only  unskilled  labor 
at  his  disposal  and  who  was 
responsible  for  running  it. 
His  name  was  Ringang.  He 
was  one  of  the  four  Tibet- 
ans who,  as  boys,  were  sent 


to  England  and  educated  at 
Rugby  He  was  also  respon- 
sible for  the  official  ciphers. 
He  arranged  for  our  bat- 
teries to  be  charged  by  con- 
necting them  in  parallel 
with  the  end  cells  of  the 
440-volt  battery. 

The  mission  was  accom- 
modated in  a  nice  villa  in  a 
garden  called  the  Dekiy 
Langka  There  were  not 
enough  rooms  for  us  all  to 
sleep  inside,  so  I  had  a  tent 
in  the  garden  in  which  I  also 
set  up  the  transmitter  and 
receiver  The  aerial  was 
supported  at  one  end  on  a 
forty-foot  mast  consisting 
of  five  of  the  eight-foot  sec- 
tions of  duralumin  The 
other  end  was  supported  on 
one  section  set  up  on  the 
flat  roof  of  the  house  Regu 
lar  contact  was  kept  with 
the  control  station  of  the 
VV  group  at  Army  head- 
quarters, Simla,  in  the  sum- 
mer, and  with  New  Delhi  in 
the  winter.  All  the  outsta- 
tions  at  various  army  sta- 
tions in  India  and  the  one  in 
Hong  Kong  were  worked  on 
the  30-meter  wave. 

Once  this  was  organized, 
I  looked  around  for  the 
20-meter  amateur  band 
This  was  soon  found  and 
the  transmitter  tuned  to  the 
band  by  netting  on  to  the 
receiver.  You  will  remem- 
ber that  each  half  of  the  di- 
pole was  25  feet  and  the 
feeders  were  40  feet,  mak- 
ing the  overall  length  of 
each  half  65  feet,  so  there 
was  no  problem  in  loading 
it  up  via  the  Collins  coupler. 


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The  first  people  to  re- 
spond to  that  historical  call, 
"CQ  de  AC4YN,"  were  VU2 
amateurs.  Before  the  Chi- 
nese invasion,  the  interme- 
diate  for  Tibet  was  AC4. 
There  was  no  licensing  au- 
thority, so  I  created  the  call 
by  adding  the  two  letters  of 
my  own  callsign  to  the  in- 
termediate, Unfortunately, 
I  did  not  make  a  copy  of  the 
log  for  my  own  records,  so  I 
have  no  recollection  of  in- 
dividual callsigns  worked. 

The  first  DX  to  be  worked 

was  VK  and  ZL.  They  were 
so  reliable  that  we  regarded 
them  as  locals.  This  was 
very  useful,  as  the  political 
officer  had  relations  in  New 
Zealand.  We  were  able  to 
pass  Christmas  greetings 
between  the  two  parties  via 
amateur  radio,  earning  con- 
siderable kudos  both  for 
amateur  radio  and  Royal 
Signals. 

As  the  year  progressed, 
our  signals  seemed  to  reach 
further  and  further  west  un- 
til, in  December,  I  raised  my 
first  C  station.  In  my  excite- 
ment, I  asked  him  if  he 
would  relay  messages  to 
my  family.  However,  I  must 
have  scared  him  off  as  he 
did  not  come  back  to  me 
again, 

I  was  not  able  to  spend 
much  time  on  the  air  as  I 
had  to  join  in  a  great  num- 
ber of  the  business  and  so- 
cial activities  of  the  mis- 
sion. We  attended  and  gave 
many  official  parties  There 
were  visits  to  the  Potala,  the 
three  huge  monasteries 
(Sera,  Drepung,  and  Kun- 
dun),  the  cathedral,  and  var- 
ious temples.  Although  the 
Tibetans  are  Buddhists, 
there  were  still  traces  of  an- 
cestor and  devil  worship.  It 
was  always  considered  wise 
to  placate  any  gods,  spirits, 
or  devils  that  may  be 
around.  One  such  temple 
was  dedicated  to  snakes. 

Besides  these  places,  we 
also  visited  the  mint,  the  ar- 
senal, and  the  Norbu  Lin- 
gha,  the  Dalai  Lama's  sum- 
mer palace  and  gardens. 
Some  of  my  time  also  was 

40     73  Magazine  *  August,  1982 


The  Potaia, 


taken    up    helping    Freddy 

Chapman  with  cipher  work 
and  photography.  On  some 
evenings,  we  gave  cinema 
performances.  These  were 
always  packed,  not  only 
with  our  own  staff  and 
friends,  but  also  by  as  many 
locals  as  could  squeeze  in- 
to the  room.  Some  of  the 
films  were  old  comics  we 
had  rented  from  a  film  li- 
brary and  brought  with  us. 
Of  these,  the  most  popular 
were  those  starring  Rin  Tin 
Tin,  since  they  reminded  lo- 
cals of  their  own  shepherd 
dogs. 


What  they  enjoyed  most 
were  films  taken  by  Chap- 
man which  had  been  sent 
down  to  Calcutta  for  pro- 
cessing and  returned  to  us. 
The  appearances  of  them- 
selves and  their  friends  on 
the  screen  were  greeted 
with  loud  applause.  Anoth- 
er thing  which  amused 
them  was  talking  into  the 
microphone  and  hearing 
their  own  voices,  amplified 
by  the  record  player  ampli- 
fier, booming  out  over  the 
loudspeakers. 

All  too  soon,  the  time 
came  when  I  had  to  leave 


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Lhasa,  the  mission,  and  all 
the  good  friends  I  had  made 
up  there,  A  frontier  war  had 
started  and  my  command- 
ing officer  demanded  my 
return  to  the  regiment.  So, 
about  mid-December,  I  set 
off  back  with  my  Pathan 
bearer  and  a  couple  of  pack 
ponies.  Traveling  light,  I  did 
double  stages.  Chapman 
came  with  me  as  far  as  the 
Yamdrok  So,  a  vast  lake  be- 
tween Lhasa  and  Gyantse, 
to  study  bird  life  and  gather 
wild  flowers.  I  crossed  the 
upper  reaches  of  the  Brah- 
maputra in  coracles,  came 
back  over  the  16,600-foot 
Karo  La,  and  went  down  to 
Gyantse  In  winter,  it  is  very 
cold  at  these  heights,  and  a 
strong  wind  blows  all  day 
raising  dust  storms.  If  Tibet- 
ans have  to  travel  in  the 
winter,  they  do  so  at  night 
when  the  wind  drops 

I  continued  these  double 
stages  back  to  Gangtok, 
and  then  went  by  taxi  to  Sil- 
iguri  and  by  train  to  Calcut- 
ta I  had  to  call  in  at  New 
Delhi  for  debriefing  before 
returning  to  my  regiment  in 
Peshawar, 

In  order  to  keep  the  radio 
in  operation  after  my  depar- 
ture, Reg  Fox,  who  was  ex- 
Royal  Signals,  was  sent  up 
from  Calcutta.  He  did  not 
arrive  until  after  I  left,  so  I 
did  not  have  the  pleasure  of 
meeting  him.  When  the  mis- 
sion closed  in  the  spring,  he 
stayed  on  in  Lhasa  and  mar- 
ried a  Tibetan  girL  He  re- 
mained until  the  Chinese  in- 
vasion, when  he  escaped  to 
India  where  he  died. 
Whether  any  of  his  records, 
logs,  or  equipment  have 
survived,  I  do  not  know. 

To  those  who  are  inter- 
ested in  reading  about  the 
mission,  I  recommend  F 
Spencer  Chapman's  book 
Lhasa,  The  Holy  City,  pub- 
lished by  Chatto  and  Win- 
dus,  London,  1938.  The  po- 
litical officer  in  Sikkim's  et- 
ter  no.  4(7)-P.37  to  the  For- 
eign Office  (dated  30th 
April  1937)  and  his  diary  of 
events  are  probably  avail- 
able from  the  Public  Rec- 
ord Office,  London. ■ 


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filters  with  a  MATCHED  PAIR  of  high-performance  FOX  TANGO  2.1kHz  BW 
discrete-crystal  filters.  Can  be  used  for  both  RX/TX  or  for  RX  only;  your  choice. 

ADVANTAGES  OF  FT  FILTERS? 
(See  Test  Data  Below) 

*  Wiih  chc  FT  2  ,V*.  i he  basic  bandpass  (BP)  tn  SSB  is  signficaiuly  narrower  and  the  shape  factor  (SF)  is  much  better 
than  that  of  the  suxk  filters  (see  Tests  I  and  1)>  But  the  difference*  art-  more  striking  when  VBT  is  used  to  hrinjji 
the  BP  of  the  sti  ck  filters  down  Co  char  of  [he  FT  filters  without  VBT  tare  Tests  2  and  % 

*  FT  2, 1  \  have  more  squnred-ofi  pasAhand  corners  making  ihe  ruuruwtf  VBT  setting  particularly  useful  tor  CW 

operation, 

*  Wiih  VBT  set  at  5O0H2*  the  FT  2.  Ps  actual  I  y  provide  a  much  better  SF  than  the  optional  Kenwood  SODHt 
o\83MHr  CW  filter;  thev  approach  that  of  ihe  Costly  Kencmod  x\)H=  45SkHr  CW  filter, 

*  With  VBT  set  for  lOOHi,  the  selectivity  of  the  FT  2. 1  \  approaches  that  nt  the  optional  Kenwood  250Hl8+S3MH: 
filtet ,  However^  the  original  2.7kHj  filters  are  not  very  useable  at  this  BW  due  to  the  large  insertion  loss  and  very 
peaked  passband.  tCompare  tests  6  tind  7). 

*  With  VBT  in  use,  the  FT  2.  J  's  significantly  reduce  the  ihaiskJer"  efiect.  The  "high  %)de'*ctacji  shows  their  greater 
ultimate  attenuation  of  close-in  signals- 


TEST  DATA  {Courtesy  of  KA2R) 


Teat  No, 
St'k  Ftra 
FT  Ft™ 
VBT  BW 
Shape  F. 
-  6dB  BW 
-60dBBW 
-SOdBBW 
Hi  Side* 
VBT  Ins  Loss 


r-£," 


„5« 


~7» 


19901 

1.45 
1995 
2900 
3090 
1320 
0 


2  k  2.7 

500 

2.74 

47S 

1270 

1540 

2620 

5dB 


300 
3.32 

318 
1110 
1195 
2995 
IDdB 


1  VBT  set  to  provide  about  same  BW  as  2x2.1  filters  without  VBT. 
Distance  (Hi)  from  USB  upper  -6dB  point  to  point  where  audio  from  S^+  lOdB  signal  becomes  inaudible. 

[Carenil  tests  are  fine,  but  the  final  proof  of  filter*  is  in  the  using.  Hcte  are  a  few  quotes  from  users:  *. , ,  Spectacular 
'improvement  in  SSB  RX  *  VBT  now  works  as  it  really  should ...  I  saved  money— I  don't  need  a  CW  filters . . ,  ex- 
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Regular  price:  $55 +$125  -$180  +  shipping 

INTRODUCTORY  PRICE  (Complete  kit). .  $150 

Includes  Matched  Pair  of  Fox-Tango  Filters*  All  needed  cables*  parts,  instructions. 

10%  quantity  discount  applies 
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Order  by  mail  or  phone.  Pay  by  VISA/MC,  Check*  M.O.,  or  C.O.D. 

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Scandinavia:  MICROTEC,  Makedien  26,        Other:  1NGOIMPEX,  Postfach  24  49 

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Phone:  (305)  683-9587  "323 


JULY  4TH 
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-/ 


42     73  Magazine  •  August,  1982 


WORLD  TIME 
WATCH 

the  first  micro  processor  watch 
made  especially  for  hams 


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water  resistant 

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resistant  to  20  meters,  the  case  is  100% 
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**$ee  List  at  Ativetusets  on  page  TT4 


73  Magazine  *  August,  1982     43 


it 


Smart"  Squelch  for  SSB 


Editor's  Note:  W9MKV  and  W9YAN"s  "Smart  Squelch"  overwhelmed  the  competition  to  win  the  first  73  Magazine  Home- Brew  Contest  The 
authors  received  a  $250  prize  in  addition  to  the  normal  article  payment.  You  can  build  this  trend-setting  project;  W9MKV  offers  a  PC  board 
for  $7.00  and  a  complete  parts  kit  is  available  from  Radiokit,  Box  411,  Greenville  NH  03048,  tor  $49.95,  Congratulations  to  W9MKV  and 
W9YAN  for  a  job  well  done* 


Frank  5.  Reid  W9MKV 
PO  Box  5263 
Bloomingion  IN  47402 

David  A.  Link  W9YAN 
211  Western  Drive 

Bloomingion  IN  47401 


This  circuit  detects  the 
human  voice  but  ig- 
nores noise,  steady  tones, 
and  the  Russian  woodpeck- 
er HF  radar  pulses.  It  re- 
quires no  receiver  modifica- 
tion and  works  even  when 
voice  signals  are  below  the 
noise  level 


A  squelch  turns  off  re- 
ceiver audio  to  eliminate 
annoying  background  noise 
when  there  is  no  signal. 
Squelch  circuits  in  AM  and 
FM  receivers  are  carrier-op- 
erated. On  single  sideband. 
which  has  no  carrier, 
squelching  is  more  difficult 
Most  SSB  rigs  with  squelch, 
e.g.,  the  popular  2-meter 
multimode  transceivers, 
use  age  (S-meter)  voltage  to 
open  squelch  in  SSB  mode 
Age-operated  squelch  is  ad- 
equate for  strong  signals  on 
relatively  quiet  channels. 
Age  and  VOX-type  squelch- 


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es  open  for  any  noise  or  het- 
erodyne that  exceeds  a  pre- 
set level.  Weak  signals  of- 
ten are  missed  because  the 
threshold  must  be  set 
above  the  noise  level. 

White  noise  sometimes 
can  make  you  imagine  tiny 
voices  in  the  noise,  but  it 
won't  fool  the  Smart 
Squelch.  Detecting  unread- 
ably-weak  signals  is  worth- 
while if  a  change  of  anten- 
na direction  or  receiver 
control  settings  will  make 
them  usable. 

The  audio- opera  ted 
squelch    circuit    described 


"  "a 


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Photo  A,  Squelch  unit  is  attached  to  the  right  side  of  the  HF  SSB  transceiver.  Rectangular 
LEDs  above  the  control  knob  indicate  circuit  status.  (Photo  by  KA9FfS} 

44     73  Magazine  •  August,  1982 


here  is  similar  in  principle 
to  Motorola's  "Constant  Si- 
nad"  squelch,  a  discrete- 
component  circuit  with  22 
transistors. 

Discriminating  the 
Human  Voice 

People  normally  speak 
about  three  syllables  per 
second.  The  squelch  works 
by  detecting  voice-band  en- 
ergy (500-3000  Hz)  which  is 
varying  in  frequency  at  a 
rate  of  0.5  to  3.25  Hz. 

The  circuit  is  a  type  of 
FM  detector  It  is  insensi- 
tive to  amplitude  variations 
throughout  the  range  where 
the  input  stage  is  not  driven 
to  saturation  but  back- 
ground noise  is  strong 
enough  to  saturate  the  lim- 
iter.  The  squelch  works 
properly  with  most  speaker- 
level  signals.  You  can  con- 
nect it  directly  to  the  re- 
ceiver's detector  output, 
adjusting  gain  of  input  buff- 
er amplifer  U1A  as  neces- 
sary. 

Performance 

A  receiver  tuned  to 
WWV  provides  a  good 
demonstration  of  the  cir- 
cuit's capabilities.  Squelch 
opens  for  voice  announce- 
ments and  ignores  the  rest 
of  the  transmissions. 

The  squelch  can  turn  on 
well  within  the  first  spoken 
syllable.  Speed  of  response 
depends  mostly  upon  the 
rise-time  of  active  low-pass 
filter  U3A  The  receiver  is 
muted  one  second  after  the 
last  voice  detection.  The 
beginning  of  a  steady  tone 


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HrsrF#£s*s   swtrctf 


Fig.  7.  Schema  t/c  diagram. 


opens  the  squelch  only  mo- 
mentarily. It  opens  intermit- 
tently on  music.  Response 
to  CW  depends  on  code 
speed  and  tone. 

A  single  squelch  circuit 
can  control  multiple  receiv- 
ers, unsquelching  them  all 
when  any  receiver  detects  a 
voice  signal.  (We  like  to 
monitor  HF  aircraft  and  ma- 
rine frequencies  plus  144.2 
MHz  — the  2-meter  SSB 
calling  frequency,) 

The  squelch  is  useful 
when  rf  radiation  from 
computer  systems  over- 
whelms the  normal  squelch 
in  a  VHF  FM  receiver  Ifs 
also  good  for  monitoring 
VHF/UHF  mobile-tele- 
phone channels  in  systems 
where  a  constant  idle  tone 
is  transmitted  while  no  call 
is  in  progress.  The  circuit 
has  other  applications  as  a 


"smart"  VOX  (voice-operat- 
ed switch)  for  transmitters, 
recorders,  intercoms,  secu- 
rity systems,  remote-base 
systems,  and  repeater  equip- 
ment. 

Circuit  Description 

U1A  is  a  unity-gain  sum- 
ming amplifier,  input  buff- 
er, and  low-pass  filter  with 
3-kHz    cutoff,    U1A   drives 

U1 B,  a  third-order  high-pass 
active  filter  with  3-d B  cut- 
off at  500  Hz.  We  chose 
high-performance  FET-in- 
put  operational  amplifiers 
so  that  active  filters  could 
use  high  resistances  and 
small  capacitors.  TheTL084 
quad  op-amp  chip  is  equiv- 
alent to  the  National  LF357. 
U1C  and  U1D  are  limiter 
amplifiers  with  a  combined 
gain  of  85  dB  U1  D's  output 
is  voice-band  audio  turned 
into   constant-amplitude 


square  waves.  The  square 
waves  trigger  CMOS  mono- 
stable  multivibrator  U2. 
Output  of  U2  is  a  train  of 
.33-miIlisecond  pulses,  one 
for  each  audio  cycle.  The 
average  voltage  of  U2's  out- 
put is  proportional  to  the  in- 
put frequency.  U2  and  the 
following  low-pass  filter 
form  a  frequency-to-volt- 
age converter,  i.e.,  FM  de- 
tector, somewhat  similar  to 
an  automobile  tachometer 
circuit. 

Active  low-pass  filter 
U3A  cuts  off  at  3,25  Hz,  the 
best  compromise  between 
noise-falsing  and  the  rate  at 

which  people  speak  sylla- 
bles.2 Note  that  U3A  has  no 
bias  network  even  though 
the  amplifier  uses  a  single- 
polarity  power  supply.  U2's 
averaged  pulses  keep  the 
output  of  U3A   at  5   to  6 


volts  with  normal  noise  in- 
put from  the  receiver.  R17, 
which  sets  U2's  period,  can 
be  varied  to  keep  U3A's  qui- 
escent output  voltage  near 
the  center  of  its  range. 

On  very  quiet  channels 
there  may  not  be  enough 
pulses  from  U2  to  keep  U3A 
properly  biased.  False  de- 
tects may  occur  as  U3A's 
output  goes  tn  and  out  of  its 
linear  range.  You  can  inject 
extra  noise  or  low-level 
tone  into  the  squelch  cir- 
cuit's auxiliary  input  to 
achieve  the  desired  results 
for  your  particular  applica- 
tion. 

U3A's  output  is  ac-cou- 
pled  to  U3B,  which  ampli- 
fies with  a  gain  of  2,  and 
thence  to  U3C,  a  unity-gain 
inverter  U3B  and  U3C  to- 
gether form  a  phase  splitter 
with  a  gain  of  2.  The  phase 

73Magazine  •  August,  1982     45 


splitter  provides  positive- 
going  outputs  for  positive 

and  negative  frequency  de- 
viations of  the  receiver 
audio. 

Comparators  U4A  and 
U4B  detect  the  rate-of- 
change-of-frequency  sig- 
nals from  the  phase-splitter 
outputs.  If  the  voltage  at 
the  inverting  (  — )  input  of 
U4A  or  U4B  exceeds  the  ref- 
erence voltage  set  by 
squelch-threshold  control 
R30,  then  the  low-going  lev- 
el at  the  comparators'  par- 
alleled open-collector  out- 
puts discharges  C  2  0 
through  R34  and  D1,  The 
discharge  time  constant  is 
10  milliseconds  C20,  R35, 
and  comparator  U4C  form 
a  timenjelay  circuit  which 
holds  squelch  open  during 
its  one-second  period  Each 
detector  output  longer  than 


10  milliseconds  resets  the 
timer  for  another  one  sec- 
ond. R35  controls  length  of 
delay, 

U4C's  output  is  the 
squelch-open  signal  (active 
high).  U4C  turns  on  hystere- 
sis-switch  transistor  Q1 
(which  lights  LED2)  and  ac- 
tivates output-driver  U4D. 
As  shown,  U4D's  output 
goes  high  to  unsquelch.  We 
used  normally-closed  relay 
contacts  so  that  the  speaker 
is  enabled  when  the  relay  is 
turned  off  or  if  power  is  re- 
moved from  the  squelch 
circuit.  To  reverse  the  sense 
of  the  output,  exchange  the 
(  +  )  and  (-)  inputs  of  U4D. 
(Jumpers  are  provided  on 
the  PC  board  )  U4Ds  open- 
collector  output  can  drive  a 
relay  in  the  speaker  lead,  as 
shown,  or  a  gated  amplifier, 
analog    gate,   optoisolator. 


or  TTL  or  CMOS  logic  cir- 
cuit. The  comparator  out- 
put can  sink  50  mA  max- 
imum. 

The  squelch  is  more  sen- 
sitive after  opening  than  be* 
fore.  The  sensitivity  change 
is  called  hysteresis.  With  no 
hysteresis,  the  squelch  may 
drop  out  while  someone  is 


3 


talking.  If  there  is  too  much 
hysteresis,  squelch  thresh- 
old becomes  hard  to  adjust 
properly.  Detector  compar- 
ators U4A  and  U4B  have 
two  levels  of  hysteresis. 
Positive-feedback  resistor 
R32  prevents  comparator 
oscillation  and  lowers  the 
threshold  slightly  during  a 


to 


$3 


2 


Fig.  2*  PC  board  (foil  side). 

46     73  Magazine  *  August,  1982 


Fig.  3.  Component  layout 


M2    ENGINEERINGS 

VHF  H.T.  CONVERTERS 


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REMEMBER  THE  FUN  AT  PLAYBOY'S  GREAT  GORGE 

RESORT  IN  1976  &  1978? 


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l  isr  of  Advertisers  on  page  i  M 


73  Magazine  *  August,  1982    47 


Photo  B.  Circuit  board  and  chassis  detail.  The  only  externa!  connections  required  are  receiver  audio   speaker   and 
12  volts  dc,  [Photo  by  KA9F}S) 


detect.  Q1  conducts  while 
squelch  is  open,  further  re- 
ducing the  threshold  volt- 
age via  R42  and  D2.  R42  de- 
termines the  amount  of  hys- 
teresis. The  100k  value 
shown  for  R42  provides 
smooth  squelch  operation. 
The  circuit  uses  25-30  mA 
plus  relay  current.  The 
eight-volt-regulator  IC,  U5, 


should  be  used  for  mobile 
operation.  Otherwise,  the 
entire  circuit  can  run  from  a 
well-regulated  12-volt  sup- 
ply. (Omit  U5  and  add  a 
jumper  between  input  and 
output  pins  of  U5  on  the  PC 
board,) 

Adjustment 

LED1  lights  whenever  the 


detector  is  active.  Listen  to 
a  voice  signal  and  adjust 
the  threshold  control  until 
LED1  blinks  for  every  spo- 
ken syllable,  then  make  fine 
adjustments  as  necessary 
for  noise  conditions.  The 
enable  switch  allows  you  to 
adjust  the  squelch  before 
activating  the  relay  and  al- 
lows you  to  unsquelch  with- 


out disturbing  the  threshold 
setting.  Scale  markings 
around  the  control  knob 
make  it  easier  to  reset  an  of- 
ten-used level, 

Construction 

Alt-new  parts  cost  about 

$40,  using  referenced  items 
from  Radio  Shack  and  ECC. 
Resourceful  hams  can  build 


Parts  List 


Semiconductors 

U1,U3 

U2 

U4 

U5 

Q1 

D1,  D2 

03 

LE01 

LED2 


TL084CquadBIFETopamp  2 

CD4047  CMOS  multivibrator  (ECG  4047}    1 
LM339quad  comparator  1 

78088-volt  regulator  (optional— see  text)  1 


2N2222  orequiv.  silicon  NPN  transistor 
1 N91 4  or  equiv.  silicon  diode 
1 N4002  or  equiv.  silicon  diode 
Red  LED  (rectangular) 
Green  LED  (rectangular) 


Capacitors  (All  20  V  or  more) 


C12 

C3.  C5,  C13 

G7,  Co 

C6 

C2 

C10.C11 

C15 

C14 

C1PC4,  C20p 

C21 
C16 

C18f  C19 
C9t  C1 7 


68pF 
1000  pF 
4700  pF,  5% 
0,047  uF,  5% 
0.056  uF 
0,1  uF 
0.22  uF,  5% 
0,47  uF,  5% 

1  uF,  electrolytic 

4,7  uF,  non-polarized  (RS  272-998) 

6  uF,  electrolytic 

47  uF,  electrolytic 


Resistors  (All  %  Watt;  *  =  5%) 

R1,R2tR3,R33,R41 

48     73  Magazine  •  August,  1982 


1 
2 

1 
1 

1 


1 
3 
2 
1 
1 
2 
1 
1 

4 

1 
2 
2 


$5.98 
1.49 
1,50 
.99 
,15 
.20 
JO 
.49 
.49 


,12 
.45 
.60 
,30 
,30 
.30 
.40 
.40 

1,60 

.99 

2.36 

2,00 


R11,  R14 

R9,  R10,  R23,  R24 

R4\  R31 

R30 

R13,  R16t  R34f  R36 

R29 

R40 

R38 

R5\  R6"r  R7,  R8.  R21 

R25,  R26,  R39,  R42 

R22,  R27,  R28 

R18*,  R19* 

R17 

R20 

R12t  R15 

R35,  R37 

R32 


1k 


Other 

Ferrite  beads 

Miniature  earphone  jacks 

Relay,  12-volt  SPDT(RS  275*003) 

Switch,  miniature  toggle  SPST 

Control  knob 

Hardware,  PC  board,  chassis 

Parts  Total 


27k 

4.7k 

6.8k 

5k J  i near  pot 

10k 

18k 

47k 

56k 

68k 

100k 

130k 

150k 

160k  (see  text) 

300k 

360k 

1M 

2,4M 

42  @  $.08  ea. 


2 
4 
2 
1 
4 
1 
1 
1 
5 
4 
3 
2 
1 
1 
2 
2 
1 


ea. 

=  $3.28 

2 

.10 

3 

1.29 

1 

2,99 

1 

149 

1 

.49 

10.00 

$40.85 


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73  Magazine  ■  August,  1982    49 


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the  circuit  for  substantially 
less. 

We  built  several  proto- 
types on  universal  printed- 
ctrcuit  cards.  The  only  criti- 
cal area  is  U1,  where  high 
li  miter-amplifier  gain  can 
cause  feedback  oscillation 
in  some  layouts.  Keep  com- 
ponent leads  as  short  as 
possible.  Use  5%  tolerance 
or  better  for  frequency-de- 
termining components  in 
active  filters.  The  Radio 
Shack  relay's  frame  must 
be  insulated  from  ground. 
Mounting  the  relay  on  a 
rubber  pad  quiets  its  click- 
ing and  isolates  it  from  vi- 
bration. 

Conclusion 

Although  squelch  effec- 
tiveness may  diminish  on 
very  crowded  amateur 
bands,  a  sensitive,  discrimi- 
nating squelch  is  very  use- 
ful for  net  operations  and 
scheduled  contacts,  espe- 
cially with  modern  digital- 
ly-tuned   receivers    which 


can  be  preset  to  precise  fre- 
quencies. 

This  circuit  can  be  a  start- 
ing point  for  many  experi- 
ments. You  could,  for  exam- 
ple, insert  an  analog  delay 
device  between  audio  input 
and  output.  If  the  delay 
were  longer  than  the 
squelch  response  timef  then 
squelch  would  open  before 
the  first  spoken  syllable 
reaches  the  loudspeaker. 

Digital  techniques  could 
perform  the  function  of  the 
analog  circuit  described 
here,  perhaps  with  improve- 
ments such  as  adaptive 
threshold  and  program-con- 
trolled time  constants.  We 
are  experimenting  with  a 
microprocessor- based 
voice  detector  which  may 
be  the  subject  of  a  future  73 
article.  B 

References 

■Don  Lancaster,  Active  Filter 
Cookbook,  Howard  W.  Sams  & 
Co.,  Inc.,  1975. 

'Motorola  Micom  HF  SSB  Trans- 
ceiver Service  Manual,  1975, 


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50     73  Magazine  •  August,  1982 


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See  Ust  of  Atiwerjfsers  on  page  t14 


73Magazine  •  August.  1982     51 


The  Ultimate  Fuse 

ac  overload  protection 


NeiUobnson  W20LU 

PO  Box  585 

South  Orleans  MA  02662 

Recently,  while  working 
on  the  design  for  a  new 
power  supply,  I  managed  to 
blow  over  a  dozen  fuses. 
My  regular  ham  buddy  was 
on  a  weekend  fishing  trip, 
so  I  kept  making  the  same, 
simple  error.  After  the  trou- 
ble was  located   and   cor- 


Fig.  1.  The  early  circuity  was 
fairly  simple,  but  half- 
wave  rectification  from  the 
120-volt  winding  caused  the 
setup  to  he  less  sensitive 
than  desired.  Added  compo- 
nents shown  connected 
with  dotted  lines  are  needed 
to  keep  the  relay  locked 
up  after  an  overload  has 
caused  the  circuit  to 
be  broken.  (Note:  Relay 
shown  at  rest,  i.e.,  non-ener- 
gizedj 

52     73 Magazine  •  August,  1982 


rected,  it  somehow  struck 
me:  There's  got  to  be  a  bet- 
ter way! 

In  the  past,  hams  who 
built  their  own  power  sup- 
plies could  depend  on  man- 
ufacturers to  offer  several 
different  types  of  relays, 
some  with  manual  reset 
capabilities  and  some  with 
electrical  reset  features, 
but  such  items  are  no  lon- 
ger available  to  the  ama- 
teur builder.  In  view  of  this 
deficiency,  a  few  years  ago 
I  offered  a  homely  solution 
to  the  dc  overload-relay 
problem:  how  to  home- 
brew what  you  can  no  lon- 
ger purchased 


It  is  common  practice  for 

commercial  and  military  in- 
stallations to  provide  cir- 
cuitry to  protect  their  pow- 
er supplies,  both  as  to  input 
and  output  Dc  overload  re- 
lays are  properly  installed 
in  the  output  of  the  rectifier 
or  filter  circuits,  and  ac 
overload  relays  are  in- 
stalled in  the  primary  cir- 
cuits of  the  various  power 
supplies,  and  so  on.  But  I 
had  yet  to  see  how  an  ama- 
teur experimenter  might 
put  together  a  suitable  sub- 
stitute for  an  ac  overload 
relay. 

In   an   earnest  effort  to 
devise  some  sort  of  simple 


WHITE  {COLD* 


LOAB 


CONTACTS 


HS  ®- 


Fig.  2.  Final  version  of  overload  relay.  SW1  selects  2.5-,  5-,  or 
10- Amp  kick  out  points, 


circuitry  for  such  a  need,  it 
came  to  mind  that  several 
factors  had  to  be  taken  into 
consideration.  The  system 
had  to  be  simple,  foolproof, 
and,  above  all  else,  inex- 
pensive.  There  is  no  logic  in 
providing  an  expensive 
method  for  the  sort  of  thing 
which  a  typical  amateur 
might  wish  to  protect  The 
setup  to  be  described  satis- 
fies all  of  the  foregoing. 

The  heart  of  the  protec- 
tive circuit  lies  in  the  utili- 
zation of  a  surplus  24-volt 
dc  relay.  These  are  widely 
available  at  low  cost.  If 
such  a  relay  can  be  incorpo- 
rated into  a  simple  circuit, 
then  we  should  end  up  with 
a  satisfactory  combination 
for  taking  care  of  ac  over- 
loads. 

Refer  to  Fig.  1 .  Note  that 
we  have  incorporated  a  sur- 
plus 2,5-volt  filament  trans* 
former  of  10-Ampere  rating. 
Since  silicon  diodes  came 
into  play  as  substitutes  for 
mercury-vapor  tubes,  such 
transformers  have  become 
a  drug  on  the  market.  But  a 
suitable  transformer  of  sim- 
ilar ratings  should  serve; 
that  is.  a  low-voltage  sec- 
ondary and  rather  high  cur- 
rent rating. 

Preliminary   experiments 


led  me  to  develop  the  most 
elementary  circuitrv  to  ful- 
fill the  concept,  When  cur- 
rent is  passed  through  the 
2.5-volt  winding  a  current 
will  be  induced  into  the 
120-volt  winding  (now  the 
secondary).  After  rectifying 
and  filtering,  the  dc  voltage 
is  used  to  actuate  the 
24-volt  dc  relay.  The  vari- 
able resistor,  Rr  can  be  ad- 
justed to  allow  various  ac 
currents  to  pass  before  the 
relay  will  trip  and  open  the 
ac  circuit. 

This  will  not  completely 
suffice,  however,  since  the 
relay  will  buzz  back  and 
forth  between  on  and  off 
unless  some  form  of  lock- 
up is  provided.  The  added 
components,  shown  by  dot- 
ted lines,  attend  to  this 
function,  Lock-up  is  ob- 
tained with  lower  current 
than  is  required  for  pull-in, 
and  simple  half-wave  recti- 
fication will  serve.  Reset  is 
furnished  by  opening  the 
switch,  which  is  normally 
closed. 

The  system  that  finally 
evolved  is  shown  in  Fig.  2. 
The  full-wave  bridge  recti- 
fier furnished  more  voltage 
than  the  original  half-wave 
circuit  and  allows  the  relay 
to  trip  out  at  a  lower  cur- 
rent. In  a  thorough  search 
for  a  relay  of  better  suitabil- 
ities, over  a  dozen  relays 
were  checked  out  experi- 
mentally, Finally,  it  was 
decided  to  opt  for  a  rela- 
tively sensitive  unit  which 
has  the  added  advantage  of 
having  three  sets  of  con- 
tacts, all  rated  at  10  Am- 
peres. To  be  on  the  safe 
side,  these  are  wired  in 
parallel. 

My  thoughts  then  were 
directed  to  the  feasibility  of 
obtaining  a  suitable  vari- 
able resistor,  in  order  to  en- 
able the  relay  to  actuate  at 
various  current  settings. 
Easier  said  than  donel 

The  three  principal  cali- 
brating resistors  are  used  in 
place  of  a  'nice  to  have" 
3000-Ohm,  10-Watt  wire- 
wound  potentiometer  The 
5-Watt,  1000-Ohm  size  is  a 

•"See  List  ot  Advertisers  on  page  U4 


fairly  common  item  in  all 
stores  which  cater  to  radio 
and  TV  servicemen.  Addi- 
tional resistors  were  added 
to  cause  the  setup  to  kick 
out  at  2.5,  5,  and  10  Am- 
peres. This  4-to1  range  is  in 
line  with  what  the  commer- 
cial makers  of  such  re- 
lays— West inghouse  for  ex- 
ample—design into  their 
products. 

Other  design  factors 
worth  mentioning  are: 
(a)  The  100-uF  electrolytic 
capacitor  seems  to  be 
about  right  in  this  setup.  A 
lower  value  may  cause  the 
dc  relay  to  buzz,  and  a  high- 
er value  can  cause  a  time 
delay  to  take  place— defi- 
nitely undesirable  in  any 
form  of  protective  circuitry 
where  high  power  is  in- 
volved; and  (b)  Avoid  car- 
bon resistors  in  the 
1000-Ohm  positions.  Care- 
ful checks  show  that  a 
1000-Ohm,  2-Watt  carbon 
resistor  will  be  dissipating 
1 ,6  Watts  or  80%  of  its  full 
value.  This  will  cause  up- 
ward change  in  the  resis- 
tance, and.  indirectly, 
"calibration  creep"  in  the 
finished  instrument 

Random  thoughts  at  this 
juncture:  Others  have 
asked  me  whether  simpler 
devices,  such  as  the  ther 
mal  overload  units  com- 
monly found  on  the  back  of 
TV  sets,  would  suffice. 
These  have  been  tried  and 
their  use  cannot  be  justified 
since  the  time  delay  is  intol- 
erable where  an  expensive 
unit  requires  protection. 
Personally,  I  almost  lost  a 
very  nice  Powers  tat®  while 
attempting  to  live  with  such 
protection. 

Perhaps  solid-state  de- 
vices might  be  designed  to 
furnish  the  same  function?  I 
would  be  disinclined  to  de- 
pend upon  such  a  setup  in 
view  of  the  relatively  high- 
voltage  spikes  which  are  en- 
countered when  a  highly  in- 
ductive component  — such 
as  the  power  transformer  in 
a  large  amateur  rig  — needs 
to  have  its  primary  circuit 
interrupted.    For   that   rea- 


Parts  List 
T—    2.5-voltP  10-A  filament  transformer 
D—   all  diodes  type  1N4007 
C—    100u.Fr  35  volts 

51—  Rotary  switch  with  3  positions 

52—  Momentary-contact  switch,  wired  for  normally-closed 
operation  {Radio  ShacN  275-619} 

K—    Potter  &  Brumfield  type  KUP  14D15  (Fair  Radio  Sales, 

Lima,  Ohio,  $2.50) 
FM-R3— 1000  Ohms,  5-Watt,  wirewound 
R4.  R5— 330  Ohms,  1-Watt 
R6— 15k  Ohms,  1-Watt 
R7—  2700  Ohms,  2-Watt 

Small  cabinet  or  chassis,  3-wireac  cord,  and  5- way  output  ter- 
minals 


son,  I  chose  1000-volt  sili- 
con diodes,  type  1N4Q07, 
for  service  in  this  unit 

So  we  have  an  ac  over- 
load relay  which  is  simple, 
inexpensive,  and  depend- 
able Furthermore,  it  can  be 
calibrated  to  kick  out  at 
several  different  amperages 
at  the  flick  of  a  switch.  I 
have  yet  to  see  such  a  sim- 
ple item  described  in  print, 
and  I  thought  it  would  be 
nice  to  share  this  knowl- 
edge with  other  members 
of  the  amateur  fraternity. 
So,  why  not  try  this  out  and 


experiment  at  ease,  without 
blowing  box  after  box  of 
fuses? 

All  of  the  foregoing  cali- 
brations were  obtained  with 
ac  loads  consisting  of  non- 
inductive  heater  coils.  If 
your  circuit  to  be  protect- 
ed is  highly  reactive,  you 
may  find  the  relay  kickout 
points  to  be  slightly  dif- 
ferent. ■ 

Reference 

1.  "Son  of  the  Overload  Relay/ ' 
73  Magazine,  January,  1977,  p. 
140. 


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ceivers Suggested  list  prtce  tor  all  models  is  $1995  the  most 
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DESCRIPTION 


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191-214     2  M.  BNC  connector 
191-219     2  Mt  PL  259  connector 


P/N  DESCRIPTION 

191-800  Wi  M,  5/16-32  stud 

191-814  VA  M,  RNC  connector 

191-819  1  %  M.  PL-259  connector 


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73  Magazine  *  August,  1982     53 


Bob  Roehrig  K9EUI 
314  5,  Harrison  Street 
Batavia  fi  60510 


Multi-Purpose  Peak  Adapter 

don't  settle  for  being  average 


This  adapter  was  origi- 
nally designed  to  be 
used  with  a  Bird  43  watt- 
meter, using  the  standard 
plug-in  elements;  however, 
this  same  unit  can  be  modi- 
fied for  use  with  almost  any 
rf  detector  or  swr  bridge. 
Circuits  can  be  easily  added 
to  provide  an  adjustable 
peak    output    indicator 


and/or  an  ale  output  for 
transmitter  control.  The 
peak  adapter  circuit  also 
can  be  used  with  an  FM 
receiver  as  a  peak-deviation 
meter.  Easily-obtainable 
parts  are  used  and  while  I 
built  mine  in  a  separate 
box,  you  might  be  able  to 
build  it  into  your  meter 
enclosure,  The  ICs  must  be 


-9V  > 


Fig.  1.  Peak  adapter.  Alt  ICs  are  MCI 458  dual  op  amps 
(Radio  Shack  276-038);  resistors  are  1/4-Watt;  57  is  a  DPDT 
miniature  toggle;  P1  is  a  Radio  Shack  274-139. 

54     73 Magazine  *  August,  1982 


kept  away  from  high  rf 
levels,  however.  The  peak 
adapter  circuit  is  shown  in 
Rg.1. 

The  unit  must  be  pow- 
ered from  a  bipolar  supply 
of  ±  6  to  ±15  volts  or  from 
a  pair  of  9-volt  batteries  If 
extended  use  of  the  adapter 
is  anticipated,  the  ac  supply 
shown  in  Fig.  2  should  be 
used.  Regulation  is  not 
totally  necessary,  but  does 
ensure  minimum  offsets 
and  prevents  transients 
from  entering  critical  cir- 
cuits 


POWER 


FUSE 


3Hh 


I00V 

4  A  BRIDGE 

Lr 


AC 


AC 


Tl 
24VTC 

li'ZA 


The  main  purpose  of  the 
peak  detector  circuit  is  to 
overcome  the  main  fault  of 
a  meter  when  trying  to  in- 
dicate peaks:  the  mass  of 
the  movement  damps  the 
response  time  such  that 
variations  of  the  applied 
current  are  averaged  out. 
The  more  sensitive  the 
movement,  the  worse  the 
damping  effect.  The  Bird  43 
uses  a  3G-jiA  movement  and 
most  swr  bridges  use  a  50- 
to  200-^A  meter. 

Even  with  the  peak  de- 
tector, the  meter  will  still 


i 


fri 

I50Q 
I/2W 
^w* •- 


Cl 

470* 

33Y 


F« 


470 
S5V 


CR2 
1N4739      ; 

<W  2EKER 


R2 
140Q 

trtm 


|W 

M # — — 


CRS 
IN4739      ; 

IV 
ZENEfl 


**9V 


C3 

50V  01SC 


~f" 


ZHC 


C4 

50V    DISC 


-9V 


Fig.  2<  Power  supply  schematic.  CR1  =  Radio  Shack 
276-7  7  77;  CR2,3^RS  276-562;  C1,2  =  RS  272-1018; 
C3f4  =  RS  272-135. 


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73  Magazine  •  August.  1982    55 


take  the  same  amount  of 
time  to  respond  to  its  high- 
est level,  but  the  circuit  has 
a  long  enough  time  con- 
stant to  ensure  that  the 
pointer  will  remain  at  the 
peak  level  long  enough  to 
be  observed.  The  Bird  43 
elements  contain  a  half- 
wave  detector  (+  output) 
and  a  small  capacitor  to  by- 
pass the  rf.  Internal  resis- 
tance of  the  30-jiA  meter  is 
1500  Ohmsr  so  to  ensure 
proper  linearity,  the  input 
of  the  peak  adapter  pre- 
sents a  1500-Ohm  load  to 
the  element 


Circuit  Description 

The  first  two  stages  are 
standard  inverting  dc  am- 
plifiers Each  stage  has  a 
gain  of  10  for  a  total  of  100. 
Thus,  a  full-scale  input  level 
of  45  mV  results  in  an  out- 
put of  4.5  V  dc  IC2A  is  a 
unity-gain  half-wave  detec- 
tor. The  diode's  placement 
in  the  feedback  loop  elimi- 
nates the  error  due  to  its 
600-mV  drop,  The  input  im- 
pedance of  IC2A  is  high,  so 
the  discharge  time  constant 
is  essentially  determined  by 
R7.  The  output  impedance 
of  IC2A  is  less  than  100 
Ohms,  so  the  charge  time  of 
C1  is  almost  instantaneous. 
IC2B  is  a  unity-gain  follow- 
er configuration  used  to 
isolate  the  load  from  CI. 
Amplifying  the  input  signal 
by  100  ensures  overcoming 
any  low-level  non-linearity 
in  CR1 ,  R8  and  R9  divide  the 
output  back  down  to  a  level 
required  to  feed  the  meter. 

Fig,  3(a)  shows  the  origi- 
nal circuit  in  the  Bird  43. 
The  meter  connects  direct- 
ly to  the  output  of  the  direc- 
tional coupler  through  a 
length  of  coax  cable.  The 
length  is  not  critical  and  is 
supplied  as  a  convenience 
to  permit  remote  mounting 
of  the  directional  coupler. 

Fig,  3(b)  shows  the  jack 
added  to  the  Bird  meter  to 
permit  connecting  the  peak 
adapter.  I  mounted  the  jack 
on  the  right  side  of  the  case, 
(Remove  the  meter  move- 

56     73Magazlne  •  August,  1982 


ment  before  drilling  the 
3/8"  hole!)  The  jack  is  a 
3-conductor,  V4"-type  with 
shorting  contacts  (Radio 
Shack  part  number  274- 
139).  The  shorting  contacts 
connect  the  meter  to  the 
coupler  when  the  remote 
plug  is  removed,  so  no 
switch  is  necessary.  Use  the 
"ring"  connection  for  the 
meter  and  the  "tip"  for  the 
coupler  output,  Break  the 
connection  at  the  positive 
lug  of  the  meter.  Even 
though  the  jack  is  grounded 
to  the  case,  it  is  a  good  idea 
to  run  a  wire  from  the  nega- 
tive meter  terminal  to  the 
"sleeve"  connection  of  the 
jack. 

Calibration  is  easily  ac- 
complished by  connecting 
the  meter  between  the 
transmitter  and  a  50-Ohm 
load.  Measure  the  power 
output  with  a  steady  carrier 
(preferably  at  least  half- 
scale).  Switch  on  the  peak 
detector  circuit  and  adjust 
R9  for  a  reading  of  1 .4  times 
the  first  reading.  The  meter 
now  is  calibrated  to  read 
peak  power  output  (with  a 
load  impedance  of  50 
Ohms). 

PEP  output  is  defined  as 
the  peak-to-peak  level  of 
the  output  signal.  It  is  not 
practical  to  have  the  meter 
read  this  since  it  would  be 
necessary  to  change  to  the 
next  higher  element.  R9 
could  be  adjusted  so  the 
PEP  would  be  read  on  the 
next  higher  scale  using  the 
same  element,  however, 
damage  to  the  element 
could  occur  since  it  would 
be  used  outside  its  normal 
range. 

When  observing  a  voice- 
produced  5SB  signal,  you 
will  have  to  talk  for  several 
seconds  to  allow  time  for 
the  meter  movement  to  re- 
spond, A  longer  "hang" 
time  can  be  obtained  by  in- 
creasing the  value  of  CI. 

The  output  of  an  swr 
bridge  is  similar  to  the  Bird 
elements  but  the  load  im- 
pedance is  usually  higher. 
To  use  the  peak  detector 
with   an   swr   bridge,   or  a 


BIRD  43 
DIRECT  10*  &L 
COUPLER 


£ 


COAX 


trj 


30m*  METER 


30*  A  METER 


— i 


BIRD  43 

DIRECTIONAL 

COUPLER 


COAX 


W 


Fig.  3.  (a)  Original  Bird  43  hookup,  (b)  Modified  hookup  us- 
ing Radio  Shack  274-27?  for  }1, 


detector  like  the  one  in  the 
Heath  Cantenna®,  change 
the  circuit  of  IC1A  to  that 
shown  in  Fig.  4.  You  will 
have  to  calibrate  the  meter 
at  several  different  power 
levels.  The  dc  output 
voltage  of  a  bridge  detec- 
tor, and  the  detector  in  the 
Cantenna,  drops  with  a 
decrease  in  frequency,  so 
calibration  at  several  fre- 
quencies in  each  band  is 
desired.  Calibration  must 
be  done  with  the  aid  of  a 
borrowed  wattmeter,  an  rf 
ammeter  or  voltmeter,  or  a 
wideband  scope  that  has  a 
vertical  amplifier  response 
flat  to  at  least  30  MHz, 

When  using  the  peak 
adapter  with  a  device  like 
the  Cantenna,  you  will  have 
to  furnish  a  meter  for  the 
adapter.  Any  movement  up 
to  S  mA  can  be  used  or  a 
VOM  on  the  2.5-  or  3-volt  dc 
range.  Just  be  sure  that  the 
VOM  you  use  will  not  de- 
tect rf  by  itself.  If  you  use  a 
1-mA  meter,  you  can  elimi- 
nate R9  and  use  a  3.9k  resis- 
tor for  R8,  Calibration  can 
be  done  with  R19.  A  typical 
swr  bridge  circuit  is  shown 
in  Fig.  5+ 

At  a  power  of  100  Watts 
rms  into  the  Cantenna,  I  ob- 
tained the  following  read- 


TERWINATING 
RESISTORS 


-* 


■» 


FROM 
StA 


1 


R19 

lOOK 
SENS 


fh 


Rl 
1004 


RZ 
IQOI 


1> 


rh 


TO 


£fi3 
>  IOOK 


fig.  4.  High-impedance  peak 

adapter. 


ings  from 

the 

Cantenna's 

detector: 

Band 

Dc  Volts 

160 

0.8 

80 

10 

40 

14 

20 

2.0 

15 

2,5 

10 

3.0 

The  circuit  of  Fig.  6  is  a 
peak-indicator  driver  with 
adjustable  threshold  con- 
trol R10  is  adjusted  with  a 
steady  carrier  to  light  the 
LED  at  the  desired  power 
level. 

Ale  voltage  can  be  ap- 
plied to  most  mixers  or  in- 
termediate stages  in  a  trans- 
mitter to  reduce  the  rf  level 
before  the  output  stage  is 
driven  into  the  non-linear 
region.  The  ale  voltage  can 
be  developed  by  adding  the 
circuit  in  Fig.  7.  It  even  can 
be  useful  for  transmitters 
that  already  have  ale  be- 
cause gain  reduction  can  be 


/77 


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m 


m 


m 


fig.  5.  Typical  swr  bridge. 


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73Magazine  *  August,  1982     57 


TO  IC2 
PIN  7 


100* 


3> 


Rt3 

560 


LED 


■®- 


RM 
IOOK 

RIO 

10* 


-WV 


J 


TH«ESH0u0 


fig.  6.  V/sua/  peak  indicator 


TO  1C2 

PIN  T    ' 


It  1+ 
■OK 
GAlH  1 


Rig 

IOOK 


/* 


CP2 
1*914 


TO  TRANSMIT TQfl 
ALC  LINE 


RI7 
IOOK 

RIB 
IOK 


*9V 


wv- 


i 


THRESHOLD 


Fig.  7.  A/c  detector. 


had  at  a  lower  level.  (Many 
transmitters  develop  ale 
voltage  when  grid  current  is 
drawn,  at  which  point  dis- 
tortion is  already  occurring,] 
With  R18  at  the  ground  end, 
ale  will  be  developed  as 
soon  as  there  is  rf  input.  R14 
determines  the  amount  of 
voltage  output  Increasing 
R18  towards  +V  permits  a 


higher  rf  level  before  ale 
starts  to  develop,  CR2 
keeps  any  positive  voltage 
from  reaching  the  ale  line. 

Both  the  circuits  of  Fig.  6 
and  7  can  be  connected  to 
IC2  simultaneously  without 
any  interaction.  Again, 
change  the  value  of  C1  if 
you  wish  to  change  the  time 


constant.  Most  likely,  you 
will  want  to  reduce  C1  to 
0.2  to  05  jiF  for  ale  pur- 
poses. A  switch  may  be  add- 
ed to  Fig.  1  to  select  various 
values  for  CI. 

Another  use  for  the  peak 
detector  circuit  is  to  use  it 
in  conjunction  with  an  FM 
receiver  as  a  peak-deviation 
meter.  Using  the  Fig.  4  mod- 
ification, connect  R19  to 
the  output  of  the  discrimi- 
nator through  a  Q/l-jiF  ca- 
pacitor. Calibration  can  be 
done  best  using  a  signal 
generator  with  calibrated 
FM  modulation  If  C1  is 
switched  out  of  the  circuit, 
the  meter  will  then  read 
average  deviation.  This 
may  be  useful  to  show  how 
much  the  transmitted  audio 
is  limited  in  the  peak  clip- 
per. In  any  case,  the  read- 
ings will  only  be  correct  if 
the  received  signal  is  full 
quieting.  A  scope  may  be 
connected  to  the  output  of 
IC1B  for  viewing  the  audio 
signal 


If  you  have  looked  at  the 
proposed  rewrite  of  the  am- 
ateur rules,  you  noticed 
that  the  FCC  is  trying  to 
come  up  with  a  different 
way  to  determine  transmit- 
ter power,  other  than  the 
present  doinput  method. 
This  peak  adapter  can  be  an 
invaluable  aid,  should  pow- 
er determination  need  to  be 
in  terms  of  peak  power.  Per- 
sonally, I  would  like  the 
rules  to  be  changed  to  pow- 
er output  measurements,  as 
is  done  commercially.  This 
could  then  permit  less  effi- 
cient transmitters  to  run  at 
a  higher  input  power.  We 
also  would  have  a  better 
idea  of  the  efficiency  of  our 
equipment  which  would  in- 
dicate when  the  finals  are 
getting  "soft." 

This  circuit  can  make 
your  wattmeter  into  a  more 
useful  instrument  at  a  frac- 
tion of  the  cost  of  a  ready- 
made  peak-reading  unit  and 
serve  other  purposes  as 
well. I 


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See  List  of  Atfvwtfsets  on  page  IN 


73 Magazine  •  August,  1982     59 


The  $100  TVRO  Receiver 

Satellite  Central,  part  VIII 


Stephen  Gibson 
PO  Box  38386 
Hollywood  CA  90038 


Dwight  "Rex"  Rexroad  with  his  Cheap  Trick  receiver. 
60     73 Magazine  *  August J982 


//^ee  first  run  movies, 
i3  sporting  events,  and 
nightclub  acts  as  secret  net- 
work feeds!"  That's  the  sort 
of  ballyhoo  you  read  about 
satellite  television  now- 
adays. But  the  price  for 
even  a  kit  setup  can  run  sky 
high!  The  only  way  to  cut 
the  cost  is  for  you  to  do  it 
all  yourself. 

But  those  build-it-your- 
self  pitfalls  can  leave  you 
wishing  you'd  never  tried. 
For  one  thing,  you're  on 
your  own  with  only  plans 
that  are  vague  or,  even 
worse,  a  set  of  PC  boards 
that  won't  work.  Sor  being 
first  on  your  block  seems  to 
carry  its  own  set  of  prob- 
lems. What  you  need  is  a 

Cheap  Trick"! 
In  the  December,  1981, 

Satellite  Central/'  I  wrote 
a  brief  overview  of  TVRO 
receiver    design.    If    you 


41 


41 


priced  some  of  the  compo- 
nents, you  know  that  a  re- 
ceiver, especially  a  dual- 
conversion  job,  will  cost 
$500  to  $700  to  build  And, 
if  you  want  real  quality 
you'd  better  plan  on  spend- 
ing more  So  how  can  some- 
thing any  good  cost  less?  As 
a  matter  of  fact,  just  a  volt- 
age-tuned oscillator  (VTO) 
runs  a  hundred  bucks!  So 
who's  kidding  whom? 

But  hold  on  there.  Just 
when  you  think  it  isn't  pos- 
sible, along  comes  a  very 
clever  engineer  like  Dwight 
(Rex)  Rexroad  who  does  it 
with  a  flair  that  shows  that 
hobbyist  thinking  and  inge- 
nuity hasn't  stagnated  after 
all.  "The  secret  here/'  says 
Rex,  "is  to  make  the  design 
non-critical  and  to  use  parts 
that  anyone  can  find  with 
ease.  Nothing  in  this  design 
is  weird.  Everything  is  off 


the  shelf "  Out  of  Rex's 
unique  approach  comes 
"Cheap  Trick/'  the  ham's 
answer  to  a  TVRO  receiver 
you  can  build  for  under 
$100! 

Cheaper  Is  Better 

Look  at  the  diagram  in 
Fig.  1(a);  Rex  downconverts 
all  twelve  transponders  on 
a  satellite (37  to  4.2  GHz)  to 
the  500-  to  1000-MHz  re- 
gion where  he  can  use 
cheaper  components.  He 
uses  a  fixed-frequency  local 
oscillator  (LO),  a  mixer,  and 
a  broadband  amplifier,  all 
of  which  may  be  mounted 
at  the  dish  in  a  small  box 
The  advantage  to  this  ar- 
rangement is  that  the  lower- 
frequency  signals  can  be 
passed  into  your  house  via 
RG-59  or  RG-6  rather  than 
expensive  cable  needed  for 
piping  4-GHz  signals, 

No  tuning  is  done  in  the 
first  conversion  — see  Fig. 
1(b).  Instead,  tuning  is  ap- 
plied at  the  second  conver- 
sion by  another  cheap  trick, 
a  UHF  TV  tuner.  The  saving 
is  enormous,  especially 
since  the  tuner  needs  very 
few  changes  to  make  it  pass 
30-MHz-wide  signals  to  a 
70-MHz  bandpass  filter  and 
rntermediate  frequency  (i-f) 
amplifier  Despite  its  re- 
duced performance  at  70 
MHz,  Rex  uses  a  typical  TV 
hf  IC,  the  MC1350.lt  s  a  log- 
ical choice  for  the  i-f  ampli- 
fier because  of  its  low  price 
and  easy  availability.  Ra- 
zor-sharp tuning  is  easily 
accomplished  using  just 
two  op  amps  with  a  solid 
afc  thrown  in  to  boot 

The  amplified  70-MHz  i-f 
signals  are  halved  to  30 
MHz  by  a  divide-by-two  cir- 
cuit and  applied  to  an 
MCI  357  quadrature  detec- 
tor IC  which,  with  suitable 
input,  can  deliver  pictures 
that  may  exceed  in  excel- 
lence those  of  a  PLL-type 
detector.  The  detected  vid- 
eo is  clamped  and  de-em- 
phasized before  output  to 
your  TV  monitor  or  modula- 
tor. The  sound  demodula- 


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oscillator. 


tor  uses  circuitry  similar  to 
that  found  in  most  televi- 
sion sets. 

Power  Supply  and 
Downconverter 

This  month,  we'll  delve 
into  the  power  supply  and 
clever  downconverter  de- 
sign and  save  the  baseband 
circuits  for  next  month.  It 
should  be  remembered  that 
this  project  is  labor-inten- 
sive. If  you  just  want  to 
watch  satellite  television, 
then  you  really  should  buy 
a  receiver  rather  than  fiddle 


with    the    "Cheap    Trick  ' 
Some    of    the    techniques 
used  here  will  surely  chal- 
lenge   your    experimenting 
abilities. 

According  to  Rexr  "The 
power  supply  is  not  quite 
typical .  .  but  close.  I  use  a 
26-volt,  1-Ampere  trans- 
former that  is  center- 
tapped.  This  is  a  common 
transformer.  Radio  Shack 
has  them.  [Rex  needed  30 
volts  for  tuning  and  took 
the  easy  way  with  an  LM31 7 
adjustable  voltage  regula- 
tor—see Fig.  2]  I  found  that 


bypassing  the  LM31 7  got  rid 
of  a  lot  of  noise,  especially 
since  we  are  dealing  with 
the  tuning  voltage  where 
noise  could  easily  FM  your 
tuner!  It's  clean  as  a  whis- 
tle." 

The  really  clever  tech- 
nique used  here  is  to  raise 
the  centertap  to  get  about 
half  the  voltage  (1 8  volts)  to 
feed  the  LNA-down convert- 
er combination.  A  7812  reg- 
ulates it  down  to  12  volts  to 
feed  the  rest  of  the  receiver. 
While  Rex  admits  this  is  not 
an    optimum    design    bal- 

73Magazine  *  August.  1982    61 


ance-wise,  it  offers  some- 
thing more  important:  It's 
cheap! 

Looking  now  at  the 
downconverter  in  Fig.  3, 
Rex  built  the  whole  unit  on 
a  piece  of  double-sided  %t" 
Teflon™  fiberglass,  In  true 
one-of-a-kind  experimenter 
fashion,  he  used  only  an 
X-acto®  knife  to  cut  out  the 
prototype.  You  can,  too. 
The  board  is  only  4  inches 
long,  so  the  input  and  out- 
put connectors  are  all  that 
are  needed  to  attach  the 
board  to  the  top  of  a  sealed 
metal  case. 

The  circuit  includes  a  dc 
block  so  that  both  the 
downconverter  and  the 
LIMA  can  receive  their  sup- 
ply voltage  through  the  sig- 
nal coax.  Beginning  at  the 
input.  Rex  uses  a  type-N 
connector  since  that's 
about  the  only  thing  that 
works  well  at  these  frequen- 
cies. An  rf  choke,  .  .which 
is  nothing  more  than  a  short 
piece  of  wire  at  4  GHz, 
feeds  dc  to  the  LNA. 

'We  do  a  little  bypassing 


with  two  chip  caps  — a 
4.7-pF  and  a  ,001-mF  work 
pretty  well  at  these  fre- 
quencies- I  bypass  darned 
near  everything  because 
stability  is  very  important. 
Especially  when  you  home 
brew/'  he  says.  , 

"I  used  a  fixed- tuned 
MRF9G1  for  the  oscillator 
so  that  I  could  save  big 
bucks  right  there!  The  real 
credit  for  this  stable  design 
belongs  to  BBC  engineer 
Steve  Birkill.  The  oscillator 
runs  at  3  2  GHz  (downside 
injection)  and  is  easily  set 
by  trimming  the  length  of 
the  baseline  with  a  knife. 

"I  used  a  7812  voltage 
regulator,  but  a  78L12 
would  also  work  since  we 
need  only  about  1 5  mA,  The 
2N2905  is  a  PNP  transistor 
that  acts  as  an  active  bias 
for  the  oscillator  It's  the 
negative  feedback  loop 
that  makes  this  trick  work- 
in  fact,  it  may  be  more  sta- 
ble than  expensive  pre- 
packaged oscillators  if  you 
use  good  construction  tech- 
nique.    And    don't    think 


FUSE 
QHrQFF      QSL 

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OPTIMAL 

U5VAC  -F^~ 
INPUT    U1    I 


f *+AOV 


Fig.  2,  The  power  supply  furnishes  +  30,  +  18,  and  +t2  volts  dc, 
62     73 Magazine  •  August.  1982 


Fig,  3,  The  mixer,  MRF-901  oscillator,  and  broadband  ampli- 
fier fit  on  a  homemade  PC  board. 

This  may  not  be  a  problem 
if  you  use  a  large  dish  and  a 
commercial  LNA. 

The  NEC  MC5121  broad^ 
band  amp  is  the  most  ex- 
pensive part  of  the  whole 
receiver  It  costs  about 
$13.30  from  Alaska  Micro- 
wave, a  73  advertiser  Kick 
in  another  25  cents  and  you 
can  get  the  spec  sheets,  too 
The  MC5121  will  give  you 
about  20-dB  gain,  so  the 
overall  converter  gain  is 
about  14  dB  not  counting 
coax  losses.  Either  a  BNC  or 
type-F  connector  will  work 
on  the  output  since  the 
signal  is  now  running 
somewhere  between  500 
and  1000  MHz.  On  a  typical 
system,  you  can  tolerate 
about  15-dB  loss  from  the 
coax  feeding  the  baseband 
unit  The  +15  to  +20  volts 
of  power  for  the  converter 
is  tapped  off  the  output 
coax  with  a  6-turn  choke 
and  some  dc  bypassing. 
There  is  no  coupling 
capacitor  on  the  MC5121 
since  it  has  its  own  internal 
caps. 

Making  It  Work 

Probably  the  hardest  part 
of  this  project  will  be  ac- 
quiring the  parts  Yes,  you 
can  do  it  for  less  than  $100. 
In  fact,  Rex  built  his  for 
$75,00! 

Dropping  down  in  the 
scale  of  hardness,  we  come 
to  troubleshooting.  Accord- 
ing to  Rex:  "A  spectrum  an- 
alyzer helps.  Use  a  micro- 


you're  locked  into  a 
2N2905,  Any  other  silicon 
PNP  of  the  same  beta 
should  work  just  as  well/' 

The  oscillator  will  come 
out  low  in  frequency  using 
the  layout  size  in  Fig.  4. 
That  way,  you  can  simply 
use  a  knife  to  chop  away 
enough  trace  to  put  it  right 
on.  The  line  from  the  oscil- 
lator is  a  50-Ohm  stripline. 
Both  the  oscillator  and  in- 
put signal  feed  a  balanced 
stripline  mixer  which  has 
about  7-dB  insertion  loss 
depending  on  the  diodes. 
Now,  rather  than  use  a 
$55.00  mixer,  Rex  literally 
chose  to  roll  his  own.  He 
uses  HN-1  diodes  at  about 
$2,00  each.  Quite  a  saving! 
It  really  doesn't  matter  how 
you  install  the  diodes;  just 
be  sure  they  are  backwards 
or  you'll  have  a  problem  If 
you  use  the  popular 
MBD-101  diodes,  you  may 
have  to  deal  with  slightly 
more  noise  out  of  the  mixer. 


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wave  frequency  counter  at- 
tached to  the  hybrid  to  tune  , 
the  LO.  Not  everyone  has 
one,  so  I  suggest  you  simply 
apply  power  to  the  unit  and 
tweak  the  oscillator  until 
the  bottom  frequency  cor- 
responds to  transponder 
one.  You'll  need  a  dish  and 
an  LNA  that  are  working  to 
do  it 

"One  thing  thafs  nice: 
Being  off  100  MHz  in  either 
direction  will  get  you  in  the 
ball  park  enough  to  trim  it 
up.  Of  course,  having  a 
friend  with  another  TVRO 
always  helps/' 

tt  is  possible  that  the  LO 
will  not  be  stable  or,  worse, 
may  not  start  at  all.  In  that 
event,  Rex  suggests  you 
move  the  shorting  strip  seen 
in  Fig.  5.  Do  a  tack-solder 
job.  You  may  find  a  region 
where  the  oscillator  is  oper- 
ating on  many  frequencies 
at  once.  It  makes  for  rotten 
pictures,  so  move  the  short- 
ing strip  to  cure  the  prob- 
lem. Trial  and  error  are  the 
only  ways  to  do  the  trim- 
ming without  an  analyzer. 

New  Life  for  UHF  Tuners 

Once  the  signal  is  con- 
verted to  the  500-tol 000- 
MHz  range,  it  is  fed  down 
the  coax  into  the  UHF  tun- 
er. Use  top-notch  RG-59  or 
better  No  CB  stuff  Rex 
used  a  Mitsumi  UES-A55F 
which  he  bought  at  a  swap 
meet  for  five  bucks.  See 
Fig.  7.  Various  mail-order 
houses  carry  this  model  for 
something  like  $25.00.  If 
you  do  some  scrounging  for 
other  parts  used  in  this  proj- 
ect, you  still  can  build 
Cheap  Trick  for  less  than 
5100. 

Now,  most  tuners  have  a 
narrow  bandwidth.  So  you 
must  modify  yours  to  pass 
30-MHz-wide  FM  Not  all 
tuners  can  be  modified,  so 
you  should  try  to  track 
down  this  particular  model. 
On  the  other  hand,  if  you've 
stayed  with  us  this  far,  you 
can  probably  handle  any- 
thing that  comes  your  way! 

As  a  rule,  the  i-f  output 
stage  is  the  culprit  See  the 

64     73 Magazine  •  August,  1982 


SCALE    EACH  SQUARE  *  \Qm« 


BOARD    LAYOUT  DOWN  CONVERTER 

3,7*4  2GHz    IN     5OD-IOO0WHI    OUT 

MATERIAL:  I/ 32   ta   THICK  TEFLON 
FIBERGLASS  COPPER  LAMINATED  BOTH 
SIDES    OPPOSITE   SCE  HOT   ETCHED 


Fig.  4.  Circuit  board  layout  tor  downconverter. 


WATERS.  l->Mto.  TFE/naERGLA55 


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Fig.  5.  Parts  placement  for  downconverter. 


"before"  and  "after"  modi- 
fication circuits  in  Figs  8{a) 
and  8(b).  According  to  Rex, 
"I  replaced  the  final  stage 
impedance-matching  net- 
work with  a  broadband 
transformer  wound  on  a  fer- 
rite  bead.  Amidon  101-43 
beads  work  pretty  well.  I 
used  them  everywhere  in 
the  project." 
The   input  stage  should 


also  be  modified  for  a  coax 
input.  Some  models  of  the 
Mitsumi  already  have  a 
75-Ohm  input.  "But  if  you 
were  stuck  with  a  300-Ohm 
model/'  says  Rex,  "just  look 
for  the  place  on  the  board 
called  L1  which  was  de- 
signed for  a  75-Ohm  link. 
You  can  couple  to  it  with  a 
little  ceramic  capacitor  so 
you  can  use  a  tVturn  choke 


to  provide  a  dc  block  to 
feed  the  coax  power  for  the 
downconverter  and  LNA, 
You'll  need  to  drill  a  hole  in 
the  tuner  for  this  feed.  I 
used  a  feedthrough  cap  so 
that  I'd  have  a  place  to 
hook  it. 

"After  these  two  mods, 
the  bandwidth  of  the  tuner 
should  be  about  45  MHz, 
and   it  will  just  cover  the 


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73Magazine  *  August.  1982     65 


Fig.  6.  The  completed  downconverter  is  housed  in  a  water- 
tight box.  The  PC  board  is  held  in  place  by  the  input  and 
output  connectors.  A  heavy  dose  oi  rubber  cement  will 
make  a  good  seal. 


tuning  range  of  all  the  input 
signals  (500  MHz)  with  a  lit- 
tle to  spare.  Here  is  where 
you  must  tweak  the  LO  in 
the  downconverter  so  that 
you  get  all  transponders 
over  the  range  of  the  UHF 
tuner.  It's  harder  to  say  it 
than  do  it,  despite  the  fact 
the  tuning  diodes  don't  give 


you   much  more  than  the 
needed  500-MHz  range." 

Rex  suggests,  "If  you  just 
drop  one  transponder,  then 
diddle  the  tuner  coils.  But  if 
you  drop  two  transponders, 
you'll  need  to  trot  out  to 
the  LO/downconverter  at 
the  dish.  You  may  have  a 
fellow  ham  with  a  frequen- 


Fig.  7.  A  Mitsumi  UES-A55F  UHF  tuner  acts  as  the  second 
converter  with  only  two  mods.  The  hf  output  coil  is  re- 
placed with  a  hand-wound  toroid.  Also,  the  input  matching 
network  is  easily  converted  for  75-Ohm  input  Mount  the 
tuner  inside  the  receiver  chassis. 


cy  counter  in  this  range 
which  should  make  the 
whole  process  very  simple/' 

The  tuner  age  bias  should 
be  about  8  volts.  The  resis- 
tors seen  in  Fig.  1  form  a 
suitable  voltage  divider. 
Eight  volts  is  maximum 
gain. 


Next  Month:  Part  Two 

After  the  tuner  comes 
baseband  processing, 
which  I'll  cover  next  month. 
Rex  uses  some  clever  ideas 
to  make  this  last  part  of  the 
project  look  easy.  In  the 
meantime,  start  hunting  for 
parts.  ■ 


Fig.  8(a).  Mitsumi  VBS-A55F  tuner  prior  to  modification.  (l)Receiving  channels -14-83  ch,  (470-890  MHz).  (2)  P.  IF-  45.75 
MHz;  SJJ.~41.25  MHz.  (3)  Supply  voltage:  87-72  V;  AFC-6S  V;  ACC-0.8  V;  VT-0.5-28  V.  (4)  TR1-3SK53; 
TR2^2SC1070;  TR3-2SC173Q;  DT1-DT4-1SV59.  All  capacitance  values  in  pF;  all  resistance  values  in  Ohms. 

66     TSMagazine  •  August,  1982 


VIDE   BAND  TRANSFORMER 

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73  Magazine   •   August,  1982     67 


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68     73Magazine  *  August,  1982 


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73  Magazine  •  August,  1982     69 


When  R  comes  to 

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RADIO  QSL's . 


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US  or  Foreign  Listings 


1982 


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70     73  Magazine  *  August,  1982 


this  new  KDK  FM2030 

the  best  2  meter  FM  radio  in  the  world? 


*  •  *  UCTO II  •  •  • 


That's  a  pretty  strong  claim  considering  the 
;ompetit«on. 

_et's  look  at  some  of  the  features  .  .  . 

•KDK  continues  the  tradition  of  being  the  ultimate  in  VHF  FM  mobile 
operations.  We  make  maximum  use  of  multiple  function,  multiple  shaft 
controls  and  only  three  sets  of  knobs  are  located  on  the  front  panel. 
Still  many  new  features  have  been  added,  such  as  digital  RIT,  reverse 
button,  memory  channel  readout  number  and  more! 

•The  new  KDK  4  bit  microprocessor  chip  has  in-house  developed 
software  which  makes  all  these  new  features  possible. 

•  Modern  styled  front  panel  with  dials  intelligently  arranged  so  you  can 
best  utilize  the  multi-function,  easy  to  handle  controls.  We  gave  it  a  very 
heavy  textured  paint  finish  that  is  highly  resistant  to  scratching! 

•  Frequency  coverage  143.005  -  148.995  mhz.  S/N  better  than  35  db 
at  1  uv  input.  Better  than  1  uv  at  12  db  SI  NAD.  Squelch  sensitivity 
better  than  .15  uv.  Bandwidth  at  -6db:  ±6khz,  at  -BOdb;  +16khz. 
Image  ratio  better  than  70db.  Double  superhetrodyne.  Transmitter  uses 
variable  reactance  frequency  modulation  with  maximum  deviation  set 
at  ±5khz. 

•RF  power  is  a  good,  clean  no  spurious  signal  of  25  watts  on  high  and 
5  watts  (adjustable)  on  low. 

•  Good  audio  with  the  famous  KDK  audio  output  capability  of  1.5 
watts ...  you  can't  blow  out  our  audio  IC! 

•  Ntcads  for  memory  retention  built  in,  nothing  extra  to  buy.  Disconnect 
the  FM2030  from  the  power  source  and  the  memories  remain! 

•Easy  to  use  mobile  mount  with  instant  disconnect  knohs  for  fast, 
simple  removal  DC  Cable  and  mounting  hardware,  spare  fuse,  external 
speaker  plug  and  complete  simplified  instruction  book  includes  circuit 
diagrams  and  even  complete  alignment  instructions!  No  extras  to  purchase! 


$309 


INTRODUCTORY  PRICE! 

Includes  Tone  Pad  Microphone 

and  all  accessories.  Shipping:   $5.00  eastern  LLS. A.  $7.50  western  U.S.A. 

•  10  memories  in  2  memory  banks  of  5  each  (A&B).  Any  memory  can 
be  changed  instantly. 

•Control  functions:  Select  memories,  show  memory  channel  number, 
or  select  memories  and  show  frequency  of  channel,  or  dial  frequencies 
with  two  speed  selectable  control.  Instant  choice  of  either  5  or  100  khz 
tuning  steps.  Programmable  band  scan  limits  and  memory  scan. 

•  Frequency  shown  in  5  bright  LED  digits.  LED  indicator  shows  when 
signal  is  received  (unsquefched),  LED  indicator  shows  transmit.  Modern 
LED  bar  meter  shows  signal  strength  of  received  signal  and  on  transmit 
shows  relative  output  power. 

•  Microphone  includes  tone  pad,  and  up  and  down  buttons  to  change 
dial  frequency  or  memory  channels. 

•A  standard  microphone  with  up-down  buttons  only  is  available 
separately. 

•  The  FM  2030  is  basically  as  easy  to  use  as  a  crystal  receiver  with 
rotary  switch  frequency  selection  for  full  "eyes-on-the-road"  mobile 
Operation. 

•  And,  in  case  we  forgot  to  mention  it,  we  are  proud  to  continue  our 
famous  KDK  quality  and  rugged ness! 

•  Smaller  case  size:  55mm  (2  3/16")  high,  t62mm  (6  3/8")  wide, 
182mm  (  7  3/16")  deep. 


WORLD'S  FAIR  NEWS1   KDK  2  meter  radios  are  the  only  FM 
units  chosen  to  be  used  at  the  World's  Fair  Ham  Station! 


NOW  YOU  HAVE  JUST  SOME  OF  THE  FEATURES . . .  ITS  UP  TO  YOU  TO  DECIDE! 


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George  L  Thurston  Hi  W4MLE 
2116  Cibbs  Drive 
Tallahassee  FL  32303 


VUM:  Volume  Units  Meter 

makes  measuring  decibels  easy 


Have  you  ever  won- 
dered if  the  audio  fil- 
ter in  your  CW  receiver  is 
really  as  sharp  as  it  is  sup- 
posed to  be?  What's  the  fre- 
quency response  of  your 
stereo  amplifier?  How 
much  insertion  loss  do  you 
get  when  you  stick  that  au- 
dio filter  into  that  line? 
What's  the  trouble  in  that 
malfunctioning  audio  am- 
plifier? 

If  you're  a  good  trouble- 
shooter,  you  can  answer 
most  of  those  questions 
with  a  scope,  an  audio  oscil- 
lator, a  VOM,  and  a  calcu- 
lator, but  you  can't  do  it 
either  quickly  or  easily. 


But  a  handy  little  device 
has  been  sitting  on  my 
bench  for  years  which  pro- 
vides the  answers  quickly 
and  accurately.  It  gets 
almost  as  much  use  as  the 
VOM  and  a  lot  more  use 
than  the  grid-dipper,  and  it 
costs  very  little  to  build. 

Let's  call  it,  affectionate- 
ly, the  V-U-M,  for  lack  of  a 
fancier  term.  Some  elec- 
tronics manufacturers 
make  similar  instruments 
which  they  call  a  "gain 
meter/'  and  they  have  a 
very  fancy  price. 

Basically,  the  VUM  is  an 
audio  amplifier  which  has  a 
calibrated  step  attenuator 


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on  the  input  and  an  audio 
voltmeter  calibrated  in 
decibels  on  the  output.  The 
meter  itself  is  commonly 
seen  on  audio  equipment  of 
all  kinds,  such  as  good- 
quality  tape  decks,  audio 
consoles,  and  such,  and  it 
goes  by  the  name  of  "VU 
meter/' 

That's  because  it  was 
originally  devised  for  the 
broadcast  industry  to  moni- 
tor 'Volume  units"  of  com- 
plex voice  and  music  wave- 
forms so  that  audio  input  to 
an  AM  transmitter  could  be 
held  within  reasonable 
limits  by  the  audio  engineer 
"riding  gain"  on  the  pro- 
gram. In  that  sort  of  situa- 


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Fig.  T.  The  VUM  (volume  units  meter),  or  calibrated  audio  dB  meter. 

72     73  Magazine  •  August,  1982 


tion,  one  'Volume  unit"  on- 
ly approximates  one  deci- 
bel But  when  sine  waves 
are  used,  as  they  are  in  vir- 
tually all  applications  of 
the  VUM,  one  VU  exactly 
equals  one  dB. 

These  meters  often  can 
be  picked  up  on  the  ama- 
teur market  or  at  harnfests 
for  a  buck  or  two.  They're 
available  from  most  parts 
houses  for  anywhere  from 
56  to  as  much  as  $125,  de- 
pending on  how  big  they 
are  and  how  fancy  they  get. 
Mine  was  rescued  from  a 
lightning-damaged  Heath 
phone  patch. 

When  using  the  VUM  to 
solve  bench  or  design  prob- 
lems, it  is  important  to  un- 
derstand something  about 
that  interesting  little  ani- 
mal, the  decibel  It  is  a  unit 
of  measurement  of  power, 
voltage,  or  current  but  you 
can't  stick  a  VUM  probe  in- 
to an  amplifier  and  say, 
"Ah-ha!  It  reads  one  dB!" 
That's  like  spotting  a  hitch- 
hiker on  the  road  and  ex- 
claiming, "Ah-ha I  He's  gone 
about  halfway!" 

Halfway  from  where  to 
where? 

A  decibel  is  a  measure  of 
comparison.  It  is  a  ratio.  It 
is  used  to  state  the  dif- 
ference between  one  level 
of  energy  and  another. 

It  is  also  a  rather  com- 


plex  little  animal.  It  is  not 
linear;  it  is  exponential  in 
nature.  If  you  increase  your 
transmitter  output  from  10 
Watts  to  20  Watts,  the  dif- 
ference is  3  dB.  If  you  in- 
crease it  again,  from  20 
Watts  to  40,  the  difference 
is  again  3  dB,  Ten  Watts  to 
40  Watts  is  6  dB,  or  two 
3-dB  steps. 

If  you  increase  line  volt- 
age  from  120  volts  to  240 
volts,  however,  the  increase 
is  6  dB.  The  basic  formula 
for  determining  the  dB  dif- 
ference between  two  volt- 
ages or  between  two  cur- 
rents is:  dB  =  20  logV2/V1. 

Now,  let's  have  another 
look  at  the  VUM,  this  time 
in  a  little  more  detail.  It  is  a 
convenient  package  of  sev- 
eral different  units: 

•  A  voltage  divider  resis- 
tor string  in  which  each  tap 
on  the  divider  provides  10 
dB  less  signal  than  the  one 
above  it. 

•  An  audio  amplifier 
whose  input  is  taken  from 
the  taps  on  the  voltage 
divider  and  which  drives 
the  VU  meter, 

•  A  separate  audio  amplifi- 
er to  let  you  hear  what 
you're  measuring. 

Additionally,  you  will 
need  a  variable-frequency 
audio  oscillator  with  ad- 
justable output  level.  This 
easily  can  be  built  into  the 
VUM  as  an  integral  part  of 
the  same  package  if  you 
don't  already  have  such  an 
oscillator.  It  can  be  a  fairly 
simple  oscillator,  covering 
the  rapge  from,  say,  50  Hz 
to  20  kHz,  built  with  ICs. 
But  there  are  plenty  of  con- 
struction articles  about 
these  units  and  I  won't  get 
into  that  project  here. 

Essentially,  the  audio  os- 
cillator provides  a  tone  of 
measurable  strength  and 
approximately-known  fre- 
quency and  the  VUM  mea- 
sures what  happens  to  that 
tone  as  it  passes  through 
amplifiers,  filters,  attenua- 
tors, and  other  exotic  de- 
vices used  by  hams  and  au- 
diophiles. 

In  my  VUM  (Fig.  1),  the 


audio  amplifiers  are  LM386 
IC  chips  [available  from 
Radio  Shack  for  about  one 
dollar  each),  which  put  out 
a  potent  little  400  mW  and 
have  a  very  wide  frequency 
response,  from  well  below 
the  audible  range,  well  into 
the  superaudible.  Other 
amplifier  chips  such  as  the 
LM2277,  LM1877,  or  LM377 
also  can  be  used.  They  pro- 
vide two  2-Watt  amplifiers 
in  the  same  chip. 

One  386  drives  the  loud- 
speaker for  aural  monitor- 
ing. The  other  drives  the 
meter.  An  even  better 
meter  driver  might  be  con- 
structed from  an  op  amp, 
such  as  a  741  or  TL081. 
which  could  drive  the  me- 
ter directly  without  help 
from  a  transformer. 

The  calibrated  voltage 
attenuator  is  simply  a  resis- 
tive divider  across  the  in- 
put. A  standard  shielded 
probe  with  a  ground  clip  is 
used  for  pickup.  A  blocking 
capacitor  keeps  dc  from  be- 
ing applied  to  the  divider, 
and  hence  to  the  FET  pre- 
amplifier gate. 

The  entire  voltage  divid- 
er, with  its  switches,  lead 
wires,  and  input  capacitor, 
should  be  shielded  from 
stray  pickup.  Without 
shielding,  it  is  subject  to 
hump  rf,  and  other  stray 
pickup  which  shows  on  the 
meter  and  is  audible  in  the 
monitor.  The  input  im- 
pedance is  approximately 
one  megohm.  Many  of  the 
pickup  problems  can  be 
solved  by  shunting  the 
whole  string  with  a  one-meg 
(or  lower  value)  resistor, 
thereby  lowering  the  input 
impedance  without  chang- 
ing the  10-dB  interval  be- 
tween attenuator  taps.  (If 
this  is  done,  it  is  necessary 
to  recalculate  the  value  of 
R7  to  give  50  dB  attenua- 
tion with  the  new  divider 
resistance.)  You  might  pro- 
vide a  switch  to  do  this,  so 
that  you  can  retain  the  one- 
meg  input  impedance  for 
use  when  you're  working 
with  very  high  impedance 
sources. 


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Fig.  2.  Power  supply  for  the  VUM. 


Resistance  values  are 
chosen  such  that  each 
switch  position  gives  10  dB 
less  signal  than  the  one 
above  it,  for  a  total  of  50  dB 
attenuation  below  the  input 
signal.  When  the  "high 
level"  switch  is  flipped,  an 
additional  fixed  50-dB  at- 
tenuator is  thrown  into  the 
circuit  and  the  switch  then 
reads  in  10-dB  steps  from  50 
to  100  dB  below  the  in- 
put—and that's  a  lot  of  at- 
tenuation! 

How  do  you  determine 
the  resistance  values?  That 
caused  me  a  lot  of  floun- 
dering around  with  my 
trusty  TI-55  calculator  and 
a  ream  of  paper  smeared 
with  several  grams  of 
graphite  scribblings,  but  it 
finally  came  clear.  As  I  said, 
the  secret  is  that  a  dB  is  a 
ratio  between  two  values, 
and  you  have  to  start  with 
one  known  value  and  go 
from  there. 

You  arbitrarily  can  as- 
sume a  total  value  for  the 
divider  of  one  megohm, 
and  calculate  each  step  as  a 
portion  of  that,  or  you  can 
arbitrarily  assume  some 
value  for  R1  and  calculate 
each  step  from  there.  I 
chose  the  latter  because  it 
enabled  me  to  use  a  10-dB 
ratio  in  all  calculations, 
thus  greatly  simplifying  the 
calculator  work. 

Now,  let's  go  back  to  the 
basic  formula  stated  earlier 
and  solve  it  for  10  dB:  10  dB 
=  20  log  V2/V1.  Therefore, 
antilog  V2/V1  =  10/20  = 
0,5,  The  antilog  of  0.5,  ob- 
tainable  from  the  calcula- 
tor or  a  log  table,  is 
3.1622777.  So:  V2/V1  = 
3.16  and  V2  =  3.16  VI. 

In  any  purefy  resistive 
network,  voltage  divides  in 


exact  direct  ratio  to  the 
resistance,  so  we  can  substi- 
tute R1  and  R2  for  VI  and 
V2  and  restate  the  formula 
R2  =  3.16  R1. 

Now,  let's  assume  a  val- 
ue of  1000  Ohms  for  R1  (see 
Fig.  1),  R2  is  then  3,1622777 
X1000  =  3162  Ohms, 

That  gives  us  the  values 
of  two  resistors  in  the  string. 
Now  let's  get  the  value  of 
R3.  We  want  a  value  which 
will  give  us  10  dB  less 
voltage  across  R1  4-  R2  than 
is  applied  across  R1  +  R2  + 
R3.  So,  R1  for  this  calcula- 
tion is  actually  the  sum  of 
R1  and  R2,  or  4162  Ohms. 
Therefore:  R3  =  3,16  (R1 + 
R2)  =  3.16X4162  =  13,146 
Ohms. 

To  get  the  value  of  R4, 
use  the  same  method,  mak- 
ing "R1"  equal  the  sum  of 
R1  +  R2  +  R3.  And  so  on, 
until  you  have  the  value  of 
all  six  resistors  in  the  string. 

Now,  it  happens  that 
1000  Ohms  is  a  standard  re- 
sistance value.  That's  why  I 
chose  it  Three  thousand 
Ohms,  however,  is  not  a 
standard  value,  and  3162 
certainly  is  not!  However, 
2700  and  470  are  standard 
values,  and  they  add  up  to 
3170  Ohms,  which  is  only 
0.2  percent  off  the  calculat- 
ed value!  Certainly  close 
enough  for  amateur  work, 

13,146  isn't  standard,  but 
13k  is,  and  it  is  only  about 
1 .0  percent  off.  If  you  want 
to  be  really  finicky,  you 
could  use  13k  and  150- 
Ohms  in  series,  but,  unless 
you're  using  very  expensive 
1%  tolerance  resistors,  the 
difference  is  academic. 
Five  percent  is  certainly 
close  enough  and  ten  per- 
cent probably  will  do  nice- 
ly. 

73  Magazine  •  August,  1982     73 


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F/g,  J.  frequency  response  of  two-toroid  CW  filter  deter- 
mined with  the  aid  of  the  VUM.  LI,  L2  —  88~mH  toroids;  CI, 
C2  —  0.69  iaF.  Bandwidth:  25  Hz  at  -3  dB;  40  Hz  at  -5dB; 
55  Hz  at  - 10  dB;  60  Hz  at  - 15  dB. 


Calculated  values  of  the 
other  resistors  can  be  ap- 
proximated in  the  same 
way,  using  standard  values 
in  series,  parallel,  or  series- 
parallel  In  most  cases, 
quarter-Watt  composition 
resistors  will  do  fine.  How- 
ever, compostion  tends  to 
change  value  slowly  over  a 
period  of  years,  especially 
when  subjected  to  heat  and/ 
or  high-voltage  stresses. 
You  could  avoid  this  with 
metal  film  resistors,  at 
much  expense,  but  one- 
Watt  or  even  two^Watt 
composition  resistors  will 
hold  their  values  for  many 
years  before  they  change 
enough  to  affect  the  accu- 
racy of  your  readings. 

The  resistors  are  easily 
mounted  on  a  small  piece 
of  perfboard  with  wires  run- 
ning to  the  six-position 
rotary  switch,  but  keep  the 
leads  fairly  short,  keep 
them  away  from  output 
leads  going  to  the  speaker 
or  meter,  and  keep  them 
away  from  power-supply 
leads.  If  possible,  enclose 
the  whole  resistor  bank  and 
switch  in  a  shielded  com- 
partment though  this  may 
not  be  necessary. 

The  FET  amplifier  is  not 
needed  to  provide  gain, 
though  it  provides  about  10 
dB.  It  is  there  to  offer  a  very 
high  impedance  to  the  volt- 
age  divider  The  input  im- 
pedance of  the  LM386s,  in 
parallel  is  about  25k  and  if 
this  impedance  paralleled 
the  attenuator,  it  would  se- 
riously affect  the  accuracy 
of  the  steps,  especially  at 
the  small  attenuation  set- 
tings.   Any    inexpensive 

74     ?3Magazine  *  August,  1982 


audio-type  N-channel  FET 
will  work  nicely.  The  FET 
drives  the  two  pots  which 
provide  separate  level  con- 
trols for  the  amplifiers. 

The  meter  amplifier  is 
coupled  to  the  4-Ohm  wind- 
ing of  a  small  audio  trans- 
former with  a  500-  or 
600-Ohm  secondary,  such 
as  those  used  to  couple 
speakers  to  music  distribu- 
tion lines.  The  purpose  of 
the  transformer  is  to  step  up 
the  low-voltage  output  of 
the  amplifier  to  the  higher 
voltage  which  the  meter 
needs.  The  meter  is  de- 
signed to  work  across  a 
nominal  600-Ohm  load. 

Except  for  lead  dress  and 
shielding  of  the  input  cir- 
cuits, nothing  is  critical 
about  construction.  The  au- 
dio amps,  including  the  FET 
circuit,  can  be  built  on  a 
single  universal  circuit 
board  such  as  the  "experi- 
menter printed  circuit 
board"  sold  by  Radio  Shack 
(catalog  number  276-1 70)  or 
any  other  "universal"  board 
with  0.1 -inch  perforation 
centers.  It  can  be  built  on 
perfboard  without  foil  us- 
ing wire-wrap  or  point-to- 
point  wiring. 

A  regulated  power  sup- 
ply [Fig.  2)  using  a  three- 
terminal  12-volt  IC  chip  is 
used  because  the  regulator 
provides  a  high  degree  of 
hum  filtration.  Voltages  are 
not  critical  at  all,  but  don't 
exceed  15  volts  — the  386s 
cannot  take  more  than  that 
Nine-volt  batteries  should 
work  fine. 

After  checking  for  wiring 
errors,  plug  in  the  ICs  and 
check    for    output.    You 


should  find  none  until  you 
provide  an  input  signal.  If 
hum  appears  on  the  meter 
and/or  in  the  speaker,  espe- 
dally  at  the  0-dB  attenua- 
tion setting,  short  out  the 
probe  terminal  and  see  if  it 
disappears,  If  it  does,  your 
problem  is  hum  pickup  in 
the  attenuator  board. 

Occasionally  IC  amplifi- 
ers will  oscillate.  This 
would  show  up  as  squeals, 
hisses,  crackles,  and  distor- 
tion in  the  speaker  and  as  a 
reading  on  the  meter,  even 
with  the  probe  input  short- 
ed or  switched  to  high  at- 
tenuation. This  usually  can 
be  cured  with  an  RC  filter 
[0.05  pf  and  10  Ohms  in 
series)  from  the  IC  output  to 
ground.  Sometimes  a  0.005- 
MF  capacitor  across  the  in- 
put terminals  at  the  IC  will 
be  necessary  The  FET  can 
be  eliminated  as  a  suspect 
oscillator  by  grounding  its 
gate  or  by  removing  its 
drain  voltage. 

After  checking  out  and 
debugging,  hook  a  source 
to  the  input  of  the  VUM. 
The  best  source  is  an  audio 
oscillator,  but  for  this  test, 
any  steady  tone  wilt  do. 

You  should  hear  it  in  the 
speaker  and  should  be  able 
to  adjust  its  loudness  with 
the  "volume"  pot. 

The  tone  also  should 
register  on  the  meter  If  it 
pegs  the  meter,  rotate  the 
attenuator  switch  until  the 
meter  drops  back  on  scale 
If  little  or  no  meter  reading 
occurs,  set  the  "calibrate" 
(Cal)  pot  at  about  half  rota- 
tion or  a  little  more,  and 
then,  if  necessary,  rotate 
the  attenuator  switch  to- 
ward the  OdB  position. 

Checking  Calibration 

Adjust  the  output  level 
of  the  oscillator  until  you 
can  set  the  attenuator  at  0 
dB  and  get  the  meter  down 
to  0  VU  (about  two-thirds 
scale)  with  the  Cal  pot.  Now 
flip  the  attenuator  to  ^-10. 
The  meter  should  drop  to 
-10.  Reset  Cat  and,  if 
necessary,  the  oscillator 
output,  to  get  0  VU  again, 
and  switch  the  attenuator 


to  —20.  The  meter  should 

again  drop  to  —10. 

Check  all  six  steps  in  the 
attenuator  in  this  way.  You 
may  find  it  necessary  to  ad- 
just a  resistor  value  here  or 
there  to  get  exact  10-dB 
steps.  [Remember  that  R6 
controls  the  first  Step  from 
OdBto  - 10  dB.R5  controls 
the  next  step  and  so  on.) 

The  full  range  of  the  Cal 
pot  will  give  you  about  25 
or  30  dB  of  adjustment. 

Using  the  VUM 

Now  you're  ready  to  put 
the  VUM  to  practical  use. 
You  have  an  audio  filter  for 
use  in  CW  reception  How 
sharp  is  it?  Put  it  on  the 
bench  and  arrange  to  drive 
its  input  with  the  audio 
oscillator  instead  of  the 
receiver.  Be  sure  that  the  in- 
put and  output  of  the  filter 
see  the  same  impedances 
they  see  when  it  is  in  the 
receiver,  then  put  the  VUM 
across  the  output  of  the 
filter  Let's  assume  that  the 
filter  was  designed  to  peak 
at  700  Hz 

Adjust  the  frequency  of 
the  oscillator  until  it  hits 
the  filter  peak,  giving  max- 
imum reading  on  the  VUM, 
Select  an  attenuation  on 
the  switch  which  will  let 
you  set  the  meter  on  0  VU 
with  the  Cal  pot. 

Note  that  your  oscillator 
frequency  is  690  H2  when 
the  filter  output  is 
peaked  — pretty  close,  if 
you  designed  it  for  700  Hz 
Now,  keeping  the  output 
level  of  the  oscillator  the 
same,  switch  the  frequency 
to  700  Hz  You'll  note  a 
slight  drop  in  the  VUM 
reading  Note  that  at  690 
Hz,  the  VUM  read  0  VU  and 
at  700  it  read,  say,  -0  5  dB 

Change  frequency  again, 
to  710  Hz,  and  note  that  the 
meter  reading  drops  to  —1 
dB  (or  VU).  Keep  going  up 
frequency  one  step  at  a 
time  until  your  meter 
readings  drop  below  —20 
dB.  Then  go  down  frequen- 
cy from  690  Hz  a  step  at  a 
timer  noting  the  meter  and 
frequency  readings  each 
time. 


When  you  finish,  plot 
your  results  on  a  piece  of 
semi-log  graph  paper  using 
the  logarithmic  scale  for 
frequency  and  the  linear 
scale  for  your  dB  readings. 
The  results  will  be  similar  to 
those  in  Fig.  3,  which 
represents  an  actual  two- 
toroid  CW  fiiter  I've  used 
for  years.  The  response 
curve  was  plotted  with  the 
aid  of  the  VUM. 

In  a  similar  manner,  you 
can  determine  the  frequen- 
cy response  of  a  stereo  am- 
plifier, beginning  in  the 
middle  of  the  audio  range, 
say  at  1000  Hz,  to  establish 
a  0  VU  reference  point  You 
will  note  that  the  meter 
readings  begin  to  drop  off 
as  the  frequency  reaches 
some  low  value,  perhaps 
below  100  Hz,  depending 
on  the  quality  of  the  ampli- 
fier A  similar  drop-off  oc- 
curs at  the  high  end  of  the 
audio  range,  say,  above  15 
kHz. 

The  frequency  response 
curve  of  the  VUM  itself  is 


shown  in  Fig,  4  and  this 
must  be  taken  into  account 
when  testing  another  ampli- 
fier. The  low  frequency 
drop-off  is  caused,  most 
likely,  by  the  core  losses  in 
the  small  output  transform- 
er used  to  couple  the  ampli- 
fier to  the  meter.  Up  to  a 
certain  point,  increasing  the 
value  of  the  output  cou- 
pling capacitor  will  extend 
the  low  frequency  re- 
sponse. You  should  use  at 
least  a  3000-^iF  coupling  ca- 
pacitor. 

An  op  amp,  such  as  an 
LM741  or  TL081  driving  the 
meter  directly  and  omitting 
the  output  transformer, 
probably  would  improve 
the  extreme  low  end  re- 
sponse of  the  VUM.  Since  I 
have  seldom,  if  ever,  been 
called  on  to  make  accu- 
rate measurements  at  these 
frequencies,  I  have  not  ex- 
plored that  improvement. 
The  high  frequency  re- 
sponse is  virtually  flat  at 
least  to  40  kHz. 

Now,  suppose  you  have  a 


do 
O 

-s 

-10 


20 


5 

l.  u  in 

f 

-It 

1 

f 

* 

»* 

a         e 

20  40    60  SO  100     200 


400  600       1000     2K  4K     6K  8*  I0K 

FREQUENCY    Hr 


20H         40K 


...h. 


Fig.  4.  Frequency  response  of  the  VUM,  ±1  dB,  100  Hz  to 
40  kHz;  ±3dB,4Q  Hz  to  65  kHz,  A  -  response  with  200-^aF 
output  coupling  capacitor  to  meter.  B  —  1200  yF. 


solid-state  audio  amp 
which  gives  only  low,  dis- 
torted output.  Apply  a  tone, 
such  as  1000  Hz,  to  the  in- 
put, at  a  level  which  the 
amplifier  is  designed  to 
handle.  Apply  the  probe  of 
the  VUM  to  the  input,  ad- 
just the  attenuator,  and  set 
Cal  for  0  dB  on  the  meter. 

Now  move  the  probe  to 
the  output  of  the  first  stage 
in  the  amp  and  note  that 
you  must  switch  in  two 
more  steps  of  attenua- 
tion-20  dB-and  the 
meter  then  reads  +2 
(Don't  touch  Cal  J 

The  readings  translate  to 
mean  that  the  first  stage  is 


providing  22  dB  of  amplifi- 
cation—a very  healthy  per- 
formance. 

Reset  Cal  to  give  0  on  the 
meter  and  move  the  probe 
to  the  output  of  the  second 
amplifier  stage.  This  time,  it 
isn't  necessary  to  switch  in 
any  more  attenuation.  The 
meter  reads  —5  dB!  That 
"amplifier"  stage  is  offering 
a  5-dB  loss!  It  is  obviously 
sick  and  needs  TLC. 

The  uses  of  the  VUM  are 
numerous  and  you  prob- 
ably can  think  of  other 
ways  to  use  it  to  compare 
the  levels  of  any  two  audio 
signals.  Often,  that  tells  the 
whole  story.  ■ 


THE  RTTY  ANSWER 


JRLFSK-SOO 


Ihift 


%\  %\%\%\t 


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Analog  Isn't  Dead 

don't  be  LED  astray  by  the  digital  revolution 


Sometimes  it  seems  that 
everything  is  going  digi- 
tal. At  first  it  was  a  novelty 
to  have  a  digital  clock— you 
know,  the  kind  with  the 
metal  plates  that  would  flip 
down  a  new  number  every 
minute.  With  the  emer- 
gence of  the  cheap  LED 
seven-segment  device,  the 
movement  to  digitalize 
everything  accelerated. 
First  it  was  digital  watches 
and  clocks,  then  calcula- 
tors; now  it's  used  on  ther- 
mometers, bathroom  scales, 
radio  dials,  gas  pumps,  and 
almost  everything  on  some 
luxury  cars,  Even  a  farmer 
friend  of  mine  brags  that 
the  speedometer  and  ta- 
chometer on  his  new  trac- 
tor is  digital.  Digital  is 
becoming  synonymous 
with  modern,  while  analog 
is  considered  outdated.  Is 
the  analog  device  a  twen- 
tieth-century dinosaur 
doomed  to  extinction  in 
this  era  of  rapidly  advanc- 
ing technology?  The  answer 
is  a  definite  "no!"  Old 
Charlie  Darwin  would  agree 
that  as  long  as  a  species  is 
successful  within  its  niche, 
it  will  survive.  As  it  has 
evolved  because  of  tech- 
nology, the  digital  species 
has  displaced  the  analog 
species  from  certain  niches 

76     73Magazfne  •  August.  1982 


in  which  the  analog  species 
was  only  marginally  fit,  yet 
digitals  are  unable  to  com- 
pete with  analogs  in  other 
areas. 

Analog  and  digital  de- 
vices each  have  distinct  ad- 
vantages and  disadvan- 
tages. By  understanding  the 
merits  of  each  system,  the 
designer/user  can  intelli- 
gently select  the  better 
device.  As  a  rule,  a  merit  of 
one  system  is  a  shortcom- 
ing in  the  other  system. 

Precision 

The  digital  device  wins 
hands-down  in  the  precision 
department.  Precision  is 
limited  only  by  the  number 
of  digits  you  can  afford  or 
can  read  without  confu- 
sion. But  don't  get  confused 
between  precision  and  ac- 
curacy Accuracy  is  the 
measure  of  how  close  you 
are  to  the  real  value,  while 
precision  is  the  measure  of 
your  confidence  in  the 
measured  value.  If  your 
new  Rockcruncher  2000  all- 
digital  transceiver  says  that 
you're  transmitting  on 
21,447,605  kHz  (a  very  pre- 
cise measurement),  but  you 
are  actually  transmitting  on 
21 ,452  kHz  (a  very  accurate 
measurement),  then  you  are 


still  likely  to  get  a  pink  slip 
from  the  FCC.  Moral:  An 
ounce  of  accuracy  is  worth 
a  pound  of  precision.  How- 
ever, if  you  have  a  high 
degree  of  accuracy  but  low 
precision,  you  won't  be 
able  to  know  just  how  ac- 
curate you  are.  You  just 
won't  collect  as  many  pink 

slips. 

Quick  quiz:  Which  digital 
frequency  meter  is  better 
(greater  accuracy  and  preci- 
sion) for  measuring  a  signal 
at  420  0000000  MHz:  a 
6-digit  meter  with  1  ppm  ac- 
curacy or  a  10-digit  meter 
with  4  ppm  accuracy?  An- 
swer: Of  course  you  knew 
all  along  that  it  was  the 
6-place  meter,  because: 

6-place  counter: 

1/1,000,000  X  420.0000000 
+  420.0000000  =  420.000 
(remember,  only  6  digits), 

10-place  counter: 

4/1,000,000  X  420.0000000 
+        420.0000000 
420.0016800. 

Wow!  The  10-place 
counter  is  really  impressive 
with  all  those  numbers.  Ifs 
too  bad  that  the  accuracy 
extends  only  to  five  signifi- 
cant figures.  The  6-place 
counter  is  not  as  flashy,  but 
it    provides    accuracy    and 


precision  to  six  significant 

figures. 

The  slide  rule  was  dis- 
placed by  the  digital  calcu- 
lator simply  because  the 
slide  rule  was  unable  to 
compete  with  the  superior 
accuracy  and  precision  of 
the  digital  calculator 

Rate  Measurement 

Imagine  that  you  have 
decided  to  update  your  old 
Rockcruncher  1000  (1967 
model  with  analog  frequen- 
cy dial  and  old-fashioned 
D'Arsonval  swinging-needle 
meter  movement).  Being 
short  of  funds,  you  select  a 
$19.95  3 Vi -digit  LED  meter 
kit  to  replace  the  old  ana- 
log movement.  After  three 
weekends,  one  trip  to  the 
hospital  emergency  room, 
and  the  kind  assistance 
from  a  friend  who  just  hap- 
pens to  have  an  MSEE  de- 
gree, you  get  the  thing  in- 
stalled. To  celebrate  the  oc- 
casion, you  turn  on  the  rig 
to  40  meters  for  a  I  ittle  QSO 
to  brag  about  how  you 
dragged  your  old  Rock- 
cruncher 1000  kicking  and 
screaming  out  of  the  1960s 
and  into  the  1980s, 

As  you  tune  in  the  first 
station,  you  get  the  first  hint 
that  all  is  not  well  with  your 
new,  state-of-the-art  digital 


meter  It  is  impressive  to 
see  all  those  LEDs  flashing, 
but  it  would  be  better  if 
they  were  readable  instead 
of  blurred  Well,  that's  the 
price  of  progress. 

Then  you  start  to  tune  up 
the  rig.  The  old  peak-and- 
dip  ritual  is  suddenly  a  wild 
and  crazy  experience.  Un- 
less you  tune  very  slowly, 
the  meter  displays  a  string 
of  eights.  Not  only  that,  but 
finding  the  peaks  and  dips 
is  almost  impossible.  Unfor- 
tunately, the  final  tubes 
hate  non-resonance  so 
much  that  by  the  time  you 
are  almost  tuned  up,  they 
collapse  in  a  molten  pud- 
dle. 

Exaggerated?  Weil,  may- 
be, but  the  point  is  that  digi- 
tal displays  are  not  suitable 
for  measuring  rapidly 
changing  values  The  digital 
display  blurs,  while  the  ana- 
log display  provides  a  us- 
able r a te-of -change  display 
by  observation  of  the  angu- 
lar velocity  (sweep  speed) 
of  the  indicator's  pointer. 
An  example  would  be  to 
compare  the  analog  and 
digital  display  of  an  air- 
craft's altitude  During  an 
aircraft's  descent,  the  ana- 
log altimeter's  pointer  "un- 
winds" at  a  velocity  propor- 
tional to  the  slope  of  the  de- 
scent The  display  remains 
readable  at  all  times  The 
digital  display  will  blur  in 
the  units  position  during  the 
slightest  descent,  and  as  de- 
scent rate  increases,  the 
tens,  hundreds,  and  eventu- 
ally thousands  positrons 
will  blur.  While  the  analog 
altimeter  provides  continu- 
ous rate  information  over  a 
wide  range  [slow  "unwind- 
ing" through  fast  "unwind- 
ing"), the  digital  altimeter 
displays  the  descent  rate  in 
a  limited  number  of  dis- 
crete steps.  For  example: 
units  blurred  — slight  de- 
scent; tens  blurred  — mod- 
erate descent,  hundreds 
blurred  —  steep  descent; 
thousands  blurred  —dive; 
ten-thousands  blurred  — 
don't  even  think  about  it, 

Why  do  race  cars  still  use 
old-fashioned    analog    ta- 


PLATE    CAPACITOR   SETTING 


(0} 


chometers  instead  of  the 
spiffy  new  digital  tachom- 
eters that  Warshawsky  and 
Co,  sells?  It  comes  down  to 
economics.  An  over-revved 
engine  with  pieces  littering 
the  track  simply  cannot  win 
a  race,  If  a  digital  tach  blurs 
on  acceleration,  the  driver 
will  be  more  likely  to  over- 
rev  the  engine  (an  expensive 
mistake].  The  subject  of 
race  car  instruments  leads 
into  the  next  criterion  for 
selection  of  the  appropriate 
analog  or  digital  device. 

When  I  first  saw  the  in- 
strument panel  on  a  race 
car,  I  noticed  that  the  in- 
struments were  installed 
askew,  with  some  turned 
clockwise  and  others 
turned  counterclockwise. 
Later  I  was  informed  that  it 
wasn't  sloppy  installation, 
but  an  intentional  arrange- 
ment The  driver  doesn't 
have  time  to  read  the  num- 
bers on  each  gauge,  so  the 
gauges  are  aligned  so  the 
pointer  is  at  12  o'clock  at 
the  ideal  (or  maximum)  set- 
ting. A  deviation  is  then 
readily  noticeable.  An  ana- 
log device  will  show  where 
you  are  with  respect  to  the 
range  of  position  An  analog 
defines  its  limits  (empty- 
full,  low-high,  0-1  mA,  0-120 
mph)  and  the  device's 
pointer  simultaneously  in- 
dicates its  relative  position 
on  the  range  of  values. 

Comparing  the  ability  of 
analog  and  digital  devices 
to  measure  position  can  be 
demonstrated  by  the  story 
about  the  hot-air  balloon- 


-l. 


2  3  4  5  6 

PLATf   CAPACITOR   SETTING 


Fig.  1. 

ists  who  became  lost  while 
drifting  over  the  country- 
side. One  of  the  balloonists 
sighted  a  farmer  in  a  field 
and  began  releasing  gas 
from  the  balloon.  As  the 
balloon  passed  over  the 
farmer,  the  balloonists 
yelled,  "Where  are  we?" 
The  farmer  replied,  "'Bout  a 
hunnerd  foot  up  in  a  hot- 
air  balloon."  The  informa- 
tion transferred  was  abso- 
lutely correct,  yet  absolute- 
ly useless  since  there  was 
neither  a  horizontal  point 
of  reference  nor  a  distance 
and  direction  from  the 
point  of  reference.  Fre- 
quently a  value  alone  can 
be  meaningless  unless  ac- 
companied by  boundary 
limits  When  using  digital 
devices,  you  often  must  be 
aware  of  limits  which  are 
not  displayed,  Since  analog 
devices  display  the  entire 
range,  hazardous  or  unde- 
sirable regions  may  be 
flagged  by  using  a  colored 
band  as  a  warning  marker, 
This  flagging  is  generally 
not  available  for  digital  dis- 
plays; however,  red/green 
bidirectional  LEDs  in  a 
7-segment  configuration 
could  be  used  in  circuitry 
that  would  allow  a  color 
change  as  an  undesirable 
region  is  entered. 

Another  kind  of  position 
utilization  in  analog  dis- 
plays is  incremental  mea- 
surement. A  good  example 
is  the  wristwatch  worn  by  a 
nurse.  It  is  never  digital  and 
always  has  a  second  hand. 
The  reason  is  that  nurses 


l .        »■        4         5 
PLATE    CAPACITOR  SETTING 

US 


take  frequent  readings  of 
patients'  vital  signs  — pulse 
and  respiration,  To  save 
time  (a  survival  skill  in  nurs- 
ing), the  pulse  and  respira- 
tion are  each  measured  for 
15  seconds.  The  procedure 
is  to  find  the  pulse,  start 
counting  the  pulse  as  the 
second  hand  passes  any 
5-second  increment,  contin- 
ue counting  until  the  sec- 
ond hand  has  traversed  90° 
from  the  starting  point,  and 
finally  multiply  this  1 5-sec- 
ond count  by  4.  The  starting 
and  stopping  points  are  of 
no  consequence,  but  rather 
the  90°  sweep  of  the  sec- 
ond hand  which  measures  a 
1 5-second  increment.  A 
similar  incremental  mea- 
surement is  used  in  trans- 
mitter tuning.  The  actual 
plate  current  reading  is  of 
little  value  until  tuning  is 
completed.  The  important 
things  are  the  relative  peaks 
and  dips  as  the  circuit  is 
brought  to  resonance- 
Continuous  vs. 
Stepped  Readings 

There  is  a  little  gadget  on 
the  market  called  the  LED 
bar-graph  display  which 
looks  like  an  analog  device, 
yet  is  still  digital.  It  has  the 
advantage  of  position  dis- 
play and  may  be  used  mar- 
ginally for  rate  measure- 
ment. Its  weakness  is  the 
one  distinct  advantage  usu- 
ally found  in  digital  devices 
—  precision.  Precision  is 
limited  by  the  discrete 
number  of  steps  (LEDs)  on 
the  bar  display.  If  8  LEDs 

73  Magazine  •  August,  1962     77 


The  Satum  V  is  a  deep  fringe  microwave  receiver  for  homeowners 
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are  used  to  measure  a  range 
of  0  to  8  units,  then  no  LED 
would  light  until  one  unit  is 
reached,  the  second  LED 
would  light  only  when  two 
units  is  reached,  and  so  on. 
The  drawback  is  that  1.00 
and  1 .99  units  are  displayed 
as  being  the  same.  Now  it's 
obvious  that  trying  to  use 
this  bar  graph  to  tune  a 
transmitter  would  be  diffi- 
cult. Fig.  1  shows  a  compari- 
son of  a  D'Arsonval  meter 
movement  and  two  LED  bar 
graphs.  Fig.  1(a)  shows  the 
actual  plate  current  (as  dis- 
played on  the  D'Arsonval 
meter).  Fig+  1(b)  shows  an 
8-LED  bar  graph,  and  Fig. 
1(c)  shows  a  16-LED  bar 
graph.  The  "peak"  on  the 
8-LED  bar  covers  over  half 
of  the  capacitor  tuning 
pan^t*,  and  the  16-LLD  bar- 
graph  "peak"  covers  over  a 
third  of  the  capacitor  tun- 
ing range  Neither  bar  graph 
has  the  sensitivity  for  tun- 
ing that  the  analog  display 
has. 


Conclusions 

Use  a  digital  device 
where  precision  is  needed, 
but  remember  that  high 
precision  cannot  improve 
accuracy.  Digital  devices 
are  especially  suited  as  fre- 
quency indicators  on  trans- 
ceivers and  frequency 
counters.  However,  if  the 
frequency  counter  you  are 
thinking  about  buying  has  9 
digits  and  10  ppm  accuracy, 
then  you  are  wasting 
money  on  the  last  4  digits. 
Six  digits  and  1  ppm  accur- 
acy is  just  right.  Don't  use 
an  LED  bar  graph  if  preci- 
sion is  essential. 

If  position-orientation, 
-tracking,  or  -setting  are  im- 
portant stay  with  an  analog 
device.  And  finally,  rate 
measurement  belongs  to 
analog  devices. 

As  an  equipment  design- 
er/user, select  the  better 
device  to  meet  your  own 
needs  — even  if  it  means  be- 
ing old-fashioned.  ■ 


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78     73Magazme  •  August,  1982 


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•  ten  VFO's 

•  one  year  factory  warranty 

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THE  NEW  FT-102 


Operating  Modes: 

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A1  AM  <USBLSB)P 
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Emission  Mode 
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A1        CW 
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SSB  CW  RTTY  Less  than  0.3  mv  for 
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{Preamp  -  On)  Less  than  0.15  j*v 
for  10dB  S  +N/N 
FM  (Preamp  -  On)  Less  than  03 
v  tor  20  dB  quieting 


DONS  CORNER 

The  Ratings  continue  -  2  meter  mobile  month:  Kenwood 
TR9130,  excellent  sensitivity,  easy  operation,  light  output; 
ICOM  IC290A,  good  performance,  cheaper  pricing;  Yaesu 
FT4B0R,  great  reliability,  medium  pricing. 

ICOM  IC25A  -  Kenwood  TR7730  -  Yaesu  FT  230  -  All 
popular,  AH  the  same  basic  flavor.  Vaesu  FT208R  -  biggest 
seller;  Kenwood  TR2500  -  durable;  Santec  Si144kP*  most 
features;  ICOM  IC2AT  -  basic  reliable  workhorse. 

Consider  the  various  Mod  Kits  out  FOXTANGO,  W6TOC 
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several  &  they  are  excel  lent,  plus  an  affordable  way  to 
"upgrade"  an  old  radio  (TS820?).  Remember  our  service 
dept  What  we  can't  fix  with  a  hammer,  we  don't  work  on. 


See  you  next  month! 


NO 


KM 

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S#«  List  Of  Aaweritsers  on  pmge  J  u 


73  Magazine  *  August,  1982    81 


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82     73 Magazine  ■  August,  1982 


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73  Magazine  •  August.  1982     83 


Line  Voltage  at  a  Glance 

at  last  a  useful  gadget 


L  0.  Cebik  W4RNL 
5T05  Hofston  Hills  Road 
Knonvitte  TN  37914 


Aline  voltage  monitor 
can  help  you  protect 
your  equipment  investment 
from  problems  that  fuses 
and  circuit  breakers  cannot 
cure.  However,  most  moni- 
tors start  with  relatively  ex- 
pensive meters.  To  expand 
their  scales  for  the  90-to- 
140-volt  range  may  require 
additional  circuitry-  There 
must  be  an  easier  way. 

The  little  monitor  de- 
scribed here  is  inexpensive, 
easy  to  build,  and  provides 
LED  indication  of  the  line 
voltage  in  five-volt  incre- 
ments, which  is  as  close  as 
most  of  us  need.  Its  accura- 
cy is  good  because  you  can 
calibrate  it  against  factory- 
or   lab-calibrated    instru- 


ments. Finally,  the  entire 
works  are  small  enough  to 
fit  inside  another  piece  of 
gear,  or  you  can  use  a  sepa- 
rate small  case.  Apart  from 
the  case,  $10-12  should  buy 
you  new  parts,  although  I 
suspect  most  junk  boxes 
have  everything  exept  the 
IC  and  the  LEDs. 

Monitoring  the  line  volt- 
age to  the  shack  has  always 
been  fairly  important.  In  re- 
cent years,  the  increasing 
incidence  of  brownouts  and 
other  line  variations  has 
made  monitoring  even 
more  important.  Occasion- 
ally voltages  will  rise  or  fall 
to  levels  which  may  en- 
danger some  equipment 
especially  motorized 
equipment.  Less  cata- 
strophicalty,  a  line  voltage 
monitor  can  help  you  trace 
unusual  glitches,  such  as  ex- 
cessive   power    consump- 


tion, to  the  voltage  entering 
the  equipment.  At  the  end 

of  the  article,  we  will  look 
at  some  applications  of  the 
simple  monitor  described 
here. 

The  Circuit:  An  LM3914 

The  LM3914  dot/bar  dis- 
play driver  is  a  versatile 
18-pin  IC  available  from 
many  sources,  including 
Radio  Shack.  Pins  1  and  18 
through  10  provide  termina- 
tions for  LEDs,  which  can 
be  set  up  to  come  on  one  at 
a  time  or  to  come  on  pro- 
gressively, depending  upon 
how  pin  9  is  connected.  Pins 
2  through  8  provide  the  sup- 
ply, control,  and  signal  in- 
puts. Fig.  1  shows  the  basic 
layout  of  the  chip. 

The  3914  consists  of  a 
highly  accurate  voltage  di- 
vider chain  controlling  the 
LED  pins  through  complex 


Interior  view  of  these  monitors  shows  two  layout  possibilities  using  peri board  construction. 
64     73  Magazine  ■  August,  1982 


internal  circuitry.  By  setting 
the  high  and  low  limits  of 
the  divider,  we  can  achieve 
a  smooth  linear  progression 
of  lights  as  the  voltage 
moves  up  and  down  at  the 
input  terminal,  pin  5.  Most 
applications  of  the  3914  are 
geared  to  low  voltages. 
such  as  audio  voltage  me- 
ters, battery  checkers,  and 
the  like.  However,  with  a  lit- 
tle care,  we  also  can  have 
the  3914  track  higher  volt* 
ages. 

To  make  the  3914  func- 
tion as  a  line  voltage  moni- 
tor, we  simply  need  a  low 
dc  voltage  which  varies 
with  the  rms  value  of  the  ac 
voltage  at  our  wall  plugs.  A 
9-  to  12-volt  dc  power  sup- 
ply with  a  relatively  con- 
stant load  wilt  do  just  this,  if 
the  supply  is  loaded  neither 
too  lightly  nor  heavily.  Ad- 
ditional drops  across  a  re- 
sistor will  also  track  the  ac. 
In  the  circuit  shown  in  Fig, 
2,  tracking  by  these  means 
has  proven  as  accurate  as 
the  expanded-scale  ac 
meters  against  which  the 
unit  was  checked. 

The  circuit  in  Fig.  2  is  an 
adaptation  of  the  3914  con- 
figuration used  by  Wein- 
stein  and  Cartman  in  their 
auto  battery  checker.1  The 
resistor  divider  networks 
ronnected  to  pins  4,  6,  and 
8  set  the  lower  and  upper 
limits  of  the  readout,  while 
the  resistor  connected  to 
pin  7  controls  the  bright- 
ness of  the  LEDs.  Pin  5  sam- 
ples the  incoming  voltage 
across    another    resistor 


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Fig.  T.  Pinout  of  the  LM3914  dot/bar  display  driver. 


divider.  Jumpering  pins  9 
and  11  allows  the  LEDs  to 
tight  one  at  a  time. 

Each  LED  lights  for  a 
five-volt  increment  from  90 
to  140  volts.  The  one  excep- 
tion is  the  last  LED,  at  the 
upper  limit,  which  remains 
lit  when  the  voltage  ex- 
ceeds 140.  The  50-volt 
range  was  chosen  for  sever- 
al reasons.  First  50  divides 
neatly  by  10,  Second,  the 
middle  four  increments 
cover  the  range  from  105  to 
125  volts,  the  recommend- 
ed range  for  the  operation 
of  most  electronic  equip- 
ment. Hence,  the  readout 
has  a  nice  symmetry,  This 
fact  also  allowed  me  to  use 
different  colored  LEDs: 
green  for  the  safe  range,  red 
at  the  dangerous  extremes, 
and  amber  in  between. 

The  zener  in  the  line 
feeding  the  limit-setting  re- 
sistors is  needed  to  hold  the 
voltage  constant  to  the 
limit  pins.  The  exact  value 
is  not  critical,  as  long  as  a 
range  of  1  to  3  volts  is  avail 
able  from  the  potentiome- 
ters. The  pots  are  10-turn 
miniature  trimmers  for  ease 
of  calibration.  (Remember 
that  what  is  called  a  10-turn 
mini  pot  may  have  from  8 
to  15  turns  depending  upon 
the  model  and  manufactur- 
er.) The  input  trimmer  is  the 
same  sort  of  miniature  po- 
tentiometer, set  to  give 
around  2  volts  for  an  ac  rms 
line  voltage  of  110. 

The    LEDs    can    be    any 


type  of  the  many  available 
across  the  counter  or 
through  mail  sources.  The 
object  is  to  create  an  easy- 
to-read  display,  remember- 
ing that  pin  1  is  the  lowest, 
pin  18  is  next,  and  pin  10  the 
highest  value.  The  1*8k  re- 
sistor controls  the  bright- 
ness of  the  LEDs,  and  the 
value  shown  provides  an 
easy-to-read  level  without 
being  too  obtrusive. 

The  remainder  of  the  cir- 
cuit is  shown  in  Fig,  3  and 
consists  of  two  different 
power  sources  for  the 
meter.  The  original  pro- 
totype was  built  with  power 
supply  components  on 
hand,  while  a  second  ver- 
sion uses  a  10-volt  ac 
adapter,  with  the  parts 
molded  into  the  plug.  Any- 
thing from  9  to  12  volts  will 
work,  so  that  the  ac  adapter 
for  a  dead  transistor  radio, 
tape  recorder,  etc.,  can  be 
pressed  into  service  with 
good  results.  The  meter  re- 
quires little  current  so  the 
current  capability  of  the 
power  supply  is  not  a  prob- 
lem. However,  whether  you 
opt  for  a  home-brew  supply 
or  an  adapter,  additional  fil- 
tration and  a  load  resistor 
(the  Ik  resistor  in  the  sche- 
matic) are  needed  to  pro- 
vide a  minimum  load  on  the 
supply. 

Construction  and 
Components 

The  meter  itself,  as 
shown  in  Fig.  2,  will  fit  on  a 


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Fig.  2  The  metering  and  LED  sections  of  the  line  voltage 
monitor.  LEDs:  R  =  red,  A  =  amber,  C  =  green. 


2"X3Yj"  piece  of  perf- 
board,  assuming  the  LEDs 
are  panel-mounted  else- 
where A  socket  for  the  IC 
simplifies  wiring  Since  only 
a  few  of  the  IC  pins  have 
more  than  one  connection, 
wiring  is  so  easy  that  no 
printed-circuit  techniques 
have  been  used,  although 
an  enterprising  builder 
might  wish  to  create  a 
board  for  himself. 

Again,  with  the  exception 
of  the  LEDs,  there  are  so 
few  external  components 
that  layout  is  no  problem. 
The  only  caution  is  to 
mount  the  trimmer  pots  so 
that  they  are  accessible  for 
calibration,  Since  they  are 
of  the  same  value,  it  will 
pay  to  label  them  as  HI,  LO, 
and  SIC.  There  is  nothing 
more  exasperating  than  to 
have  the  unit  in  the  final 
tweaking  stages  of  calibra- 
tion, only  to  move  the 
screwdriver  adjustment  of 
the  wrong  pot  and  have  to 
start  over. 

Different  types  of  LEDs 
and  panel  arrangements 
can  be  used  with  equal  suc- 
cess. Rectangular  bar-graph 
LEDs  from  Radio  Shack 
have  been  used  in  one 
model.  They  are  mounted 
on  a  piece  of  perf  board, 
with  leads  running  to  termi- 
nal pins  on  the  board  A 
smaller  unit  uses  jumbo 
LEDs  in  plastic  mounting 
lenses.  The  zigzag  line  of 
ten  LEDs  across  the  face  of 
the  unit  makes  identifica- 
tion of  the  five-volt  incre- 


ment very  easy,  and  once 
panel  markings  are  added, 

readout  is  even  simpler. 

Fig.  4  shows  a  sketch  of 
the  front  panel  with  the  col- 
ors of  LEDs  identified.  The 
arrangement  from  red 
through  amber  to  green  and 
back  again  is  not  only  sym- 
metrical, but  also  reflects 
the  levels  of  potential  trou- 
ble from  line  voltages  that 
wander  too  far  from  the 
norm.  In  purchasing  LEDs, 
especially  green  jumbos,  be 
sure  to  buy  more  than  you 
need  and  match  them  for 
brightness.  The  reds  and 
ambers  seem  to  be  most 
consistent,  but  surplus 
greens  appear  to  vary  quite 
a  bit. 

The  importance  of  using 
LEDs  of  approximately  the 
same  brightness  stems  from 
the  fact  that  as  the  voltage 
nears  a  transition  from  one 
increment  to  another,  two 
LEDs  may  be  lit  simultane- 
ously. If  the  LEDs  are  well- 
matched.  the  relative 
brightness  of  the  two  will 
tell  you  which  side  of  the 
dividing  line  the  voltage  is 
on  at  a  given  moment.  Mis- 
matched LEDs  can  misin- 
form you,  This  trouble  was 
not  encountered  with  bar- 
graph  LEDs.  The  degree  of 
overlapping  of  LEDs  seems 
to  vary  from  IC  to  IC,  but  in 
no  case  has  it  proven  to  be 
such  a  problem  as  to  pro- 
duce false  impressions  of 
the  line  voltage. 

If  you  use  a  home-brew 
power    source,    you    can 

73  Magazine  •  August,  1982    85 


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fig  3,  Power  and  signal  source  for  the  tine  voltage  monitor, 
(a)  Home-brew  power  source,  (b)  Ac  adapter  module  power 
source. 


build  it  on  a  separate  board 
or  use  one  board  for  the 
supply  and  meter  sections. 
With  an  ac  adapter,  the  ad- 
ditional components  can  go 
on  the  meter  board  with  the 
IC  and  pots.  The  only  pre- 
caution with  the  power 
source  is  to  use  it  for  no  oth- 
er purpose.  The  varying 
load  created  by  a  second- 
ary use  will  alter  the  volt- 
age to  the  signal  input ,  de- 
stroying the  utility  of  the 
meter. 

The  entire  assembly  is 
compact  and  will  fit  cases 
as  small  as  2"  X  2"  X  4" 
(with  an  ac  adapter  supply). 
The  components  also  can 
be  mounted  within  another 
piece  of  equipment  as  long 
as  there  is  room  somewhere 
for  the  LED  display.  If  your 
shack  has  a  master  ac  con- 
trot  panel,  a  small  corner 
will  be  enough  for  the  LED 
array, 

Calibrating  the  Meter 

Many  of  us  have  grown 
accustomed  to  using  fixed 
components  or  having 
equipment  factory-cali- 
brated. In  the  process,  we 
may  lose  sight  of  the  fact 
that  building  an  adjustable 
circuit  can  lead  to  a  far 
more  accurate  instrument 
Hence,  potentiometers 
have  been  used  rather  than 
fixed  voltage  dividers. 

The  line  voltage  monitor 

86     73 Magazine  •  August,  1982 


described  here  can  be  cali- 
brated at  two  levels  of  ac- 
curacy: close  and  right  on. 
Close  calibration  requires 
only  a  fairly  accurate 
VTVM  and  a  little  arithme- 
tic. To  get  the  meter  right 
on  requires  a  factory-cali- 
brated meter  (for  ac  and  dc 
voltages)  and  a  simple  test 
circuit.  The  close  calibra- 
tion technique  is  also  a 
good  preliminary  step  for 
later,  more  precise  calibra- 
tion. 

Let's  begin  with  a  little 
math.  Suppose  we  let  a  sig- 
nal input  voltage  of  2  volts 
dc  to  pin  5  of  the  LM3914 
equal  110  volts  ac.  The  volt- 
age division  factor  is  55, 
(We  could,  of  course,  use 
other  ratios,  within  limits,) 
This  factor  will  apply 
throughout  the  meter 
range.  Dividing  90  volts  ac 
by  55  gives  us  a  value  of 
1.64  volts  dc  as  the  lower 
limit  control,  Measure  the 
voltage  at  pin  4  and  set  the 
LO  pot  for  this  voltage.  Sim- 
ilarly, 140  volts  ac  divided 
by  55  gives  2,55  volts  dc  as 
the  value  we  want  at  pin  6; 
adjust  the  HI  pot  for  this 
value.  The  HI  and  LO  pots 
may  interact  a  bit  for  this 
degree  of  accuracy,  so 
tweak  both  several  times  to 
set  thefinal  values.  Now  ad- 
just the  SIG  pot  until  the 
correct  LED  lights  for  the 
actual  value  of  ac  voltage. 


Use  caution  here.  Most 
kit  VTVMs  were  aligned  for 
110  volts  ac  from  the  exist- 
ing line  voltage.  Thus,  they 
will  be  no  more  accurate  on 
ac  than  the  original  adjust- 
ment. If  you  can  borrow  a 
well-calibrated  instrument 
or  visit  a  lab  bench  for  a  few 
minutes,  you  can  set  the 
line  monitor  on  target 
quickly.  Do  not  expect  to 
read  exactly  2  volts  for  110 
volts  ac,  because  there  will 
be  a  slight  offset,  but  the 
degree  of  inaccuracy 
caused  by  this  is  under  1 
percent.  With  a  little  tweak- 
ing back  and  forth  of  the 
signal  input  pot,  you  will  be 
able  to  set  the  voltage  very 
accurately  by  watching  for 
the  overlap  effect  on  the 
LEDs, 

The  monitor  is  very 
usable  calibrated  this  way, 
but  if  you  wish  to  be  more 
accurate,  try  the  circuit  in 
Fig,  5.  This  circuit  lets  you 
vary  the  ac  voltage  to  the 
monitor  across  the  full 
range  of  the  instrument. 
Use  care,  because  the  volt- 
age can  be  lethal,  and  there 
is  a  tendency  to  grow  a  bit 
careless  after  handling  the 
low  voltages  we  use  on  ICs, 
The  5k  pot  should  be  4 
Watts  or  more  and  well  in- 
sulated from  your  hands. 

As  the  drawing  shows,  we 
will  monitor  the  line  volt- 
age as  we  calibrate  the  me- 
ter. If  we  wish,  we  also  can 
monitor  the  voltage  to  the 
control  and  signal  pins,  but 
this  is  not  strictly  necessary. 
If  we  have  performed  an  ini- 
tial calibration  as  described 
above  with  some  care,  we 
should  be  close  enough  to 
make  the  precision  calibra- 
tion easy. 

First,  recheck  that  the 
correct  LED  lights  with  a 
voltage  in  the  110-to-120 
range,  Now  we  will  run  the 
ac  voltage  up  and  down, 
checking  the  voltage  at 
which  the  LEDs  change 
from  one  to  the  next.  (For 
these  tests  we  will  ignore 
the  absolute  limits,  since 
the  transitions  are  more  ac- 
curate.) If  the  voltage  tran- 


sitions are  not  at  the  five- 
volt  marks  and  they  are 
consistently  off  by  a  con- 
stant amount  in  the  same 
direction  (for  example,  a 
volt  too  high  or  a  volt  and  a 
half  too  low),  then  adjust 
the  SIC  pot  to  bring  the 
transitions  on  line.  If  the 
amount  of  error  at  transi- 
tion toward  the  low  end  of 
the  scale  is  not  constant 
after  bringing  the  SIC  pot  as 
close  as  possible  to  the 
right  point,  then  adjust  the 
LO  pot  until  the  changes, 
especially  the  95-volt  transi- 
tion, are  correct.  Do  the 
same  for  the  upper  end  of 
the  range. 

Remember  that  the  two 
pots  may  interact  just  a  bit, 
so  recheck  each  end  of  the 
line.  Be  sure  to  make  all  ad- 
justments slowly,  and  verify 
that  you  are  moving  in  the 
correct  direction  before 
making  a  sizable  change. 
Large  hasty  changes  can 
throw  everything  off.  But  if 
everything  does  go  askew, 
you  can  set  it  back  in  the 
ball  park  with  a  repeat  of 
the  first  alignment  pro- 
cedure. 

Now  recheck  the  align- 
ment, and  you  should  be 
right  on,  At  most,  you  may 
have  to  adjust  the  SIG  pot  a 
hair  more.  Although  the  re 
sistor  divider  circuits  show 
combinations  of  fixed  and 
variable  resistors,  they 
could  be  replaced  by  50k 
pots.  However,  there  would 
be  a  loss  of  fine  calibration 
control,  so  the  cost  of  the 
three  fixed  resistors  is  well 
justified. 

After  using  the  monitor 
for  several  weeks,  recheck 
the  calibration.  Compo- 
nents do  change  value  dur- 
ing their  lives,  but  most  of 
the  change  (if  not  cata- 
strophic) is  either  very  early 
or  very  late  in  their  life- 
times. Hence,  after  "burn- 
ing in"  the  monitor  for  a 
few  weeks,  a  check  of  the 
calibration  should  produce 
a  stable  monitor  that  needs 
to  be  tested  only  during 
your  regular  station  main- 
tenance checks. 

Reader  Service  for  facing  page  *ffr+ 


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Fig,  4.  One  of  many  possible  panel  layouts  for  the  LEDs. 


What  the  Monitor 
May  Tell  You 

The  line  voltage  monitor 
described  here  is  designed 
to  be  accurate,  but  not  to 
yield  precise  voltage  mea- 
surements. Within  close 
limits,  it  will  indicate  the 
five-volt  range  of  the  cur- 
rent ac  line  voltage  feeding 
your  equipment.  For  many 
purposes,  these  readings 
will  be  sufficient.  Closer 
readout  of  the  voltage  re- 
quires either  a  meter  or  a  re- 
design of  the  present  cir- 
cuit- By  adjusting  the  upper 
and  lower  limits,  a  smaller 
voltage  range  can  be 
spread  across  the  same  ten 
LEDs.  For  example,  within 
the  general  parameters  of 
the  two-step  calibration 
procedure  described  ear- 
lier, setting  the  LOHI  range 
between  2.09  and  2.27  volts 
would  permit  you  to  read 
the  ten  volts  between  115 
and  125.  If  such  precision  is 
desired,  a  second  set  of  re- 
sistor dividers  might  be 
switched  in  and  out  of  the 
circuit  (in  place  of  the 
50-volt  dividers)  with  a 
DPDT  switch. 

Since  the  primary  func- 
tion of  a  line  voltage 
monitor  in  the  shack  is  to 
warn  of  possibly  dangerous 
conditions,  such  precision 
is  rarely  required,  Most  of 
the  monitor's  utility  is  pro- 
vided by  the  wider  limits. 
This  is  especially  true  in  this 
day  and  age  of  brownouts, 
when  power  companies  — 
with  or  without  warning- 
may  lower  the  line  voltage 
to  100  volts  or  less.  Like- 
wise, in  some  regions  with  a 
heavy  industrial  daytime 
load,  early  evening  voltages 
have  been  reported  occa- 
sionally to  reach  135  volts. 

Most    household    equip- 

88     73  Magazine  •  August,  1982 


ment,  including  ham  gear, 
falls  into  four  main  catego- 
ries: motors,  lighting,  heat- 
ing, and  electronic  devices. 
Variations  in  line  voltage 
can  affect  all  four  types  of 
equipment,  some  more  rad- 
ically than  others.  Motor- 
ized equipment  such  as 
furnace  fans,  refrigerators, 
air  conditioners,  vacuum 
cleaners,  stove  fans,  and 
the  like  all  operate  less  effi- 
ciently as  the  voltage  is  re- 
duced. Some  types  of  mo- 
tors can  be  damaged  if  the 
voltage  drops  too  low  and 
the  motor  is  loaded  heavily. 
In  general,  if  the  voltage 
either  drops  below  105  or 
rises  above  125,  it  is  best  to 
shut  down  motors  which 
must  work  hard.  This  in- 
cludes air  conditioners,  re- 
frigerators, power  tools, 
and  similar  equipment. 
Lighter  duty  motors,  such 
as  fans,  may  be  run  to  wider 
voltage  I  imits,  but  do  not  be 
surprised  should  one  fail.  If 
any  part  of  the  motor  has  a 
weak  spotP  radical  voltage 
excursions  are  one  way  of 
discovering  it  These  cau- 
tions do  not  mean  that  ev- 
ery drop  or  rise  in  voltage 
will  mean  catastrophe;  rath- 
er, they  are  suggestions  for 
preventing  a  possibly  siz- 
able replacement  cost. 

Lighting  devices  are  gen- 
erally of  two  sorts:  incan- 
descent and  fluorescent. 
Light  bulbs  wilt  react  to  line 
voltage  variations  by  pro- 
ducing more  or  less  light 
and  heat.  The  power  drawn 
by  the  bulb  will  vary  ap- 
proximately as  the  square 
ot  the  voltage  changes, 
since  the  current  will  also 
rise  and  fall  with  the  volt- 
age. The  relationship  is  not 
exact,  since  filaments 
change  their  resistance  with 
heat.   While  reduced  volt- 


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Fig.  5,  Test  setup  for  calibrating  the  line  voltage  monitor. 


age  is  an  annoyance  due  to 
the  reduced  light  output  of 
bulbs,  excess  voltage  is  a 
bulb  killer.  A  10%  voltage 
rise  means  approximately  a 
20%  power  increase,  with 
an  accompanying  increase 
in  heat  Using  the  national 
average  ac  line  voltage  of 
117  as  a  standard,  as  little 
as  129  volts  will  produce 
this  effect.  Fluorescent  fix- 
tures are  less  evident  in 
their  reaction  to  line  volt- 
age variations,  but  harder 
starting  may  not  always 
mean  a  bad  condenser  A 
quick  check  with  the  line 
voltage  monitor  is  in  order 
first 

Electrical  heating  de- 
vices, such  as  stove  and 
oven  elements,  are  much 
like  incandescent  bulbs. 
Their  heat  output  will  vary 
as  the  line  voltage  varies, 
and  so  will  the  mechanical 
wear  of  the  element.  These 
are  usually  hardy  devices, 
and  often  the  adjacent  wir- 
ing has  a  shorter  lifetime 
than  the  element  Nonethe- 
less, expect  slower  cooking 
during  brownouts. 

Electronic  devices  react 
to  line  voltage  variations  in 
many  ways,  Simple  devices, 
such  as  tabletop  radios  and 
stereo  equipment,  usually 
show  no  effects  from  mod- 
erate drops  or  rises  in  line 
voltage.  More  complex 
equipment,  such  as  televi- 
sion sets,  may  show  some 
effects,  especially  with  age. 
If  accumulated  dirt  and 
other  factors  have  lowered 
the  high  voltage  to  where  it 
just  holds  the  picture  at  full 
size,  a  brownout  can  show 
itself  as  picture  shrinkage. 
Other  effects  are  usually 
minor, 

Critical  equipment,  such 


as  computer  terminals, 
should  have  heavy,  very 
well  regulated  supplies,  and 
the  voltage  feeding  the  reg- 
ulator should  not  be  mar- 
ginal If  these  conditions 
are  met,  then  there  are  usu- 
ally few  problems  How- 
ever, if  the  supply  voltage 
to  the  regulator  is  marginal, 
a  severe  drop  in  line  voltage 
may  yield  a  temporarily  un- 
regulated supply,  with  con- 
sequent problems  in  TTL 
chips,  memory,  and  other 
parts  of  the  system. 

Amateur  transmitters 
and  amplifiers  will  show  the 
effects  of  line  voltage  varia- 
tions in  power  output  read- 
ings In  a  transceiver  or  an 
average  transmitter,  plate 
voltage  is  usually  not  me- 
tered. Suppose  your  power 
output  meter  shows  a  10% 
drop  from  the  previous 
day's  reading.  One  suspi- 
cion that  naturally  arises  is 
that  the  final  tubes  might 
be  going  soft.  However,  a 
drop  in  line  voltage  can  pro- 
duce the  same  effect.  A 
10%  drop  in  line  voltage 
may  reduce  the  plate  volt- 
age by  60  to  75  volts,  de- 
pending upon  transmitter 
design.  Control  positions 
also  may  change  under 
these  conditions,  since  the 
tube  now  exhibits  a  differ- 
ent plate  resistance. 

Rising  line  voltage  also 
can  yield  misleading  symp- 
toms. Many  of  us  have 
grown  used  to  tuning  up  a 
transmitter  to  maximum 
power  output,  as  read  from 
an  rf  wattmeter  or  relative 
power  indicator.  A 10%  rise 
in  plate  voltage  may  give  us 
a  temporary  boost  in  power 
output  a  condition  which 
may  make  us  proud  for  a 
moment  of  the  equipment 


manufacturer's  ingenuity. 
However,  if  the  line  voltage 
is  in  fact  high,  then  the  best 
bet  is  to  reduce  power 
slightly  in  exchange  for 
longer  tube  life.  The 
miniscule  difference  in 
power  at  a  receiving  station 
cannot  be  noticed,  but  the 
cost  of  replacement  finals 
is  almost  always  notice- 
able. 

Amplifiers  capable  of  the 
maximum  legal  power  for 
amateurs  must  have  a 
means  of  measuring  both 
voltage  and  current  so  that 
we  can  hold  them  within 
limits.  Since  most  amplifi- 
ers are  capable  of  loading 
to  greater  than  1000  Watts 
dc  or  2000  Watts  PEP  input 
we  cannot  simply  choose  a 
standard  level  of  plate  cur- 
rent and  assume  that  we  are 
within  the  legal  power  limit, 
A  10%  rise  in  line  voltage 
can  produce  a  correspond- 
ing rise  in  plate  voltage.  Re- 
ducing plate  current  is  then 
the  only  way  to  hold  the 
power  within  limits. 


These  sample  potential 
problems  and  conditions 
make  a  strong  case  for  mon- 
itoring line  voltage.  Some 
of  us  are  lucky  enough  to 
live  in  areas  which  never  — 
or  hardly  ever— have 
brownouts.  High  line  volt* 
ages  are  even  more  rare. 
However,  the  small  price  of 
a  monitor  will  be  more  than 
offset  if  we  detect  a  condi- 
tion early  enough  to  save 
the  cost  of  a  service  call  or 
replacement  parts.  For  this 
degree  of  safety  and  pre- 
ventive medicine,  we  need 
an  accurate  monitor, 
although  we  do  not  always 
need  to  know  the  exact 
number  of  volts.  The  LED 
line  monitor  described  here 
can  fulfill  the  need,  while 
providing  an  interesting 
weekend  of  building  and 
calibrating.  I 

Reference 

"Guard  Your  Battery  with  PMs 

Charge  Checker/"  Weinstein 
and  Gartman,  Popular  Mechan- 
ics, May,  1979,  p.  94. 


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73  Magazine  •  August,  1982    S9 


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See  Ust  of  Advertisers  on  page  1 14 


73  Magazine  •  August,  1982     91 


(   SOCIAL  EVENTS 


Ustfng$  in  this  column  am  provided  tree  of 
charge  on  a  space-available  basis.  The  tol- 
lowing  information  should  be  included  in 
every  announcement  sponsor,  event  date, 
time,  place,  city,  state,  admission  charge  Of 
anyk  features,  talkin  freouencies,  and  the 
name  of  whom  to  contact  tor  further  informa- 
tion. Announcements  most  he  recerved  at  73 
Magazine  by  the  first  of  the  month,  two 
months  prior  to  the  month  in  which  the  event 
takes  place.  Mat}  to  Editorial  Offices,  73  Mag- 
azine, Pine  Street.  Peterborough  NH  03458, 


FLAGSTAFF  AZ 
JUL  30-AUG  1 

The  Amateur  Radio  Council  of  Arizona 
will  hold  its  32nd  annual  ham  fast  from  July 
30  through  August  1,  1982,  at  the  Fort  Tul 
hill  Fairgrounds,  just  a  tew  miles  south  of 
MO,  Flagstaff  AZ,  There  will  be  thousands 
of  do  liars  In  prizes,  Improved  XV  L  activities, 
a  swap Jost.  a  transmitter  hunt,  speakers, 
forums,  awards,  exhibits,   and  entertain 
ment  on  Friday  and  Saturday  nights.  Over 
night  camping  facilities  will  be  available 
Talk-rri  on  1 47.870/  146270   For  furthe*  in* 
formation,   contact  Wm,   Oliver  Grieve 
VV7WGW,  4301  N.  31  si  Avenue.  Phoenix  AZ 
85017.  or  call  C60z>24dO20u\ 

K1NGSFORD  Mr 
JUL  31  AUG  1 

The  MIchA-Con  ARC  will  hold  the  34lh 
annual  UP  Hamfest  en  Saturday.  July  31. 
and  Sunday.  August  1, 1982,  at  the  Dickin- 
son County  Armory  on  M-96.  Kingsford  Ml. 
Tickets  are  $2  50  at  the  door  (no  advance 
sales)  and  registration  will  begin  at  9:00 
am  on  both  days.  There  will  be  prizes,  fam- 
ily activities,  and  a  Saturday  night  ban- 
quet. Advance  banquet  reservations  are 
needed  since  seating  is  limited.  Plenty  of 
free  parking  will  be  available.  Talk-In  on 
146.25/85  and  3922.  For  further  in  forma 
lion,  write  UPHAMFEST.S2,  105  East  Brel* 
tung  Avenue.  Kingsford  Ml  49801. 

ANGOLA  IN 
AUG  1 

The  Steuben  County  Radio  Amateurs  will 
hold  the  24th  annual  FM  Picnic  and  Ham- 
test  on  Sunday,  August  1, 1982,  at  Crooked 
Lake,  Angola  IN.  Admission  Is  $2.50,  There 
will  be  prizes,  picnic  style  BBO  chicken,  In- 
side tables  tor  exhibitors  and  vendors,  and 
overnight  camping.  (A  fee  will  be  charged 
by  county   park.|  Talk-in  on   140.52  and 

PITTSBURGH  PA 
AUG  1 

The  45th  annual  South  Hills  Boss 
Pounders  and  Modulators  Manifest  will  be 
held  on  August  1,  1982,  from  10;00  am  to 
4:00  pmr  at  South  Campus,  Community 
College  of  Allegheny  County,  Pittsburgh 
PA.  Admission  is  $2  00  or  3  for  $5,00 
There  will  be  computer.  OSCAR,  and  ATV 
demonstrations  as  well  as  a  flea  market, 
Talk-in  on  1 46,13473  and  148  52.  For  fur- 
ther information,  contact  Andrew  L  Palo 
WA3PBD  1433  Schauffler  Drive,  West 
Homestead  PA  15120. 

BELVIDERE  IL 
AUG  1 

The  Big  Thunder  ARC  will  hold  its  annual 
hamfesi  on  Sunday,  August  1,  1982,  at  the 


Boone  County  Fairgrounds,  Route  76.  BeM- 
dere  IL  Admission  is  $200  In  advance  and 
$2.50  at  the  gate  A  fee  wilt  be  charged  for 
8-foot  tables  and  there  will  be  indoor  space 
available  in  the  exhibit  building,  as  well  as 
outdoor  space  In  swappers  row.  Sellers 
will  be  able  to  set  up  Saturday  evening  or  at 
?  00  am  on  Sunday.  Features  will  include 
door  prizes,  a  main  prize,  food,  and  refresh 
ments.  Camping  will  be  available  on  Satur 
day  evening  (there  will  be  a  charge  for  elec- 
tricity). Talkin  on  148.52  and  147.975/ 
147.375.  For  further  information  or  tickets, 
send  an  SASE  to  Jim  Grimsby.  418  Beacon 
Drive,  Belvidere  IL  61008. 

LEVELLAND  TX 
AUG1 

The  Hockley  County  Amateur  Radio  Club 
and  thB  Northwest  Texas  Emergency  Net 
will  hold  their  17th  annual  picnic  and  swap- 
test  on  Sunday,  August  1,  19B2,  beginning 
a  I  8:00  am  at  the  city  park  in  Level  land  TX. 
This  event  Is  for  the  entire  family.  Bring 
your  own  pic  n  ic  bask  e  M  or  lunch  a  1 1 2:30.  A 
two-meter  FM  transceiver  is  the  grand 
prize.  A  S3  00  registration  is  requested  but 
not  required.  There  will  be  swapping  all  day, 
with  tables  provided.  Talk-in  on  .28/88 

AUQ1 

The  Black  River  Amateur  Radio  Club  will 
hold  the  29th  annual  Southwestern  Michi- 
gan VHF  Picnic  on  Sunday.  August  1, 1982. 
at  the  West  Side  County  Park  tmat  Glen  Ml 
(Take  exit  30  from  i -196  and  follow  the 
signs.)  There  will  be  swimming,  a  of  ay- 
ground,  *  small  flea  market,  and  door 
prizes.  There  is  no  food  available  at  the 
parte,  so  bring  your  own  picnic  basket  Reg- 
istration is  $t  00,  For  additional  inform  a- 
tion,  contact  Ed  Alderman  KIBZ.  RR  #2,  Box 
44,  Lawrence  Ml  49064 

POMONA  CA 
AUG  7 

The  Tn-Couftty  Amateur  Radio  Associa- 
tion will  hold  Its  annual  hamf est/ picnic  on 
Saturday,  August  7,  1982,  from  7:00  am  to 
1:00  pm,  at  the  Los  Angeles  County  Fair- 
grounds, Pomona  CA.  Ail  buyers,  sellers, 
and  computer  buffs  are  welcome.  There  will 
be  prizes,  exhibits,  and  refreshments.  Talk- 
in  on  148,0Z6A625,  For  more  Information, 
write  to  TGARA  Hamfest  Chalrrhan  W6ELZ. 
PO  Bo*  142,  Pomona  CA  917$9. 

JACKSONVILLE  FL 
AUG  7-8 

The  Greater  Jacksonville  Hamfesi  Asso- 
ciation will  hold  the  annual  Jacksonville 
Hamfesi  and  Northern  Florida  ARRL  Con- 
vention on  August  7-8,  1982,  at  the  Orange 
Park  Kennel  Club,  located  near  the  Inter- 
section of  (295  and  US  17  Just  south  of 
Jacksonville,  Advance  registration  is  S3. 50 
and  is  available  from  Robert  J.  Cutting 
W2KGI,  1249  Cape  Charles  Avenue,  At  Ian- 
tic  Beach  FL  32233.  Registration  at  the  door 
is  $4.00.  The  FCC  will  administer  amateur 
and  commercial  radio  operator  exams  on 
Friday,  August  8th,  at  the  hamfesi  site. 
Those  wishing  to  take  the  exams  should  ap- 
ply to  the  Atlanta  FCC  office  as  soon  as 
possible.  Swap  tables  are  112.00  per  table 
for  both  days  (no  one-day  tables)  and  table 
reservations,  as  well  as  advance  registra- 
tions,  are   available  from  Andy   Burton 


NX4G.  5101  Yotinis  Road,  Jacksonville  FL 
32218,  A  lull  stale  of  programs  is  sched- 
uled, aiong  with  meetings  Of  statewide  and 
regional  nets  and  organizations,  plus  com- 
petitions including  a  rabbit  hunt  and  pileup 
contest.  The  head  Qua  tiers  hotel  is  the  Best 
Western  First  National  Inn  Just  across  from 
the  hamfest,  Special  rates  may  be  obtained 
by  writing  to  Jim  Can  field  KD4CG,  996 
Dostie  Circle,  Orange  Park  FL  33073.  TaIMn 
On  146,16/76  and  148.07/67. 


MONTGOMERYVILLE  PA 
AUG  8 

The  Mid  Atlantic  Amateur  Radio  Club  an- 
nounces Its  annual  J.  B.  M.  Hamfest  to  be 
held  on  Sunday,  August  8,  1982,  from  9:00 
am  to  4:00  pm,  rain  or  shine.  Tailgate  setup 
begins  at  8:00  am.  Located  at  ihe  Route  309 
Drive-fn  Theater,  1/4  mile  north  of  Route  83, 
Montgomery^! He.  PA  (6  miles  north  of  the 
Fort  Washington  interchange  of  the  Penn- 
sylvania Turnpike).  Ad  miss  ion:  £2  SO,  with 
Si. 00  additional  for  each  tailgate  space. 
Non-licensed  XYLs  and  children  admitted 
free.  Ample  parking,  refreshments,  raffles, 
door  prizes,  and  more,  Talk-in  on  WB3JOE/R 
(147.66/.061  or  148.52  simplex.  For  further  In- 
formation,  write  the  club,  PO  Box  352, 
Vlilanova  PA  19085. 

SAUK  RAPIDS  MN 
AUGS 

The  St.  Cloud  Radio  Club  will  hold  its 
annual  hamfest  on  Sunday,  August  8. 
1982*  from  8  30  am  lo  4:00  pm,  at  the  Sauk 
Rapids  Municipal  Park,  Sauk  Rapids  MN 
Talk-in  on  146.34/.94.  For  more  intorma- 
tion,  contact  Mike  Lynch,  21  \5-isl  Street, 
St.  Cloud  MN  56301,  or  call  (612)  251  2297. 

SONOMA  CA 
AUG  6 

The  Valley  of  the  Moon  Amateur  Radio 
Club  will  herd  its  third  annual  ham  break- 
fast and  swap  meet  on  Sunday.  August  8, 
1982,  from  9:00  am  lo  4.-00  pm,  at  the 
Sonoma  Community  Center,  276  East  Napa 
Street.  Sonoma  CA.  Breakfast  is $3.50  each 
for  sduits  and  SU5  each  for  children  under 
12,  Waitresses  will  serve  breakfast  to  peo- 
ple manning  swap  tables.  Hot  dogs  will  be 
served  for  lunch,  Swap  spaces  are  $5.00 
each  and  tables  can  be  set  up  beginning  at 
8:00  am,  (Since  there  are  only  30  tables 
available,  plan  io  bring  your  own.j  Admis- 
sion, including  a  raffle  ticket,  ts  Si. 00  and 
tykes*  YLs.  and  XYLs  will  be  admitted  free- 
Featured  will  be  computer  displays  and 
demonstrations,  an  operating  10-meter  FM 
station,  a  Sonoma  Valley  Quitters"  table,  an 
amateur  television  display,  an  open  auction 
at  2:00  pm,  and  a  raffle  at  3:30  pm.  Talk-In 
on  147.47  simplex  and  146.13/73,  For  fur- 
Iher  information,  call  Darrel  WD6BOR  at 
f7O7V938'8086;  for  swap  space  reser- 
vations, write  VGMARC,  353  Patten  Street. 
Sonoma  CA  95476,  enclosing  paymesrt 
Of  15.00. 

HOUSTON  TX 

AUG  13-15 

The  Texas  VHF  Society  1982  Summer 
Meeting  will  be  held  on  August  13-15, 1982, 
at  the  Nassau  Bay  Resort  Motor  Inn.  John- 
son Spacecraft  Center,  Houston  TX  Pre- 
registration  Is  $5.00  for  all  three  days  and 
includes  one  free  ticket  for  a  pre-registra- 
tion  drawing.  Each  additional  prize  ticket  is 
Sr  00.  Registration  at  the  door  Is  16.00  and 
does  not  includes  prize  ticket  There  will  be 
special  tours  of  NASA,  exhibits,  a  flea  mar- 
ket, a  ham  astronaut  speaker,  space  shuttle 
communications,  and  VHF  and  ARRL  semi- 
nars. Prizes  include  en  all-mode  VHF  trans- 
ceiver. Talk-In  on  146  04/64  and  147,75/,  15. 
For   pre- registrar  on   Information,  write 


Texas  VHF  FM  Society,  Summer  Session, 
C/0  PO  Box  73,  Texas  Cm/  TX  77590. 

TACOMA  WA 
AUG  14-15 

The  Radio  Club  of  Tacoma  will  hold 
Hamfair  62  on  August  14*15,  1982.  at  Ihe 
Pacific  Lutheran  University  campus,  Ta- 
coma WA.  Registration  Is  S5.0Q  and  dinner 
is  $7.50.  Activities  will  include  technical 
seminars,  a  ilea  market,  commercial 
booths,  an  ARRL  meeting,  a  repeater  fo- 
rum, a  VHF  tweak  and  tune  clinic,  prizes, 
raffles,  and  a  loggers'  breakfast,  Talk-in 
on  i47.B&/,28-  For  more  information,  con- 
tact Grace  Teitzel  AD7S.  70t  So.  120th, Ta- 
coma WA  98444,  or  phone  (206)<  564^6347. 

WILMINGTON  OE 
AUG  15 

The  seventh  annual  New  Delmarva  Ham- 
fesi will  be  held  on  Sunday.  August  15, 
1382,  from  8:00  am  lo  4:00  pm  at  Gloryland 
Park.  Bear  DE  (5  miles  south  of  Wilming- 
ton}. Admission  is  $2-25  in  advance,  $2,75  at 
the  gate.  Tail  gating  Is  $3.50.  Limited  tables 
will  be  available  under  the  pavilion,  bul 
bring  your  own  to  be  sure.  Food  and  drinks 
will  be  available.  First  prize  Is  an  Atari* 
Home  Video  Game  System,  Talk-In  on  ,52 
and  -13/.53.  For  more  Information  and  a 
map,  send  an  SASE  to  Stephen  Momot 
K3HBP.  14  Balsam  Road;  Wilmington  DF 
19804.  For  advance  tickets,  make  checks 
payable  to  Delmarva  Hamfest,  Inc. 

AMESIA 
AUG  15 

The  Iowa  75  Meter  Net  will  hold  a  picnic 
and  swapfest  on  Sunday,  August  15, 1982, 
at  River  Valley  Park,  Ames  I  A.  A  pot  luck 
meal  will  be  held  at  12:00  noon,  with  a  pro- 
gram and  prizes  to  follow.  Talk-in  on  ,16/ 
.78-  For  further  information,  contact  Lovetle 
J.  Pederson  WBflJFF.  Hudson  IA  50643. 


LAFAYETTE  IN 

AUG  15 

The  Tippecanoe  Amateur  Radio  Associ 
ation  will  hold  Its  nth  annual  hamfest  on 
Sunday,  August  15,  1982r  beginning  et 
7:00  am.  at  the  Tippecanoe  County  Fair- 
grounds, Teal  Road  and  128th  Street.  La- 
fayette IN,  Tickets  are  $3.00  Features  will 
include  a  large  flea  market,  dealers,  fun, 
refreshments,  and  prizes.  Talk-in  on 
13/.73  or  ,52.  For  advance  tickets  or  addi- 
tional information,  write  Lafayette  Ham- 
fesi, Route  1,  Box  63,  West  Point  IN  47992. 


TIOGA  COUNTY  PA 
AUG  21 

The  Tioga  County  PA  ARC  8th  Annual 
Amateur  Radio  Hamfest  will  be  held  on  Sat- 
urday. August  21. 1982,  from  0800  to  1600  at 
a  new  location  at  Island  Park,  just  off  US 
Rte  15,  Blossburg  PA.  There  will  be  a  flea 
ma/ket.  food,  free  camping,  an  auction,  an 
H/T  door  prize,  etc.  Tatk-in  on  Jf|r.79  and 
52  For  more  information  or  advance  tick- 
ets, write  Tioga  Co,  ARC,  PO  Box  56,  Mans- 
field PA  16933,  or  contact  Paul  San  do 
KC2AZ,  606  Reynolds  Street.  Elm  Ira  NY 
14904  on  A 9/ 79 or  96/36 


DUNKIRK  NY 
AUG  21 

The  Northern  Chautauqua  Amateur 
Radio  Club  will  hold  the  4th  annual  Lake 
Erie  International  Hamfesi  on  Saturday, 
A  ug  ust  21 . 1 982,  at  the  Chautauq  u  a  Coun  ty 
Fairgrounds.  Dunkirk  NY,  There  will  plenty 
of  outdoor  and  Indoor  flea-market  space. 
Prizes  will  include  an  I  com  IG-2A.  Talk- In  on 
146.25^85  and  146.07/67.  For  more  informa- 


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73Magazine  •  August,  1982     93 


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Hon,  contact  fton  Warren  WA2LPB,  PO  Box 
455,  Dunkirk  NY  1404& 

OAKLAND  NJ 
AUG  21 

The  Ramapo  Mountain  Amateur  Radio 
Club  (WA2SNA)  will  hold  its  6th  annual  f tea 
market  on  August  21.  1982,  al  ihe  Oakland 
American  Legion  Hall,  65  Oak  Street. 
Oakland  NJ+  only  20  miles  from  the  GW 
Bridge  Admission  is  Si. CO;  non-ham  family 
members  will  be  admitted  free.  Indoor 
tables  are  S6  50  and  tai  [gating  is  S3  00 
There  will  be  a  quality  open  kitchen,  and 
door  prizes,  including  an  tcom  iC^ZAT,  wilt 
be  given  away  Talk  in  on  1 47.49* 146.49  and 
.52,  For  additional  information,  contact 
Walt  Zierenberg  WD2AAI,  34J  Union 
Avenue,  Bloomingdala  NJ  07403,  or  phone 
(2Q1)-83S-7565 

HUNTSVILLE  AL 
AUG  21-22 

The  Huntsvitte  Hamfest  will  be  he*d  on 
Saturday  and  Sunday,  August  21-22,  1962. 
at  tne  Von  Braun  Civic  Center  in  Huntsville 
AL  There  is  no  admission  charge.  There 
will  be  prizes,  exhibits,  f arums,  an  air-condi- 
tioned indoor  flea  market,  and  non-ham  ac- 
tivities- Tours  of  the  Alabama  Space  and 
Rocket  Center  are  available  For  the  family. 
A  limited  number  of  camping  sites  with 
hookups  are  available  at  tne  VBCC  on  a 
lirstHcome,  first-served  basis  Flea-market 
tables  are  available  for  $4.00  a  day  Talk-in 
on  3.965  and  -34/94.  For  more  ^formation. 
write  Huntsville  Hamfest,  PO  Box  4583, 
Huntsville  AL  35802 

MARYSVILLE  OH 
AUG  21-22 

The  Union  County  Amateur  Radio  Club 
will  hold  the  Marysvllle  Hamfest  On  Satur- 
day afternoon  and  all  day  Sunday.  August 
21-22, 1962,  at  the  fairground  in  Marysviile 
{near  Columbus}  OH.  Admission  is  52  00 
in  advance  or  S3  00  at  the  gale  Hea  mar- 
ket space  ts  SI. 00  Food,  beve rages,  and 
free  overnight  camping,  movies,  and  pop- 
corn will  be  available.  Featured  on  Satur- 
day night  will  be  a  free  square  dance  (with 
a  hve  band)  fallowed  by  a  big  country 
breakfast  available  all  night.  Door  prizes, 
ladies'  programs,  and  ARRL  FCC,  and 
MARS  meetings  will  be  featured  on  Sun- 
day. TaJk-in  on  146  52  and  T 4 7. 99/39,  For 
additional  information,  write  UCARG, 
13613  US  38.  Marysviile  OH  43040.  or  call 
(513^644-0468, 

WENTZVULE  MO 
AUG  £2 

The  St.  Charles  Amateur  Radio  Clubr 
Inc.  will  hold  Hamfest  82  on  August  22. 
1982,  at  the  Went  iv  I  lie  Community  Cen- 
ter, Wentzvtlle  MO.  Tickets  in  advance  are 
Si  00  each  or  *  for  S3. 00;  at  the  door,  they 
are  SI  .50  each  or  4  for  S5.00  Admission  is 
S1.00  per  car.  There  will  be  prizes,  con- 
tests, a  flea  markei,  food,  and  air  condi- 
tioned exhibitions  buildings.  For  tickets, 
motel  and  camping  information,  prize 
lists,  dealer  reservations,  etc.,  write 
SCARC  Hamfeat  82,  c/o  Mike  McCrann 
WDQGSY,  25  Elm  Street,  St  Peters  MO 
63370. 

ST.  CHARLES  IL 
AUG  22 

The  Fox  River  Radio  League  wilt  host  the 
Illinois  State  ARRL  Convention  In  conjunc- 
tion with  its  annual  hamfest,  both  to  be 
held  on  August  22,  1962,  Irom  8"00  am  to 
4:00  pm,  at  the  Kane  County  Fairgrounds, 
St.  Charles  IL  Tickets  are  $2.00  in  advance 
and  $3.00  at  the  gate.  For  advance  tickets, 
send  an  SASE  lo  J,  Dubeck  KA9HQVT 1312 


94     73Magazine  •  August,  1982 


Bluebeif  Lane.  Batavia  IL  60510.  Them  will 
be  commercial  exhibits,  a  flea  market,  con- 
tests, demon sirat fens,  forums,  prizes,  and 
hot  food.  Talk-in  on  146,34.  Exhibitors,  deal 
ers,  and  vendors  snouKJ  contact  G.  R.  Isety 
WD9GIG,  736  Fellows  Street,  St.  Charles  IL 
60174 

ARGOS  IN 
AUG  29 

The  7th  annual  Marshall  County  ARC 
Hamfeal  will  be  held  on  Sunday,  August  29, 
1082.  from  B:00  am  to  2:00  pm,  at  Ihe  Mar- 
shall County  4H  Fairgrounds,  Argos  IN 
Eight-foot  tables  ate  available  for  S3.00  and 
dealers  will  be  abie  to  set  up  at  6:00  am. 
Features  will  include  commercial  exhibits, 
a  flea  market  refreshments,  and  hourly 
drawings,  Grand  prize  Is  £200.  Talk-in  on 
,07/.S74  146.52,  and  2229/224.5.  For  addl* 
ftonai  information  or  reservations,  write 
MCARC.  Box  151,  Plymouth  IK  46563. 

FLINT  Ml 
AUG  31 

The  Genesee  County  Radio  Club,  the  Bay 
Area  Amateur  Radio  Club,  the  Lapeer  Coun- 
ty Amateur  Radio  and  Repeater  Club,  the 
Saginaw  Valley  Amateur  Radio  Associa- 
tion, and  the  Shiawassee  Amateur  Radio 
Association  will  hotd  the  sixth  annual  Five 
County  Swap-rvShop  on  Sunday.  August 
29h  1962;  from  8:00  am  to  3:00  pm,  at  Sentiey 
High  School  1150  Qelsay  Road,  Flint  ML 
Tickets  in  advance  are  $2.00  per  person;  at 
t  he  door ,  S3 .00.  Ch  i  Idren  under  1 2  wl  H  be  ad- 
milted  free.  There  will  be  a  food  conces- 
sion, free  parking,  and  prizes,  including  a 
first  prize  of  a  Ten-Tec  580  Delta  and  280 
power  supply  or  S50Q  cash.  Talk-in  on 
146.52  and  I47.87y.27.  For  table  reserva- 
tions, contact  Perry  Baker  WASTHK,  9055 
Grand  Blanc  Road.  Gaines  Ml  46436,  or 
phone  (313^63S  7287. 


LEBANON  TN 
AUG  20 

The  Short  Mountain  Repeater  Club  will 
hold  the  Lebanon  Hamfest  on  Sunday. 
August  29,  1982,  at  Cedars  Of  Lebanon 
State  Park,  US  Highway  231 ,  Lebanon  TN. 
There  will  be  outside  facilities  only  and 
exhibitors  should  bring  their  own  tables. 
Food1  and  drink  wiU  be  available.  Talk- in 
on  146.31/146.91.  For  further  information, 
contact  Mary  Alice  Fanning  KA4GSB. 
4936  Danby  Drive.  Nashville  TN  3721V 

SEW  ELL  NJ 
AUG  29 

The  Gloucester  County  Amateur  Radio 
Club  will  hold  Its  fourth  annual  GCARC 
Ham/Compfest  on  Sunday  August  29, 
1962,  from  6:00  am  (o  3:00  pm  at  the 
Gloucester  County  Cor  lege.  Tan  yard  Road. 
Sewell  NJ.  Tickets  are  $2.00  in  advance 
and  $2.50  at  the  door.  The  tallgatersJ  and 
dealers1  charge  Is  $6.00  and  Includes  one 
free  admission.  Doors  wiJJ  open  at  7:00  am 
for  setup.  There  will  be  speakers,  semi- 
nars,, contests.  FCC  exams,  and  prizes,  in- 
cluding a  Radio  Shack  TRS-BO  computer 
and  a  Yaesu  FT-208R.  Talk-In  on  146.52 
and  147.78/,  18.  For  more  information,  con- 
tact GCARC  Mam  feat  Committee.  PO  Box 
370,  Pitman  NJ  08017.  or  phone  (609M56- 
0500  or  <609)-336-4841  (days)  or  (609)^29- 
2064  (evenings). 

HARRIS  BURG  FA 

bep  a 

The  Central  Pennsylvania  Repeater 
Association  wltl  hold  the  9th  annual 
Hamfest/Computerfest  on  September  5, 
1962.  beginning  at  B:00  am,  ai  the  Har- 
hstwrg  Farm  Show  parking  lot.  off  the 
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2-meter  band  Hjgh  efficiency  design  hoida 
down  generated  heat,  low  input  VSWR 
saves  battery  dram  by  your  radio's  t\nal 
amp.  Use  the  chart  to  see  which  VoCom 
Power  Amplifier  gives  you  the  power  out 
you'd  like  from  the  power  that  you  now  have 

Power  Pocket"  Mobile  Amplifier/Charger 

—  Simply  plug  in  your  Icom  IC-2A(T)  and 
you  have  a  25W  synthesized  mobile  rrg  — 
take  it  out  again,  ail  charged  and  rear 
when  you  want  hand-held  operation.  A 
cepts  any  IC-2A  version    Delivers  25W  RF 
output.    2'..W   audio    with   4"   speaker  to 
overcome   road  noise    Charge  pockei 
accepts  alt  Icom  battery  packs,  has  inc 
pendent   charging   switch,   indicator    M<c 
preamp  makes  Power  Pocket  compatible 
with    any    mobile    microphone   and   with 
Icom  speaker/mic 

5/8  HT  Gain  Antenna  boosts  reception  white 
giving  your  hand -held  full  quieting  out  of 
spots  you're  nearly  dead  in  with  a  rubber 
duck;  provides  excellent  improvement  Only 
8"  telescoped.  47"  extended  Better  than 
t  5:1  VSWR  BNC  connector 

Spnng-toaded    il4   wave   antenna  and  4" 
stubby  duck  also  available.  See  your  favonte 
amateur  radto  deafer, 

VoCom 

PRODUCTS  CORPORATION 

65  East  Palatine  Road 
Prospect  Heights,  IL  60070 

(312}  459-3680 


'Vc'O'.- 

' 


m-Amer«-ji  \wc 


w^Seir  List  of  Advertisers  on  page  tt4 


73  Magazine  •  August,  1982    95 


— 


signs  to  the  Farm  Show  building.}  Registra- 
tion is  £1.00;  sellers'  TOfool  space.  S5.QO. 
taitgaung.  Si. 00  Talk-in  on  144.876.47, 
1 46. 16/.  76,  and  .52^  For  more  information  or 
a  map,  contact  irvin  Sanders  K3IUY,  RD  #3. 
Box  FA53h  Harrlsburg  PA  17112,  or  phone 
f7l7HG9-2l8& 

HAMBURG  NY 
SEP  10-11 

Ham-O-Rama  *82  will  be  held  on  Frtday 
and  Sat  ur  day,  Sept  ember  10-11, 1962,  at  the 
Ene  County  Fairgrounds  near  Buffalo  NY, 
Hours  are  6:00  pm  to  9:00  pm  on  Friday  and 
7:00  am  to  5:00  pm  on  Saturday.  Advance 
ticket  a  are  $3.50  (deadline:  September  1st) 
and  tickets  at  the  gate  will  be  $4  50  Chil- 
dren under  12  will  be  admitted  free.  The  out 
side  f tea  market  is  $3.00  per  space  and  the 
inside  Ilea  markei  is  Si 0-00  per  space.  Fea- 
tures will  include  new  equipment  displays, 
computers,  technical  programs,  ladies'  pro- 
grams, and  valuable  awards.  Talk-in  on 
146,31/31.  For  advance  tickets,  send  an 
SASE  to  Dave  Baco  WA2TVT,  130  Veoola 
Avenue,  Cheek  tow  ago  NY  14225. 

UNIONTOWN  PA 
SEP  11 

Trie  Unioritown  Amateur  Radto  Club  will 
hold  its  33rd  annual  gatrfest  on  Saturday! 
September  1 1 .  1982,  on  the  club  grounds  lo- 
cated on  the  Old  Pittsburgh  Road,  Just  off 
Route  51  and  the  119  bypass,  Unlontown 
PA.  The  pr ^registration  fee  is  £2,00  each  or 
3  for  15,00,  There  will  be  free  parkins,  free 
coffee,  and  free  swap  and  shop  setups  with 
registration.  Prizes  will  be  awarded,  includ- 
ing a  first  pnze  of  a  Ten-Tec  Argosy  525  HF. 
Featured  will  be  a  OX  contest,  demonst ra- 
tions, and  refreshments-  Talk-in  on 
147.D45/.B45,  144.57M45.17  and  146.S2/.52. 
For  further  Information,  contact  UARC 
G  ablest  Committee,  do  John  T.  Cermak 
WB3DOD,  PO  Bom  433,  Republic  PA  15475T 
or  phone  (412^24&287a 

AUGUSTA  NJ 
SEP  11 

The  Sussex  County  Amateur  Radio  Club 
will  hold  its  fourih  annual  SCARC  82 
hamlnsl  on  Saturday,  September  11.  1962, 
at  I  he  Sussex  County  Farm  and  Horse 
Show  grounds,  Plains  Road  off  file  206, 
Augusta  NJ.  just  north  of  Newton.  Pre- 
registration  tot  outdoor  flea-market  sellers 
is  $4,00.  at  the  gate,  S5.00.  Pre-regtst ration 
lor  indoor  flea-market  setters  is  $5,00;  at  the 
gate.  S6.00.  Other  registration  is  $2,00. 
There  will  be  door  prizes  and  acres  of  Free 
parking.  Talk  in  on  147,90/30  and  146.52 
For  additional  J n formation  or  pre-regis- 
tratlon.  write  Sussex  County  Amateur 
Radio  Ctub.  PO  Box  11,  Newton  NJ  07860. 
or  Lloyd  fluchhoitz  WA2LHX,  10  Black  Oak 
Drive  Vemon  NJ  07462 

MARION  IN 

SEP  11 
The  Grant  County  Amateur  Radio  Ctub 
Hamfesi  will  be  held  on  Saturday, 
September  Ht  1982,  at  McCarthy  Hailp 
Marion  IN,  from  8:00  am  until  4:30  pm  Ad- 
mission is  $2.00  in  advance  and  $300  at  the 
gate.  There  will  be  good  home  cooking, 
hourly  drawings,  and  major  prizes.  TaJk-*n 
on  146.1*. 79  and  146.52  For  more  informa- 
tion or  tickets,  send  an  SASE  to  Beecher 
Waters  WB9YHF,  RR  #1,  80x357.  Converse 
IN  46919. 

MELBOURNE  FL 
SO*  11-12 

The  Platinum  Coast  Amateur  Radio 
Society  will  hold  ita  17th  annual  hamfest 
and  indoor  swap-and-shop  flea  market  on 
September  11-12,  1982,  at  the  Melbourne 


Auditorium,  Melbourne  FL  Admission  is 
S3  00  in  advance  and  $4.00  at  the  door. 
Swap  tables  are  $1000  for  one  day  and 
$15.00  for  both  days.  There  will  be  unlimited 
free  parking,  a  tail-gate  area,  air-condi- 
tioned swap  and  exhibit  area,  awards,  for- 
ums, and  meetings.  Talk-In  on  2SI.B5  and 
.52/.S2.  For  reservations,  tables,  and  infor- 
mation, write  PCARS,  PO  Box  1004.  Mel- 
bourne FL  32901.  or  call  P06>245-5116. 

BUTLER  PA 
12 


The  Butler  County  Amateur  Radio  Asso- 
ciation will  hold  its  annual  hamfest  on  Sun- 
day, September  12,  1962,  from  9:00  am  to 
4;00  pm,  at  the  Butler  Farmshow  Grounds 
at  Roe  Airport,  Butler  PA.  Fly 4a  at  Butler 
Farmshow  Airport.  Aomission  is  a  S1 .00  do 
nation  and  children  under  12  will  be  admit- 
ted fuse.  Overnight  campers  are  welcome 
and  food  and  refreshments  wiH  be  avail- 
able- There  will  be  an  indoor  flea  market 
(vendor  space  will  be  $3.00  per  3-foot  table), 
a  free  outside  flea  market  free  parking  (In- 
cluding for  the  handicapped),  and  prizes,  In- 
cluding a  Kenwood  TS-8305  HF  transceiver 
Talk  in  on  147.96/36,  .52, and  1 47.S4/.24  For 
additional  information,  contact  Leigh  ton 
Fennel  Crestmofit  Drive,  RD  fi,  Buiier  PA 
16001,  or  phone  (4l2}-58&9622. 


WILLIMANTICCT 
SEP  12 

The  Natchaug  Amateur  Radio  Associa- 
tion will  hold  a  giant  flea  market  on  Sunday, 
September  I2+  1982,  from  9:00  am  until  4:00 
pm.  at  the  Elks  home,  off  Rtes  32  and  6, 
vVrllimantic  CT  Tables  may  be  reserved  in 
advance  tor  $5. 00  until  September  1st;  after 
that  dale,  they  will  be  $7.00  at  tne  door  Ad- 
mission is  $1  00  There  will  be  Iree  parking, 
as  well  as  raffles  and  door  prizes.  Talk  In  on 
147.30  and  147.90/.50.  For  further  informa- 
tion, contact  Clifton  Pease  KA1HYW,  26a 
Main  Street.  WiNJmaniic  CT  06226.  or  phone 
(2Q3H5&1432  after  4:00  pm. 

CARTERVILLE  IL 
SEP  12 

The  Shawnee  Amateur  Radio  Assoc  let  ion 
will  hold  Its  28th  hamfest,  SARAFEST  H2, 
on  Sunday,  September  12.  1982,  at  John  A, 
Logan  College.  Highway  13,  Cartervilte  IL 
Admission  Is $200  in  advance  and $3.00  ai 
the  door.  There  will  be  an  air-conditioned 
flea  market,  forums,  computers  refresh- 
ments, contests,  and  prizes,  including  a 
first  arize  choice  of  a  Kenwood  130S  HF 
transceiver,  a  microwave  oven,  an  RCA  col- 
or TV.  or  an  automatic  dishwasher.  Talk-In 
on  146.2S/.S5,  146,52,  and  3.925,  For  further 
Information,  contact  William  May  KB9QY 
BOO  Hi  11  date  Avenue,  Herri n  IL  62946.  or 
phone  (618^942-2511  days. 

GRAND  RAPIDS  Ml 
IS 


The  Grand  Rapids  Amateur  Radio  Asso- 
ciation, Inc.,  will  hold  its  annual  Swap  and 
Shop  on  Saturday,  September  18,  1982,  at 
the  Hudson vl He  Fairgrounds.  There  will  be 
prizes  and  dealers,  with  an  indoor  sales 
area  and  an  outdoor  trunk  swap  area.  Gates 
will  open  at  3:00  am  for  both  swappers  and 
the  public.  Talk-in  on  T  46  16/76.  For  more 
information,  write  Grand  Rapids  Amateur 
Radio  Association,  Inc.,  PO  Box  1248, 
Grand  Rapids  Ml  49501, 

PEORIA  IL 

SEP  16-19 

The  Peoria  Area  Amateur  Radio  &ub  win 
hoid  Ihe  Peoria  Super? est  '82  on  September 
18-19, 1982,  ai  the^x  posit  ion  Gardens.  W. 
Northmoor  Road,  Peona  IL.  The  gale  opens 
ai  6:00  am;  the  commercial  building  at  0:00 


am  Admission  is  $300  in  advance  or  $4,00 
at  the  door.  Activities  include  forums,  ama- 
teur radio  and  computer  displays,,  a  free 
flea  market,  and,  on  Saturday  evening,  an 
informal  get-together  at  the  Heritage 
House  Smorgasbord.  At  the  hamfest  site, 
there  will  be  free  movies  Saturday  night. 
Full  camping  facilities  are  aval  table,  as  well 
as  a  Sunday  bus  to  Northwoods  Mall  for  the 
ladies.  Talk-in  on  I 46  16/76.  Fo?  more  infor- 
mation, contact  Charles  W  Kuhn 
WD9EGW,  PAARC  Director.  7005  N  Toot 
Lane,  Peoria  tL  61614. 

MONTGOMERY  AL 
SEP1S 

The  Central  Alabama  Amateur  Radio 
Association  will  hold  Its  5th  annual  ham- 
fest on  Sunday.  September  19, 1982,  ai  the 
Civic  Center,  downtown  Montgomery  AL 
There  wall  be  free  admission,  free  parking, 
and  22.000  square  feet  of  air-conditioned 
activities,  including  a  Ilea  market,  Setup 
will  be  at  0600,  doors  will  be  open  from 
0800  to  1500,  and  a  prize  drawing  will  be 
held  at  1400  COST.  Restaurants  and  motel 
accommodations  are  located  within  a 
short  walk  of  the  Civic  Center  and  refresh- 
ments will  be  available  in  the  Civic  Center, 
Talk-in  on  14&04S4,  146.3U91,  I477&.ia 
or  147.045/  ±600X  For  further  information 
or  market  reservations,  write  Hamfest  Com- 
mittee, 2141  Edinburgh  Drive,  Montgomery 
AL  301 16(  or  calt  Phil  at  (205}-272-79aO 
evenings. 


VENICE  OH 
SEP  19 

The  Forty-Fifth  Annual  Cincinnati 
Hamlest  will  be  held  on  Sunday.  September 
19,  1962.  at  Strieker  s  Grove,  Stale  Route 
126.  Venice  r, Ross)  OH.  Admission  and  prize 
ticket,  £5.00.  There  will  be  exhibits  and 
booths,  prizes,  a  flea  market  (radio-related 
products  only),  a  hidden  transmitter  hunt, 
and  an  air  show.  Food  and  refreshments 
will  be  available.  For  further  information, 
write  Uiuan  Abbott  K8CKL  317  Green  well 
Road.  Cincinnati  OH  4S23S. 

NEW  KENSINGTON  PA 
SEP  19 

The  Skyview  Radio  Society  will  hoid  Its 
annual  hamfest  on  Sunday,  September  19t 
1982.  from  noon  until  4:00  pm.  at  the  club 
grounds  on  Turkey  Ridoe  Road.  New  Ken- 
sington PA.  Registration  fee  is  $2.00;  ven- 
dors, $4.00.  There  will  be  awards.  Talk-in  on 
.047.64  and  .52. 

NEWTOWN  CT 
SEP  19 

The  Candlewood  Amateur  Radio  Associ- 
ation will  hold  a  flea  market  and  auction  on 
Sunday,  September  19T  1982,  rain  or  shine, 
at  the  Essex  House,  Rte.  6,  exit  8  off  1-84, 
Newtown  CT,  from  10:00  am  to 4;00  pm.  Ad- 
mission fee  of  $1.00  includes  one  door  prize 
chance.  Tables  are  $6,50.  Featured  will  be 
an  equipment  raffle  of  a  TR-2500  handie- 
talkie,  dealers,  and  a  magic  show  for  the 
kids.  Refreshments  will  be  available.  Talk- 
in  on  147.72/.12-  For  advance  table  reserva- 
tions, write  CARA,  PO  Box  188.  Brook  field 
Center  CT  06805,  For  more  information,  call 
George  WB2THN  at  {9l4h533-2758.  Ken 
KAiGDS  at  (203>744-6S63.  or  George  AF1U 
at  {203H3&054& 


ELMIRA  NY 
SEP  25 

The  Elmira  Amateur  Radio  Association 
will  hold  the  seventh  annual  Elmira  interna- 
tional Hamfest  on  September  25,  1962.  at 
the  Chemung  County  Fairgrounds.  Break- 
fast will  be  available  for  several  hours  after 


the  gates  open  ai  6:00  am.  Advance  tickets 
are  S2_00  and  tickets  at  Ihe  gate  are  Sa.0a 
Featured  will  be  tech  talks,  a  free  flea  mar- 
ket, dealer  displays,  and  prizes,  including  a 
grand  prize  of  an  loom  IC-730.  Friday  night 
camping  will  be  available  on  a  limited  basis 
at  the  fairgrounds  and  lunch  will  be  avail- 
able starting  at  1 1 :0O  am  on  Saturday.  Talk- 
In  on  147m 36,  146,10/70.  and  146.52.  For 
advance  tickets,  write  John  Breese  340 
West  Avenue,  Horseheads  NY  14545. 

GAINESVILLE  GA 
SEP  26 

The  0th  annual  Lanierland  ARC  Hamlesl 
will  be  held  on  September  26. 1982,  begin- 
ning at  £00  am,  in  the  Holiday  Hall  at  Holi- 
day Inn,  Gainesville  GA  There  will  be  free 
tables  and  an  inside  display  area  for  deal- 
ers and  distributors  (doors  will  open  at  6  00 
am  for  dealer  setups).  Prize  tickets  are  Si. 00 
each  or  6  for  S5.00.  Food  and  drink  will  be 
available,  as  well  as  a  large  parking  lot  for  a 
free  flea  market  A  boat  anchor  auction  will 
be  held  and  all  activities  and  faci lilies  will 
be  free.  Talk-In  on  146,07,67.  For  informa- 
tion and  free  Space  to  dealers,  contact  Phil 
Loveless  KC4UC.  3574  Thompson  Bend. 
Gainesville  GA  30506.  or  phone  |404> 
532-91 60. 


YONKERS  NY 
OCT  3 

The  Yonkers  Amateur  Radio  Club  will 
hold  its  electronics  fair  and  flea  markei  on 
Sunday,  October  3,  1982,  from  9:00  am  to 
5:00  pm.  rain  or  shine,  at  Yonkers  Munici- 
pal Parking  Garage,  comer  of  Nepperhan 
Avenue  and  New  Main  Street.  Admission 
is  $2.00  each,  children  under  12  will  be  ad- 
mitted free.  Sellers'  spaces  are  $6,00 
(bring  your  own  table)  and  include  one  ad- 
mittance. Gates  will  be  open  to  sellers  ai 
9:00  am,  There  will  be  live  demonstra 
tions.  hourly  prizes,  an  auction,  free  park 
ing,  refreshments,  and  unlimited  free  cof 
fee  all  day  Talk-in  on  146.265/146.853,  .52. 
or  CS  channel  4  For  further  information, 
write  YARC,  53  Hayward  Si  reel.  Yonkers 
NY  10704,  or  phone  (914J  969^1053. 

CHELSEA  MA 
OCT  17 

The  19-79  Repeater  Association  of  Chel- 
sea MA  will  hold  its  annual  flea  market  on 
Sunday,  October  17, 1962,  from  1 130  am  to 
4:00  pm  (sellers  admitted  ai  ifttiG  am),  at 
the  Beachmont  VFW  Post,  150  Bennington 
Street,  Revere  MA.  Admission  is  St  .00.  Sell- 
ers1 tables  are  $6.00  In  advance  and  $8.00  el 
Ihe  door.  If  available.  Talk- in  on  .19/. 79  and 
.52,  For  table  reservations,  send  a  check  to 
19-79  Repeater  Association,  PO  Bom  171. 
Chelsea  MA  02150. 


NORTH  HAVEN  CT 
NOV  7 

The  Southcentral  Connecticut  Amateur 
Radio  Association's  (SCARA's)  third  annu- 
al electronics  flea  market  will  be  held  on 
Sunday,  November  7,  1962,  indoors  at  the 
North  Haven  Recreation  Center  on  Unsley 
Street  in  North  Haven  CT.  Regular  admis- 
sion is  S1.25:  children  under  12  with  an 
adult  will  be  admitted  free.  Sellers'  spaces 
are  S6.0Q.  The  best  spaces  will  be  assigned 
first.  A  limited  number  of  free  tables  will  be 
provided  to  the  first  reservations  received. 
When  those  tables  are  gone,  space  will  be 
available  for  sailing  from  the  floor  or  from 
your  own  table.  Food  will  be  available.  Sell 
ers  may  set  up  at  3:00  am,  and  waJk-ms  will 
be  admitted  from  900  until  3:00.  For  reser- 
vations, send  check  or  money  order  pay- 
able to  "SCARA"  to  Ed  Goldberg  WA1ZZO, 
433  Ellsworth  Avenue,  New  Haven  CT 
06511.  Include  an  SASE  for  confirmation 


96     73Magazfne  *  August,  1982 


MM  HELP 


I  need  Information  on  an  Abbott  TR-4  and 
an  Abbott  TR-4B,  I  would  also  like  informa- 
tion on  Navy  type  CRl-43044.  a  unit  of 
Model  TBY-8  and  ModeJ  TBY  7. 

Craig  Renler 

7416  Lose da  Dr. 

Baltimore  MD  21207 


I  am  in  need  of  a  schematic  or  manual  for 
an  RCA  Institute  scope.  Tubes  are  W2, 
6BL6,  6010.  6X4WA,  (2)  12AU7*,  and 
WX5078  Pi.  I  wiil  pay  tor  the  informal  Ion. 

J.  W.  Hopson  W4AEM 

959  Overhl!l  Drive 

Alexander  City  AL  35010 


Ducks  arc  setting 

smaller! 
and 


(  need  operating/maintenance  manuals 
for  the  following  equipment:  Yaesu  FT*707; 
Astro  150A;  Hewlett-Packard  Model  122AR 
oscilloscope;  Anton  El  eel.  Corp.  75*505  D/U 
VTVM;  and  ShallcroB3  2M  3/U  capacitance 
analyzer 

I  will  buy  originals  or  pay  for  copying. 

H-  H  utehi  son 

N4GQE,  HP1XHH,  N4GQE/TSI 

U5MIL0P,  El  Salvador 

APO  Ml  34023 

I  am  looking  tor  a/i  instruction  or  techni- 
cal manual  for  an  old  BC  211M  frequency 
meter  as  well  as  tor  a  CW  filter  for  a  Galaxy 
Gl  550 A  transceiver,  I  will  pay* 

Bob  Currier  KA6ETF 

5529  Marblehead 

Jackson  MS  39211 

i  would  appreciate  any  Information  on  a 
frequency  counter  which  could  be  used 
with  the  Collins  51S-1  and  51J-4  receivers,  I 
am  also  looking  tor  anyone  who  Has  modi- 
fied a  51 J4  to  receive  FM  or  who  may  be 
able  to  supply  a  suitable  modification, 

Cieno  Strachan  C6ANI 

PO  Box  N4106 

Nassau  NP 

Bahamas 


I  need  the  GSL  cards  of  those  who  are 
Church  of  Ghrtst  hams  for  the  1983  Church 
of  Christ  Cafibook  I  am  putting  together, 

Ray  Hawk  NW4L 
1461  East  Chester 
Jackson  TN  36301 


I  would  like  to  purchase  Original  manuals 
for  the  Hickok  Model  1 805 A  oscilloscope  and 
Tektronix  Model  N  preamp. 

Eitehl  Takarada 

1423  Vassar  Rd 

RockfordlL  61103 

Would  the  fellow  who  sold  me  the  Co m- 
co  business- band  handie-talkie  at  the 
Dayton  Ha  invention  please  com  act  me,  I 
would  like  to  buy  the  Model  43  Teletype 
machine  thai  you  had  shown  me.  Please 
call  collect  after  6:00  pm.  (61^922  2652 

Denial  Durgin  KA1AFJ,'8 

121  Lake  St. 

Uhhchevllla  OH  44683 

I  would  like  to  hear  from  anyone  who  has 
a  cure  for  the  Smeler  drift  prodtem  in  the 
Tempo  1  transceiver 

Dick  Roux  N1AED 

25  Greenfield  Or. 

Merrimack  NH  03054 


better! 


NEMAL  ELECTRONICS 

COAXIAL  CABLE  SALE 


Because  you  and  the 
leading  radio  manu 
facturers  want  the 
best-performing,  the 
best  looking  antenna; 
Centurion  has  grown 
to  be  the  Chick  leaden 
We've  developed 
many  smaller  antennas 
to  make  the  hand- 
held radio  perform 
better,  and  now  the 
newest  di  uf 

Duck  "mir 

shorter  (about  3")  yet 
it^s  a  full  1/4  wave 
radiator  on  VHF 


RG6U-2G  ft.,  PL-25§ea.  and , . . .  ♦ ,  $4,95 

RG2l4Udbl  silver  shield.  50  ohm. S1.35rfL 

100  ft  RG8U  with  PL  259  on  each  end  $1995 
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73  Magazine  *  August,  1982     97 


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51 


MICROLOG 


**See  List  of  Advertisers  on  page  114 


INNOVATORS  IN  DIGITAL  COMMUNICATIONS 

73  Magazine  ■  August.  1982    99 


D.  N.  Ellis  WA2FPT 
RD  7,  Box  tOBA 
Ulster  Park  NY  12437 


Confessions  of  a 
Counter  Evolutionary 

the  best  circuit  yet? 


Editor's  Note:  The  LSI  Comput- 
er Systems  LS7030  counter 
chip  used  in  this  project  is 
available  from  Belco  Electron* 
tcs.  43  South  49th  Ave,.  Bell 
wood  IL  60104,  for  $12.75  plus 
shipping,  Next  month  well 
bring  you  the  conclusion  of 
WA2FPTS  discussion. 

As  many  of  you  may 
have  done  already,  I 
had  vowed  never  again  to 
be  lured  into  reading  anoth- 
er frequency  counter  arti- 
cle, one  more  of  those  ubiq- 
uitous "counter  updates/' 
or  even  another  of  the 
scores  of  ads  splashed  over 
the   pages   of    ham    maga- 


zines. I  was  certain  that  I 
had  been  told  more  than  I 
ever  wanted  to  know  about 
counters. 

Why  have  I  yielded  to 
temptation  (lured  by  the 
possibility  of  publication) 
and  become  a  part  of  this 
ever-increasing  problem?  I 
confess!  The  truth  is,  I  was 
seduced  by  an  LSI  counter 
chip,  the  LS7030  from  LSI 
Computer  Systems,  Inc. 
This  little  beauty  measures 
a  full  40  (pins,  that  is)  and  is 
an  8-decade,  multiplexed 
up  counter  It  counts  direct- 
ly to  5  MHzr  is  CMOS  and 
TTL-voltage    compatible, 


Photo  A.  Push-button  selection  is  used  to  control  the  7030 
Universal  Counter 

100     73  Magazine  •  August,  1982 


and  has  BCD  and  7-segment 
multiplexed  display  out- 
puts. It  also  employs  and 
enjoys  leading-zero  blank- 
ing and  very  low  power  con- 
sumption. A  real  gem! 

Even  with  all  this  on  a 
chip,  what  would  cause 
anyone,  much  less  an  impa- 
tient convenience-seeker 
like  me,  to  take  the  trouble 
to  design  a  frequency 
counter  when  there  are  a 
host  of  appetizing  kits  well 
within  the  one  "centi-buck" 
range?  I'll  answer  this  in 
terms  of  the  WA2FPT  7030 
Universal  Counter's  fea- 
tures: 

•  10-MHz  oven-controlled 
crystal  oscillator 

•  Full  8-digit  resolution 
with  no  least-significant- 
digit  bobble  (no  ±  1  count 
uncertainty) 

•  Four  selectable  timebase 
gate  times:  .01,  .1, 1,  and  10 
seconds 

•  Hi-Z  dc  to  5-MHz  preamp 
input 

•  Lo-Z  5-500-MHz  preamp 
prescaler  input 

•  Kilo  hertz,  megahertz 
readout  with  automatic 
decimal  point  placement 

•  Period  measurement 
with    20-period    average. 


with  direct  readout  in  jisec 
to  99,999,999  (equivalent  to 
01  Hz) 

•  Events  mode  [totalizing) 
with  manual  front-panel 
controls  and  remote  rear- 
panel  control  inputs 

•  Separate  power  regula- 
tors for  the  master  oscilla- 
tor, front  ends,  displays, 
and  counter 

•  10-MHz  TTL  test  output 
and  6  additional  buffered 
CMOS  oscillator  timebase 
signal  outputs  from  10  Hz 
to  1  MHz 

•  25-pin  E1A  RS-232C  type 
monitor  jack  for  future  re- 
mote-data acquisition  and 
control 

•  Push-button  front-panel 
operation  with  LED  indica- 
tors—no rotary  switches 

•  90%  wire-wrapped  non- 
critical  construction 

If  these  features  are  in* 
teresting,  then  read  on  to 
see  how  to  build  this  deluxe 
counter  for  truly  a  fraction 
of  the  cost  of  a  commercial 
equivalent. 

Before  we  get  tangled  up 
in  our  wire-wrapping,  here's 
a  short  review  for  those 
who  don't  live  and  breathe 
digital  counters.  If  you  are 
one  of  those  fortunate  few 


who  do,  then  skip  this  short 
primer. 

Elementary  Counting 

The  simplest  form  of  a 
counter  is  one  that  only  to- 
talizes incoming  events. 
Fig.  2  shows  three  basic 
functional  parts.  The  input 
conditioner  transforms  a 
physical  event  into  electri- 
cal signals  that  are  used  to 
increment  the  second  part. 
The  decade  counter  counts 
from  0  to  9  and  provides  a 
carry-out  to  the  next  digit 
counter.  The  third  vital  ele- 
ment is  the  indicator.  It  de- 
codes and  converts  the  out 
puts  of  the  decade  counter 
to  a  visual  presentation 
hopefully  useful  to  some 
observer. 

Fig.  3(a)  shows  a  simple 
frequency  counter.  To 
count  frequency,  a  ''win- 
dow" or  "gate"  must  open 
and  close  for  a  specified 
time  interval  to  give  counts 
per  second,  or  even  "fur- 
longs per  fortnight."  Any 
number  of  something 
counted  in  a  unit  of  time  is 
an  expression  of  frequency. 
Simple  enough. 

Two  extra  items  are  need- 
ed, however,  to  make  a  fre- 
quency counter  useful:  a  re- 
set and  a  holding  or  loading 
device.  The  reset  is  needed 
to  ensure  that  the  counter 
begins  counting  from  zero 
at  the  beginning  of  the  gate 
time.  The  loading  device  re- 
tains the  value  of  the  last 
count  and  then  updates  the 
display  with  that  value  after 
the  counting  window  has 
shut,  This  "new  improved" 
simple  frequency  counter  is 
shown  in  Fig.  3(b). 

Period  counters  measure 
the  time  between  events. 
Often  period  measurement 
is  used  to  accurately  calcu- 
late very  low  frequencies. 
This  becomes  necessary  as 
the  value  of  the  frequency 
approaches  the  frequency 
of  the  counting  gate.  To  ap- 
preciate the  added  resolu- 
tion available  for  such  low- 
frequency  measurement, 
suppose  you  wanted  to 
measure  the  ac  line  fre- 
quency.   It's  60  Hz,   right? 


Well,  if  you  want  to  mea- 
sure it  to  four  significant 
digits,  you  would  need  a 
gate  time  of  at  least  100 
seconds  (to  give  a  60  00-Hz 
display)  — a  long  time  to 
wait.  A  simple  period 
counter  could  enable  us  to 
obtain  the  required  resolu- 
tion by  using  our  "un- 
known" line  frequency 
(suitably  conditioned  for 
our  digital  circuitry)  as  the 
gate  for  a  much  higher 
known  frequency,  say  10 
kHz  (often  readily  available 
in  timebase  oscillator  divid- 
er chains). 

Suppose  these  10-kHz 
pulses  are  then  counted 
and  displayed  as  before. 
Fig,  4  shows  how  the  60-Hz 
signal  gives  a  count  of  1668. 
This  value  is  .01668  sec- 
onds, the  period  of  the  line 
frequency.  As  frequency  = 
1  /period,  and  vice-versa, 
our  4-place  readout  is  readi- 
ly converted  to  frequency 
by  using  a  calculator  to  di- 
vide 1  by  0.01668,  Answer: 
59.95  Hz,  All  we  did  to  get 
this  handy  period  counter 
was  to  interchange  the  "un- 
known" signal  and  the  gate 
time.  There  is  no  waiting 
100  seconds,  either,  as  the 
display  could  normally  be 
updated  about  60  times  per 
second. 

Now  that  you're  all  en* 
lightened,  let's  be  counter 
productive  and  get  back  to 
the  real  counter. 

Master  Oscillator 

The  evolution  and  pro- 
gression of  the  WA2FPT 
Universal  Counter  will  be 
covered  in  pieces  by  look- 
ing in  some  detail  at  each  of 
the  Fig.  1  blocks. 

The  beating  heart  of  any 
counter,  the  master  oscilla- 
tor, will  be  described  first. 
The  one  shown  in  Fig  5  is 
based  on  a  10-MHz  AT  high 
accuracy  series- mode 
quartz  crystal  matched  to 
its  85°  oven.  Both  the  crys- 
tal and  oven  were  pur- 
chased  from  International 
Crystal  Manufacturing  Co.f 
10  North  Lee,  Oklahoma 
City  OK  73102.  The  bucks 
spent  here  or  on  a  similar 


MULTIPLE 

VOLTAGE 
REGULATED  POWER 


7^ 


a  FNQ-SOQ 

DJSPLAVS 
AfcB  DRIVERS 


REMOTE   INPUTS 


REMOTE      .- 
MONl'l.h     *" 


I 


REAfl 

PANEL 

CIRCUIT 


3- SO  OWN*  >- 

INPUT 
SIGNALS 

DC- 5MHt X 


LO-£ 

AMPLIFIED 

PRE  SCALER  -KM 


Ml    l 
INPUT 

I'HF  AMPLIFIER 


I 


GATE 
CtMTfH  L 
CIRCUIT 


FRONT  PANEL 

SWITCHES  AND 
CONTROLS 


I0MH* 

CRYSTAL  OSCILLATOR 

AND    OVEN 


Lsroao 

PM05  6  DECADE 
5MH*  COUNTER 


TIME    BASE 
OSCILLATOR 
DIVIDER 
CHAIN 


T 


TEST 
OUTPUTS 


Fig.  7.  Block  diagram. 


affair  will  be  well  worth  it 
to  provide  stability  and  ac- 
curacy  for  your  counting 
machine. 

The  oscillator  itself  is  a 
5400  TTL  quad  2-input  gate. 
A  7400  could  be  used,  but 
the  "Milspec"  5400  in  its  ce- 
ramic package  was  also 
chosen  for  stability  (and  be- 
cause I  had  one!).  The  volt- 
age regulation  for  the  oscil- 
lator is  provided  by  a  dedi- 
cated 723  wired  to  give  a 
5-6-volt,  150-mA  output 
The  oscillator,  along  with  a 
74LS90  decade  divider, 
draws  about  130  mA,  which 
provides  a  desirably  con- 
stant load.  The  variable  ca- 
pacitor serves  as  a  coarse 
frequency  trimmer  Except 
for  the  frequency  and  the 
723  portion,  this  circuit  is 
the  same  as  the  one 
WA1FUE  described  in  his 
excellent  counter  article  in 
the  December,  1976,  issue 
of  73  Magazine. 

I  had  hoped  originally  to 
build  the  5400  into  the  ov- 
en,  but  soon  found  there 


wasn't  enough  room.  Be- 
cause there  is  a  double  ov- 
en, there  is  room  for  a  trim- 
mer cap  as  well  as  the  crys- 
tal inside.  The  oven  plugs 
into  an  octal  socket  mount- 
ed  on  a  small  aluminum 
minibox  containing  the 
5400,  the  723,  and  the  rest 
of  the  oscillator  compo- 
nents. 

An  extremely  simple 
printed  circuit  board  layout 
is  shown  in  Fig.  6(a).  This 
full-size  board  is  copper- 
clad  epoxy  glass  with  01 " 
centered  holes  (Vector 
169P44C1  or  equivalent). 

Keeping  the  trimmer  ca- 
pacitor in  the  oven  solves  a 
significant  source  of  oscil- 
lator variance  due  to  trim- 
mer cap  temperature  drift. 
As  the  oven  heats  up  to  85° 
Cf  the  trimmer  heats  up, 
and,  as  the  oven  stabilizes, 
so  does  the  trimmer.  As  you 
might  imagine,  a  decent  mi- 
ca or  ceramic  trimmer 
(25-75  pF  or  so)  is  required 
here.  The  oven  cover  may 
have  to  be  left  off,  depend- 


INDIC  ftTQH 


OBSERVER 


/V\M- 


"REAL 
WORLD' 


I  I 

SIGNAL 
CONDITIONER 

DECADE: 
COUNTER 

ru-LrLTL. 

u 

DIGITAL 
SIGNAl, 

£N 


- 1? 


Fig.  2.  Simple  events  counter. 

73Magaztne  •  August,  1982     101 


couwt 

*AT£ 
TWER 
I  SEC 


J    C*EK    [      CLOSE 


lMDfCATO* 


00  SERVER 


yv 


INPUT 

SIGNAL 

CONDITIONER 


JT-TLTLTL 


CARAT 
OUT 


DECADE 

COUNTER 


DIGITAL 
PULSES 


1™ 
■ 

1 

1 

1 
f 

J 

£s 


-v- 


EVENTS    PER     SECOND 
A    FREQUENCY 


Fig.  3(a).  Basic  frequency  counter 


COUNT 
GATE 

TIWE» 


LOAD 

A.FTER 
CLOSE 


|  OPEN  ] 


CLOSE 


-vv 


INPUT 

SIGNAL 
CONDITIONER 


_n_TLJi, 


c 


CARRY 
OUT 


DECADE 
COUNTER 


INDICATOR 
I 


STORAGE 
LATCH 


u 


RESET 

BEFORE 
ORE* 


Fig.  3(h)*  Improved  simple  frequency  counter 


ing  on  the  size  and/or  acces- 
sibility of  the  capacitor's 
adjustment  screw. 

In  addition  to  the  trim- 
mer capacitor,  there  is  a 
fine  frequency  adjustment 
The  723  has  a  ten-turn 
500-Ohm  pot  to  give  con- 
troifed  millivolt  level 
changes  in  the  5-6-volt 
range  of  the  723  output. 
This  allows  minute  tweak- 
ing of  the  output  frequen- 
cy A  screwdriver  access 
hole  for  the  trimmer  pot 
screw  was  planned  and  cut 
in  the  minibox  housing  and 
through  the  counter  chas- 


sis. Binding  posts  were  pro- 
vided on  top  of  the  minibox 
near  the  plug-in  crystal  ov- 
en for  monitoring  the  out- 
put of  the  723,  This,  with  a 
rear-panel  BNC  10-MHz  test 
jack,  allows  convenient  ac- 
cess to  long-term  oscillator 
drift  and  aging  data  versus 
voltage,  if  there  should  be  a 
need  for  such  logging.  The 
74LS90  is  wired  to  produce 
a  symmetrical  1-MHz 
square  wave,  and  miniature 
coax.  RG-174  or  its  equal, 
routes  this  signal  to  pin  22 
of  a  44-pin  edge  connector 
on  the  main  counter  board 


AC 

LIME 

VOLTAGE 

(FREQUENCY 
"UNKNOWN") 


INPUT 

SIGNAL 

CONDITIONERS 


OPEN 


CLOSE 


COUNT 
Try  Eft 


*■ 


LOAD 

AFTEJB 

CLOSE 


KNOWN 

DIGITAL 

PULSE 

SOURCE 


i_rLnj-LruTLn_r 

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DISPLAY    INDICATORS 


FOUR    PIGJT 

STORAGE 

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Fig,  4+  Period  counter  example. 

102     73 Magazine  •  August,  1982 


Timebase 
Oscillator  Dividers 

The  timebase  oscillator 
dividers  {TBOD)  are  mount- 
ed on  wire-wrapped  sockets 
on  the  main  board  of  the 
counter— a  4.5"  x  6"  Vec- 
tor 3662.  The  wiring  for  the 
TBOD  is  shown  in  Fig.  7.  ICs 
3,  8,  9,  and  10  are  74C90s, 
while  ICs  2,  5,  and  6  are 
4029  types. 

The  74C90  devices  are 
wired  as  decade  dividers, 
with  the  output  of  the  -=-5 

portion,  pin  11,  fed  into  the 
input  of  the  -*-2  section  at 
pin  14.  The  4029  is  a  dual- 
mode  [decade  or  binary]  up- 
down  [user- selectable) 
counter  in  a  16-pin  pack- 
age. In  this  application  it  is 
wired  as  a  decade  up  count- 
er There  is  no  reason  why 
74C90s  could  not  be  used 
exclusively  as  they  are 
cheaper  to  buy  and  use 
cheaper  sockets.  I  used 
both  chips  because  I  had  a 
few  of  each  on  hand. 

The  TBOD,  as  is  custom- 
ary in  electronic  counters, 

provides  a  number  of  im- 
portant signals  that  are  dis- 
tributed throughout  the  ma- 
chine. The  signal  frequency 
and  its  destination,  togeth- 
er with  a  brief  description, 
comprise  the  list  of  pulses 
picked  off  the  IC  chain  (see 
Table  1).  As  long  as  the  mas- 
ter oscillator  runs,  these  sig- 
nals are  present- 
Display 

The  eight  seven-segment 
common-cathode  displays 
in  this  counter  are  FND  500 
.5"  right-hand  decimal- 
point  devices.  They  can  be 
purchased  for  under  a  dol- 
lar apiece  from  many 
sources  and  are  entirely  ad- 
equate. 

The  displays  are  multi- 
plexed, which  is  a  fancy 
way  of  saying  that  one  digit 
is  lit  at  a  time.  Our  persis- 
tence of  vision  will  see  all 
eight  digits  lit,  however,  if 
the  scanning  rate  is  fast 
enough.  This  technique 
greatly  reduces  power  sup- 
ply drain  and  just  happens 
to  be  built  into  the  7030 


chip.  The  7030  implements 
this  feature  with  an  on- 
board digit-scanning  gener- 
ator that  strobes  the  digits 
sequentially  from  left  to 
right  (digits  8  to  1)  when  a 
pulsing  signal  is  input  to  pin 
39.  There  is  also  a  built-in 
digit-scanner  oscillator  re- 
quiring only  an  external  ca- 
pacitor between  pins  39 
and  40,  Since  the  TBOD  has 
a  plentiful  supply  of  sig- 
nals, a  1-kHz  signal  was 
used  for  scanning,  and  it 
works  well,  A  scan  reset  is 
needed,  according  to  the 
7030  data  sheet,  to  avoid 
display  damage  and  for 
leading-zero  blanking.  I 
used  a  20-Hz  signal,  allow- 
ing 50  display  scans  before 
a  reset  blanks  the  display 

The  result  is  a  nice  bright 
display  with  an  almost  im- 
perceptible flicker.  Faster 
scanning  rates  are  possible, 
and  faster  resets  will  pro- 
duce no  visible  flicker 
whatsoever,  but  the  bright- 
ness will  suffer  This  is  be- 
cause the  digit  strobe  duty 
cycle  is  only  about  12% 
The  scanning-oscillator  sig- 
nal is  divided  into  eight 
such  sequential  strobes. 

These  strobes,  as  MOS 
outputs,  are  not  sufficient 
to  drive  display  diodes  di- 
rectly. Instead,  the  strobes 
are  sent  to  75492  hex  MOS- 
to-LED  drivers,  which  have 
six  drivers  per  package, 
each  capable  of  sinking  250 
mA. 

The  seven-segment  infor- 
mation is  similarly  ampli- 
fied by  75491s,  which  are 
quad  MOS-to-LED  segment 
drivers.  The  seven  seg- 
ments, labeled  a-g,  plus  the 
decimal  point,  fully  use  two 
75491  chips. 

In  a  multiplexed  dis- 
play system,  the  seven-seg- 
ment outputs  are  "daisy- 
chained"  to  all  digits.  That 
is,  all  the  "a"  segments  for 
all  the  digits  are  wired  to- 
gether, and  the  "b"  seg- 
ments are  wired  to  each 
other,  and  so  on. 

As  the  seven-segment  in- 
formation is  sent  to  all 
those  diodes,  only  the  di- 


odes  in  the  digit  that  re- 
ceives a  strobe  will  light  up, 
A  simplified  pseudo- 
schematic  could  help  illus- 
trate this  in  Fig,  8,  Assume 
that  the  three  digits  8,  7, 
and  6  all  have  ones  to  be 
displayed.  The  active  seg- 
ment outputs  from  the 
75491  are  the  "b"  and  "c" 
segments  that  will  give  a 
one  when  each  digit  is 
strobed.  To  forward  bias 
the  LEDs,  the  high  pulse  to 
the  75492  is  inverted  to  a 
low,  which  will  provide  the 
proper  bias  solely  for  digit 
8.  The  next  strobe  will  acti- 
vate digit  7  (turning  off  8), 
and  the  next,  digit  6  (turning 
off  7\  All  seven-segment  in- 
formation is  synchronized 
by  the  digit  strobes,  and  we 
see  the  result  arranged  as 
numbers  0-9.  When  the 
scan  reset  occurs,  the  scan 
oscillator  restarts  at  posi- 
tion 8,  the  most  significant 
digit. 

One  of  the  many  econo- 
mies resulting  from  display 
multiplexing  is  the  elimina- 
tion of  the  usual  current- 
limiting  resistors.  They  are 
not  needed  here  because 
the  scanning  rate  is  suffi- 
cient to  keep  the  average 
current  through  the  LEDs  at 
an  acceptable  level.  A  "di- 
rect drive"  B-digit  display 
with  decimal  points  could 
require  8  latches,  8  decoder 
drivers,  and  64  current-lim- 
iting resistors.  The  overall 
brightness  of  the  display 
may  be  varied  by  changing 


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the  supply  voltage  to  the 
75491  and  75492  devices 
and  the  scan  rate. 

The  FND  500s  are  not  as 
efficient  as  they  are  inex- 
pensive, and  the  overall 
brightness  was  enhanced  by 
using  an  8-volt  regulator,  an 
LM340T-8,  solely  for  the 
panel  LEDs  and  the  eight 
seven-segment  display  driv- 
ers. 

If  you  decide  to  use  dif- 
ferent displays  in  your  ver- 
sion, you  will  probably 
want  to  experiment  a  little 
with  different  voltages  and 
scanning  rates  to  optimize 


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Fig.  5.  Master  oscillator. 

the  display  presentation  to 
your  liking.  Fig.  9  shows  the 

complete  8-digit  wiring 
used  in  this  counter. 

The  7030  has  a  lamp-test 
input  (pin  38)  that,  when 
brought  high  (4*5  volts], 
will  light  all  segments  of  all 
eight  digits,  showing  all  8s.  I 
couldn't  resist  putting  a 
'lamp-test"  push-button  on 
the  front  panel  for  that  pur- 
pose. The  circuit  used, 
though,  does  provide  a  use- 
ful function,  because  a 
counter  overflow  condition 
is  also  incorporated 

The   7030   has   its   three 


most  significant  decade 
overflow  outputs  for  digits 
8,  7,  and  6  brought  out  to 
pins  14,  15,  and  16,  respec- 
tively, of  IC1.  Because  this 
machine  is  an  8-digit  count- 
er, it  made  sense  to  use  the 
eighth  decade  overflow 
output  from  pin  14  to  set 
the  overflow  input  latch  at 
pin  13  of  the  7030.  An  inter- 
nal flip-flop  holds  the  over- 
flow indication  until  a 
counter  reset  (not  a  scan  re- 
set) occurs.  As  the  overflow 
output  becomes  active,  it 
sets  the  4013  IC31  in  the 
lamp-test  circuit  causing  a 


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Fig.  6(a),  Master  oscillator  PC  layout 


Fig.  6fb|  Parts  placement  for  master  oscillator  hoard 

73 Magazine  •  August,  1982     103 


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Fig,  7T  Timebase  oscillator  divider  chain. 


display  of  all  8s,  They  will 
remain  lit  until  the  counter 
is  reset.  Should  the  over- 
flow input  be  left  unused, 
the  counter  display  will 
"wrap  around"  to  zero  after 
99  999,999  and  begin  count- 
ing again  from  zero.  This 
probably  wouldn't  occur  in 
frequency  counting,  but 
could  be  an  important  con- 
sideration in  events  totaliz- 
ing. 

The  manual  lamp-test 
push-button  [as  shown  in 
Fig.  10]  is  connected  to  acti- 
vate the  lamp-test  flip-flop 
(IC31)  via  the  direct  set  in- 
put. An  unused  74C0O  gate 
i£  used  as  an  inverter  The 
overflow  latch  output  is 
sent  to  the  data  input,  and 


Signal     Source 

1  MHz     Master  oscillator 

Edge  connector  pin  22 
100  kHz  fC2pin7 


10  kHz     IC3pln12 
1  kHz       fGS  pin  7 


100  Hz     IC6  pin  7 
20  Hz       lC10pin11 
10  Hz       IC10pin12 


1  Hz        IC9pin12 

0.1  Hz      IC0  pin  12 


when  clocked  by  a  conve- 
nient source  (1  kHz  here),  it 
also  activates  the  lamp  test, 
separately  from  the  pre- 
vioi  described  manual 
operation. 

This  arrangement  is  only 
one  of  several  possibilities, 
but  it  uses  leftover  gates 
and  flip-flops.  Other  un- 
used gates  don't  appear  in 
the  schematic,  but  have 
their  inputs  grounded  The 
CMOS  doesn't  like  loose 
ends. 

Counter  Tactics 

Now  that  the  timebase 
and  display  have  been  de- 
scribed, let's  journey  into 
the  bowels  of  the  counter 

The  counter  has  two  in- 


Destination 

IC41  pin  3 

IC2  pin  15 
IC3  pin  1 
IC41  pin  5 
IC12  pin  6 
IC41  pin  7 
IC1  pin  39 

IC41  pin  9 
ICI  6  pin  12 
IC41  pin  11 
IC1  pin  38 

IC16  pin  13 
IC41  pin  14 

tCl6pin  5 
IC16  pin  2 


Comments 

CMOS  buffer 
Input  to  TBOD 
TBOD 

CMOS  buffer 
Lamp  test 
CMOS  buffer 
Scan  input  for  mul- 
tiplexed display 
CMOS  buffer 
Gate  time  .01  sec 
CMOS  buffer 
Scan  reset 
Resets  display 
Gate  time  0.1  sec 
CMOS  buffer 
Gate  time  1  sec 
Gate  time  10  sec 


Table  1. 


puts,  in  contrast  to  the  sim- 
ple demonstration  exam- 
ple. These  two  inputs  are 
shown  with  the  gate  con- 
trols in  Fig.  11(a).  The  two 
input  sources  are  condi- 
tioned to  provide  CMOS- 
compatible  square  waves 
that  swing  from  almost 
ground  to  the  supply  volt- 
age of  +  5  volts. 

The  PM  line  controls 
which  of  the  two  input  sig- 
nals is  allowed  through  the 
remaining  two  input  NAND 
gates  of  IC14.  These  com- 
prise a  2-to-1  data  selector; 
that  is,  the  condition  (GND 
or  +5)  of  the  PM  line  al- 
ways enables  one  or  the 
other,  but  not  both,  of  the 
signals  through  the  gates  to 
finally  output  the  signal  to 
be  counted  on  pin  6  of  ICI  4, 
A  low  on  the  input  of  a 
NAND  will  keep  its  output 
high.  Because  of  this,  IC14 
A  and  C  will  be  controlled 
by  the  PM  line  with  the  aid 
of  IC14  D,  an  inverter  made 
from  the  remaining  NAND 
gate.  As  the  signal  will  suf- 
fer two  inversions,  whether 
through  the  path  of  ICI  4  C 
and  B,  or  A  and  B,  the  out- 
put at  pin  6  is  logically  iden- 
tical to  either  of  the  select- 
ed inputs. 

The  input  then  goes  to  a 
74C90,  whose  -M0  output 
is  used  solely  in  the  period 
mode,    and    then    into    a 


74C1 57.  The  74C1 57  is  a  de- 
vice containing  four  2-to-1 
multiplexers  that  operate 
logically  the  same  as  the 
one  formed  by  ICI 4.  The 
74C157  uses  a  single  select 
line  (pin  1)  to  route  one  of 
the  two  inputs  for  passage 
at  a  time.  The  two  inputs  A 
and  B  are  shown  for  each  of 
the  four  2-to-1  multiplexers 
native  to  a  74C157.  A  high 
(or  1 )  level  (^5  volts)  on  the 
select  input  chooses  the  B 
input  for  transmission, 
while  a  low  (or  0)  level 
(M3ND)  lets  the  A  input 
pass. 

Fig,  11(b)  shows  the  gate 
synchronizer  lifted  out  of 
the  rest  of  the  schematic  for 
clarity.  The  input  to  the 
counter  will  not  be  the  in- 
coming frequency  when  the 
P  (for  Period)  line  is  at  a  1 
level.  For  events  totalizing 
and  for  frequency  mode, 
the  signal  pulses  are  sent  to 
a  NAND  gate  (pin  4)  and  to 
the  clock  input  (pin  3)  of 
IC13,  a  74C74  D-type  flip- 
flop.  The  purpose  of  the 
other  half  of  ICI  3  will  be  ex- 
plained shortly. 

Notice  how  the  output  of 
ICI 3,  pin  5,  is  combined 
with  the  clock  signal  in  the 
NAND  gate  accompanying 
pins  4,  5,  and  6.  This  is  the 
circuit  that  synchronizes 
the  timebase  with  the  input 
to  eliminate  the  least-signif- 
icant-digit jitter.  The  flip- 
flop  "remembers"  the  time- 
base  input  at  the  pin  2  data 
input  and  transfers  the  rise 
or  fall  of  the  timebase  sig- 
nal to  the  Q  output  only 
when  clocked  by  the  incom- 
ing event.  This  timebase 
output  enables  the  NAND 
gate,  and  the  resulting  out- 
put at  pin  6  is  the  integer- 
valued  pulse  train  that  is 
counted  by  the  7030  at  pin 
32.  The  7030  counts  on  the 
negative  edge  of  the  incom- 
ing signal,  so  NAND  pro- 
vides exactly  the  right  com- 
bination of  input  and  out- 
put levels.  When  the  time- 
base  at  pin  5  falls,  the  out- 
put of  the  NAND  goes  high, 
shutting  the  gate  to  the 
7030  counter. 

This  is  an  example  of  the 


104     73  Magazine  •  August,  1982 


2/4   OF  A    ?949t 


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PULSE 


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Fig,  8,  Simplified  multiplexed  display  example. 


incoming  pulses  both  start- 
ing and  stopping  the  actual 
timebase  at  IC13  pin  2, 
which  is  shifted  by  the  inter- 
val between  event  pulses. 
As   long   as   this  period   of 


time    between    arriving 

pulses  is  longer  than  the  dif- 
ference between  the  propa- 
gation delay  of  the  74C74, 
the  circuit  will  synchronize 
beautifully,    alEowing    only 

DfGtT   STffQBES 


whole  numbers  of  pulses  to 
be  counted,  This  limitation 
is  never  realized  because  of 
the  5-MHz  maximum  count 
frequency  into  the  7030. 

Page  208  in  Don  Lancas- 
ter's TTL  Cookbook  sparked 
my  imagination  and  curiosi- 
ty about  eliminating  the 
usual  last-digit  jitter  found 
in  most  digital  counting  in- 
struments. This  ±1  digit 
ambiguity  is  an  error  source 
that  is  inversely  proportion- 
al to  the  measurement  fre- 
quency. To  keep  the  f Grow- 
ing example  simple,  let's  as- 
sume a  1 -second  timebase. 
For  a  10-Hz  frequency,  the 
±1  count  results  in  a 
±10%  error  per  sample.  At 
100  kHz,  the  error  de- 
creases to  ±01%  If  any- 
one wants  an  easily-forgot- 
ten formula,  try  this:  %  er- 
ror =  ±  100/fHXg),  where 
H  =  frequency  in  Hz  and 
"g"  is  the  gate  time  in  sec- 
onds. Notice  that  this  par- 


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CONN  10 


CONN  J* 


CONN  l6 


CONN  15 


Fig,  9.  Eight-digit  multiplexed  display. 


ticular  source  of  measure- 
ment imprecision  is  in  addi- 
tion to  timebase  instability, 
noise,  jitter  in  triggering, 
and  all  the  other  digital 
counter  gremlins. 

Now  you  can  appreciate 
the  slight  cost  of  the  couple 
of  extra  ICs  to  eliminate  this 
error,  especially  for  lower- 
frequency  measurements, 
This  important  feature  is 
overlooked  by  virtually  all 
manufacturers  of  digital  in- 
strumentation in  the  hobby- 
ist's realm. 

If  you  are  wondering 
about  the  other  half  of 
ICI 3,  it  is  used  to  produce 
the  proper  duration  of  the 
timebase.  Feeding  pin  8 
back  to  pin  12  gives  a  tog- 
gle action,  dividing  the  in- 
coming timebase  by  two 
This  gives  a  symmetrical 
signal  high  for  the  originally 
selected  time,  and  then  low 
for  the  same  time  This 
"open  gate"  signal  exits 
from  pin  9  and  then  goes  to 
the  pin  2  data  input  of  the 
previously-explained  gate 
synchronizer, 

A  green  LED  on  the  front 
panel  indicates  gate  inter- 
val. It  is  taken  from  IC1 3  pin 
5,  enabled  by  the  AND  gate 
in  ICI  8  and  driven  from 
IC39f  a  75492.  A  220-Ohm 
resistor  limits  the  current 
An  interesting  side  benefit 
is  that  uneven  triggering  of 
the  gate  synchronizer  will 
show  up  as  irregular  flash- 
ing of  the  gate  LED,  This  is  a 
"poor  man's"  trigger-thresh- 
old indicator,  since  the  in- 
coming events  must  be  con- 
tinually starting  the  time- 
base  and  turning  on  the 
gate  LED  for  reliable  count- 
ing. 

Remember  the  reset  and 
update/ load  functions 
needed  to  make  our  ultra- 
simple  counter  accurate 
and  convenient?  Here's 
how  they  are  generated  in 
this  counter 

The  timebase  representa* 
tion  from  Fig.  3(a)  will  serve 
as  a  point  of  reference. 
Ideally,  the  load/update  sig- 
nal for  the  display  should 
occur  immediately  after 
OPEN,  at  the  beginning  of 

73  Magazine  *  August,  1982     105 


*5v 


R2T 

ION 


L.4MP 
TEST 


OVERFLOW 

OUT   fKOl*  1  C  h     >- 

FlN   12 


*  IC  I   PfN  3B  LAMP   TEST 


I  KHl   FROM  IC3% Li  j. 

PiN  T  ^ 


m 


Fig.  10.  Overflow  lamp-test  circuit. 


CLOSE.  The  reset  pulse 
should  occur  just  prior  to 
the  start  of  the  OPEN  time, 
at  the  end  of  CLOSE  time. 
We  have  to  ensure  that  the 
7030  is  undisturbed  for  the 
entire  prescribed  interval, 
or  the  display  will  not  be 
valid. 


The  load/update  pulse  is 
derived  economically  from 
the  falling  edge  of  the  time- 
base  Q2  output  of  IC13  at 
pin  5.  This  signal  is  capaci- 
tively  coupled  through  the 
parallel  combination  of  C6 
and  C7  to  the  resistor  net- 
work of  R6  and  R7.  Normal- 


ly held  at  +4  volts,  the 
junction  of  all  these  com- 
ponents will  dip  low  on  the 
falling  edge  of  the  time- 
base.  This  "down"  time  is 
determined  by  the  RC  time 
constant  of  Q>+  C7  (capaci- 
tive  values  add  in  parallel 
connections)  and  R5/R7. 
This  is  close  to  15  j/s  for  the 
values  shown.  The  7030 
needs  a  load  pulse  of  at 
least  12  fis  to  allow  for  inter- 
nal settling. 

The  reset  pulse  is  slightly 
more  trouble.  It  cannot  be 
taken  directly  from  the  ris- 
ing edge  of  the  count  inter- 
val because  that  would  re- 
sult in  a  reset  pulse  occur- 
ring  within  the  counting  in- 
terval, destroying  any  hope 
of  an  accurate  count,  Not 
wanting  to  infringe  on  that 


JT1 


IC  IT  v       mmT 

Pl«  »o>~ — 


OIAECI 

ic  17  y     utmia 

PrN  1  ?-     


PIP!  4  CS^ 


:*.*,*, 


UQ    I 


I 


7549? 


IC7 
74C90 


I- 


l; 


u 


•14   Pill  j.i 


H4  i-ih* 


74  CO  8 


IC  e 


IC27 

PIN  * 


IC  Z4 


IC  27 

PIN  to 


TIME    BASE 
P4N   t      li=^ 


IC  12 
74CI37 


M 


KM****     PIN  14    ^" 


a 


42 


az 


I 


I] 


IC 


t>il 


9* 
T4C74 


+  5V 


T" 


! 


IC  is 

74CT4 


T4C00 


INPUT 
COUNTS 
IC  I 

PIN  32 


*     RESET    -  3,»& 


-**<!'- 


I5HOIFED 


LvlCl«   PIN  ll 
LOAD   -IS#5 


J 


™4  5V k 


fft 


Fig,  Ufa).  Gate  controls. 


accuracy,  the  reset  has  to 
occur  after  the  load  pulse, 
or  the  counter  would  dis- 
play only  zerosi 

After  some  trial  and  error 
(mostly  error!  I  discovered 
a  combination  that  pro- 
vides the  properly-timed 
pulse.  The  successful  cir- 
cuit is  shown  in  Fig.  11(b). 
Half  of  IC15  is  used  The 
raw  timebase  frequency 
(before  division  by  two) 
from  the  clock  input  (pin 
11)  of  1C13  is  enabled  for 
the  "no  count"  time  by 
IC1 3  pin  6,  which,  of  course, 
is  the  out-of-phase  (oppo- 
site polarity)  synchronized 
timebase.  The  resulting  out- 
put at  IC15  pin  11  is  the  in- 
verse of  what  is  needed,  so 
it  is  inverted  by  the  next 
NAND  at  pin  8  Events 
mode  disables  the  reset  by 
forcing  a  high  output  with  a 
low  at  pin  9.  The  output  at 
pin  8  is  the  needed  high-to- 
low  transition  that  occurs 
only  during  the  no-count  in- 
terval and  not  during  events 
mode.  From  there  it  goes  to 
the  RC  network  where,  simi- 
lar to  the  load  RC  network, 
a  brief  negative  pulse  is 
generated  In  this  case  it  is 
about  5  y&t  the  proper  dura- 
tion for  the  7030  reset 
circuitry. 

In  both  these  RC  net- 
works, the  rising  edge 
"glitch"  will  be  ignored  be- 
cause of  the  bias  level  pro 
duced  by  the  selected  resis- 
tors and  the  forgiving  char- 
acteristics of  CMOS, 

The  mechanism  for  ob- 
taining the  period  of  the  in- 
put is  basically  the  same  as 
the  one  used  in  the  Elemen- 
tary  Counting  section 
above.  The  timebase  and 
the  input  signal  are 
swapped  with  portions  of  a 
74C157  doing  the  traffic  di- 
rection. The  input  signals 
are  first  sent  through  1C7,  a 
74C90,  for  division  by  ten, 
and  then  through  half  of 
IC13  for  an  additional  divi- 
sion by  two.  This  gives  a  sig- 
nal, now  divided  by  twenty, 
that  will  become  the  "time- 
base"  in  period  measure- 
ment. The  P  (for  Period)  se- 


106     7$Magazine  •  August,  1982 


12 


11 


MERE,  T  AND 
INPUT  ARE 
■Vtf  f  IN 
PHASE 


INPUT 

PULSES        >- 
CE  VENTS) 


JTJT_TLrLrLrL 


SYNCHRO*  LIED 
TIME    BASE 


_r^n_ 


INTEGER 
NUMBER   OF 

fulses  TO 

COUNTER 


Fig.  11(b),  Gate  synchronizer. 


lect  line  properly  routes  the 
B  inputs  of  IC12  to  accom- 
plish this  When  P  is  low, 
however,  the  A  signals  are 
digitally  massaged  to  pro- 
vide  the  normal  frequency 
display, 

Now  that 
function  has 
the  counter  needs  a  source 
of  pulses  to  count.  A  50- 
kHz  signal  is  picked  off  the 
TBOD  chain.  This  frequen- 
cy, when  gated  by  a  signal 
divided  by  twenty,  gives  a 


our    period 
a    timebase, 


readout  in  microseconds. 
The  load  and  resets  remain 
the  same  as  before. 

The  reason  for  prescal- 
ing  the  "unknown"  low  fre- 
quency is  to  reduce  effects 
of  noise  on  the  input  sig- 
nal Because  low-frequen- 
cy signals  for  which  the  pe- 
riod mode  is  used  often  are 
slow-rising  leisurely  func- 
tions of  time,  noise  on  the 
signal  can  cause  false,  pre- 
mature, or  late  triggering 
of   the   counter.   The   ran- 


dom nature  of  noise  can 
be  put  to  use  in  the  pre- 
scaling,  or  averaging,  of 
the  input  signal  The  uncer- 
tainty in  triggering  is  re- 
duced by  the  correspond- 
ing scale  factor.  This 
counter  uses  a  factor  of  20 
for  period  averaging  as  a 
reasonable  compromise 
between  extreme  precision 
and  convenient  utility. 

The  price  to  be  paid  for 
the  averaging  improve- 
ment is  a  correspondingly 
longer  interval  before  the 
calculated  period  display 
is  updated.  For  instance,  if 
the  period  of  a  20-Hz  sig- 
nal was  directly  measured, 
the  updates  would  arrive 
every  .05  seconds.  Prescal- 
ing  by  20  would  divide  the 
noise  error  by  20,  but  the 
display  would  be  updated 
only  every  second  (20 
times  .05=1  second).  If 
your  requirements  dictate 
greater  period  averaging 
factors,  more  74C90  divid- 
ers could  readily  be  insert- 


ed into  the  period-mea- 
surement circuitry,  with 
another  pulse  source  cho- 
sen to  give  a  display  of  the 
resulting  period  in  ytsec. 

The  events-mode  opera- 
tion of  the  counter  only  re* 
quires  the  withholding  of 
the  timebase  and  the  subse- 
quent resets  of  the  counter. 
By  having  manual  as  well  as 
automatic  controls  over  re- 
sets and  display  updates  in 
the  counter,  elapsed  time/ 
event  functions  are  defined. 

You're  still  here?  Great! 
Next  month  I  will  cover  the 
rest  of  the  Universal  Count- 
er. We'll  look  at  the  front- 
panel  design  which  features 
push-buttons  rather  than 
rotary-style  switches.  The 
counter's  front  endp  deci- 
mal point  and  power  sup- 
ply circuitry  are  waiting, 
too.  Rounding  out  the  story 
will  be  a  discussion  of  con- 
struction techniques.  Just 
why  did  I  wire-wrap  my 
counter?  Read  next  month's 
article  and  find  out  ■ 


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108     73 Magazine  •  August,  1982 


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Front 


MAGAZINE 


THE  1982  EDITION 

GENERAL  LICENSE 
STUDY  GUIDE 

by  Timothy  M.  Daniel  N8RK 

This  is  the  complete  guide  to  the  General  License. 
Learning  rather  than  memorizing  is  the  secret.  This 
is  not  a  question-and-answer  guide  that  will  gather 
dust  when  the  FCC  issues  a  new  test.  Instead,  this 
book  wilt  be  a  helpful  reference,  useful  long  after  a 
ham  upgrades  to  General.  Includes  up-to-date  FCC 
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ORDER  yours  today  and  talk  to  the  world, 
SG7366       $6.95 

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110     73  Magazine  •  August  J  982 


RADIO 


~\ 


FOR  THE  NOVICE 

New,  updated  editions 

of  our  famous  novice 

license  study  guide  and  novice  study  tapes 


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•  NOVICE  LICENSE  STUDY  GUIDE—  by  Timothy  M,  Daniel  N6RK  Here  la  the  moat  up  to  dale  novice 
.in]-'  available.  II  la  complete  with  information  about  learning  Morse  Code,  has  the  latest  FCC  amateur 

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GENERAL  LICENSE  STUDY  GUIDE— By 

Timothy  M.  Daniel  N8RK  This  is  the 
complete  guide  to  the  General  License. 
Learning  rather  than  memorizing  is  the 
secret.  This  is  not  a  question-and- 
answer  guide  that  will  gather  dust  when 
the  FCC  issues  a  new  test.  Instead,  this 
book  will  be  a  helpful  reference,  useful 
long  after  a  ham  upgrades  to  General. 
Includes  up-to-date  FCC  rules  and  an 
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-GENESIS" 

5  WPH— CT73Q5— This  is  the  beginning  tape  for  people 
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204  WPM— CT7320— Code  is  what  gets  you  when  you 
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'"OUTRAGEOUS" 
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RADIO 


HAND  BOOKS  FOR 
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TEST  EQUIP  LIB  Sf3— AUpID  TESTERS 

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SIMPLE  iOW  COST  «ftfl£  ANTENIlAS 
FOR  RA0<0  AMATEURS  i  6ft 

SOME  OF  ThE  BEST  FROM  KClOSAuD 

1 10  ft 
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TOOLS  1  TECHNIQUES  $  4  ft 

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UNDERSTANDING  1  PROGRAMMING 
MICROCOMPUTERS  1 10  ft 

.  :    AVATEUflRAOtOCHARr  |i  ft 

VERTICAL  BEAU  4  TTttANGLE  ANTNS 

5  5  50 

VHF  ANTENNA  HANDBOOK  I  5ft 

I  HAKDOOOKFOR  RADIO  AMATEURS 

t  *  ft 
WEATHf  o  SAT  I  LUTE  MANDBOOft  J  1 50 
WORLD  PRESS  SERVICE  FREQUENCIES 

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WORLD  RADIO  TV  HANDBOOK.  S1S50 

WORLD  REPEATER  ATLAS- $  *  95 


114     73Magaiine  •  August,  1982 


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TSMagazine  •  August,  1982     115 


__ 


FUN! 


John  Edwards  Kf2U 
78  56  86th  Street 
GlendateNY  71385 


HAM  RADIOS  GOLDEN  YEARS 

When  were  ham  radio's  golden  years?  It  probably  all  depends  on 
when  you  first  entered  the  hobby.  My  golden  years  were  the  1960s: 
Benton  Harbor  lunch  boxes,  Allied  catalogues,  New  York's  radio  row 
and  the  introduction  of  transistors.  For  others,  the  60s  may  have 
meant  incentive  licensing,  a  declining  ham  population,  and  the  first 
CBers  hitting  our  bands.  For  meT  however,  those  years  will  always  be 
the  sweetest. 

This  month's  column  is  all  about  ham  radio's  golden  years.  1  hope 
youll  find  a  question  or  two  about  your  era. 


ELEMENT  1— CROSSWORD  PUZZLE 
(Illustration  1) 

Across 


1)  Old  top  ticket 

7)  Iran  prefix 

9)  A  traditional  ham 
12)  A  Zepp*  for  instance 
14)  Big  time  for  traffic 

16)  Not  ac<abbr) 

17)  First  tube 

21)  VHF  rice  container 
23)  Slang  for  17  across 

26)  Iceland  prefix 

27)  Amateur  practice 

Down 

1)  Commission  before  the  FCC 
(2  words) 

2)  Plate  current  (abbr.) 


3)  No  danger 

4)  Morse  greeting  (abbr.) 

5)  A  satellite  signal  path 
6}  Bug  maker 

8)  Old  modulation  (abbr.) 

10)  Signal  way 

11)  Operates 

13)  Spark  discharge 

15)  Ireland  prefix 

16)  Morse  slash 

18)  Contest  double-copy 

19)  Finland  prefix 

20)  Japan  prefix 

22)  New  electronics  type  (abbr.) 

24)  Transceiver 

25)  Morse  double  dash 


2 

i       l 

5" 

e 

t 

^i 

B 

to 

11 

12 

13 

14 

15 

F^^ 

24 

17 

18 

19 

vs 

22 

23 

26 

^^^^_ 

il 

ELEMENT  2— MULTIPLE  CHOICE 

T)  In  1958,  Lee  De  Forest  was  asked  by  a  reporter  what  would  have 
been  his  reaction  if  transistors  had  suddenly  been  developed  during 
the  early  years  of  the  century.  What  did  De  Forest  reply? 

1.  Ml  would  have  fainted." 

2.  u\  would  have  invented  the  printed  circuit 
board.*' 

3.  "I  might  never  have  invented  the  audron  " 

4.  "Weren't  they?" 

2)  What  news  did  thousands  of  amateurs  hear  over  their  wireless 
sets  on  the  night  of  November  8t  1916? 

1.  News  of  the  formation  of  the  ARRL 

2.  The  first  election  night  broadcast 

3.  News  of  the  sinking  of  the  Titanic 

4.  Word  of  the  first  transatlantic  QSO 

3)  Remember  those  Fort  Orange  Radio  ads  that  appeared  In  QST 
in  the  1950s?  In  the  ad,  what  was  flying  out  the  end  of  Uncle 
Daves  cigar? 

1.  Lightning  bolts 

2.  Smoke 

3.  Radios 

4.  Money 

4)  Which  year  saw  the  introduction  of  the  Hallicrafters  SX-71? 

1.  1920 
^1934 
3,  1950 
4.1958 

5)  In  the  introduction,  I  mentioned  New  York's  "radio  row."  What 
stands  on  this  site  today? 

1.  The  new  Madison  Square  Garden 

2.  The  Metropolitan  Opera  House 

3.  Shea  Stadium 

4.  The  World  Trade  Center 


ELEMENT  3— TRUE  FALSE 


True 


False 


1)  Howard  Hughes  was  a  ham. 

2)  The  man  who  played  Andy,  on  radio's 
"Amos  *n'  Andy,"  was  a  ham, 

3)  The  Conditional  class  license  was 
phased  out  beginning  In  1976. 

4)  In  1951,  the  US  government  forbade  the 
ARRL  to  send  its  publications  to  the 
Soviet  Union. 

5)  In  its  advertisements  for  the  KWS-1f 
Collins  claimed  that  SSB  signals  were 
"distortion  free,'1 

6)  The  1947  WARC  was  held  in  New 
Jersey. 

7)  Novices  have  never  had  phone 
privileges, 

8)  The  Heath  Company  got  its  start  with 
"build-them-yourseir   airplane   kits. 

9)  NBVM  was  a  popular  operating  mode  tn 
the  1930s. 

10)  A  "Model  15"  was  a  type  of  SSTV  gear 


ELEMENT  4— SCRAMBLED  WORDS 

Unscramble  these   names  of  1950s   ham   equipment   manu- 
facturers. 

SNOHJNO                  LINLCOS  IONTANLA  LAMCE 

NORAS                       SNEOGT  HTAIKHTI 


THE  ANSWERS 


Element  1: 

See  Illustration  1A. 


Illustration  t 


Element  2: 

1—3  That  Lee,  What  a  wit. 

2 — 2  The  only  problem  wast  the  broadcast  proclaimed  Charles 


116     73  Magazine  *  August,  1982 


Evans  Hughes— instead  of  Woodrow  Wilson— as  the  winner.  Oh, 
well— guess  they  had  to  wait  for  the  invention  of  the  computer. 
3—1  Forming  the  phrase  ''calling  CQ."  Love  them  rf  cigars. 
4—3  A  staple  for  many  Novices  in  the  1960s. 
5—4  And  I  still  feel  bitter. 

Element  3: 

1  —True.     Yes,  indeed.  His  call  was  5CY. 

2— False.     Freeman  Gosden,  "AmosTM  was  the  ham. 

3— True.    To  the  dismay  of  cheats  everywhere. 

4— True.    Wouldn't  want  the  Russkies  to  get  any  of  the  League's 

precious  secrets,  would  you? 

5— True.     No  consumer  advocates  back  then. 

6— True.     Atlantic  City,  to  be  precise. 

7— False,    They  must  have  had  the  privileges  back  in  the  1960s,  or  a 

lot  of  my  friends  were  breaking  the  law. 

8— True.     Troubleshooting  section:  Plane  flies  backwards.  Check 

motor  polarity. 

9—  False.     Baldwin's  folly. 

10— False.     Better  check  "RTTY  Loop/* 

Element  4: 

JOHNSON,  SONAR,  COLLINS,  GONSET,  NATIONAL,  HEATHKIT, 

ELMAC. 


Must  ret  ion  1  A 


SCORING 

Element  1: 

Twenty-five  points  for  the  completed  puzzle,  or  one-half  point  for 

each  question  correctly  answered. 

Element  2: 

Five  points  for  each  correct  answer. 

Element  3: 

Two  and  one-half  points  for  each  correct  answer. 

Element  4: 

Three  and  one-half  points  for  each  correct  answer. 
How's  your  memory? 

1-20  points— Erased 
21-40  points— Faulty 
41-60  points— 16K 
61-60  points— Sharp 
81-100+  points— Golden  OldiesI 


FUN!  MAILBOX 

I  feel  i  must  point  out  an  error  in  the  True-False  section  of  the  May 
column.  The  Hazel  episode  that  dealt  with  TV!  showed  a  pretty  good 
example  of  misunderstanding  and  jumping  to  conclusions.  Mr  Bax- 
ter thought  his  TVI  was  caused  by  the  ham— because  his  son  was 
visiting  the  neighbor  ham  at  the  same  time.  Mr.  Baxter  also  injured 
his  back  playing  golf  and  was  using  a  heating  pad  while  he  was  try- 
ing to  watch  TV,  At  the  end  of  the  program  an  engineer  from  the  elec- 
tric company  tracked  down  the  TVI  with  an  RDF  unit.  The  heating 
pad  had  a  bad  thermostat  and  this  was  the  cause. 

Daniel  L  Guigg  WD4IRK 
Lexington  KY 

You're  absolutely  correct.  I'd  like  to  say  that  t  slipped  in  that 
question  just  to  keep  my  readers  on  their  toesf  but  I  didn't 
f  goofed*  For  penance,  I  had  myself  strapped  into  a  chair  and 
forced  to  watch  that  episode  50  times  on  my  VCR.  As  Hazel  would 
sayt  "What  a  doozey!"—J.  E. 


READERS  CORNER 

Well,  I  finally  got  around  to  checking  the  responses  to  February's 
Reader's  Corner,  The  Magic  Square's  solution,  not  surprisingly,  is 
l(73/T  The  following  readers  correctly  guessed  the  answer:  Frank 
Waldhaus  WB1CSE,  Dick  Milewski  N2ABA,  Edward  Baker  N3CLPT 
Jim  Higgens  KB3PUT  Bemie  Lavezza  N4FOC.  Jim  Morris  WA6KGBt 
David  Fox  KA8CXQT  John  Hufschmtd  KI9J.  Dave  Karr  KA9FUR, 
Wayne  Schuler  AI9QP  L  Zender  W9IQK,  and  Jerry  Moore  WflHMA. 

Late  arrival:  Found  one  solution  to  January's  DX  puzzle— 
J.  Edgar  McDermott  AH2K. 


LETTERS 


VIVA  "OLF.  OM 


ti 


] 


I've  been  receiving  73  for  3 
months  now.  So  far,  so  good.  I'm 
surprised  to  see  someone 
agrees  with  my  philosophies  so 
extensively.  Keep  up  the  good 
work. 

As  far  as  getting  more  young- 
sters into  ham  radio  goes,  I  think 
the  key  is  reaching  out  more  on 
their  level:   demonstrations   in 


science  classes  and  public 
places;  offering  classes  in  ham 
radio  for  beginners  (WA3WKA 
and  I  have  had  several  suc- 
cessful "graduates'");  and  final- 
ly |ust  showing  ourselves  in  a 
good  light  all  the  way  around. 
And,  of  course,  once  the  spark 
takes,  it  must  be  kindled  with 
good  examples  from  the  old* 
timers.  One  of  the  reasons  for 
some  of  the  bad  operating  prac- 
tices today  is  that  the  old-timers 
can't   or  wonTt    put   their  feet 


down  and  correct  a  beginner's 
mistakes.  {Is  letting  him  develop 
into  a  lid  doing  him  a  favor? 
VivaQLF!) 

Larry  Gotts  WA3UKC 
Pleasant  Mount  PA 

PS.  I'd  sure  like  to  catch  you  on 
the  air,  or  for  an  eyeball  some- 
time, Wayne.  We'd  have  a  lot  to 
rag  chew  about! 


Larry,  you're  right  about  getting 
teenagers  interested,  it  they 
don't  see  amateur  radio  work- 
ing, how  can  they  get  interested 
in  it?  Look  for  me  around  the 
tow  end  of  20m  phone.  That's 
where  I  hang  out  when  t  get 
on. — Wayne. 


RIGHT  ON,  WAYNE! 


I  have  always  wanted  to  drop 
you  a  line;  renewal  time  seems 
to  be  a  good  time  to  do  so.  I  have 
been  foflowing  your  articles, 
magazines,  and  other  achieve- 
ments since  I  was  first  licensed 
in  1959,  You  have  not  always 
been  in  the  forefront  of  popular* 
ity,  but  you  have  usually  been 
"right/"  and  I  have  enjoyed  ail  of 
it.  I  am  a  member  of  the  ARRL 
and  therefore  feel  that  I  am  en* 
titled  to  say  whatever  I  wish.  Ail 
organizations  I  have  ever  been 
associated  with  have  benefited 
from  criticism,  and  the  ARRL 
should  be  no  exception,  I 
sometimes  tire  of  those  who  at- 

73Magazine  *  Augustt1982     117 


tack  you  or  73  Magazine  be- 
cause you  choose  to  change. 

Change  is  usually  for  the  bet* 
ter.  I  joined  the  ranks  of  ama- 
teurs in  the  middle  of  the  furor 
over  AM  vs.  SSB,  a  change  for 
the  better.  The  same  happened 
on  6  and  2  meters,  where  I 
worked  AM.  Now  we  have  a  nice 
proliferation  of  repeaters.  I  re- 
member the  huge  rock-mounted 
transmitters  and  now  you  could 
hold  the  modern  equivalent  in 
one  hand.  Drive  ont  Wayne! 
There  are  many  loyal  supporters 
in  your4,silent  majority."  You  do 
grace  the  bands  with  your 
presence,  and  it  is  a  pleasure  to 
work  you. 

Mike  Davis  K4WYC 
Durham  NC 

By  golly,  Mike,  it  has  been  a  long 
time,  Yep,  I  generated  a  lot  of  un- 
fans  when  f  pushed  for  side- 
band. More  when  I  pushed  for 
solid  state  in  the  60s.  Then  a 
whole  new  bunch  hated  me 
when  I  pushed  for  FM  and  re- 
peaters on  VHF.  I  don't  seem  to 
be  able  to  shut  up  and  leave 
things  alone.  Oht  t  grumble  and 
beef  when  the  FCC  does  some- 
thing sitiy  or  bad  tor  us. . .  ditto 
when  the  ARRL  does  it...  or 
Bash,  But  you  know,  there  are  a 
lot  of  hams. .  .a  whole  tot. . . 
who  agree  about  the  FCC,  agree 
about  Bash.  ..and  then  get 
furious  when  I  mention  the 
ARRL.  No,  you  can't  be  honest 
about  them  or  try  to  put  'em  Into 
perspective.  It's  like  religion  and 
pofitic$t  a  matter  of  emotion  and 
to  hell  with  facts,  Guess  I'll 
never  team  to  keep  my  mouth 
shut  or  my  typewriter  turned  off* 
Thanks  for  sticking  with  me  tor 
so  long,  Mike. — Wayne. 


IDIOTS? 

After  years  of  being  interest* 
ed  in  ham  radio  from  afar,  last 
year  I  got  with  it  and  got  my  li- 
cense. I  find  the  technology  fas- 
cinating, but  it  wasn't  long  until  I 
became  disenchanted  with  the 
content  of  the  QSOs  on  the  air. 
Banal  rambtings  which  go  on 
and  on  and  on  yet  say  noth- 
ing. .  .excruciatingly  redundant 
callsign  exchanges  with  every 
transmission . . .  and,  of  course, 
the  very  prevalent  "CB  syn- 
drome/' which  manifests  its 
presence  with  seemingly  uncon- 
trollable overmodulation  and 
heavy  breathing  In  the  mike. 
Idiots.  I  thought  that  there  was 
intelligent  life  on  the  ham 
bands.  There  are  exceptions,  of 

118     73Magazine  *  August,  1962 


course,  but  it  seems  like  hardly 
anyone  wants  to  discuss  any- 
thing  of  any  consequence.  Has 
it  always  been  like  this? 

Keith  Orosz  N8FQE 
Seal  Beach  CA 

intelligent  life  on  the  ham 
bands?  Surety  you  are  jesting! 
No*  as  a  matter  of  fact  though  it 
is  hidden  from  casual  detection, 
it  is  there.  But  I  have  some  bad 
news  for  you,,. it  witf  rarefy 
show  its  head.  The  fact  is  that 
before  you  will  discover  intelli- 
gence, you  have  to  exhibit  it.  t 
realize  that  this  is  a  painful  tact 
to  face.  Keith.  I've  been  ham- 
ming tor  a  long  time  now  and  t 
manage  to  find  interesting  peo- 
ple to  talk  with.  Often*  Oh,  I 
agree  that  there  are  some  hams 
who  are  almost  without  redeem- 
ing qualities*  There  are  some 
who  are  so  afraid  of  talking  that 
the  best  you  can  get  is  an  anten- 
na discussion,  which  is  not  one 
of  my  favorite  topics.  Keith. . .  it 
you  look  hard  and  work  out  ways 
of  getting  through  the  layer  of 
insulation,  you  7/  find  absolutely 
fascinating  people  who  will  en- 
joy talking  with  you.  There  are  a 
thousand  things  I  enjoy  talking 
about.  I  give  hints  about  some  of 
them  in  my  editorials.  I'm  alive 
with  information,  ideas,  inter 
esting  experiences . . .  and  yet 
hundreds . .  .perhaps  thou- 
sands- .  f  of  hams  have  contact- 
ed me  without  ever  giving  either 
of  us  a  chance  to  enjoy  the  con* 
tact.  Thousands  have  contacted 
me  and  had  a  contact  to  remem- 
ber It's  all  in  yout  Keith,  not 
us. —  Wayne. 


MORE  ABOUT  CHARLIE 

Upon  returning  from  a  meet- 
ing of  the  Montserral  Amateur 
Radio  Society  last  night,  I 
opened  your  magazine  (which 
had  been  given  to  me  that  day) 
and  I  found  your  article  "Mes- 
sages from  Station  Charlie." 

During  the  war,  I  was  a  mem* 
ber  of  the  Women's  Transport 
Service,  F.A.N.Y.,  and  I  was  sta- 
tioned both  at  the  camp  shown 
in  the  photograph  and  also  at 
another  nearby  station,  I  was  a 
W.T.  operator,  I  was  able  to 
recognize  the  faces  in  the  pic* 
ture.  but  unfortunately  J  was  un- 
able to  put  names  to  the  faces. 

It  may  interest  you  to  know 
that  the  Special  Forces  Associa- 
tion Signals  Section  is  still  very 
much  a  group,  having  a  newslet- 
ter published  every  four  months 
and    meetings    twice    yearly. 


Several  of  the  members  are  still 
operating* 

I  will  be  writing  to  the  Associ- 
ation to  tell  them  all  about  the 
article.  I  thank  you  for  helping 
me  to  contact  the  people  men- 
tioned in  the  article. 

Ursula  M.  Sadler 
Montserrat.  West  Indies 


[ 


FIRST  CLASS  TAPES 


I  passed  my  amateur  Extra  ex- 
am last  week  in  Atlanta  and 
would  like  to  extend  my  thanks 
for  your  first-class  code  practice 
tapes.  My  only  complaint  is  that 
the  text  proved  to  be  so  much 
easier  than  the  random  groups 
on  the  tape  that  I  could  have 
gone  a  couple  of  weeks  earlier! 
HI. 

Alan  P.  Biddle  WA4SCA 
Huntsville  AL 

Sure,  Alan,  you  could  have  gone 
earlier.  .  .butf  wanted  you  to  be 
so  good  at  the  code  that  you 
would  not  freeze  up  when  faced 
with  the  test.  By  making  you 
able  to  copy  far  faster  than 
needed,  you  probably  found 
yourself  feeling  confident  when 
the  code  test  started. .  .and 
able  to  go  right  on  through  it 
with  no  problem.  Remember 
that  with  the  old-style  code  test, 
you  had  to  copy  only  one  minute 
solid  of  that  test,  but  with  the 
new  one  if  you  don't  get  the 
whole  test  solid,  you  can  get 
tripped  up  by  one  of  the  ques- 
tions. No*  you  want  to  have  that 
code  sound  stow  when  you  sit 
down  to  copy  it  and  that's  what 
my  tape  does  for  you.— Wayne. 


CRANKY  CURMUDGEONS? 

As  a  new  ham,  here  are  a  few 
observations  on  this  wonderful 
world  of  amateur  radio,  But  first: 
I  am  retired,  having  been  a  pro- 
fessional pilot  and  a  business- 
man for,  well,  a  long  time. 

I  received  my  Novice  license 
in  November,  1981 1  my  Techni- 
cian this  past  February,  and 
plan  the  General  soon.  Ham 
radio  was  a  natural  selection 
since  my  fascination  with  elec- 
tronic things  began  with  watch- 
ing the  old  Collins  airborne 
transceivers  whir  and  grind  to 
produce  some  new  frequency 
that  would  let  you  talk  to  where 
you  were  going.  That  was  espe- 
cially nice  if  you  had  been  flying 
over  water  for  about  8  hours.  But 
enough  of  that  or  shortly  I'll  be 
talking  Ford  Tn- motors. 


So,  what  is  this  piercing  clari- 
ty I  propose  to  offer  about  ama- 
teur radio?  First,  that  I  like  it  very 
much.  The  logic  of  the  licensing 
program  (learn  and  work  code 
as  a  Novice;  upgrade  for  addi* 
tlonal  privileges)  seems  too  deli- 
cious to  have  been  government- 
produced.  And  the  things  you 
hear  about  meeting  great  peo- 
ple on  the  air  are  really  true. 

But  1  am  dumbfounded  at  the 
customer  relations  to  be  found 
in  a  radio  store.  Passing  the 
FCC  tests  Is  a  minor  part  of 
becoming  a  ham.  The  big  thing 
to  learn  is  how  to  get  along  with 
the  omniscient,  crotchety  peo- 
ple who  sell  the  radios. 

Perhaps  I  can  never  achieve 
the  stature  of  these  Ancient 
Icons,  but,  boy,  I  really  tire  of  the 
idiot  treatment,  And  if  I  am  not 
received  as  an  imbecile,  I  am 
labeled  an  intruder  wantonly  In- 
vading the  A. Us  busy-work-de- 
stroying thoughts  of  dreadful 
complexity. 

I  really  feel  that  a  person  us- 
ing the  simplest  sales  technique 
{be  cheerful,  knowledgeable, 
helpful)  coutd  walk  off  with  the 
business. 

These  observations  don't 
emanate  from  just  one  store. 
They  include  everybody,  Wayne, 
you  have  sagely  said  that 
amateur  radio  needs  new  blood. 
I  think  the  first  new  blood  to  hit 
the  sales  end  of  hamming  will 
blow  the  curmudgeon  contin- 
gent right  out  of  the  water.  I 
would  not  weep. 

But  I  love  the  rest  of  it.  I  really 
do.  I  guess  that's  really  why  I 
wrote  this  letter. 

R.  J.  Richardson  KA6RJJ 

Burbank  CA 

Hey,  is  R.  J-  right  about  this?  t 
have  been  so  well  received  in  the 
ham  stores  I've  visited  that  t  am 
not  a  good  judge  of  what  the 
newcomer  faces.  How  about 
some  letters  from  readers  which 
might  hefp  ham  dealers  under- 
stand  what  is  going  on. .  .and 
how  to  fix  it?—  Wayne. 


I 


RAG-CHEW  AWARDS 


After  having  read  and  appreci- 
ated your  editorials  for  several 
years,  two  ideas  come  to  mind 
for  your  or  anyone's  considera- 
tion. 

First  off,  why  doesn't  some- 
one establish  an  award  for  DX 
rag  chewing?  I  can't  do  it  my- 
sell  Say  the  minimum  qualifica- 


tions  to  be  a  half-hour  QSO  on 
phone  or  SSTV  or  fifteen 
minutes  on  CW  or  RTTY  with 
one  ham  from  each  of  100  courv 
tries.  Additional  endorsements 
could  be  for  conversing  with  a 
second  ham  in  each  of  the  same 
100  countries  or  for  each  of  the 
100  QSOs  to  be  in  the  OX  ham's 
native  tongue.  The  certificate 
awarded  should  be  suitable  for 
the  effort  involved;  25-50  hours 
as  a  minimum  amount  of  time 
requires  brass  plaques  on 
walnut  or  similar  cetif icates. 

Second,  I  strongly  suspect 
that  there  is  a  huge  demand  for 
radios  with  an  amateur  appear 
ance,  especially  in  the  2-meter 
FM  field.  By  amateur  appear- 
ance,  I  mean  big,  bulky,  ugly 
boat  anchors  with  a  myriad  of 
gauges,  knobs,  levers,  handles, 
and  hasps  rather  than  miracu- 
lous, neat  little  units  which 
could  fit  in  a  shirt  pocket,  I  find 
nothing  wrong  with  the  neat 
units  on  the  market,  but  some- 
how I  think  that  non-hams  ex- 
pect us  to  show  up  with  boat  an- 
chors. Recently,  at  an  emergen- 
cy communications  center, 
after  just  seeing  the  neat  little 
boxes,  a  person  in  control  re- 
ferred to  the  hams  in  attendance 
as  a  group  of  CBers.  Major 
bloodshed  was  averted  only  by 
heroic  efforts. 

So  maybe  III  buy  a  bigT  ugly, 
military  surplus  chassis  and 
stuff  it  with  a  2-meter  rig,  power 
supply,  thermos  for  coffee,  and 


a  cooler  for  the  beer,  I'll  hang 
some  gauges  on  it  and  be  pre- 
pared for  the  next  emergency. 

Chris  Creasy  III  WB3AAM 
Catawissa  PA 

Chris,  I  used  to  have  an  award 
for  long-winded  folk  tike  me.  It 
was  the  Real  Rag  Chewers  Club 
(RRCC)  and  one  had  to  talk  with 
a  station  for  at  ieast  six  hours  to 
get  the  award.  Several  hundred 
were  a  wa  rded.  —  Wa  yn  e. 


BANGING  CODE 


First  off— keep  gunning! 
Amateur  radio  needs  awakening 
if  it's  to  continue  as  a  living, 
growing  service. 

I  agree  with  you  about  the  re- 
laxed technical  standards  need- 
ed for  a  given  license,  \  am  not  a 
ham  — l  have  an  A.A.S.  in  elec- 
tronics and  am  taking  a  General 
class  study  class  that  the  Kala- 
mazoo amateur  club  offers.  I 
was  totally  surprised  at  how  lit- 
tle J  had  to  know  about  electron- 
ics to  pass  a  test!  The  code 
should  be  an  added  privilege 
(frequencies  w/  license  grade) — 
not  a  requirement  for  a  license. 
Most  newer  hams  are  more  in* 
terested  in  interfacing  a  com- 
puter to  their  rigs,  ATV,  micro- 
waves, etc.,  than  banging  code. 
I'm  having  trouble  learning  the 
code  and  may  have  to  settle  for 
a  Technician's  license,  which 
would  be  OK  since  my  main  in- 
terest is  with  the  possibilities 


available  to   me  at   VHF  and 
above. 

Once  again,  Wayne,  keep  rat- 
tling the  cage,  and  let's  both 
hope  the  Amateur  Radio  Service 
lasts  long  enough  for  the  old 
blood  to  pass  on  and  the  newer 
aspirations  of  innovation  come 
into  controf  to  "pressure"  the 
FCC  into  awakening. 

John  E.  Allgaier,  Jr. 
Kalamazoo  Ml 


YES  TO  CODE 


J 


I  think  you  are  wrong  about  a 
code-free  test  for  a  ham  ticket. 

I  am  75  years  old  and  I  passed 
the  code  test  3  years  ago  with  no 
problem.  The  main  reason  you 
want  to  get  more  hams  on  the  air 
is  to  sell  more  of  your  maga- 
zines and  books. 

The  biggest  reason  why  more 
people  don't  go  ham,  is  the  cost. 

Instead  of  all  the  adds  for  TV 
satellite  material,  print  more 
plans  for  low-cost  transmitters 
and  receivers  for  beginners. 

I  have  had  a  lot  of  young  peo- 
ple talk  to  me  about  ham  radio 
and  when  you  tell  them  what  it 
costs  to  start,  they  lose  interest. 

I  have  contacted  most  of  the 
European  countries  with  only  30 
Watts  output 

I  am  sure  some  of  the  com- 
panies could  put  out  low-priced 
sets  for  people  who  can't  afford 
$700  to  $2,000. 

Yes,  most  of  the  people  who 


take  the  Bash  Test  pass.  But  2 
days  after  the  test,  they  couldn't 
answer  one  simple  question  on 
theory. 

What  we  need  is  a  way  to  get 
young  people  interested, 

I  am  willing  to  give  free  code 
lessons  and  simple  theory  to 
anyone  in  my  area. 

If  other  hams  would  do  this,  I 
am  sure  It  would  work.  Keep  the 
CW. 

R.  Spencer  KA1CEV 
Franklin  MA 

So  the  whole  thing  is  a  con  to 
sell  magazines,  eh?  You  sure 
are  a  nasty  one,  Spencer  And 
with  NTs  costing  a  couple  hun- 
dred dollars,  I'm  not  as  con- 
vinced as  you  about  money  be- 
ing any  serious  problem.  Indeed, 
it  has  been  my  experience  that 
kids  seem  to  have  tittle  trouble 
getting  the  money  they  need  for 
drugs  and  cars,  so  perhaps  ham 
gear  would  not  be  that  difficult  if 
they  were  interested.  My  high 
school  informants  are  adamant 
when  they  say  that  it  is  the  code 
which  is  turning  the  kids  off. 
They  want  to  know  why  they 
should  learn  the  code  to  operate 
phone,  RTTY,  stow  sea n,  and  so 
on.  I  don't  have  a  rational  an- 
swer for  them.  And  I  note  that 
the  FCC  seems  to  be  going  in 
the  same  direction,  with  a  drop- 
ping of  the  code  requirement  for 
the  Tech  ticket  a  good  bet.  By 
the  way,  Spencer,  a  couple  of 
companies  did  put  out  tow- 
cost  low-band  rigs  and  no  one 
would  buy  them> — Wayne, 


CONTESTS 


Robert  Baker  WB2GFE 
15  Windsor  Dr. 
Atco  NJ  08004 

NEW  JERSEY  QSO  PARTY 
2000  GMT  August  14  to 

0700  GMT  August  15 
1300  GMT  August  15  to 

0200  GMT  August  16 

The  Engtewood  ARA  invites 
all  amateurs  worldwide  to  par- 
ticipate in  the  23rd  annual  NJ 
QSO  Party.  Phone  and  CW  are 
considered  the  same  contest.  A 
station  may  be  contacted  once 
on  each  band.  Phone  and  CW 
are  considered  separate 
"bands."  but  CW  contacts  may 
not  be  made  in  phone  band  seg- 
ments. NJ  stations  may  work 


other  NJ  stations,  and  NJ  sta* 
tions  are  requested  to  identify 
themselves  as  "OE  NJ'\ 

EXCHANGE: 

QSO  number,  RS(T),  and 
ARRL  section,  country,  or  NJ 
county. 

FREQUENCIES: 

1810+  3535,  3900,  7035,  7135, 
7235,  14035,  14280,  21100, 
21355,  28100,  and  28610.  Sug- 
gest phone  activity  on  the  even 
hours;  15  meters  on  the  odd 
hours  (1500  to  2100  GMT);  160 
meters  at  0500  GMT, 

SCORING: 
Out-of-state  stations  multiply 


< 

Aug  7*& 

CALENDAR 

AfiRLUHF  Coniest 

Aug  14-15 

European  DX  Con  lest— CW 

Aug  14-16 

New  Jersey  0S0  Party 

Aug  21-22 

SAHTG  Worldwide  RTTY  Contest 

Aug  21-22 

A5  Magazine  FSTV  UHF  Contest 

Aug  28  29 

Occupation  Contest 

Aug  28  29 

Ohio  QSO  Party 

Sep  11-12 

ARRL  VHF  QSO  Party 

Sep  11-12 

European  DX  Contest  — Phone 

Sep  11  12 

Cray  Valley  RS  SWL  Contest 

Sep  18  ■  1*J 

New  Mexico  QSO  Party 

Sep  18-20 

Washington  State  QSO  Parly 

Oct  2  3 

California  QSO  Party 

Oct  16-17 

ARC!  QRP  CW  QSO  Party 

Oct  16-17 

Pennsylvania  QSO  Party 

Oct  16-17 

BCD  A  Jamboree-on  the  Air 

NovB-7 

ARRL  Sweepstakes—  CW 

Nov  13*14 

European  DX  Contest— RTTY 

Nov  20-21 

ARRL  Sweepstakes— Phone 

Dec  4*5 

ARRL160-Meter  Contest 

Dec  1112 

ARRL  10- Meter  Contest 

Dec  19 

CARF  Canada  Contest 

Jan  ft 

73  Magazine  40- Meter  World  SSB  Championship 

Jan  9 

73  Magazine  M- Meier  World  SSB  Championship 

Jan  15-16 

73  Magazine  160  Meter  World  SSB  Championship 

73 Magazine  •  August,  1982     119 


GEARVAKf 

-BULLETIN- 


NEWSLETTER  CONTEST  WINNER 

For  more  than  22  years,  the  GEARVAKf  Bulletin  has  inflicted 
its  own  peculiar  brand  of  madness  on  the  world  of  amateur 
radio  newsletter  publishing.  It's  time  the  Bulletin  received  rec- 
ognition for  its  many  journalistic  achievements. 

Founded  sometime  in  the  murky  past  by  the  very  distin- 
guished Dr.  Felix  R.  Onehundredton,  GEARVAKf  is  more  prop- 
erly known  as  the  Greater  Enon  AmateuRadioVention  And 
Kite  fly  (the  *T  is  silent).  Depending  solely  on  reader  contribu- 
tions, this  august  society  produces  one  and  sometimes  two 
issues  of  its  amusing  Bulletin  each  year. 

The  GEARVAKf  Bulletin  strives  to  cover  stories  which  are 
overlooked  or  ignored  by  traditional  amateur  journals.  Two 
years  ago,  for  instance,  the  Bulletin  broke  the  exclusive  story  of 
the  raging  fire  that  nearly  destroyed  the  20-meter  band.  A 
follow-up  article  detailed  FCC  plans  to  install  a  sprinkler 
system  to  guard  against  future  conflagrations. 

Strong  technical  content  is  a  hallmark  of  the  GEARVAKf 
Bulletin.  The  newsletter  has  published  pioneering  articles  on 
such  diverse  subjects  as  the  Exploding  Rat  Amplifier  and  the 
early  closing  of  the  10-  and  1 5-meter  bands  due  to  FCC  budget 
cuts.  The  exploits  of  researchers  such  as  Dr  Phugoid  G.  Dutch- 
roll  keep  GEARVAKf  at  the  cutting  edge  of  technology. 

The  Butiefin  frequently  publishes  the  results  of  GEARVAKf 
member  poJIs,  which  are  conducted  by  the  GEARVAKf  Public 
Opinion  Subcommittee,  Members  were  asked  recently;  "How 
do  you  feel  about  current  issues?''  Fully  64%  voted  "no,"  with 
11%  "yes"  and  5%  "undecided"  about  current  issues.  That 
says  it  all. 

For  wackiness  above  and  beyond  the  call  of  duty,  editor/ring- 
leader K8DMZ  and  his  cronies  deserve  heartiest  applause.  Con* 
gratulations  to  our  newsletter  of  the  month,  the  GEARVAKf 
Bulletin.— WBQBTH. 


the  number  of  complete  con- 
tacts with  Nj  stations  by  the 
number  of  NJ  counties  worked 
(21  maximum).  NJ  stations 
count  1  point  per  W/K/VBVO 
QSO  and  3  points  per  DX  QSO. 
Multiply  total  QSO  points  by  the 
number  of  ARRL  sections  {in- 
cluding NNJ  and  SNJ;  maxi- 
mum: 74).  KP4T  KH6t  KL7,  etc., 
count  as  3*point  DX  contacts 
and  as  section  multipliers. 

AWARDS: 

Certificates  will  be  awarded 
to  the  first-place  station  in  each 
NJ  countyt  ARRL  section,  and 
country.  In  addition,  a  second- 
place  certificate  will  be  awarded 
when  4  or  more  togs  are  received. 
Novice  and  Technician  cer- 
tificates will  also  be  awarded, 

ENTRIES: 

Logs  must  show  date/time  in 
GMT,  band,  and  emission.  Logs 
must  be  received  not  later  than 
September  11th,  The  first  con- 
tact for  each  claimed  multiplier 

120     7$  Magazine  *  August  1982 


must  be  indicated  and  num- 
bered and  a  check  list  of  con- 
tacts  and  multipliers  should  be 
included.  Multi-operator  sta 
tions  should  be  noted  and  calls 
of  participating  operators  listed. 
Logs  and  comments  should  be 
sent  to:  Englewood  Amateur  Ra- 
dio Assoc,  Inc.,  Post  Office  Box 
528,  Engiewood  NJ  07631-0528. 

A  #10  size  SASE  should  be  in- 
cluded for  results.  Stations 
planning  active  participation  in 
NJ  are  requested  to  advise  the 
EARA  by  August  1st  of  their  in- 
tentions so  that  they  can  plan 
for  full  coverage  from  all  coun- 
ties. Portable  and  mobile  opera* 
lion  is  encouraged. 

EUROPEAN  DX 

CONTEST— CW 

Starts:  0000  GMT  August  14 

Ends:  2400  GMT  August  15 

Sponsored  by  the  Deutscher 
Amateur  Radio  Club  (DARC). 
Only  36  hours  of  operation  out 


RESULTS 


3RD  ANNUAL  160METER  SSB  CONTEST" 
(Claimed  Scores  Ovef  100,000) 

SINGLE  OPERATORS: 

Callsign  QTH 


IftW 

IN 

W8LRL 

WV 

WB3GCG 

MD 

WMJGffl 

OH 

W1CFJ1 

MA 

woacftv 

m 

WBOCMM 

CO 

KJ9D 

IN 

KC8P 

Ml 

N5IJ 

TX 

NSATR 

OH 

K9QIL 

IL 

WICM 

KS 

KffU 

IL 

KB0HW 

Ml 

N5CG 

OK 

W3BGN 

PA 

W9DUB 

Wl 

KC40V 

TN 

K1MNS 

NK 

K1LPS 

VT 

W4TMR 

NC 

KA7BTQ 

ID 

KfSTI 

5D 

W4VKK 

GA 

W2FJ 

NJ 

N7DF 

UT 

mm 

FL 

MULT/  OPERA  TOR: 

WBNGO 

Ml 

W4CN 

KY 

AK2E 

NY 

K9ZUH 

IN 

K9YUG 

IL 

K9£X 

IL 

Claimed 
Score 

371580 
350  JOO 
322,660 
315.315 
236,280 
234.240 
230,895 
184,670 
169,600 
169,650 
194,640 
160.950 
147.600 
142,500 
138.320 

ias,*io 

135J30 
135.660 
130.140 
120,725 
119,610 
117.720 
111,605 
109,060 
106.020 
104,430 
103,880 
101,100 


273.900 
236,950 
224,750 
213.230 
152,400 
13Qt9oQ 


Full  details  and  final  scores  will  be  feaiured  Ln  a  future  Issue  of  73.  W&J1  ever 
1.000  stations  competed— Ihe  best  year  EVER! 

*  sponsored  by  73  Magazine 


of  the  48-hour  period  are  permit- 
ted for  single-operator  stations, 
The  12  hours  of  non-operation 
may  be  taken  in  not  more  than 
three  periods  at  any  time  during 
the  contest  Operating  classes 
include:  single-operator,  all- 
band  and  multi-operator,  single* 
transmitter.  Multi-operator, 
single-transmitter  stations  are 
only  allowed  to  change  band 
one  time  within  a  15-minute 
period,  except  for  making  a  new 
multiplier.  Use  all  amateur 
bands  from  3-5  through  28  MHz. 
A  contest  QSO  can  only  be 
established  between  a  non- 
European  and  a  European  sta- 
tion. Each  station  can  be 
worked  only  once  per  band, 

EXCHANGE: 

Exchange  the  usual  six-digit 
number  consisting  of  RST  and 
progressive  QSO  number  start* 
ing  with  001. 

SCORING: 

Each  QSO  counts  1  point, 
Each  QTC  (given  or  received) 
counts  1  point.  The  multiplier  for 


non-European  stations  is  deter 
mined  by  the  number  of  Euro- 
pean countries  worked  on  each 
band.  Europeans  will  use  the 
last  ARRL  countries  list.  In  addi- 
tion, each  call  area  in  the  follow- 
ing countries  will  be  considered 
a  multiplier:  JA,  PYT  VEf  VO,  VK, 
W/Kp  ZL,  ZS,  UA9HJAI&.  The 
multiplier  on  3,5  MHz  may  be 
multiplied  by  4t  on  4  MHz  by  3, 
and  on  14  through  28  MHz  by  2. 
The  final  score  is  the  total  QSO 
points  plus  QTC  points  multi- 
plied by  the  sum  total  multipliers. 

QTC  TRAFFIC: 

Additional  point  credit  can  be 
realized  by  making  use  of  the 
QTC  traffic  feature.  A  QTC  is  a 
report  of  a  confirmed  QSO  that 
has  taken  place  earlier  in  the 
contest  and  is  later  sent  back  to 
a  European  station,  it  can  only 
be  sent  from  a  non-European 
station  to  a  European  station. 
The  general  idea  is  that  after  a 
number  of  European  stations 
have  been  worked,  a  list  of  these 
stations  can  be  reported  back 
during  a  QSQ  with  another  sta- 


tion.  An  additional  one-point 
credit  can  be  claimed  for  each 
station  reported. 

A  QTC  contains  the  time,  call, 
and  QSO  number  of  the  station 
being  reported,  e+g,F  1300/ 
DA1AA/134.  This  means  that  at 
1300  GMT  you  worked  DA1AA 
and  received  number  134,  A 
QSO  can  be  reported  only  once 
and  not  back  to  the  originating 
station.  Only  a  maximum  of  10 
QTCs  to  a  station  are  permitted. 
You  may  work  the  same  station 
several  times  to  complete  this 
quota,  but  only  the  original  con- 
tact has  QSO-point  value,  Keep 
3  uniform  list  of  QTCs  sent.  QTC 
3/7  indicates  that  this  is  the  3rd 
series  of  QTCs  sent  and  that  7 
QSOs  are  reported,  Europeans 
may  keep  the  list  of  the  received 
QTCs  on  a  separate  sheet  ff  they 
clearly  indicate  the  station  that 
sent  the  QTCs, 

AWARDS: 

Certificates  to  the  highest 
scorer  in  each  classification  in 
each  country,  reasonable  score 
provided.  Continental  leaders 
will  be  honored  with  plaques. 
Certificates  will  also  be  given 
stations  with  at  least  half  the 
score  of  the  continental  leader 
or  with  at  least  250,000  points. 
The  minimum  requirements  for 
a  certificate  or  a  trophy  are  100 
QSOs  or  10,000  points. 

ENTRIES: 

Violation  of  the  rules, 
unsportsmanlike  conduct,  or 
taking  credit  for  excessive  dupli- 
cate contacts  will  be  deemed 
sufficient  cause  for  disqualifica- 
tion The  decisions  of  the  Con- 
test Committee  are  final  it  is 
suggested  you  use  the  log 
sheets  of  the  DARC  or  equiva- 
lent. Send  a  large  SASE  to  get 
the  wanted  number  of  logs  and 
summary  sheets  (40  QSOs  or 
QTCs  per  sheet).  SWLs  apply 
the  rules  accordingly.  Entries 
should  be  sent  no  later  than 
September  15th  to:  DARC  DX 
AWARDS,  PO  Box  1328,  0*895 

Kaufbeuren,  West  Germany. 

EUROPEAN  COUNTRY  LIST: 

G31,  CT1,  CT2,  Di_  DM,  EA, 
EA6,  EL  F,  FC.  G,  GC  Guer,  GC 
Jer,  GD,  Gl,  GMT  GM  Shetland, 
GW,  HA,  HB9f  HB0,  HV,  I,  IS,  IT, 
JW  BearP  JW,  JX,  LA,  LX,  LZ,  Ml, 
OET  OH,  OH0,  OJ0.  OKT  ON,  OYT 
OZ,  PA,  Sfvt,  S,  SV,  SV  Crete,  SV 
Rhodes,  SV  Athos,  TA1  ( UA1 346, 
UA2,  UBS,  UC2,  UNI,  U05.  UP2, 
UQ2.  UR2(  UA  Franz  Josef  Land, 
YO.  YU,  ZA.AB2,  3A,  4U1,  9H1. 


45  MAGAZINE 

FSTV  UHF  CONTEST 

Starts:  1800  EDT  August  20 

Ends:  1800  EDT  August  22 

Over  $750  worth  of  prizes  will 
be  awarded  in  the  1982  A5 
Magazine  North  American  FSTV 
UHF  Contest.  This  48-hour  ATV 
contest  is  designed  for  the  UHF 
specialized  communications 
operator  to  work  as  many  FSTV 
contacts  as  possible  with  re- 
warding bonus  multipliers  and 
additions  for  quality  picture 
transmissions,  DX  distance  ac- 
complishments, and  bands  uti- 
lized. All  ATV  stations  in  the 
United  States,  Canada,  and 
Mexico  are  eligible  for  entry. 
Even  stations  without  transmit 
capability  can  participate  utiliz- 
ing a  secondary  frequency  for 
voice  confirmation  of  received 
video.  Please  note  that  dates 
and  times  are  in  Eastern  Day- 
light Time  (EDT). 

Contacts  must  be  made  on 
authorized  amateur  bands  and 
within  power  limitations  as  set 
forth  by  the  governing  agency. 
Transmission  of  TV  signals  In 
recognized  SSB,  EME,  FM,  or 
satellite  portions  of  the  UHF 
bands  will  not  be  recognized 
and  becomes  grounds  for  im- 
mediate disqualification  of  en- 
try. No  station  may  claim  an- 
other station  more  than  one 
time  per  band,  Crossband  con- 
tacts are  encouraged  and 
authorized. 

Portable,  mobile,  and  air- 
mobile, etc.,  contacts  are 
allowable  as  long  as  verification 
of  location  and  simplex  trans- 
mission is  used.  Contacts  via  re- 
peaters or  any  type  of  relaying 
device  are  prohibited.  This  is  not 
to  discourage  ATV  repeater  use, 
but  merely  to  establish  operator 
and  station  self-accomplisrv 
ment.  Secondary  audio  frequen- 
cies for  signal  coordination  are 
recommended,  such  as  146.43 
MHz  FM,  7.290  MHz,  and  3.990 
MHz,  Any  locally-utilized  sec- 
ondary voice  frequency  may 
be  used. 

For  a  valid  contact  to  occur, 
verification  must  be  established 
by  both  the  receiving  and  trans- 
mitting stations.  This  can  be  ac- 
complished by  video  return, 
voice  communications,  hard- 
copy  photography,  or  lettered 
QSL.  Proof  of  contact  to  be  in- 
cluded as  logbook  entry  with  re- 
quired information  or  enclosed 
photographs  to  A5. 


At  the  core  of  the  Big  Apple 


JUNIOR    HIGH    SCHOOL    22,    ARC 

111    Columbia    Street  .^?i05v 

New  York,    N.Y.      1000?        ^M^^ff&& 


Wri 


RADIO 


a 


DATf 

1 

UTC 

RSI 

R«G 

ANTENNA 

OPERATOR 

QSL  OF  THE  MONTH:  WB2JKJ 

Joe  Fairclough  WB2JKJ  had  this  to  say: 

I  am  a  Junior  High  School  English  teacher  and  have  been  since 
1968.  I  have  been  an  amateur  operator  since  1962. 

After  several  years  of  using  the  conventional  methods  of  teaching 
English  and  finding  they  simply  do  not  work  on  the  7th  and  8th 
graders  I'm  dealing  with,  I  decided  it  was  time  lor  a  change.  There 
had  to  be  a  better  way.  If  a  child  is  interested  and  wants  to  be  in 
school  he  will  learn. 

With  the  idea  of  creating  interest  and  excitement,  I  took  the  stan- 
dard English  curriculum  and  revised  it  alt  around  ham  radio.  Very 
basically  and  briefly,  this  is  what  I  developed: 

1,  Teach  the  children  Morse  at  the  beginning  of  the  term  and 
get  them  to  a  point  at  which  they  can  copy  their  spelling  and 
vocabulary  in  GW\ 

2,  Use  the  Novice  handbook  as  the  class  textbook,  Diagram  its  sen* 
tences,  examine  its  parts  of  speech,  etc. 

3,  Reading  assignments  from  73,  QST,  CO,  and  any  other  suit- 
able publications. 

Our  program  receives  no  funds  from  any  government  agency  or 
even  the  school  itself.  We  are  totally  self-supporting.  AIJ  our  equip- 
ment was  purchased  from  the  fund-raising  efforts  of  the  students 
and  myself.  Even  down  to  the  postage,  it*s  all  done  by  the  kids.  It's 
very  difficult  to  survive  this  way,  but  It  makes  for  a  great  spirit  of 
everyone  pulling  together,  and  besides,  hams  are  great  people  and 
without  them,  this  wouldn't  be  possible. 

So  listen  for  us  on  15.  We'll  be  listening  for  you. 


RESULTS 


1382  SSTV  CONTEST  RESULTS 

Activity  during  this  year's  SSTV  contest  was  relatively  mild,  but  there  were  In- 
dications of  video  enthusiasm  and  acceptance  by  amateurs  on  the  bands.  Slow 
scanners  were  noted  on  several  HF  bands,  many  exchanging  reports  via  color 
rather  than  black-and-white  SSTV.  Quite  often,  we  also  noticed  contest  activity 
giving  way  to  general  interest  SSTV  views  and  idea  exchanges.  Great!  If  such  In- 
terests are  sparked  and  a  general  attitude  of  friendship  developed,  a  worthwhile 
purpose  is  definitely  served.  DX  signets  poured  Into  the  US  on  both  10  and  20  me 
tars  during  the  contest's  morning  period s,  and  again  during  the  last  hours  of 
each  day's  operation. 

We've  received  requests  lor  shitting  the  SSTV  contest  period  from  April  to 
January  or  February  (its  close  proximity  to  Dayton  in  April  creates  a  "strain14  on 
contesters).  What's  your  opinion?  Another  item  of  interest  concerns  holding 
crossband"  SSTV  activities  between  Advanced  class  end  General  class 
SSTVers  during  the  first  15  minutes  of  each  contest  hour.  Let's  hear  your  opin- 
ions either  via  mail  or  via  the  Saturday  SSTV  net — and  soon.  Announcement 
deadlines  for  the  next  contest  are  nigh.  Truthfully,  we  must  show  more  contest 
participation,  gang,  or  the  contest  will  be  doomed  to  failure.  We  know  many  of 
you  operated,  but  where  are  tnose  logs? 

This  year's  SSTV  contest  winner  was  Mike  Di  Persio  KC2Q,  ol  Bradley  Beach 
NJ.  Congratulations.  Mike,  and  enjoy  your  year's  subscription  to  73. 

Thanks  to  all  for  the  participation,  and  we  look  forward  to  /our  support  next 
lime.  See  you  on  the  Saturday  SSTV  net  (1600  UTC,  14,230  kHz). 

Dave  Ingram  MTWJ 
Richard  'Brooks'  Kendall  W1JKF 


73  Magazine  *  August ,1982    121 


Video  pictures  transmitted 
must  contain  as  a  minimum  the 
station  callsign  and  location 
along  with  a  signal  report  of  the 
video  received.  Standard  "'P1' 
signal  reports  will  be  used. 

Quality  multipliers,  DX  dis- 
tance additions,  and  band 
usage  multipliers  will  be  used  as 
shown  later.  Standard  air  or  road 
maps  may  be  used  to  determine 
recorded  distances.  A  circle 
radius  should  be  drawn  from  the 
location  of  the  operating  station 
with  increments  of  25  miles  and 
dots  showing  locations  of  sta- 
tions worked.  The  map  used 
must  be  submitted  to  the  AS 
Magazine  contest  editor  along 
with  all  log  entry  information. 

Winners  with  the  highest 
score  in  each  US  call  area, 
Canadian  province,  or  Mexican 
XE1,  XE2,  or  XE3  areas  will 
receive  a  free  one-year  subscrip- 
tion to  A5  Magazine,  a  copy  of 
the  new  ATV  book  Everything 
You  Always  Wanted  To  Know 
About  ATV  But  Were  Afraid  To 
Ask,  and  a  gold  Specialized 
Communications  Achievement 
Award  certificate  suitable  for 
framing.  All  entries,  regardless 
of  placement,  will  receive  a  gold 
certificate  showing   participa- 


tion. The  hrghest-scohng  North 
American  winner  will  also  re- 
ceive a  wooden  plaque  engrav^ 
ing  with  a  large  orthodon  video 
tube  similar  to  the  A5  Magazine 
Good  Image  award,  along  with 
his  photo  in  A5  Magazine, 

All  entries  are  encouraged  to 
send  photos  of  station  opera* 
tion  and  contacts  received  which 
will  be  returned  by  A5  Magazine. 
Entries  must  be  postmarked  no 
later  than  September  1st,  allow- 
ing one  week  for  lettered  verifi- 
cations. All  logs  will  be  returned. 
Please  include  A5  ATV  Maga- 
zine subscription  expiration 
date  information  with  your  entry. 

SCORING: 

The  base  points  awarded  are 
determined  by  the  type  and 
strength  of  signal  received. 
Many  times  on  long  distance 
contacts  or  weak  band  condi- 
tions, only  the  sync  bar  level  is 
seen,  without  a  video  picture.  If 
indeed  verification  can  be  ac- 
complished by  both  stations  on 
a  secondary  frequency  utilizing 
the  "onoff*  method  with  the 
receiving  station  stating  the  ac- 
tual "on-off"  reception  test 
signals,  then  low-level  points 
can  be  achieved,  it  is  to  the  ad- 
vantage of   both    stations   to 


FSTV  UHF  CONTEST  SCORING 


Base  Pomt  Table 
Points        Contact  Type 


1 

2 

3 

6 

10 

15 

20 

30 

40 

4S 

90 

as 


1<way,  verified  sync  or  audio  tone  bar  display 

2-way,  verified  sync  or  audio  tone  bar  display 

1-way,  audio  sound  delected  only  (subcarriar  or  on-carrier) 

2-way.  audio  sound  delected  only  {subearrier  or  on-carrier) 

i  way.  video  picture  (b&wi  detected 

1-way,  video  picture  (b&w)  detect  ad  with  sound 

2  way.  video  picture  (b&w)  detected 

2-way,  video  picture  {b&wi  detected  with  sound 

1-way.  color  picture  detected 

1-way.  color  picture  and  sound  detected 

2-way.  color  picture  detected 

2-way.  color  picture  with  sound 


Picture  Quality  Muttiplimts 

tease  poinl  times  P  signal  quality  level} 

Base  times  1  =P  0  to  P-t  picture 

Not  usable,  lost  In  noise,  limited  use 
Base  times  2  pP*2  picture 

Passable  picture,  high  noise  level 
Base  times  3  =P-3  picture 

Fair  picture,  noticeable  noise 
Base  times  4  =P-4  picture 

Good  picture,  slight  noise  visible 
Base  times  b=P5  picture 

Excellent,  closed  circuit,  no  noise  visible 

DX  Df stance  Addition 

(Base  point  times  P-signal  quality  multiplier  plus  DX  points) 

Note:  Distance  figured  In  miles  and  rounded  to  nearest  25-mile  marker,  plus 

25  points  tor  25  mile*.  M  points  lor  50  miles,  75  points  for  75  milea.  etc 

Band  Used  MutUphers 

(Base  limes  P  signal  multiplier  plus  DX  limes  band  used) 

1200  MHz  =  times  2 

2300  MHz  =  times  3 

Higher  frequencies  -times  4 


watch  the  bands  or  apply  more 
power  to  obtain  a  better-quality 
contact  with  higher  points.  Con- 
tinued quality  upgrades,  in* 
eluding  cofor  reception  with 
sound,  enhance  higher  point 
totals.  In  case  of  better  condi* 
tions  further  along  in  the  con* 
test,  previous  claimed  contacts 
may  be  ©rased  and  upgraded  if 
desired. 

OHIO  OSO  PARTY 
Starts:  0000  GMT  August  28 
Ends:  2400  GMT  August  29 

Sponsored  by  the  Cuyahoga 
Falls  Amateur  Radio  Club,  the 
contest  is  open  to  all  radio 
amateurs  worldwide. 

EXCHANGE: 

RS(T)   and   ARRL  section, 

DXCC  country,  or  Ohio  county, 

SCORING: 

Score  2  points  for  each  con* 
tact  with  an  Ohio  station.  Con- 
tacts with  a  Falls  member  will 
be  worth  10  points  and  contacts 
with  W8VPV,  the  club  station, 
will  count  25  points.  Outside 
Ohio,  multiply  your  total  QSO 
points  by  the  number  of  Ohio 
counties  worked  on  all  bands. 
Ohio  stations  will  score  5  points 
for  out-of-state  contacts  plus 
the  member  and  club  station 
bonuses.  Multiply  your  050 
point  total  by  the  sum  of  coun- 
ties (max.:  88).  ARRL  sections 
(max.:  74>f  and  DXCC  countries 
on  each  band.  Phone  and  CW 
are  considered  two  bands. 

AWARDS: 

Plaques  to  the  top  station  in 
Ohio  and  outside  Ohio,  Certifi- 
cates to  the  top  station  in  each 
ARRL  section,  Ohio  county,  and 
DXCC  country.  All  awards  will 
be  made  out  to  the  station  call 
on  the  entry. 

ENTRIES: 

Each  log  must  show  the  date/ 
time  in  GMT,  band  and  mode, 
and  the  complete  exchange.  A 
copy  of  the  official  log  sheet  and 
reporting    form   are   available 


from  the  club  by  sending  an 
SASE-  Dupe  sheets  must  be 
completed  for  any  stations  with 
more  than  200  contacts.  Some 
form  of  summary  sheet  showing 
the  scoring  and  usual  signed 
declaration  are  also  requested. 
Send  a  large  SASE  for  a  copy  of 
the  results.  Deadline  for  logs  is 
Sept.  29th.  All  entries  and  re- 
quests for  forms/logs  should  be 
addressed  to:  The  Cuyahoga 
Falls  ARC,  PO  Box  6.  Cuyahoga 
Falls  OH  44222, 

OCCUPATION  CONTEST 

Starts:  1600  GMT  August  28 

Ends:  2400  GMT  August  29 

The  Radio  Association  of  Erie 
PA  is  sponsoring  their  second 
annual  contest.  The  contest  is 
open    to   all    amateur    radio 

operators. 

EXCHANGE; 

RS{T);  occupation;  and  state, 
province,  or  country.  Please  try 
to  keep  occupations  in  general 
fields  such  as  engineer,  teehnl* 
cian,  machinist,  salesman,  etc. 

FREQUENCIES: 

CW— 50  kHz  from  the  bottom 
of  the  ham  bands.  Phone— 50 
kHz  from  the  top  of  the  ham 
bands.  Repeater  contacts  are 

not  permitted. 

SCORING: 

Count  1  point  per  QSO,  with 
multipliers  determined  by  the 
number  of  similar  occupations 
worked.  One  multiplier  point  is 
given  for  every  3  similar  occupa- 
tions. Final  score  is  the  product 
of  the  QSO  points  times  the  to- 
tal multiplier. 

AWARDS: 

A  plaque  will  be  given  to  the 
top-scoring  station.  Certificates 
for  the  top  stations  in  each 
state,  province,  and  country. 

ENTRIES: 

The  mailing  deadline  for  logs 
is  Oct,  1st.  They  are  to  be  sent 
to:  Chris  Robson  KB3Ar  6950 
Kreider  Rd,,  Fairview  PA  16415. 


HAM  HELP 


l  would  lite  to  know  rf  the  speaker-m^o- 
phone  SMC-24  is  available  for  Ihe  Kenwood 
TR-2400  2-meter  NT  f*om  a  commercial  dis- 
tributor of  an  individual. 

Stephen  J.  O'Malley  N2CLE 

35-54  160  Street 

Flushing  NY  1135A 


I  am  looking  lor  any  informal  ran  on  the 
Bendix  A  vial  ton  Corp,  Model  2V13E  450- 
MHz  FM  mobile  radio— particularly  the 
manual  and  schematic. 

Michael  Bilow  N1BEE 

Forty  Plantation! 

Cranston  Rl  02920 


122     73  Magazine  •  August,  1932 


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leaEures  low  wind  loading  jnd  easy  installation 

Win  (his  package  you  are  ready  Tot  tieurs  ol  Amateur  television  entertainment  Just  aim  the  antenna,  conned  one  75  cable  Iron  the 
antenna  Id  the  power  supply  arid  a  second  line  Irom  the  power  supply  id  your  TV,  and  you  are  on  the  aft 

All  downcenvener  moaets  use  micros!  rip  const  ruction  (or  tong  and  reliable  operation  A  low  noise  mfcrwsve  preamplifier  is  iisea  tor 
pulling  m  weak  signals  The  downconventr  also  includes  a  broad- band  output  amplifier  married  to  75  ohms  Trie  flP  model  is  retonv 
mended  for  up  to  15  miles  Over  a  range  ot  1 5  lo  25  miles.  Ine  gp  +  wsuch  has  a  lower  noise  and  higher  gain  RF  amplifier  stage. 
provides  better  television  reception  These  ranges  are  necessaniy  approximate,  as  signal  strength  is  very  sensitive  to  line  ot  sight 
obstructions  For  insiat&iions  over  25  miles,  an  RPC  un«l  which  uses  a  separate  antenna  is  available.  All  models  are  warranted  tor 

■*■■■  uniT 
DUE  fBdl 


Prices  including  UPS  shipment  are  as  toiiows 

Model  FtP  receiver  package ..._$l35 

Model  8P  ■+■  receiver  pjrkagn ,„..,,....,■■■■„  rt*^5 

Model  RPC  receiver  package .™.™»««™J155 


^*65 


K.  &  S.  Enterprises 

P.O.  Box  741,  Mansfield,  MA  02048 


J  Put  Your  Computer, 

1      "On-The-Air"      ■ 


The  interface 


tm 


Sugg,  price  $189.95 

Your  personal  computer  becomes  a  complete  cw/ 
RTTY/ ASCII  send  and  receive  terminal  with  The  Inter- 
face linking  it  to  your  transceiver. 

If  you  own  an  Apple  1 1  or  Apple  n  Plus,  Atari  400  or  800, 
trs-80  Color  Computer,  or  vic-20,  The  interface  will 
put  your  computer  "On-The-AIr". 

Software  for  each  system  features  split  screen  dis- 
play, buffered  keyboard,  status  display,  and  message 
ports.  Attach  any  Centronics  compatible  printer  for 
hard  copy.  Software  Is  available,  on  diskette  for  the  Ap- 
ple and  program  boards  for  tire  others,  at  an  additional 
cost. 

Apple  Atari  VIC-20  TRS-80C 

diskette  board  board  board 

$29.95  $49.95  $49.95  $59.95 

See  The  Interface  at  your  authorized  Kantronics  deal- 
er, or  contact: 


EKantronics 


(913)842-7745    1202  E.  23rd   Lawrence,  Kansas  66044 


**See  Ltst  of  Advertisers  on  page  7 14 


73  Magazine  *  August,  1962     123 


CUSHCRAFT 

A3  3  Element  T riband  Beam  $16700 

A4  4  Element  T riband  Beam        ,  $204-00 

A743  7  &  10  MHz  Add  On  tor  A3  $55.00 

A744  7  &.   1Q  MH;  Add  On  tor  A4  $55.00 

AV3  3  Sand  Vertical   10-20m  141,00 

AV4  4  Band  Vertical   IQ^tOm  $82. 00 

AV5  5  Band  VertJcaf  1"-80m.  $38.00 

R3  14.2V28  MHZ  Ringo                               .  .  S2O4.0G 

32  19  Boomer  19  Element  2m  $75.00 

214B  Jr    Boomer  14  Element  2m  $61.00 

A147  11  2m  11   Element  Antenna  $34  00 

A.147-4  2M  4  Element  Antenna  523,00 

ARX-2B  134-164  MH2  Rmgo  Ranger  II  $34.00 

A144  10T  145  MHz  10  Elemenl  $41,00 

A432-20T  432  MHz  20  Elemeni  $41.00 
A14T-MB  Tw»sl  Mounting  Boom  &  Bracket  $21.00 

Fult  Line  Available  on  Sale  .CatL 

ROHN 

30Q  10  H   Stacking  Sector  $32,00 

25G  10  ft   Stacking  Secuon      .  .  $39,50 

45G  10  ft   Stacking  Section  $67.50 

25AG  2,3  or  4  Top  Section  $52.50 

HDBX  4S  4B  fl    Free  Standing  Tower .  S32Q.0Q 

HBX56  56  It    Free  Standing  Tower  $340.00 

FK254B  48  it    25G  Foldover  Tower  $725.00* 

TB3  Thrusi  Bearing                     .  .  $4000 

SB25G  Short  Base  for  25G $16,50 

BPH25G  Hinged  Base  Ptate  S59  75 

AS25G  Accessory  Shell  59.50 

KB  25  AG  14     House  Bracket $14  50 

BPC25G  Cement  Base  Plate  $32.00 

BA525G  Shori  top  section  wtecc   shelf  $36.00 

M2O0  16  gauge.  10  ft.  2      QD   Mast    .  519  50 

M200H   V6"  wall    10  It    T  O  D    Mast  $36.00 

Freight  prepaid  on  Paid  over  towers  Prices 
10%  higher  west  of  Rocky  Mts 


MINI-PRODUCTS 


HQ  1  Mmi  Quad  &Wnbi20m  Antenna  $129.95 

B-24  2  Element  HF  Mint- Beam  6n0j't5j'20rn  $99.00 
RK  3  3rd  Element  Add  on  lor  B  24. 

Improves  T0-20m  $67-00 

C-4  Mini  Vertical  6M0M5;2Om  $5900 


The  Antenna  Bank 
[703)  569- 12001 


HUSTLER 

4BTV  40  10  Mtr    VerUcal  .  . 
58TV  SO- 10  Mir    Vertical  , 
M01/M02  HF  Mobde  Mas! 
HF  Mobile  Resonators.    Sid.  40QW 
10  or  15m  $9,00 

20m  $11.00 

40m  $13.00 

75  Of  SOm  $14.00 

BHM  Bumper  mt    wilh  S.S    Strap 
5SM  2  Commercial  S  S    Bait 
SF^2  5,'S  Wave.  2  Me  lei  Antenna 
HOT  Husiloff  Mi.  with  Swivel  batl 
G6  144B  2M  Colmear.  fixed  Station.  6db 
G7  144  2M  CoMneaj.  Mxed  Statron.  7db 

Full  Line  Available  on  Sale  Call 


$79.00 

$100.00 

$18.00 

SUPER  2KW 

$13.00 

$16.00 

$m.  oo 

$29,00 

$1300 
$1400 
$9,00 
$14.00 
$66.00 
$99,00 


IJ^ORDERS  ONLY 

800-336-8473 


•  Stepping  charges  not  included 

•  Pnces  subiect  to  criange  wtlhoul  notice 

•  Limited  quantities 

•  No  COD'S 


fj 


VJ 


Van  Gordon  and  B&vV  in  stock  at  special  prices 


HY-GAIN 

TH3JRS  Jr    Thunderbird.  750W  PEP  $150.00 

HO-2S  Hv  Quad.  2  Element  $235.00 

THSDXS  Thunderbird,  5  Element    ..  $215.00 

TH3MK3S  Thunderbird.  3  Element  $19500 

TH2MK3S  Thunderbird.  2  Elemen:  $12600 

TH7DX  Thunderbird.  7  Element  $336.00 

392$  TH6DXX  Conversion  Kit  to  TH70X  $135.00 

105BAS  5  Element   Itim   Jjonq-John"  $114.00 

~lSSBAS"&"FTe?nent  15m    Long  John""  ~$16T 

205BAS  h  Element  20m     Long  John  $269.00 

14AVQArVBS  10  40m  Verticil  $49.96 

16AVTWBS  I0'80m  Verrhcal  $87.50 

V2S  Cclinear  Gam  Vertical  138  174  MR;  $33.75 

BN  66  Feirite  Balun.  10-80  meters  $13.00 

HDP  300  Deluxe  Ftoiw   DigMal  Readout  S37B.0O 

*      SUPER  HY-GAIN  PACKAGE      *_ 


HG52SS   52    Self  Sup    Crank  Up 

TH7QX  Thunderbrrd    7  Element 

HM  IV  Rotor 

COA  (3}  Coax  Arms 

HG  10  Mast  Mast   10 

$1377  SALE     SAVE  $449.90 


HG50MT2    50  fl    side  sup.  Crank-up  tower 
TH3MK3S  3  Element  Thunderbird       ^„n  0^ 


CD. 45  Rotor 

COA  3  Coax  Arms 
HG-5  Mast 

$1005.00  SALE  SAVE  $303  45 


**crftf* 


ffee 


f^1' 


PhJIly  Siran  Guy  Cable  in  stock 

NO  SUBSTITUTIONS  PLEASE 

ROTORS  &  CABLES 

CDE  HAM  IV  Rotor 
CDE  T2X  Rotor 
CDE  45     Rotor 
Alliance  HD-73  Rotor 
Alliance  U100  Rotor 
fiG-6/U    Foam  Coax  9^%  Shietd 
RG-213  Coax.  Mil    Spec 
Mini-B  Coax  95%  Shield 
Rolor  Wire  &  Conductor 
4  Conductor, 


$17500 
5244.00 
$9200 
$92.00 
$4200 
24«/f1. 
2e*rh\ 

!2i/fr 

16c/fl. 
75i/ft. 


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CALL  NUMBER  ONE! 

CARLOAD  INVENTORIES  •  ROCK  BOTTOM  PRICES 

SUPER-FAST  SERVICE 


UNES     AEA 

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KANTRONICS 

MINI-PRODUCTS 

NYE 

TEN  TEC       ^ 

AVANTI 

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COLLINS 

HY  GAIN 

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UNIVERSAL 

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REGENCY 

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call  toll  FREE  1-800-325-3609 

MID-COM  ELECTRONICS   •    8516  MANCHESTER  ROAD   •    BRENT 


lf\g%        IN  MISSOURI 

f\J&    314-961-9990 

BRENTWOOD,  MO  63144 


^52 


124     73Magazine  *  August J982 


1900  -  2500  MHZ    KITS 


down  CQNVEpTER  KIT 
$19.95 


ANTENNA  KIT 
S19*95 


V^ 


POWER  SUPPLY  KIT 
SI99S 


PPE-DPIUEDAND 
SOt PER  FLOWED 

3  MPE90 I  TRANS, 
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6    CfflP  CAPS 'tARGE" 
8    RESISTORS 

4  PREPAIRED  COttS, 
FACTOR?  WOUND 

JfQMfPCAP^ 
SUPPLY  CABINETS 

fCttlf    ItfFftf  K'T ...rr„.  -ft-  *  2 

MANUFACTURED 
CASU  SETS 

t§gtr,  rtvi  str. „„,.t.//t. fj 

titt.  n*$ tfj....^.^» ns.*$ 

$ *tt.  n i/t  i ri. ,... ,t  ti.  ?i 


33    WASHERS 

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DISCOUNTS 

I  1*4.. i,ii »>/** 

it  r*  }*.... .....lift 

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JT         ■     ™         "    t-  -4l^L'JJI    fc  B  B  B  B  J    B  ■    J    W  W™ 

144  T&  tf  ,!<!._.•■■■■...<■■■■».  J  SM 

£   W  W  W     Ww*  J  I  iiiiuirimi  FT  FBI!  T  '  "^"' 


/    PC  BOARD 
t    POWER  TRANSf. 
1    3 1  ?t  ADJUSTABLE 
REGULATOR 

t    PINE  TUN/NO  POL 
WITH  SWITCH 

COARSE  TUNING  POT 

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7" CONNECTORS 
4    POWER  DIODES 
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3    DISK  CAPS. 
I     1000  MFD  CAP. 
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SWITCH 

I    LED  WITH  HOLDER 


MAIL  ORDERS 

AOD  S5.00  FOR  SHIPPING  AND  HAN- DUNG 
INDIANA  RESIDENTS  ADD  4%   SALES  TAX. 


American 
Express" 

Cards 
Wcome 


TRIONYX  IND.  INC, 
6219  COFFMAN  RD. 

INDIANAPOLIS,  IND. 
46  2  88       t*  "104 
(317) 291-7260 
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FAST: 

=  SCAN 


$399 


Have  you  tried  it  yet? 
ATV  TRANSMiTTERICONVERTER 

MO  Watts  Output 

"Standard  Frequencies  Available 

*  Broadcast  Standard  Sound 

*  High-resolution  &  color  video 

*  Regulated  AC  Supply  Built  In 

jq -|  *Tuneabie  Downconverter  &  Preamp 

Connect  to  the  antenna  terminals  of  any  TV  set,  add  a  good 
450  MHz  antenna,  a  camera  and  there  you  are-  .  .Show  the 
shack,  home  movies,  computer  games,  video  tapes,  etc, 

ATV  DOWNCONVERTER 

For  those  who  warn  to  see  the  ATV  action 
before  they  commit  to  a  complete  station, 
the  TVC-4  te  for  you.  Great  For  public  ser- 
vice setups,  demos,  and  getting  a  buddy 
interested.  Just  add  an  antenna  and  a  TV 
set  tuned  to  CH.  2, 3,  or4and  pJuginto1l7  TWa  a 

volts  a  c    $69.00  I  VU-4 

TVC-4L  extra  tow-noise  version .  .  .  $105  delivered  in  USA 

HOMEBREWERS:  ASK  FOR  OUR  BASIC  FOUR-MODULE  PACKAGE 

CALL  OB  WRITE  FOR  OUR  COMPLETE  LIST  OF  SPECIFICATIONS,  station  set- 
up diagrams,  and  optional  accessories  which  include  antennas,  modulators, 
detectors,  test  generators,  cameras,  etc,  WE  ARE  A  FULL-LINE  SUPPLIER  Of 
ALL  YOUR  ATV  NEEDS. 

TERMS:  VISA  or  MASTER  CARD  by  telephone  or  mail,  or  check  or  money  order  by 
mall.  All  prices  are  delivered  in  USA,  Allow  three  weeks  after  order  for  delivery. 


(213)  447-4565 

P.C.  ELECTRONICS    2522  Paxson  Lane, 
TomweoRG    M.rytnn  wfieYSS  Arcadia,  California  91006 


/ 


/     /   / 


'/ 


i        •     iii..:     i.   / 

*      •  «      ft      *      *      *  ####  »•#*•**♦ 

(We  Speak  Your 
Language.) 

Backed  by  over  54  years  of  experience,  Harvey 
continues  to  offer  the  broadest  selection  and  finest 
service  available  for  the  amateur  radio  community, 
this  experience  has  taught  us  that  the  ham  needs 
special  treatment  and  that  is  why  Harvey  has  estab- 
lished a  special  division  dedicated  to  the  needs  of 
the  U.S.  and  foreign  ham  alike. 

One  thing  is  for  certain.  A  ham  will  never  get  the 
run  around  from  Harvey.  If  we  don't  have  something 
in  stock,  we  say  so  and  will  order  it  for  you— or— tell 
you  where  to  get  it.  However,  we  are  sincerely  dedi- 
cated to  the  ham  community  and,  as  a  result,  our 

expansive  in- 
ventory means 
that  more  than 
likely,  we  will 
have  what  you 
are  looking  for 
in  stock. 


AGA 

Affiance 

Antenna  Specialists 

Astron 

Bearcat 

Bencher 

B&W 

Centurion 

G  a  E. 

Cushcraft 
ft,  L  Drake 
Gotham  Antennas 
Grundig 
Henry  Radio 

H.M.  Electronics 

loom 
Kantronics 


K.  D.  rt 
Larsen 

McKay  Dymek 
M.F.J. 
Midland 
J.  W.  Miller 
Mirage 
Wm>  M.  Nye 

Pace 
Regency 


Ritron 

Russefl 

Signals 

Sinclair 

Teiex  Hygain 

Trilectric 

System  One 

VoCom 

WrS.  Engineering 

Yaesu 


CALLTOLLFREE: 

1-800-223-2642 

Ask  for  Dou  "Joe"  Chin -KB2MU 


**See  List  of  Advertisers  on  page  t  U 


73  Magazine  *  August,  1982     125 


A/Eiy  PRODUCTS 


LINEAR  AMPLIFIER 

A  1200^Watt  SSBt  1000*Watt 
CW  linear  amplifier  covering 
160P  80,  40,  30,  20,  17,  and  15 
meters  is  available  from  Den- 
Iron  Radio  Co, 

The  "Gaiion"  amplifier  tea* 
tures  a  rugged,  reliable  3-500 
grounded  grid  triode,  full-func- 
tion metering,  and  internal  in- 
out  switching.  A  built-in  dual 
power  supply  allows  it  to  oper- 
ate from  either  120-  or  240-V  ac 
lines  while  reduced  voltage  tune 
ensures  peak  efficiency  regard- 
less of  mode.  The  Gaiion  ampli- 
fier includes  a  tuned  input  cir- 
cuit for  compatibility  with  either 
solid-state  or  tube-type  exciters 
of  any  manufacturer. 


Improved  reliability  and  per- 
formance are  provided  through 
an  exclusive  linearity  test  cir- 
cuit, which  instantly  verifies 
proper  tune-up  and  operation, 
and  a  two-speed  blower  to  pro- 
vide high  volume  cooling 
capacity. 

A  modification  kit  available 
for  the  Gaiion  amplifier  will  ex- 
tend frequency  coverage  to  the 
12-  and  10-meter  amateur  bands 
and  associated  MARS  frequen- 
cies. The  Gaiion  amplifier  is 
priced  at  $695, 

For  more  information  on  the 
Gaiion  linear  amplifier,  contact 
DenTron  Radio  Co.,  inc.,  1605 
Commerce  Drive,  Stow  OH 
44224;  (216)688-4973,  Reader 
Service  number  482. 


The  Gallon  linear  amplifier  from  DenTron. 


Compensating  dipoie  antenna  from  Snyder. 


COMPENSATING  DIPOLE 

Snyder  Antenna  Corporation 
now  offers  self-compensating 
dipoles  that  offer  all  the  advan- 
tages  of  a  conventional  dipoie 
plus  increased  efficiency.  These 
full-band  antennas  have  no  re- 
sistors or  capacitors  and  can  be 
used  with  50-  or  70-Ohm  feed- 
lines.  Available  in  40-meter, 
75/80-meter,  and  160-meter 
models,  prices  start  at  $109.95. 
For  more  information,  contact 
Snyder  Antenna  Corporation, 
250  East  17th  St.t  Costa  Mesa 
CA  92627;  (714}-7B0-BBB2. 
Reader  Service  number  485. 

COMMUNICATIONS  TERMINAL 

Macrotronics,  Inc.,  has  in- 
troduced TERMINALL,  an  in- 
tegrated hardware  and  software 
system  which  converts  the  Apple 
II  or  Apple  II  Plus  into  a  state-of- 
the-art  communications  ter- 
minal. 

TERMINALL  includes  all  the 
necessary  computer-interfacing, 
audio-demodulating,  AFSK  tone- 
generating  and  transmitter- 
keying  hardware  integrated  in 
one  cabinet.  This  reduces  equip- 
ment  interconnection  to  a  min- 
imum and  allows  the  operator  to 
be  on  the  air  receiving  and  trans- 
mitting Morse  or  RTTY  or  ASQ1 
in  minutes.  Plug  it  into  the  re- 
ceiver headphone  jack  and  copy 
Morse  code,  Baudot,  or  ASCII. 
Plug  it  into  the  CW  key  jack  and 
send    Morse   code.   Attach   a 


microphone  connector  and  send 
Baudot  or  ASCII  using  audio 
tones  (AFSK). 

TERMINALL  T2  requires  an 
Apple  II  or  Apple  II  Plus,  48K 
RAM,  and  disk  drive.  Software 
provided  on  disk  in  DOS  3.2  for- 
mat  (MUFFIN  to  3.3).  Latched 
and  buffered  cable  plugs  into  any 
card  slot  (1  through  7), 

TERMINALL  comes  complete 
with  software  on  disk,  as- 
sembled and  tested  hardware, 
and  an  extensive  instruction 
manual.  List  price  is  $499.  For 
complete  information,  contact 
Macrotronics,  inc.,  1125  N. 
Golden  State  Btvd„  Turiock  CA 
95380;  (209^667-2888 \  Reader 
Service  number  484. 

6-METER  MULTIMODE 

The  IC-505  is  a  fully- 
synthesized  multimode  trans- 
ceiver covering  50  to  54  MHz  on 
FM  (option),  USB,  LSB,  and  CW. 
Utilizing  an  internal  battery  pack 
(9  C-size  batteries),  the  IC-505 
puts  out  3  Watts  of  rf  power 
when  run  on  its  batteries,  or  10 
Watts  when  connected  to  an  ex- 
ternal 13,6-voit  dc  source;  low 
power  is  0.5  Watts. 

IG-505  features  include  an 
LCD  frequency  display  for  low 
battery  consumption,  provision 
for  internal  memory  backup, 
dual  vfo's,  5  memories  plus  a 
call  channel,  memory  scant  pro- 
gram scan,  sideband  squelch, 
LCD  annunciators  for  vfo,  scan, 


TERMINALL  communications  terminal  from  Macrotronics, 
126     73  Magazine  *  August,  1982 


iC-505  transceiver  from  icom. 


memory  channel,  call  and  splitT 
and  split  frequency  operation. 
The  transceiver  has  a  list  price 
of  $449. 

For  more  information,  con^ 
tact  icom  America,  inc.,  2112 
116th  Ave,  NE,  Betlevue  WA 
98004;  (2Q6)-454~8155. 

SOLAR  MODULE 

A  photovoltaic  module  that 
produces  40  Watts  of  peak 
power  using  35  solar  ceils  is 
available  from  ARCO  Solar,  Inc. 

The  M51  module  is  designed 
for  high  voftage  applications 
where  efficiency  and  reliability 
are  critical  considerations.  It 
maximizes  Watt-hours  per  day 
while  keeping  balance  of  sys- 
tem costs  down.  It  has  been  sue- 
cessfully  tested  beyond  in- 
dustry standards. 

The  new  I*x4'  module  is 
10.75%  efficient-  Using  single 
crystal  silicon  cells,  it  can  even 
charge  batteries  at  five  to  ten 
percent  of  noontime  sun.  Under 
such  low  light  level  conditions, 
ARCO  Solar  analyses  show  the 
M51  can  deliver  up  to  25  percent 
more  energy  than  a  typical  mod- 
ule of  poly  crystal  line  design. 

Solar  cells  in  the  M51  are  100 
percent  electrically  matched  to 
ensure  maximum  power  output. 
Each  series-connected  cell  em- 


ARCO  Solar's  M51  module. 


ploys  44  contacts  for  enhanced 
reliability. 

For  more  information,  con- 
tact ARCO  Solar,  Inc.,  20554 
Ptummer Street,  Chatsworth  CA 
91311;  (213)^700-7458,  Reader 
Service  number  481. 

SATELLITE  RECEIVER 

The  unique  two-piece  design 
of  the  International  Crystal  ICM 
TV-4400  satellite  receiver  per- 
mits mounting  the  downconvert- 
er  at  the  LNA.  Signal  is  fed  to  the 
baseband  unit  via  RG-59  coax  at 
70  MHz-  The  dual-conversion 
receiver  features  step-switch 
tuning  with  variable  fine-tuning 
control,  A  subcarrier  output  may 
be  used  with  audio  accessories- 
There  are  two  standard  audio 
outputs  and  a  built-in  dc  block 
for  LNA  power.  The  ICM  TV-4400 
has  a  list  price  of  $1295  and  is 
available  from  International 
Crystal  Mfg.  Co.,  Inc.,  10  North 
Lee,  Oklahoma  City  OK  73102, 
Reader  Service  number  478, 

INTERFERENCE  TRAP 

The  Model  3966  is  a  micro- 
wave trap  for  preventing  strong 
microwave  carriers  from 
reaching  Earth  station  down- 
converters. 

The  trap  can  block  out  up  to  6 
microwave  telephone  carriers 
(offset  10  MHz  from  transponder 
frequencies).  Connectors  are 
type  N  and  the  trap  passes  dc 
power  to  the  LNA. 

The  trap  is  custom-made  to 
customer's  specific  microwave 
offenders.  Price  is  $180.00  for  a 
single  carrier  trap  plus  $90.00 
per  additional  interfering  car- 
rier. Delivery  is  10  days.  For 
more  information,  contact  Emily 
Bostick,  Microwave  Filter  Co., 
Inc.,  6743  Kinne  Street,  East 
Syracuse  NY  10357;  UB00H48- 
1666.  Reader  Service  number 
483- 

1:1  BALUN 

Hustler,  Inc.,  now  offers  a  1:1 
ratio  baiun  to  complement  their 
line  of  HF  amateur  antennas. 

The  balun,  designated  model 
MBLN,"  features  a  low-loss  air- 
core  design  eliminating  satura- 
tion at  high  power  levels  while 
maintaining  a  uniform  power 
balance  in  the  system. 

BLN  features  include  a  1-kW 
input  rating  and  bandwidth  of  7 
to  35  MHz  with  under  2:1  vswr 

All  stainless-steel  hardware 
and  flying  leads  are  supplied  for 
connection  to  the  driven  ele- 
ment of  beams,  quads,  or  di- 


TV-4400  satellite  receiver  from  international  Crystal, 


poles  and  coax  termination  into 
an  SO-239  connector.  The  BLN 
is  priced  at  $21,95. 

For  additional  information, 
contact  Hustler,  Inc.,  Sales 
Department,  3275  North  B 
Avenue,  Kissimmee  FL  32741. 


NOVICE  COURSE 

A  complete  Novice  course  is 
available  from  VHF  Communi- 
cations. The  course  features  six 
hours  of  theory  sent  by  Morse 
code.  The  copy  is  then  given  in 
voice  so  that  the  student  may 
check  his  or  her  progress.  The 
package  includes  a  copy  of  the 


Ameco  Novice  Guide,  The  in- 
troductory price  is  $21.95.  For 
more  information,  contact  VHF 
Communications,  915  North 
Main  St.t  Jamestown  NY  14701. 
Reader  Service  number  479. 


APPLE  SSTV 

The  COMMSOFT  Photo- 
Caster™  provides  an  easy  way 
for  hams  who  own  Apple  com- 
puters to  get  started  on  SSTV 
with  a  full-featured  black-and- 
white  and  color  system.  Photo- 
Caster  includes  a  circuit  board 
to  interface  an  APPLE  to  a  TV 
camera  and  a  receiver/trans- 


fa  rth  station  interference  trap  from  Microwave  Filter  Co. 


1:1  BLN  balun  from  Hustler, 

73Magazine  •  August ,1982     127 


muter,  plus  a  twodisk  software 
package  which  incorporates 
many  advanced  features. 

tn  addition  to  transmitting 
and  receiving  pictures,  Pho- 
toCaster has  provisions  for  add- 
ing titles  and  graphics,  creating 
video  special  effects,  enhancing 
images,  retrieving  and  storing 
pictures  on  disk,  printing  high- 
resolution  pictures  with  an 
MX-80  printer,  and  much  more. 


Black-and-white  pictures  are 
processed  with  a  resolution  of 
128  by  128  pixels  and  16  levels  of 
gray.  Shades  of  gray  are  pre- 
sented on  a  standard  CRT  mon- 
itor by  using  dot  dithering,  In  the 
color  mode,  8  colors  are  avail- 
able with  16  saturation  levels. 
Color  pictures  are  taken  with  an 
unmodified  black-and-white  TV 
camera  using  a  three-frame 
RGB  sequence.  Standard  RGB 


transmission  formats  are  avail- 
able in  addition  to  a  unique 
Appie-to-Apple  single  frame  col- 
or mode  which  takes  8  instead 
of  the  usual  24  (or  more)  sec- 
onds to  transmit  a  color  picture. 

PhotoCaster  requires  an  Ap- 
ple II  or  Apple  II  Plus  computer 
with  48K  of  RAM  and  one  disk 
drive.  The  price  of  PhotoCaster 
is  $499.95  for  the  basic  system 


which  includes  an  assembled 
and  tested  circuit  board  and 
software.  A  complete  system 
consisting  of  a  Panasonic 
WV1400  camera,  board,  and 
software  is  available  for  $749  95. 

For  more  information,  con- 
tact COMMSOFT,  Inc.,  665 
Maybeli  Avenue,  Palo  Alto  CA 
94306;  (41 5)- 493-2184,  Reader 
Service  number  480. 


Chod  Harris  VP2ML 

Box  4881 

Santa  Rosa  CA  95402 


FCC  SAYS  MORE  20-METER 
SSB  FREQUENCIES 

Expand  the  20-meter  phone 
subband?  The  FCC  is  consider- 
ing just  this  action.  Add  good 
sunspots  and  you  have  DXer 
heaven!  But  what  will  FCC 
Docket  82-83  realty  do  for  DX? 

The  DXers,  nets,  and  DX  pres- 
ently in  the  14200-14250  range 
immediately  will  move  down  to 
fill  the  new  subband.  These  op^ 
erators  want  to  be  near  the  DX 
portion  of  the  band  and  will 
move  accordingly.  In  weeks— if 
not  days — the  new  frequencies 
will  be  every  bit  as  crowded  as 
the  bottom  end  of  the  20-meter 
phone  band  is  today,  With  any 
luck,  however,  the  SSTV  crowd 
will  stay  put  on  1 4230t  which  will 
finally  get  them  out  of  the  DX 


The  hams  who  wilt  benefit  the 
most  from  the  expansion  will  be 
the  General  class  amateurs. 
They  stand  to  gain  the  greatest 
percentage  increase  in  frequen- 
cies and  (depending  on  the  final 
FCC  decision!  they  might  also 
gain  access  to  that  prized  bot- 
tom 50  kHz\  Wouldn't  that  be  a 
switch!  They  would  go  from  the 
status  of  a  poor  relation  in  the 
20-meter  DX  world  to  head-to- 
head  battles  with  top  DXer 
W6AM.  More  likely,  the  FCC  will 
settle  for  contiguous  subbands 
and  the  Generals  will  gain 
14225-75.  The  66%  increase  will 
propel  many  a  DXer  into  the 
ranks  of  DXCC. 

Are  there  any  losers  in  this 
proposed  expansion?  What 
about  the  DX  hams  who  use 
141 5<M 4200  now?  The  top  half 

128     73  Magazine  *  August,  1962 


of  that  range  contains  many  of 
the  DXers,  DX  nets,  and  long- 
haul  communications.  These 
hams  will  share  with  those 
stateside  or  move  down,  de- 
pending on  interference  lo  their 
operation.  Below  this  DX  layer 
lurk  the  personal,  non-DX  QSOs: 
long-standing  skeds.  families 
and  friends,  non-English  QSOs. 
They  will  be  the  real  losers.  The 
RTTY  just  below  14100  acts  as  a 
floor  to  phone  operators;  voice 
communication  below  14100  is 
almost  unknown.  Those  ama- 
teurs who  view  amateur  radio  as 
a  communications  tool— and 
not  as  a  pursuit  in  itself— are 
the  amateurs  who  will  be 
squeezed  from  the  top  as  the 
DXers  descend. 

Will  these  hams  jump  below 
the  RTTY,  down  to  14050-80? 
That  is  the  present  home  of  the 
CW  rag-chewerT  traffic  nets,  and 
domestic  communications.  You 
won't  find  many  sharp  CW  fil- 
ters here  and  SSB  interference 
will  hurt.  Further  down,  the  bot- 
tom of  the  band  roars  with  the 
CW  DX  crowd,  with  kilowatts 
and  fitters.  They  will  survive  any 
pressure  from  above. 

So  DXers  will  be  the  prime 
beneficiaries  of  the  new  fre- 
quencies. 

What  about  the  other  HF 
bands?  In  the  same  docket,  the 
FCC  wants  amateur  opinion  on 
expanding  other  phone  sub- 
bands*  80-10  meters.  How  might 
these  changes  affect  DX? 

Ten  meters  doesn't  need  any 
more  phone  frequencies;  we  sel- 
dom fill  what  we  have  at  the 
peak  of  the  sunspot  cycle.  Fif- 
teen meters,  on  the  other  handf 
cries  out  for  phone  expansion 
almost  as  much  as  20.  A  hun- 
dred additional  kHz,  relocating 


the  Novices  to  21050-21150, 
would  attract  a  lot  of  the 
20-meter  operators  except  at  the 
bottom  of  the  sunspots. 

Any  40-meter  expansion 
would  force  the  Novices  to  move 
down  to  7050-7100,  still  head-to- 
head  with  the  VEst  but  at  least 
away  from  the  shortwave  broad- 
cast stations.  This  move  might 
be  a  welcome  change!  But  there 
is  no  DX  outside  the  western 
hemisphere  above  7100,  so 
phone  expansion  would  be 
meaningless  to  the  DXer.  Now,  if 
they  could  only  get  the  foreign 
broadcast  stations  to  go  some- 
place else  (I  can  think  of  a  cer- 
tain, overly-warm  location),  40 
meters  could  be  a  great  band. 
But  phone  expansion?  No, 
thank  you, 

An  additional  25  kHz  on  75 
meters  wouldn't  revolutionize 
DX  on  the  band,  but  it  might  go  a 
long  way  in  that  direction, 
75-meter  DX  is  the  exclusive 
province  of  the  Extra,  If  other  li- 
cense classes  get  privileges  be- 
low 3800T  a  whole  new  world  of 
75-meter  DX  might  open  up. 

But  don't  rush  onto  the  pro- 
posed 20-meter  frequencies  just 
yet.  The  FCC  moves  slower  than 
New  Hampshire  molasses  in 
January,  and  it  will  be  a  while  be- 
fore we  can  begin  moving  down. 
To  help  our  DX  totals  mean- 
while, we  might  keep  an  ear  out 
for  Erik  SM0AGD,  from  some- 
where  in  the  South  Pacific. 

ERIK  SJOLUND  SM0AGD: 

DXPED1TIONER 

EXTRAORDINAIRE 

Erik  SJofund  left  this  spring 
for  an  extended  DXpedition 
through  the  South  Pacific,  as 
one  of  the  four-man  crew  of  the 
50' yacht  Marathon  AQ.  Erik  was 
lured  from  "retirement"  from 
DXpedition ing  by  the  fact  that 
the  skipper  of  the  ship  is  a  de- 
scendant of  Leif  Ericson.  The 
support  of  the  Sundsvall  DX 
group  and  the  Northern  Califor- 
nia DX  Foundation  help  make 


the  trip  possible.  The  trip's  itin- 
erary reads  like  an  atlas  of  the 
area  (and  a  ham's  dream-come- 
true);  North  Cook  Islands  ZK1, 
Tokelau  ZM7,  Central  Kiribati 
T31,  American  Phoenix  KH1, 
East  Kiribati  T3,  Tuvalu  T2,  and 
more.  The  1983  itinerary  is  even 
more  ambitious  and  includes 
Spratiy  1S!  The  last  group  to  op- 
erate from  Spratiy  had  to  dodge 
bullets  (more  about  Spratiy  in  a 
future  column). 

What  kind  of  amateur  would 
head  off  on  a  scheduled  two- 
year  voyage,  which  includes  ac- 
tively disputed  territories,  just  to 
hand  out  radio  contacts  to  the 
deserving  few?  Erik  Sjoiund 
SMQAGD  is  a  very  special  ama- 
teur and  a  special  person  who 
has  operated  from  more  than  his 
share  of  rare  and  difficult  loca- 
tions. 

Erik  began  his  DXpedilioning 
career  about  1 1  years  ago,  when 
he  traveled  to  Rhodes  SVG  for  a 
vacation.  Although  he  had  been 
an  active  amateur  for  about  20 
years  prior,  this  was  the  first 
time  Erik  operated  from  outside 
his  native  Sweden.  The  DXpedi- 
tion bug  bit,  and  bit  hard. 

Erik  traveled  extensively 
through  his  job  with  the  Euro- 
pean Space  Agency,  and  he  car- 
ried a  radio  even/ where  he  went: 
Easter  Island  CE0A,  the  Falk- 
lands  (or  is  it  the  Malvinas?) 
VP8T  and  others.  Erik  then  began 
traveling  for  the  Swedish  gov- 
ernment to  various  embassies 
all  over  the  world. 

The  well-known  neutrality  of 
the  Swedish  government  helped 
open  many  doors  for  Erik.  Swe- 
dish embassies  in  such  out-of- 
the-way  places  as  Bangladesh 
or  Botswana  were  perfect  loca- 
tions for  radio  operations,  and 
Erik's  diplomatic  connections 
paved  the  way  for  licensing.  Erik 
also  operated  from  Lesotho  7P8, 
Guinea-Bissau  CR3t  Laos  XW8. 
Iraq  Y\t  Turkey  TA,  and  many 
more.  Quite  an  impressive  list! 
Finally,  Erik  "retired"  and  re- 


turned  to  his  home  and  wife,  on- 
fy  to  head  off  again  this  spring. 
On  his  way  to  the  South  Pacif- 
ic, Erik  stopped  by  the  Interna- 
tional DX  Convention  in  Visalia 
CA.  While  there  he  shared  some 
of  his  experiences,  including  his 
recent  trip  to  JSt  Guinea-Bissau, 
with  the  hundreds  of  CA  ama- 
teurs and  guests. 

THESUNDSVALL  DXPEDITION 
TO  GUINEA-BISSAU  J5AD 

Erik  had  always  wanted  to  re- 
ward his  hard-working  and  dedi- 
cated QSL  manager,  Jorgen 
Svensson  SM3CXS,  with  a  fully- 
conducted  DXpeditron,  His 
chance  came  in  1981,  when  Erik 
unexpectedly  received  permis- 
sion to  operate  from  Guinea- 
Bissau  J5.  Although  greatly 
troubled  by  a  bad  knee,  Erik  im- 
mediately begain  preparing  for 
the  trip:  food,  hotel,  transporta- 
tion, equipment,  customs,  an- 
tennas. A  seasoned  DXpedition- 
er,  Erik  completely  constructed 
and  fully  tested  each  antenna 
before  leaving  Sweden. 

The  travel  arrangements  cen- 
tered on  Gambia  C5r  a  popular 
tourist  spot  for  Scandinavians 
on  the  west  coast  of  Africa ,  Erik, 
Jorgen,  and  other  members  of 
the  SundsvaM  DX  Group  ar- 
ranged to  fly  a  small  plane  the 
300  km  from  Gambia  to  the 
tiny  capital  of  Bissau,  To  see 
the  countryside,  they  would 
chance  driving  back—a  deci- 
sion which  would  almost  prove 
their  undoing! 

Use  of  the  smalf  plane  severe- 
ly restricted  the  amount  of 
weight  the  group  could  carry, 
and  radio  gear  consumed  most 
of  that.  Erik  had  purchased 
enough  food  for  the  entire  two- 
week  trip,  but  there  simply  was 
too  much  weight.  So  the  group 
sat  down  to  eat  the  two  weeks 
worth  of  food  before  they  left 
two  days  later! 

Erik  maneuvered  the  group's 
gear,  including  2  Iconn  transceiv- 
ers, 2  amps,  and  a  couple  of  ver* 
tical  antennas,  through  Gambia 
customs  and  rendezvoused  with 
their  pilot,  C5ADX.  A  sandstorm 
in  Guinea-Bissau  delayed  depar- 
ture for  a  day,  but  the  group  fi- 
nally arrived  and  was  met  by 
J5HTL,  who  helped  secure  li- 
censes and  provided  other  loca* 
assistance. 

Their  troubles  were  not  over, 
however.  Minutes  after  firing  up 
the  radios  and  getting  on  the  air 
for  the  first  time,  bang!  The 
room  went  dark.  No  power*  Out- 


Erik  Sjofund  SMQAGD  on  his  way  to  an  extended  DXpeditron  to  the 
South  Pacific. 


side,  the  entire  town  of  Bissau 
was  dark.  " Maybe  we  shouldn't 
have  used  the  amplifier,"1  Erik 
mumbled,  looking  out  over  the 
dark  city  of  110,000  people. 

The  lack  of  power  turned  out 
to  be  a  regular  occurrence. 
Whenever  the  enormous  foot- 
ball (we  call  it  soccer)  stadium 
turned  on  its  lights,  the  entire 
city  was  blacked  out.  Fortunate- 
ly (that's  experience  and  fore* 
sight),  Erik's  radios  could  oper- 
ate on  car  batteries,  without  the 
amplifiers.  A  portable  generator 
powered  the  amplifier  when  the 
group  was  away  from  the  hoteL 

Despite  the  hardships  of  in- 
constant power  and  stomach 
problems  from  trying  to  eat  two 
weeks'  worth  of  food  in  two 
days,  J5AD  managed  20t400 
OSOs  in  9  days.  Contacts  were 
about  evenly  split  between  SSB 
andCW. 

Now  came  the  drive  back  to 
Gambia,  300  km  north.  i410 
hours/'  the  driver  promised. 
That's  about  20  mph  on  the  tor- 
tuous dirt  roads.  The  driver  ap- 
peared with  his  battered  ''taxi," 
but  the  trunk  was  completely 


filled  with  a  barrel  of  oil.  The 
driver  claimed  he  needed  that 
much  oil  for  the  trip,  and  there 
wouldn't  be  any  gas  stations 
along  the  way.  More  likely,  he 
was  afraid  someone  would  steal 
his  precious  barrel  of  oil  if  he  left 
it  behind  for  a  day.  He  was  prob- 
ably right. 

Erik  finally  convinced  thedriv- 
er  to  unload  the  oil  and  load 
their  gear,  and  the  car  began  to 
lurch  toward  Gambia.  But  Gam* 
bia  is  a  small  country  complete- 
ly surrounded  by  Senegal t  and 
one  must  pass  through  Senegal 
on  the  way  to  Gambia.  The  trou- 
ble began  at  the  Senegal  border. 

Dead  tired  from  the  trip  and 
still  bothered  by  his  bad  knee, 
Erik  refused  to  pay  the  implied 
bribe  for  passage  through  Sene- 
gal. The  border  guards  retaliat- 
ed with  a  three- hour  lunch,  leav- 
ing the  SundsvaM  DX  Group 
sweltering  in  the  tropical  sun. 
Finally,  the  two  sides  reached  a 
compromise  and  Erik's  party 
headed  north.  But  now  the  bor- 
der guard  insisted  on  accom- 
panying the  travelers  and 
craimed  the  front  seat.  It  was  a 


long  ride  to  Banjul,  Gambia. 

Erik  Sjofund  and  friends  sur- 
vived the  trip,  however,  and 
pleased  thousands  of  amateurs 
in  the  process.  And  now  the 
modern-day  Leif  Ericson  is  off 
again,  this  time  with  transceiver 
in  hand,  and  SMQAGD  portable 
wherever  is  on  the  air  again. 

QSL  Erik's  operation  via 
SM3CXS,  as  usual.  Please  in- 
clude a  separate  envelope  for 
each  different  callsign,  since 
the  cards  will  be  handled  in 
more  than  one  location. 

You  can  recognize  Erik  by  his 
clean,  crisp  operating  style  and 
his  courtesy.  Erik  also  works  an 
even  balance  between  phone 
and  CW.  In  honor  of  Erik,  and  to 
compensate  for  the  remarks 
above  about  the  expansion  of 
the  phone  bands,  let's  look  at  a 
CW  topic:  zero-beating. 

ZERO-BEATING  FOR  DX  FUN 
AND  PROFIT 

Zero-beating  is  the  process  of 
aligning  the  transmitting  fre- 
quency to  that  of  another  sta- 
tion. While  important  In  SSB  op- 
eration, zero-beating  is  crucial 
to  successful  CW  DXing. 

The  best  way  to  work  a  DX 
station  in  a  CW  pileup  is  to 
transmit  on  exactly  the  same 
frequency  as  the  last  successful 
station.  This  implies  the  ability 
to  align  the  transmitting  fre- 
quency lo  that  of  another  sta- 
tion. How  do  you  accomplish 
this? 

The  DXer  can  zero-beat  sepa- 
rate receivers  and  transmitters 
by  means  of  the  spot  switch: 
Tune  in  the  desired  frequency 
on  the  receiver,  press  the  spot 
button,  and  adjust  the  vfo  for  an 
identical  note  in  the  receiver. 
The  transmitter  is  now  on  the 
same  frequency  as  the  receiver. 

But  most  of  us  have  transceiv- 
ers without  separate  external 
vfo's.  No  spot  switch.  Now 
what? 

Again,  tune  in  the  desired  fre- 
quency on  the  rig.  Most  trans- 
ceivers employ  an  800-Hz  offset 
for  CW.  This  means  that  when 
the  dial  is  aligned  on  14030,  for 
example,  the  CW  receiving  beat 
oscillator  in  the  rig  (which 
generates  the  audible  tone  in 
the  product  detector)  oscillates 
800  Hz  away  from  the  frequency 
of  the  transmitting  oscillator.  If 
the  audible  tone  is  800  Hzt  the 
transmit  and  receive  frequen- 
cies are  identical. 


73 Magazine  •  August,  1962    129 


^ 


But  I  prefer  to  copy  CW  at  a 
tower  frequency  than  800  Hz,  If  I 
adjust  my  receiver  to  my  pre- 
ferred note  of  650-700  Hz,  my 
transmit  frequency  will  move  up 
100-150  Hz  above  that  of  the 
other  station,  That  station  will 
shift  up  in  frequency  to  match 
my  transmitted  frequency. 

I  then  shift  up  still  further 
when  the  DX  station  comes 
back,  and  we  dance  up  the  band. 
More  likely,  we  will  lose  contact 


or  never  meet  in  the  first  place. 

We  can  avoid  this  problem  in 
either  of  two  ways.  First,  we  can 
learn  to  recognize  and  listen  to 
the  800-Hz  note  which  the  rig 
manufacturers  have  selected. 
Or  we  can  adjust  the  RIT  or  clari- 
fier  to  compensate  for  our  per- 
sonal preferences.  I  prefer  the 
latter  approach. 

Tune  in  a  strong,  steady  carri- 
er, such  as  WWV,  In  the  CW  po- 


sition, tune  across  the  carrier 
until  the  note  drops  in  tone  until 
it  disappears.  Now  move  up  ex^ 
actly  800  Hz.  Your  transmitted 
frequency  should  be  exactly  on 
the  carrier.  Adjust  your  RIT  for 
your  preferred  note  and  mark 
the  position  of  the  pointer. 

Now,  to  zero-beat  the  DX  sta- 
tionf  tune  the  rig  for  your 
favorite  beat  note  and  you  will 
be  very  close  to  the  correct  fre- 
quency! 


NOTES  FROM 
HERE  AND  THERE 

The  French  amateur  radio  so- 
ciety suggests  watching  for 
3A2ARM,  the  official  club  sta- 
tion of  Monaco,  which  is  often 
on  14  and  21  MHz  Saturdays, 
0900-1 100Z, 

Heard  Island  plans  move 
ahead,  with  the  support  of  the 
Wireless  Institute  of  Australia. 
An  extended  stay  on  Heard  is 
scheduled  for  early  '83. 


REVIEW 


THE  HEIL  EQ-200 
MICROPHONE  EQUALIZER 

If  you  actively  seek  to  improve 
your  transmitter's  audio,  sooner 
or  later  you'll  discover  the  con- 
cept of  equalization  (hereafter 
referred  to  as  EQ).  Simply  putt 
EQ  is  the  boosting  or  cutting  of 
specific  frequencies  {or  bands 
of  frequencies)  within  the  audio 
spectrum,  in  public  address  sys- 
tems, EQ  is  used  to  flatten  out 
the  frequency  response  of  the 
system,  allowing  maximum  gain 
at  all  frequencies  before  feed- 
back. In  the  recording  studio, 
engineers  apply  EQ  to  sweeten 
sound  and  make  it  more  pleas- 
ing to  the  ear 

Obviously,  in  amateur  radio 
we  needn't  concern  ourselves 
with  either  audio  feedback  or 
sweetening  our  sound.  So  why 
worry  about  equalization?  Be- 
cause many  years  ago  research- 
ers discovered  that  boosting 
certain  bands  of  frequencies  im- 
proved intelligibility.  A  slight 
boost,  say,   in  the  upper-mid- 


range  area,  makes  our  voices 
easier  to  understand.  Because 
of  this,  microphone  and  trans- 
mitter manufacturers  have  been 
building  such  a  boost  into  their 
equipment  for  years.  More  than 
anything  else,  this  accounts  for 
the  subjective  differences  we 
detect  between  the  qualities  of 
various  microphones  and  rigs. 
And  it  is  precisely  where  we  be- 
gin to  run  into  some  interesting 
compatibility  problems.  There  is 
no  agreement  between  manu- 
facturers as  to  how  much  boost 
is  necessary  or  at  what  frequen- 
cy it  should  take  place.  Worses 
some  feet  that  the  equalization 
should  be  done  at  the  micro- 
phone, while  others  argue  that  it 
should  be  done  at  the  rig.  You 
can  imagine  the  problems  this 
presents!  If  both  the  micro- 
phone and  the  rig  you  buy  have 
substantial  boosts  at  the  same 
frequencies,  your  audio  is  likely 
to  sound  "honky1'  and  unpleas- 
ant. And  if  a  manufacturer  de- 
signed his  rig  with  the  charac- 


EGUALIZING  THE  MOBILE  SIGNAL 

When  a  commercial  sound  contractor  writes  the  specifications  for  a  sound 
system  to  be  installed  In  a  large  auditorium,  he  must  know  the  room's  resonant 
frequency.  The  dominance  of  this  frequency  can  cause  feedback,  resulting  In  a 
less  than  optimal  gain  vatue  for  the  sound  system .  By  adding  an  active  equalizer 
that  notches  out  the  room's  dominant  frequency,  the  likelihood  of  feedback  Is 
reduced,  allowing  more  gain  to  be  used. 

The  very  same  sound  analysis  procedure  was  applied  to  the  internal  cavity  of 
four  automobiles.  The  results  were  astonishing  I  From  a  Honda  Civic  to  a  GftriG 
van,  they  exhibited  a  large  rise  in  the  40X3-  to  700-Hz  range,  the  exact  same  place 
that  rnobije  signals  have  a  large  peak  in  their  audio. 

If  you  think  about  it,  you  will  probably  realize  that  all  mobile  signals  sound 
alike.  It  makes  no  difference  what  kind  of  microphone  or  transmitter  Is  being 
used.  These  signals  are  characterized  by  tow  frequency  rumble  and  vey  littie 
high-end  audio  response,  and  I  n  most  cases  are  very  hard  to  copy  when  they  are 
Immersed  in  noise. 

The  fact  Is  that  the  frequency  of  the  car's  Internal  cavity  is  reproduced 
through  the  mobile  microphone  and  causes  ait  of  the  signals  to  include  a  rum- 
ble. The  hand-held  microphones  favored  by  most  mobile  operators  only  make 
matters  worse;  they  have  very  filtte  high-end  response,  with  their  -3-dB  "hinge 
point"  often  lytng  as  low  as  IflOQ  Hz. 

Results  from  a  typical  on-the-air  mobile  setup  are  shown  In  Fig.  1.  A  Kenwood 
TS-120  transceiver  with  MC-30S  microphone  was  inslalled  in  a  GMC  van.  The  sig- 
nal was  received  on  a  Kenwood  TS-820S  and  analyzed  with  a  Hei  I  A A-t  audio  an- 
alyzer. Before  equalization,  a  pronounced  peak  was  found  at  500  Hz,  verifying 
the  resonance  check.  By  using  a  two-band  equalizer  between  the  microphone 
and  righ  the  resonant  frequency  of  the  passenger  compartment  was  notched  out, 
giving  the  audio  a  fiat  response.  Next,  boost  was  added  to  the  high  end,  making 
up  for  the  deficiency  of  the  microphone.  Receiving  stations  and  the  audio  ana- 
lyzerback  in  the  lab  all  reported  a  6- to  fO-dB  difference  and  there  was  a  marked 
improvement  in  the  intelligibility  of  the  speech. 

We  found  that  articulation  is  the  key  factor  In  understanding  a  mobile  signal. 
The  alMmportant  articulation  is  lost  when  the  low  frequencies  predominate.  In 
the  worst  case,  these  lows  can  overdrive  the  microphone  preamplifier,  leading 
to  terrible  distortion.  The  application  of  proper  equalization  to  the  audio  section 
of  an  SSB  transmitter  will  provide  this  necessary  articulation  without  distortion. 

Bob  Hell  K9EID 
Marissa  IL 


teristics  of  a  particular  micro- 
phone in  mind,  results  will  be  un- 
predictable with  another  mike. 
The   combination    may    lack 


highs,  lows,  or  anything  in  be- 
tween.  Or   it   might   have  too 
much  of  something! 
Which  brings  us  to  the  Hei! 


> 

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1 1 

5  SB  MOBILE  EQ  TEST 
EQ  ZpQH&L 

*EQ  CONTROLS   SET:    +3ae   @    |_0,  +8dB  ®    Hi 

1- 


2Q 


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The  Heit  EQ 200 microphone  equalizer  (Photo  by  KA7LR/4) 
130     73  Magazine  •  August,  1982 


I0Q  200  500  lOOO       2000  5000       IQ000      2O00O 

FREQUENCY.  CYCLES  P£ft  SECOND  (HERTZ! 


Fig.  t  SSB  mobile  EQ  test  results  for  the  Hell  EQ-200. 


microphone  equalizer  The  idea 
Is  to  connect  the  equalizer  be- 
tween microphone  and  rig.  The 
LO  and  HI  controls  allow  you  to 
cut  or  boost  the  two  bands  of 
frequencies,  correcting  any  defi- 
ciencies and  hopefully  improv- 
ing intelligibility.  A  third  control 
permits  you  to  match  the  output 
level  to  what  your  rig  wants  to 
see.  Does  ft  work?  Weil,  yes  and 
no.  if  you  just  need  to  perk  up 
your  audio  a  Jittle  bit,  dialing  in  a 
little  LO  or  HI  boost  can  improve 
things.  But  it's  important  to  re- 
member that  changes  you  make 
will  only  be  audible  to  someone 
listening  to  your  signal.  If  you 
are  dumb  enough  to  adjust  your 
rig  on  the  basis  of  what  some- 
one you  may  or  may  not  know  is 
telling  you  over  the  air,  you  de- 
serve what  you  get!  You  really 
need  a  means  of  listening  to 
your  own  signal  while  you  make 
adjustments.   You're   in   good 
shape  if  you  have  one  of  the  few 
transceivers  with  a  monitor  cir- 
cuit. Turn  it  on,  plop  on  a  pair  of 
headphones,  and  you*!!  get  a 
pretty  good  idea  of  what  you 
sound  like  to  the  rest  of  the 
world.  If  you  have  a  second  re- 
ceiver, you  are  even  better  off. 

One  problem  we  noted  in  our 
installation  is  that  the  gain  con- 
trol had  to  be  run  at  a  fairly  high 
level.  The  EQ-200  uses  a  pair  of 
741  op  amps  to  do  its  work,  and 
the  noise  performance  of  these 
devices  is  less  than  exciting— 
i.e.,  you  hear  some  hiss.  While 
this  may  or  may  not  be  notice- 
able in  other  installations,  I  rec- 
ommend that  Heil  use  a  slightly 
better  op  amp  In  the  future.  After 
all,  if  someone  rs  picky  enough 
to  want  to  EO  their  mike  line, 
they  aren't  going  to  want  to  add 
hiss  to  their  signal! 

The  second  problem  I  see  is 
the  placement  of  the  controls  on 
the  front  panel.  Once  you  have 
gone  to  all  the  trouble  to  careful- 
ly set  them,  you  don't  want  any- 
body  messing  them  up.  Internal- 
ly mounted  trimpots  with  three 
small  access  holes  for  a  screw- 
driver  would  make  the  most 
sense  to  me. 


For  more  information,  con- 
tact Heil  Sound,  Marissa  IL 
62257.  Reader  Service  number 
475. 


PaulGruppKAlLR 
Cassefberry  Ft 

Editor's  note:  Heil  Sound  re- 
ports that  a  design  change  was 
made  to  the  finai  amplifier  stage 
of  the  EQ-200,  By  lowering  the 
gain,  they  achieved  a  20-dB  re- 
duct  ion  of  the  noise  level  leav- 
ing the  unit  This  should  help  in 
solving  the  problem,  reviewer 
Grupp  reports. 


Conclusions 

Used  correctly,  the  Heil 
EQ-200,  which  sells  for  $49,95, 
can  improve  the  intelligibility  of 
many  microphone/transceiver 
combinations.  Used  incorrectly, 
it  could  make  a  good  signal 
sound  terrible,  Please,  if  you 
don't  have  the  knowledge  or  pa- 
tience to  adjust  this  or  any  other 
audio  processing  device  cor- 
rectly, don't  buy  it! 


SILICON  SYSTEMS 
DTMF  DECODER 

Anyone  who  has  tried  to  tame 
a  dual-tone  frequency  (DTMF) 
decoder   using   the   ubiquitous 
567   IC  has  probabiy  thought 
that  touchtone™  control  prob- 
ably isn't  worth  the  hassle.  The 
567  decoder,  although  versatile, 
is  far  from  ideal  for  decoding 
DTMF  signals  that  have  a  vari- 
ety of  levels  of  distortion  and 
volume.  The  567  can  give  false 
outputs  if  input  levels  aren't 
carefully  controlled,  and  fre- 
quency stability  is  only  as  good 
as  the  timing  network.  In  short, 
getting  a  567-based  decoder 
working  reliably  at  a  remote  re- 
peater site  is  a  lot  like  searching 
for  an  honest  man— you're  al- 
ways disappointed  m  the  end. 

But  take  heart.  Time  and  tech- 
nology have  passed  the  567  by, 
and  thanks  to  the  development 
of  switched-capacitor  filters,  we 
now  have  DTMF  decoders  in  a 
single  package  which  offer 
more  features  and  better  relia- 
bility than  a  handful  of  567s.  Sil- 
icon Systems,  Inc.,  the  people 
who  first  made  commercial  use 
of  switched-capacitor  technol- 
ogy, have  a  chip  representative 
of  this  new  breed  in  their 
SSI-201,  a  22-pin  IC  which  re- 
quires only  four  external  com- 
ponents to  operate  as  a  com- 
plete DTMF  decoder. 

The  SSI-201  uses  40  poles  of 
switched-capacitor  filtering  to 
detect   the  presence  of  valid 
DTMF  tones  at  the  input.  The 
filter  center  frequencies  and 
bandwidths  are  controlled  by  a 
3.58-MHz  crystal  (one  of  the  out- 
board components^  so  frequen- 
cy drift  and  temperature  insta- 
bility are  a  thing  of  the  past.  A 
valid  tone  can  be  detected  in  as 
little  as  20  milliseconds  and  the 
audio  input  can  be  anything  from 
53  mV  to  1.3  V.  A  60-Hz  notch 
filter  on  the  chip  reduces  sus- 


ceptibility to  overload  from  hum. 
Implementing  the  SSI-201  is 
very  easy.  Power  required  is  12 
volts  at  about  30  mA.  When  valid 
tones  are  present  at  the  input, 
the  four  output   lines  present 
either  a  hexadecimal  (similar  to 
BCD)  or  binary-coded  2-of-8  out- 
put, selectable  by  tying  one  pin 
high   or   low   respectively.  The 
outputs  may  be  configured  for 
either   standard   CMOS   or  tri- 
state  (high   impedance)   use. 
Another  control    pin    allows 
detection  of  the  full  16-digit  set 
or  the  more  standard   t2-dfgrt 
set.  A  strobe  output  is  available 
to  ease  interface  with  clocked- 
logic  systems. 

A  minor  flaw  with  the  SSI-201 
is  that  the  problem  of  tempera- 
ture immunity  has  not  been 
completely  solved.  The  chip  is 
specified  to  operate  only  down 
to  Ga  C  (32°  F),  so  you'll  have  to 
provide  some  sort  of  heat  at 
your  outdoor  repeater  site.  The 
answer  could  be  as  simple  as 
letting  some  current  flow 
through  a  couple  of  resistors 
mounted  near  the  chip. 

This  chip  Isn't  cheap— $60  in 
single  units  (if  you  buy  10  or 
more,  the  price  drops  to  $40.54). 
I   buffered  all  its  connections 
with  the  real  world,  I  used  a  741 
op  amp  as  an  audio  buffer,  by- 
passed the  power  bus,  used  a 
series  diode  to  protect  against 
reverse  polarity,  and  used  a  4049 
inverter  package  to  buffer  the 
digital  outputs.  All  this  may  not 
be  necessary,  but  l  feel  a  lot 
safer  knowing  that  there's  an  op 
amp  between  the  phone  line  and 
my  expensive  chip. 

When  all  things  are  con- 
sidered, using  a  chip  like  the 
SSI-201  is  well  worth  the  addi- 
tional cost  Now  I  know  that  my 
control  system  is  reliable  and 
that  old  Ernie  with  the  weird 
voice  won't  bring  up  the  auto- 
patch  every  time  he  says,  "Well, 
fine  business,  old  man." 

For  more  information,  con- 
tact Silicon  Systemst  Inc.,  14351 
Myford  Road,  Tustin  CA  92680. 
Reader  Service  number  477, 

John  Ackermann  AG9V 
Green  Bay  Wl 


to-peakt  full  load  and  minimum 
line  voltage.  Load  regulation  is 
50  mV.  This  is  what  would  be  ex- 
pected from  an  industrial  power 
supply,  but  it's  much  better  than 
many  of  the  supplies  built  for 
amateur  service.  A  look  at  the 
schematic  and  the  construction 
explains  the  performance.  The 
regulator  is  a  723  IC,  a  some- 
what elderly  but  altogether  re- 
spectable  chip.  Regulator  sens- 
ing is  done  at  the  output  termi* 
nals,  and  the  sense  leads  are 
twisted  to  minimize  magnetic 
pickup    from   the  transformer. 
The   circuit    includes   not  only 
fofdback  current  limiting,  but  a 
crowbar  circuit  as  well!  Thus  the 
unit  resists  damage  very  effec- 
tively, and  if  the  regulator  or  the 
pass  transistor  should  ever  mal- 
function, the  crowbar  will  blow 
the  primary  fuse  and  shut  every* 
thing  down  In  a  millisecond  or 
so.    The    pass    transistor    is 
mounted  on  a  heat  sink  outside 
the  back  of  the  case,  so  ventila* 
Hon  is  unnecessary.  This  keeps 
dirt  out  of  the  guts.  That,  in  turn, 
means  that  the  regulator  is  un- 
likely to  become  humidity-sensi- 
live  in  its  old  age. 


ASTRON  RS*7A 
POWER  SUPPLY 


The  RS-7A  is  one  of  a  series  of 
13.8-V-dc  supplies  with  ratings 
ranging  from  4  to  35  Amps.  The 
7A  is  good  for  5  Amps  continu- 
ous or  7  Amps  at  50%  duty  cy- 
cle. I  paid  $64.95  for  mine. 

Rippfe  is  spec'd  at  5  mV  peak- 


73 


My  unit  has  a  varistor  across 
the   transformer   primary,    al- 
though the  schematic  doesn't 
show  it.  Nothing  could  be  more 
convincing  evidence  of  a  thor- 
oughly   professional    job   of 
powepsupply  design,  if  the  rig  is 
expected  to  be  available  for  op- 
eration in  a  disaster,  it's  ex- 
tremely important  to  protect  the 
circuitry  against  lightning  dam- 
age. Several  pieces  of  gear  in  my 
shack  failed  during  a  lightning 
storm  a  couple  of  years  ago. 
After   I   put   varistors   across 
power  and  telephone  line  con- 
nections, there  was  no  more 
trouble  in  subsequent  storms.  If 
there  are  any  early-production 
units  out  there  without  varistors 
(or  any  other  kind  of  station  sup- 
ply, for  that  matter),  I  recom- 
mend putting  a  GE  V150LA2QB 
across  the  primary, 

The  packaging  is  what's  re* 
quired,  and  no  more.  It's  a  sim- 
ple modified  steel  minibox-style 
case,  with  the  lid  held  on  with 
sheet  metal  screws.  Nothing  is 
mounted  on  the  cover;  the  unit  is 
structurally  complete  when 
opened  up  for  service.  The  line 
cord  is  solidly  anchored. 

The  parts  are  good  quality. 
The  main  capacitor  looks  to  be 
either  industrial  grade  or  com- 
puter grade.  I  didn't  recognize 
the  part  number,  but  it  sure  isn't 
any  fugitive  from  a  TV  set.  The 

Magazine  »  August,  1982     13t 


transformer  was  obviously  cus- 
tom-designed for  the  job,  a  re- 
quirement when  a  linear-regula- 
tor supply  has  to  operate  effi- 
ciently over  the  105*1 25- V  range. 

On-the-air  tests, . . I  hooked  it 
up  to  my  UV-3  and  dialed  up  a 
couple  of  repeaters  1  could  hit 
full  quieting.  The  signal  reports 
said  there  was  no  audible  hum. 
Key-down  operation  for  30  sec- 
onds caused  barely  noticeable 
warming  upot  the  heat  sink.  Not 
having  access  to  a  power  supply 
test  set  these  days,  I  didn't  carry 
the  testing  beyond  that.  From 
looking  at  the  size  of  the  heat 
sink,  Id  have  some  doubts 
about  running  at  5  Amps  contin- 
uously at  the  maximum  rated 
line  voltage,  but  if  that  became 
necessary  it  would  be  no  trick  at 
all  to  put  on  a  heat  sink  about 
four  times  as  big. 

To  summarize:  Whoever  de- 
signed this  thing  has  an  under- 
standing of  what  a  ham  station 
indoor  power  supply  has  to  do 
and  knows  how  to  design  power 
supplies.  This  is  probably  the 
most  cost-effective  supply  pos- 
sible, and  it  leaves  nothing  to  be 
desired  technically,  it's  the  kind 
you  turn  on  and  just  forget 
about. 

For  more  information,  con- 
tact Astron  Corporation,  2852 
Walnut— Unit  E.  Tustin  CA 
92680.  Reader  Service  number 
476. 

John  A.  Carroll  AB1Z 
Bedford  MA 


Hameg's  HM203  dual-trace  oscilloscope. 


HAMEG  HM203 
OSCILLOSCOPE 

The  Hameg  HM203  oscillo- 
scope is  much  like  ham  radio: 
both  are  international  phenom- 
ena. The  HM2G3,  a  newcomer  to 
the  US  market,  features  a 
rugged  yet  precise  feel  that  one 
would  expect  of  a  piece  of  gear 
designed  and  originally  manu- 
factured in  West  Germany.  The 
outstanding  performance/price 
ratio  reminds  you  of  similar  gear 
from  the  Far  East.  And  not  to  be 
neglected  is  the  fact  that  the 
HM203  is  manufactured  and  ser- 
viced right  here  in  the  United 
States. 

Oscilloscopes  can  be  incred- 
ibly useful  test  instruments. 
Unfortunately,  many  hams  are 
only  familiar  with  the  expensive 
laboratory-grade  units  found  at 
work  and  school  or  the  inexpen- 
sive surplus  or  used  models  that 
sell  for  a  song  at  any  swapfest, 
Hameg  has  managed  to  come 
up  with  an  excellent  compro- 

132     73Magaztne  •  August,  1982 


mise.  Now  you  can  have  a  dual- 
trace  scope  that  has  a  20- MHz 
(-3-dB)  Of  30- MHz  {-6-dB> 
bandwidth,  3%  accuracy,  and 

variable  triggering  for  under 
$600+ 

Weighing  just  over  12  pounds 
and  measuring  approximately  6 
inches  high,  1 1  inches  wide,  and 
15  inches  deep,  the  HM203  is 
designed  with  field-service  ap- 
plications in  mind.  The  units 
compact  front  panel  also  lends 
itself  to  fitting  into  a  tightly- 
packed  workbench.  One  half  of 
the  unit  is  devoted  to  the 
cathode  ray  tube,  which  mea- 
sures 5  inches  diagonally.  The 
usable  screen  is  an  adequate  10 
cm  x  8  cm,  and  the  dark  red 
grid  allows  you  to  interpolate 
measurements  to  about  0.1  cm. 

One  feature  common  to  all 
Hameg  oscilloscopes  is  a  sub- 
divided control  section.  The  up- 
per half  of  the  HM203  is  devoted 
to  the  power  switch,  intensity, 
and  focus  control,  plus  all  of  the 
timebase  or  horizontal  display 
functions. 

The  lower  half  consists  of 
controls  for  the  two  Y  or  vertical 
channels.  The  back  panel  is  void 
except  for  ac  power  connection 
(with  removable  line  cord)  and 
sockets  for  direct  connection  to 
the  CRTs  vertical  and  horizon- 
tal control  plates. 

Dual  Trace  Capability 

Two  identical  vertical  chan- 
nels are  available.  Each  has  a 
12-step  frequency-compensated 
input  attenuator  giving  scales 
from  5  m V/cm  to  20  V/cm.  The  at- 
tenuator is  followed  by  a  diode- 
protected  FET  preamplifier  that 
has  a  40-MHz  bandwidth.  Con- 
spicuous by  its  absence  was 
any  kind  of  continuously- 
variable  vertical  sensitivity  con- 


trol. The  lack  of  this  kind  of  con* 
trol  did  not  prove  to  be  a  serious 
problem,  I  just  made  do  by  ad* 
justing  the  vertical  position 
potentiometer. 

The  1 -megohm.  25-picofarad 
vertical  inputs  can  be  switched 
between  ac,  dc«  and  ground.  For 
single-trace  or  "mono"  applica- 
tions, you  can  use  either  chan- 
nel. For  those  jobs  that  require 
two  signals  to  be  displayed,  just 
push  in  the  mono-dual  switch 
and  you  connect  your  second 
signal.  Triggering  can  be  done 
on  either  channel  (More  on  trig- 
gering later.) 

The  Alt/Chop  switch  is  an  im- 
portant part  of  successful  dual- 
trace  operations.  If  the  signals 
have  a  low  frequency  (less  than 
1  kHz),  the  display  will  tend  to 
flicker  if  both  traces  are 
displayed  independently.  By 
choosing  the  Chop  mode,  the 
scope  switches  back  and  forth 
between  the  traces  at  a  120kHz 
rate,  displaying  both  signals  on 
the  same  sweep  and  eliminating 
the  flicker. 

Timebase 

According  to  Hameg,  the 
HM203  uses  a  new  type  of  trig- 
gering circuit.  There  is  no  need 
for  any  sort  of  stability  adjust- 
ment, since  most  of  the  pro- 
cessing is  done  by  a  voltage 
comparator  chip  whose  TTL  out- 
put drives  the  sweep  generator 
directly.  The  result  is  trouble- 
free  triggering,  even  with  fast- 
Ghanging,  high-frequency,  or 
low-amplitude  signals. 

The  sweep  can  be  triggered 
by  either  vertical  channel,  the 
line,  or  an  external  source.  A 
choice  can  be  made  between  a 
positive  or  negative  trigger  edge 
and  the  trigger  level  is  adjust 
able.  A  time  axis  can  be  dis- 


played even  when  no  signal  is 
present — just  place  the  203  in 
the  Auto  trigger  mode.  Service 
technicians  may  be  interested 
in  the  TV  trigger  mode  which 
operates  off  the  line  or  frame 
frequency* 

A  non-swept  or  X-Y  mode  is 
available  by  pressing  the  Hor 
Ext  switch,  The  X  signal  is  pro- 
vided via  the  Y  channel  I  input. 
The  bandwidth  of  the  X  amplifier 
is  approximately  2  MHz,  with 
any  phase  difference  between 
the  two  axes  becoming  ap- 
parent above  50  MHz, 

Looking  Inside 

In  addition  to  the  controls  and 
inputs  already  mentioned,  the 
HM203  has  front-panel  access 
to  the  TR  (trace  rotation)  control, 
which  allows  you  to  compen- 
sate for  variations  in  the  earth's 
magnetic  field  that  cause  a  mis- 
alignment of  the  trace.  The  back 
panel  includes  access  to  the 
power  supply  fuse  and  the  abil- 
ity to  change  between  1 10-,  125- , 
220-,  and  240-volt  power 
sources. 

Taking  the  HM203  apart  is 
simple.  You  just  remove  two 
screws  and  slide  the  case  off 
the  chassis.  Once  it's  apart, 
youli  discover  a  straightforward 
yet  impressive  layout.  The  vast 
majority  of  the  203rs  compo- 
nents reside  on  two  circuit 
boards.  This  includes  most  of 
the  controls  which  are  con- 
nected to  the  front  panel  via 
mechanical  links.  With  service 
in  mind,  Hameg  has  used  sock- 
ets for  most  of  the  ICs  and  FETs. 
The  cathode  ray  tube  is  sur- 
rounded by  Mumetal  screening, 
reducing  the  likelihood  of  stray 
magnetic  fields  causing  a 
problem. 

Accessories  and 
Documentation 

The  HM203  is  ready  to  use  the 
day  it  arrives.  Each  one  comes 
with  two  X1/X10  probes.  The 
Hameg  penchant  for  quality  is 
seen  here— the  probes  include  a 
compensation  adjustment  and 
feature  interchangeable  tips. 
Although  the  203  is  good  to 
almost  30  MHz,  the  probes  sup- 
plied top  out  at  around  10  MHz. 
For  measurements  in  the  higher 
range,  you  can  try  some  of  the 
other  Hameg  probes.  The  line  of 
accessories  includes  test 
cables,  a  50-Ohm  terminator, 
and  a  simple  component  testing 
jig  (to  be  reviewed  in  a  future 
issue  of  73). 

The    HM203    manual    thor 


oughty  documents  correction 
operation  of  the  instrument  and 
even  Includes  a  brief  discussion 
of  errors  that  can  affect  your 
measurements.  Plenty  of  ser- 
vice information  is  given,  with 
emphasis  on  diagnosing  and 
correcting  the  problem  wilhout 
using  expensive  test  gear.  A 
complete  set  of  schematics  is 
included  and  they  are  large 
enough  to  be  pored  over  by  the 
armchair  circuit-design  crowd. 

Conclusions 

Six  weeks  of  using  an  HM203 
at  home  and  at  work  have  rein- 
forced  my  first  opinions  about 
this  scope,  it  works  as  billed. 
The  drawbacks  such  as  the  ab- 
sence of  a  continuously- variable 
vertical  attenuator  are  offset  by 
extras  like  a  built-in  calibration 
signal,  I  found  that  the  HM203 
fulfilled  my  needs,  which  vary 
from  designing  simple  digital- 
electronics  circuits  to  trouble- 
shooting a  flaky  SSB  modulator 
to  monitoring  the  stability  of  the 
power  in  the  73  darkroom.  (In 
the  darkroom  application,  the 
HM203  was  left  turned  on  for 
almost  three  days  and  exhibited 
no  signs  of  Instability  or  drift!) 

I  would  be  the  first  to  admit 
that  the  HM203  does  not  equal 
the  performance  you  get  from 
many  laboratory-grade  instru- 
ments. But  how  often  do  you 
need  100-MHz  bandwidth  and 
features  such  as  trace  highlight- 


ing? The  HM203  is  adequate  for 
many  service  jobs  and  should 
fill  the  needs  of  almost  any  hob- 
byist. With  a  special  amateur 
price  of  $529,  it  beats  just  about 
everything,  including  units  that 
you  build  from  a  kit. 
The  HM203  is  available  from 

Rivendefl  Associates,  RFO  5, 
Warner  Hittt  Oerry  NH  03038, 
Reader  Service  number  487. 

Tim  Daniel  N8RK 
73  Magazine  Staff 


MICRO  CONTROL 

SPECIALTIES1 

VHF/UHF  CONTINUOUS-DUTY 

POWER  AMPLIFIER 

Reliability  is  the  name  of  the 
game  when  repeater  hardware 
is  concerned.  The  equipment 
must  be  of  conservative  design 
unless  you  enjoy  unscheduled 
trips  to  the  repeater  site— trips 
which  always  seem  to  entail  a 
20-mile  drive  through  the  sea- 
son's worst  storm. 

The  power  amplifier  ts  a  case 
in  point.  You  can't  simply  graft 
an  everyday,  mobile-type  ampli- 
fier onto  a  repeater  system  and 
expect  it  to  provide  trouble-free 
service.  Such  amplifiers  are  not 
designed  for  (he  long  periods  of 
continuous  duty  which  are 
faced  by  most  repeaters  during 
some  part  of  each  day, 

A  better  choice  is  an  amplifier 
buift  from  the  ground  up  for  re- 


peater operation,  such  as  the 
PA-75  power  amplifier  from 
Micro  Control  Specialties 
(MCS).  This  continuous-duty, 
75*Watt  amplifier  is  available  in 
144-,  220-T  and  440-MHz  ver- 
sions.  It  provides  full  output 
with  10-15  Watts  of  drive.  In  the 
interest  of  reliability,  each  PA-75 
is  burned  in  for  four  (count  "em, 
four)  days  before  being  shipped. 
Most  VHRUHF  amplifier  cir- 
cuits are  designed  to  operate 
from  a  12-V  dc  power  source.  In 
contrast,  the  circuits  in  the 
PA-75  use  24  V  dc,  which  Is  pro- 
duced by  a  built-in  105-1 25- V  ac 
supply.  The  24*V  design  means 
that  the  amplifier  runs  more  effi- 
ciently, and  it  allows  the  power 
supply  to  be  made  physically 
smaller.  The  amp  will  operate 
from  an  external  12-V  dc  source 
and  automatically  switches 
from  the  ac  lines  to  the  dc 
source  in  the  event  of  an  ac 
power  failure,  Output  power  is 
reduced  to  50  Watts  when  the 
amp  operates  on  12  V  dc.  A  pair 
of  2N5643  final  transistors  gives 
the  PA-75  its  punch.  The  amp 
features  excellent  output  filter- 
ing, with  harmonics  suppressed 
at  least  65  dB. 

The  enclosure  of  the  PA-75 
fits  standard  19*inch  equipment 
racks.  The  front  panel  is  kept  as 
simple  as  possible — just  three 
fuse  holders  and  a  dc  ammeter 
for  measuring  amplifier  current. 
Cooling  for  the  finals  is  provided 


by  a  large  heat  Sink  and  a  high- 
volume  fan.  The  fan  also  cools 
the  power  supply. 

In  our  2  meter  repeater  instal- 
lation, an  amplifier  was  needed 
to  improve  the  signal  on  the  far 
side  of  a  mountain  ridge.  Since 
we  were  already  using  the  MCS 
Mark  3CR  repeater  with  good 
success,  it  seemed  only  natural 
to  give  the  matching  PA-75  a 
tryout. 

Installation  could  not  have 
been  easier,  We  simply  placed 
the  amp  in-line  after  the  exciter 
output  and  plugged  it  in.  Voila! 
Our  repeater  was  transformed 
from  a  15-Watt  into  a  75-Watt 
machine. 

The  amateur  net  price  for  the 
PA-75  is  $493  for  the  2-meter  ver- 
sion, $544  for  220  MHz  and  $595 
for  440  MHz.  A  $50  discount  Is 
available  if  the  amp  is  pur- 
chased at  the  same  time  as  an 
MCS  repeater. 

In  five  months  of  operation, 
our  PA-75  has  been  completely 
trouble-free.  It  has  performed 
precisely  as  advertised  and  has 
enabled  us  to  fill  some  annoying 
gaps  in  our  coverage.  The  PA-75 
is  a  rugged,  reliable  answer  to 
the  repeater  amplifier  question. 

For  more  information,  con* 
tact  Micro  Control  Specialties, 
23  Elm  Park,  Groveland  MA 
01834,  Header  Service  number 
486- 

Jeff  DeTray  WB8BTH 
73  Magazine  Staff 


AWARDS 


Bill  Gosney  KE7C 
Micro-dO,  Inc. 
2665  North  Busby  Road 
Oak  Harbor  WA  98277 

WORKED  TRUMBULL  COUNTY 
AWARDS 

The  Warren  (Ohio)  Amateur 
Association,  Inc.,  announces  its 
Worked  Trumbull  County  (WTC), 
Worked  Trumbull  County  Mobile 
(WTC-M),  and  Worked  Trumbull 
County  YL  (WTC-YL)  awards. 
These  programs  are  designed  to 
promote  increased  amateur  ra- 
dio activity  among  and  with 
Trumbull  County  Amateur  Radio 
Operators.  The  awards  are  also 
award  operating  achievements. 

Application:  Send  applica- 
tions and  all  correspondence  to 
Don    Lovett    K8BXT,    Awards 


Chairman,  WARA,  PO  Box  809, 
Warren  OH.  One  dollar  must  ac- 
company applications  from  W, 
K,  and  VE  amateurs;  all  others 
should  send  Ihree  IRCs  with  ap- 
plication. Only  Trumbull  County 
applicants  must  submit  actual 
QSL  cards.  All  others  should 
have  certification  letters  from 
two  other  radio  amateurs  who 
signify  that  they  have  seen  and 
checked  the  applicant's  OSLs. 
Each  application  must  also  be 
accompanied  by  a  list  of  the 
calls  worked,  with  full  log  data 
for  each  contact. 

Requirements: 
•  WTC— For  each  certificate  or 
endorsement,  Trumbull  County 
applicants  must  have  20  con- 
tacts with  other  Trumbull  County 
amateurs.  Other  W,  KT  and  VE 


stations  must  contact  10  Trum- 
bull County  amateurs,  while 
DX  applicants  must  have  five 
contacts. 

•  WTC-M  — For  each  certifi- 
cate or  endorsement,,  Trumbull 
County  applicants  must  have  20 
contacts  with  other  Trumbull 
County  amateurs  operating  mo- 
bile in  Trumbull  County,  Other 
WT  KT  and  VE  stations  must  con- 
tact 10  Trumbull  County  ama- 
teurs operating  mobile  in  Trum- 
bull County,  while  DX  applicants 
must  have  five  contacts. 

•  WTC-YL— For  each  certifi- 
cate or  endorsement  Wt  K,  and 
VE  stations  must  contact  10 
Trumbull  County  YL  or  XYL  ama- 
teurs, while  DX  applicants  must 
have  three  contacts. 

Award:  A  certificate  will  be 
issued  on  each  approved  appli- 
cation but  in  order  to  appear  on 
the  certificate,  special  endorse- 
ments must  be  filed  with  the  ini- 
tial filing,  each  containing  at 
least  25  percent  new  contacts. 
Initial  endorsements  are  free  of 


charge  but  endorsements  made 
on  later  dates  will  take  the  form 
of  WTC  certificates.  Applica- 
tions for  these  must  contain 
proper  filing  fees.  Endorse- 
ments may  be  "All  One  Mode." 
"All  One  Band,"  "AM  Mobiles 
Mobile;1  or  "All  Members  of  the 
Warren  Amateur  Radio  Associ- 
ation, Inc," 

Net  contacts,  contacts  made 
through  repeaters,  and  contacts 
made  before  January  1,  1959, 
cannot  be  counted. 

WORLDWIDE  AWARDS 
DIRECTORY,  VOL,  I 

If  you  like  to  go  after  awards 
or  win  contests,  this  directory  is 
a  must!  Volume  I  lists  over  270 
awards  from  all  over  the  world, 
with  names  and  addresses, 
costs,  and  descriptions.  $9.95 
brings  Volume  1  to  your  door- 
step. Volume  2  is  in  production 
now  and  will  cost  $5.95  for  an 
additional  130  awards.  Why  not 
order  Volumes  1  and  2 for  a  com- 
bined  price  of   $12.75?  The 

73  Magazine  *  August,  1982    133 


Worldwide  Awards  Directory  is 
for  the  amateur  radio  operator 
who  is  interested  in  showing  his 
proficiency  to  others  at  radio 
communications  throughout 
the  world.  You  will  never  know 
how  easy  it  is  unless  you  know 
how  to  go  about  it  You  probably 
already  have  enough  QSLs  in 
your  fiJes  lor  some  of  the 
awards.  $9.95  includes  all  post- 
age and  handling.  COD  extra. 
Quantity  discounts  available. 

Also,  if  you  know  of  some 
awards  that  you  would  like 
listed,  please  let  Larry  know  and 
they  will  appear  in  the  next 
volume.  Write  to:  Larry  KebeJ 
KmZP.  736~39th  Street,  West 
Des  Moines  I A  50265. 

HONG  KONG  AWARDS 

HARTS  meets  every  Tuesday 
at  1700  local,  excluding  public 
holidays,  at  the  China  Fleet 
Club,  Arsenal  Street,  Wanchat, 
Hong  Kong  Island. 

Nine  Dragons  Award 

One  contact  with  a  country  in 
each  of  the  following  9  zones; 
18,  19f  and  24  to  30,  Contact  for 
zone  24  must  be  a  VS6.  Stations 
within  the  9  zones  require  2  con- 
tacts  in  each  zone,  with  2  VS6 
contacts.  Contacts  after  Jan.  1, 
1979,  only,  are  valid.  Fees  are  US 
$3f  AusL  S3,  jCt,50p<  postal 
order,  or  24  IRCs. 

Firecracker  Award 

Six  contacts  with  different 
VS6  stations.  Stations  in  zones 
18,  19,  and  24  to  28  require  10 
contacts  with  different  VS6  sta- 
tions. Contacts  after  January  1, 
1964,  only,  are  valid.  Fees  are  US 
$2,  Aust  $2,  £1  postal  order,  or 
10  IRCs. 

Usual  Conditions 

Certified  log  extracts  only — 
no  QSL  cards  are  required.  Pay- 
ment to  be  made  fn  cash;  no 
bank  drafts.  Postal  orders  to  be 
left  blank.  Claims  to:  Awards 
Manager,  HARTS,  GPO  Box  541, 
Hong  Kong, 

HAROAA  AWAR0S 
AND  CERTIFICATES 

These  awards  are  of  high 
quality  and  will  make  a  very  nice 
addition  to  any  radio  room.  The 
awards  are  available  to  all  li- 
censed amateurs  and  amateur 
stations.  Please  do  not  send 
QSL  cards.  A  list  showing  full 
details  of  the  contacts  (log  infor- 
mation) should  be  certified  by 
one  other  amateur  or  radio  club 
officer.  Photocopies  of  your 
QSL  cards  or  original  log  will 

134     73Magazine  •  August,  1982 


also  be  permitted.  At  your  re- 
quest, special  endorsements 
will  be  added,  such  as:  CWr  SSB, 
all  YL,  QRP,  RTTY.  SSTV,  one 
band,  etc.  If  you  so  desire,  you 
may  request  separate  awards 
for  each  special  endorsement 
Contacts  may  be  made  over  any 
period  of  years.  Contacts  made 
through  repeaters  cannot  be 
used.  Satellites  permitted. 
Please  pass  this  award  informa- 
tion  along  to  another  amateur  or 
post  it  at  your  local  club.  All  cor- 
respondence or  applications 
should  be  sent  to:  HAROAA,  PO 
Box  341,  Hinckley  OH  44233, 
Attn:  Awards  Manager  Gary 
Zimmerman  WB8RTR. 

Application  for  each  award 
must  be  accompanied  by  three 
US  dollars  to  cover  handling  and 
award  costs.  Payment  may  be 
made  by  cash,  personal  check, 
money  order,  ten  IRCs,  or  first- 
class-rate  US  postage  stamps. 
DX  applicants  may  send  a 
money  order  made  out  In  US 
funds,  ten  IRCs,  or  any  of  the 
above. 

if  at  any  time  your  award  is 
lost,  misplaced,  or  damaged  in 
any  way.  send  the  date,  award 
number,  and  pertinent  informa- 
tion, and  we  will  replace  it  free  of 
charge.  All  awards  include  the 
special  HAROAA  gold  seal 

Great  Lakes  Award 

This  requires  one  contact 
with  each  state  bordering  the 
Great  Lakes:  New  York,  Penn- 
sylvania, Ohio,  Michigan,  Indi- 
ana, Illinois,  Wisconsin  and 
Minnesota. 

Super  Certificate  Hunter  Award 

Thts  HAROAA  award  is  de- 
signed for  the  serious  certificate 
hunter.  To  earn  this  award,  you 
must  have  a  minimum  of  ten 
amateur  radio  operating 
awards.  Simply  list  the  awards 
that  have  been  issued  to  you- 
Special  endorsements  are  10. 
25,  50,  75,  100  plus. 

HAROAA  DX  Award 

This  is  obtained  by  working 
DX  stations.  It  is  the  number  of 
stations  worked  that  is  impor- 
tant. Each  DX  station  counts  as 
one,  even  if  several  are  from  the 
same  country  or  area.  Special 
endorsements  for  this  award  are 
10,  25,  50,  75,  100,  200  and  500 
DX  contacts. 

HAROAA  Insomnia  Award 

This  award  is  earned  by  com- 
municating with  one  other 
amateur  radio  station  for  a 
minimum  of  one  hour  between 


the  hours  of  1 :00  and  5:00  am.  A 
super  conversation  piece  for 
your  shade 

HAROAA  Super  Operator  Award 

This  certificate  is  rendered  for 
those  providing  a  service  on 
behalf  ot  amateur  radio,  such  as 
weather  observation,  public  ser- 
vice, emergency  work,  helping  a 
new  ham,  providing  communi- 
cations for  a  community  func- 
tion, etc.  The  requirements  are 
for  the  applicant  to  briefly  de- 
scribe the  event  or  service*  The 
officials  of  HAROAA  will  deter- 
mine whether  it  deserves  this 
special  recognition. 


HAROAA  Official  Traffic 
Handler  Award 

This  award  is  a  self-issued 
achievement,  allowing  you  to 
display  the  fact  that  you  are  in- 
deed an  official  handler  of  radio 
traffic. 

ISLAND  DX  AWARD 

The  IDX  Award,  sponsored  by 
the  Whidbey  Island  DX  Club,  is 
probably  one  of  the  most  sought 
after  awards  in  the  DX  commu- 
nity. This  award  is  available  to 
licensed  amateurs  and  short- 
wave listeners  worldwide. 

The  IDX  Award  is  issued  for 


ISLAND  D*  COUNTRY  LISTING 

The  IDX  Awards  Program  uses  DXCC  countries  which  ar*  bona  iide  islands  as 
recognized  by  the  National  Geographic  Society.  The  first  criterion  is  thai  they 
must  have  been  DXCC  countries  on  or  alter  October  \ ,  t  § 77.  as  staled  on  the 
DXCC  List  of  the  ARRL  Any  qualifying'  DXCC  country  omitted  from  this  list  by 
error  or  which  has  oeen  Fecognized  for  DXCC  after  the  release  of  this  listing  win 
be  added  the  next  time  it  goes  to  press.  In  the  meantime,  applicants  may  count 
these  new  countries  in  their  tally. 


A3 

KH1HKB 

VP2S 

A9X 

KH2,  KG6 

VP2V 

BV 

KH3,  KJ 

VPS 

C2 

KH4H  KM 

VPS  (Falkland) 

C6 

KH5,  KP6  iKmg) 

VPS.  LU  (Orkney) 

CBIA 

KH5,  KP6  (Palmyras 

VPS,  LU  (Sandwich) 

CE*X 

KH6,  AH6,  WH6T  NHS(Haw| 

VPS.  LU  (Shetland) 

C£#2 

KM6,  KH7  iKurer 

VPS,  LU  (Georgia) 

CO,  CM,  KG4 

KHo.  K5o 

VP9 

CT2 

KH9>  KW 

VQ9 

CT3 

KH«,  KM2   KG6iMari) 

VBt  (SeeT3) 

04 

KC6  (West) 

.'R4  (See  H4} 

D6 

KC6  (East! 

VR7 

DtJ 

KP  {Desolh) 

VS5.  9MG  9M6 

EA6 

KP1.  KC4iNavassai 

VS6 

EAB 

KP2.  KV 

V59  {See  BO) 

El,  Gl 

KP3.  KS4P  HK§(RanSer) 

VS9K 

FBBW 

KP4.  NP4  {Puerto  Rico) 

VU 7  (Andaman] 

F98X 

KX 

VU7  [Lacca) 

FB8Z 

OHB 

XF4 

FC 

OJQ 

XP  {See  OX) 

FG  (Quad) 

OX,  XP 

YB.  YC.  YD 

FG,  FS 

OY 

Yj 

FH8 

P20 

WO 

FK 

PJ  (Neih  Ant} 

ZD7 

FM 

PJ  (St  Maarteni 

ZD8 

FCHChqperton) 

PY0  (Fern) 

ZOO 

FO  (Tahiti) 

PY»  (Peter  Pau l| 

IF 

FP 

PYt(Tnru) 

ZK1  (North) 

FH  fGtorJ 

S7 

ZK1  (South J 

FR(Juan) 

S9.CR5 

ZK2 

FH  (Reunion} 

SV  (Crete) 

ZL  (New  Zealand} 

FR  (Tromttni 

SV  tDodecam 

ZL  rAuck-Camp} 

FW 

TO.  VR1  (Central  Kirt> 

2L  (Chatham) 

G  GM.  GW  (G   Brit) 

T3.  VB1  (East  Kin  bat) 

ZL  IKerm) 

GC.  GU  (Guern) 

T3k  VRi  (West  Kiribai) 

ZM7 

GC.  GJ  (Jersey) 

TF 

ZS2(Mari-PrEd) 

GD 

TI9 

IS 

Gl.  El 

UA1,  UK1  (Franz  Jos} 

386,  3B7 

H4tVFW 

VE1  (Sable) 

3BB 

HCo 

VE1  {St  Paul) 

3B9 

HH,  HI 

VK  (Lord  Howe) 

3C0 

HKQ(Bato) 

VK9  (Willis) 

302 

HK9{MaJp) 

VK9(Chrtstmasi 

3Y 

HKIMSan  An) 

VKt  (Cocos) 

45 

fS 

VK9(Melkish) 

SB.  ZC 

J3.VP2G 

VK9  (Norfolk) 

W 

JS.  VP2L 

VK9  (Heard) 

5W 

J7.  VP2D 

VKft  (Mac  quartet 

«Y 

JA-JR.KA 

VPZA 

8Q.VS9 

JD  KA1  (Minai 

VP2D  (See  J7j 

BP 

JD,  KA1  (Ogasa) 

VP2E 

9H 

JDf  7J1  {OMno) 

VP2G  (See  J3) 

9M6,  9M8  [See  VS5) 

JW 

VP2K 

9V 

JX 

VP2L  (See  J6) 

9Y 

KG4  (See  CO,  CM) 

VP2M 

2  x  SSB,   2  x  CW,  2  x  RTTY, 

2  x  SSTV,  and  mixed  mode,  as 
well  as  mixed-  and  single-band 
accomplishments,  To  meet  the 
minimum  qualifications,  appli- 
cants must  work  fifty  (5GJ  IDX 
islands  for  the  basic  award-  En- 
dorsements are  given  in  incre- 
ments of  50  islands,  up  to  and 
including  the  maximum  number 
of  islands  possible. 

All  DXCC  countries  which  are 
bonafide  "islands"  are  the  only 
qualifying  contacts.  A  special 
IDX  listing  appears  within  this 
column.  To  be  valid,  all  contacts 
must  have  been  made  after  Oc- 
tober 1 ,  1977. 

To  apply,  prepare  a  fist  of 
qualifying  contacts  in  prefix 
order.  Please  number  your  con- 
tacts 1  through  50.  etc.  Include 
the  call  of  the  station  worked, 
IDX  island  name,  band,  mode, 
datet  and  GMT. 

Do  not  send  QSL  cards!  Have 
your  list  verified  by  two  ama- 
teurs or  local  radio  club  offi- 
cials. Confirmation  of  each  con- 
tact must  be  in  the  applicant's 
possession  at  the  time  it  is  be- 
ing verified. 

Send  your  list  of  contacts 
along  with  $4  in  US  funds  only 
and  a  4-  x  9-inch  busmess*we 
self-addressed  stamped  enve- 
lope to  the  following  address 
(foreign  stations  may  substitute 
for  the  fee  by  enc  losing  an  SASE 
and  20  IRCs):  Whidbey  Island  DX 
Club,  Attn:  IDX  Award,  2665 
North  Busby  Roadf  Oak  Harbor 
WA  96277. 

Rules  governing  this  award 
program  are  reviewed  annually 
in  the  month  of  September, 
Please  enclose  an  SASE  with 
any  enquiries  regarding  this 
award  program. 

ELMIRA  NY 

Elmira  area  amateurs  will 
operate  W2ZJ  from  Chemung 
County's  1st  Annual  Good 
Neighbor  Festival  1300Z,  July  31 
through  2100Z,  Aug.  1.  Frequen- 
cies; 30  kHz  up  from  the  tower 
edge  of  the  General-class  phone 
band  on  20,  40,  and  80  meters. 
Special  certificate  for  large 
SASE  to:  ARS  W2ZJ,  General 
Delivery,  Elmira  NY  14904. 

MT.  DAVIS  PA 

The  Somerset  County  ARC 
will  operate  AK3J  for  the  second 
annual  DXpedition  from  the 
highest  point  in  Pennsylvania. 
Mt  Davis,  from  1800  UTC 
August  7th  to  1800  UTC  August 
8th.  Frequencies  will  be  the  first 


25  kHz  in  the  General  section  for 
phone  and  the  Novice  section 
for  CW.  A  beautiful  certificate 
will  be  sent  upon  receipt  of  QSL 
card  and  $100,  QSL  to  Box  468, 
Somerset  PA  15501. 

SMYTH  COUNTY  VA 

The  amateur  radio  operators 
of  Smyth  County  VA.  in  celebra* 
tion  of  the  county's  sesquicen- 
tenmal.  will  be  on  the  air  Aug.  21, 
1982  from  0000Z  until  2100Z. 
Frequencies  will  be  15,  40,  and 
80  meters,  up  10  kHz  from  the 
bottom  of  the  general  phone 
band  and  Novice  CW  band  (as 
activity  dictates).  The  call  used 
will  be  W4KON.  Please  QSL  with 
a  large  SASE  for  an  attractive 
certificate  and  booklet  about 
the  county  to;  Ken  Sturgill 
KC4IH.  PO  Box  526,  Marion  VA 
24354. 

SOUTH  BASS  ISLAND  OH 

The  Huron  County  Amateur 
Radio  Club  will  celebrate  the 
169th  anniversary  of  the  Battle 
of  Lake  Erie  by  operating  from 
Perry's  Victory  and  International 
Peace  Memorial  on  South  Bass 
Island  in  Lake  Erie.  The  station, 
WA8HUR,  will  be  on  the  air  be- 
ginning at  10002  August  21, 
1982,  til  0000Z  August  22,  1982. 
Operating  on  SSB,  the  frequen- 
cies  will  be:  3910,  7250,  14280, 
21360  and  28550  kHz.  The  CW 
station  will  be  found  at  40  kHz 
up  from  the  bottom  of  each  HF 
band,  A  Novice  station  will  be 
found  at  3720  kHz  and  at  7115 
kHz.  An  FM  station  will  be  oper- 
ated on  146.52  MHz.  A  special 
QSL  card  will  be  issued  to  all 
those  making  contact  who  send 
their  QSL  and  an  SASE  to  ARS 
KF80. 

FLUSH  KS 

The  Kansas  St&te  University 
Amateur  Radio  CLub,  W0QQQ, 
Manhattan,  Kansas,  and  the 
Manhattan  Area  Amateur  Radio 
Society  announce  the  first  an- 
nual DXpedition  to  Flush,  Kan- 
sas, in  Pottawatomie  County.  It 
will  be  held  on  August  29t  1982, 
for  24  hours  of  continuous  oper- 
ation beginning  at  00002. 

CW  operators  can  work 
W0QQQ  around  21.112  MHz  or 
7.112  MHz,  and  phone  operators 
will  find  WflOQQ  around  14.292 
MHz  or  3,892  MHz,  depending  on 
band  conditions. 

Successful  participants  will 
receive  a  handsome  8^x10" 
certificate  by  sending  an  SASE 


to  W0QQG,  Electrical  Engineer- 
ing Dept.,  Kansas  State  Univer* 
sity,  Manhattan  KS  66506, 

Flush  is  a  quaint  metropolis 
in  the  beautiful  Flint  Hills  region 
of  Kansas,  12  miles  east  of 
Manhattan,  home  of  Kansas 
State  University. 

MT,  PLEASANT  I A 

The  Mount  Pleasant  Amateur 
Radio  Club  will  be  operating  a 
station  at  the  Midwest  Old 
Threshers  Reunion  in  Mount 
Pleasant,  lowaT  September  2*6, 
1982.  Using  club  call  W0MME, 
they  will  be  operating  in  the 
General  portion  of  80, 40,  and  20 
meters. 

Amateurs  from  the  Mount 
Pleasant  area  will  also  be  han- 
dling emergency  communica- 
tions on  the  grounds  and  will  be 
providing  taik-in  on  147.99/.39 
(WQMME/R)  and  146,52  simplex 
for  those  attending. 

Several  hundred  amateurs  are 
among  the  250,000  people  an- 
nually that  attend  this  display  of 
memorabilia  from  America's 
past.  Such  things  as  steam  en- 
gines,  vintage  cars,  trolley  cars, 
antique  radios,  and  threshing  by 
horse  and  steam  power  will  be 
on  display. 

Hams  attending  are  invited  to 
visit  the  ham  shack  and  sign  the 
guest  book.  Admission  for  the 
five  day  event  is  S4.00.  Camping 
is  available  on  the  grounds.  For 
further  Information,  contact 
Dave  Schneider  WDQENR,  507 
Vine,  Mount  Pleasant  IA  52641. 

PIQUA  OH 

The  Piqua  Amateur  Radio 
Club  (W8SWS/8)  of  Piqua,  Ohio, 
will  operate  from  the  Colonel 
John  Johnston  Farmstead,  an 
historical  Indian  museum,  on 
September  4-6  from  1400  to  0000 
UTC. 

Colonel  Johnston,  a  federal 
Indian  agent,  built  his  Dutch  co- 
lonial farmhouse  in  1808;  it's  the 


only  Indian  agent  house  in  Ohio. 

This  is  Piqua  Heritage  Festival 
Days,  the  first  celebration  of  its 
kind  in  the  state.  Piqua  is 
cefebrating  its  175th  birthday. 

A  special  picture  OSL  card 
and8'/2"x  11 M  certificate  will  be 

sent  to  all  stations  who  QSL 
with  a  large  SASE  to  Larry  Un- 
derwood W8UO,  811  N.  Sunset 
Dr.,  Piqua  OH  45356. 

Frequencies  for  W8SWS/8 
will  be  SSB  3.900,  7,250,  14.290T 
146.460,  and  7.115  (1800-2000 
UTC). 

PALMYRA 

The  M.O.T.H.E.R.S,  (Marengo 
Over-The-Hill  Electric  Radio 
Society),  an  informal  group  of 
radio  amateurs  in  the  north- 
central  Illinois  area,  have  been 
planning  a  DXpedition  for  some 
time.  So  far,  the  destination  and 
duration  of  the  expedition  had 
only  been  speculation.  Last 
month,  however,  the  destina- 
tion, Palmyra,  was  announced. 
This  came  after  confirmation  of 
a  landing  permit  and  operatfng 
permission  had  been  received 
from  local  authorities.  The  fact 
that  this  Palmyra  is  located  in 
south-central  Wisconsin  hasn't 
dampened  the  spirits  of 
WB9NKH,  K9UA,  KF9E,  KC9DC, 
or  WA9TAH,  the  expected 
operators. 

The  DXpedition  will  attempt 
the  landing,  initial  setup,  and 
possibly  some  limited  operation 
on  September  11,  1982,  with  a 
full-blown  multi-transmitter 
operation  expected  on  Septem- 
ber 12, 1982,  from  approximately 
0700  to  2100  CDT.  The  operating 
frequencies  will  be  up  30  kHz 
from  the  bottom  of  the  CW  band 
edges  and  the  General  phone 
band  edges. 

Since  Wisconsin  and  Illinois 
have  fully  reciprocal  licensing 
agreements,  the  DXpedition  will 
use  the  call  WA9TAH,  with  QSLs 
available  for  an  SASE. 


CORRECTIONS 


The  crystal  X1  used  In  the 
British  VHF  converter  project 
(April.  1982)  is  correctly  listed  as 
38.667  MHz  m  the  text  and  Parts 
List.  The  value  shown  on  the 
schematic  is  incorrect. 

Minor   engineering    changes 


made  since  the  design  was  pub- 
lished include  substituting 
BF274s  for  the  BFW92s  used  for 
Q3  and  Q4.  C6  has  been 
changed  from  22  pF  to  47  pF. 

Tim  Daniel  N8RK 
73  Magazine  Staff 


73 Magazine  •  August,  1982    13S 


Wayne  Green  Books 


i 


"" — T  "    r 


-< 


TEXTEDIT 

a  complete 
worc^proce^jig 
system  In  kit 

by 
Irwin  ftappaport 


A  WAYND  UHEEW 
PUBLICATION 


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'TRS-80  and  TRSDOS  are  trademarks  of  the  Radio  Shack  Di- 
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TEXTEDIT— A  Complete  Word  Processing  System  In 
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TEXTEDIT  is  an  inexpensive  word  processor  that  you  can  adapt  to  su*1  your  needs,  From 

i«riling  form  letters  to  large  tents  li  4  written  in  modules,  so  you  can  load  and  use  only 

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TEXTEDIT  15  *ntten  m  TRS^80*  Disk  BASIC,  and  the  modules  are  documented  in  the 

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BASIC  programming  was  supposed  10  be  simple— a  beginner's  programming  language 
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Annotates  8*StC  explains  in*  compie*>i<es  of  modem  BASIC  It  includes  complete 
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136     73  Magazine  ■  August,  1982 


r 


the 


5. 
6. 


7. 
8. 


10. 
11. 


NEVER  SAY  DIE  — If  you  want  controversy. 
Wayne  Green  W2NSD/1  will  give  it  to  you.  His 
popular  column  ranges  from  travelogue  to  tirade 
and  is  guaranteed  to  entertain,  inspire  and 
enlighten  you, 

DX  — This  globe-trotting  column  keeps  you  in- 
formed about  the  news  of  the  DX  world  from  King- 
man Reef  to  Bahrain. 

CONTESTS  — You  get  all  the  news  on  the  contest 
wortd  from  Robert  Baker  WB2CFE  Hell  give  you 
information  on  upcoming  events  and  results  from 
recent  contests. 

FUN  — Just  for  fun,  John  Edwards  KI2U  provides 
you  with  wacky  puzzles,  quizzes,  and  games  that 
test  your  ham  mettle. 

FCC  —  If  you're  looking  to  the  future,  these  out- 
takes  from  the  Federal  Register  chronicle  changes 
in  policy  and  regulations  that  relate  to  amateur 
radio, 

RTTV  LOOP  — To  keep  you  abreast  of  radiotele* 
type  developments,  Marc  Leavey  WA3AJR  ex- 
plains the  new  RTTY  equipment,  the  increasing 
role  of  computers  in  RTTY.  and  other  matters  of 
interest  to  digital  communications  fans 

REVIEWS— Before  you  buy,  save  yourself  some 

money  check  73's  in-depth  evaluation  of  the 
latest  gear. 

HAM  HELP  — As  a  service  to  you,  73  prints  your 
questions  \n  our  magazine.  This  helps  you  to  ob- 
tain hard-to-get  parts,  schematics,  and  owner's 
manuals, 

SATELLITES -From  Phase  HI  to  TVRCX  73  Maga- 
zine covers  the  news  of  the  satellite  world  like  no 
other  radio  amateur  magazine. 

NEW  PRODUCTS— This  brief  look  at  the  latest 
ham  equipment  on  the  market  keeps  you  on  top  of 
new  developments  in  amateur  radio. 

AWARDS  —  To  find  out  what  certificates  are  avail- 
able where,  read  Bill  Gosney  KE7C's  coverage  of 
all  the  ham  radio  awards. 


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SOVIET  SURPRISE! 

On  May  17,  World  Telecommunications  Day,  the  Soviet  Union 
placed  yet  another  amateur  radio  satellite  into  orbit.  However,  the 
unusual  manner  of  its  launch  and  the  technical  details  so  far  re- 
teased  make  it  clear  that  this  is  no  ordinary  amateur  bird. 

The  satellite,  called  ISKRA  2  ("iskra"  is  Russian  for  "spark"),  was 
put  into  orbit  by  two  Soviet  cosmonauts  who  simply  pushed  the 
spacecraft  out  an  airlock  aboard  the  Salyul  7  orbiting  space  station. 
Several  sources,  including  Radio  Budapest,  have  said  that  ISKRA-2 
carries  a  15-to- 10-meter  communications  transponder,  which  would 
be  the  first  use  of  the  21-MHz  band  for  an  amateur  communications 
satellite.  Telemetry  beacons  from  the  new  bird  have  been  copied  on 
the  high  end  of  10  meters  at  29.576  and  29.875  MHzt  using  the 
callsign  RK02.  At  press  time,  no  transponder  activity  had 
been  heard, 

ISKRA-2  is  in  a  rather  low  orbit,  less  than  225  miles  high.  This 
means  that  the  satellite  will  have  a  rather  limited  lifetime,  unless  it 
carries  some  means  by  which  to  raise  its  orbit. 

The  launch,  which  was  shown  on  Soviet  television,  is  apparently 
only  the  second  of  its  kind.  In  1972,  the  Apollo  16  astronauts  placed 
a  small  satellite  into  orbit  around  the  moon, 

PHASE  1MB 

It  now  appears  that  the  long-awaited  launch  of  the  Phase  1MB 


DONT  TIME  OUT 


TIME  IN 


TMO   Um*    mlwti    tot 
to  tt bid  timing  oul 
(Patented! 

'Sens  Unfit  •rmugh  lor  HTS 
"An lorn* lie;  S*nu»  HF  cim*f  nocon 
nscOorrf  10  rig 
"Battery  pownrttd 

*  Reseti  on  carrier  drop-out 

*  Adjust»bl#  Owing  pano4 
"Si»    S    1/4  -:  3    ^19  v  T    3M 

*  W«*gM  6  w/224  I  Crims 
Piercing.  &  5  KH*  iJ*Tt  lone 


Uoti»\  mo  miTfitiJtd 
Med*i  n-iOh.  in  \otm 


is: 
iddii 

■nd  Documm 


Introducing  Toggle  Time 

Toggl*  T\m9  In  tO  minule  limw  Itutt 
would  fa*   utllljvd  by   ft  ham  lo  k«ip 
within  f  CC  1 Q  tnln.  ID  rultt  II  i s  ae l u 1 1 
«d  by  *  loggl*  twitch  which  i««u  iwo 

EHjrQQMV 

1  SUrt»  Timer 

2  Titfiu  ort  Power 

Onf f  on«  i vklth  on  b(H  i«  4i  ttHl  It  pf# 
sent  Pnce  f  14.95 


tatton  120 


Wlier*  ordering,  pie***  specify  model 


^140 


COMSTAR  RESEARCH 

P.O.  BOX  771     Madison  Heights,  Ml  48071 


REGENCY  SCANNERS 

T720A«  T6SQ0  0810  27000 

D100  15900  M100  20500 

D300  20900  M400  24500 

All  BmxJy  low  proline  I C  SocHets  jus!  H  per  pin 

Example;  S  pin— Be.  40  pin— 40c  pet  pin  UG  176  Reducer— 1 0ft  1  99 

Ham  IV  Ro1w-S165.00  SO  239-1055.89 

Columbia  a  Con  r2*na£tl  22}-l7crii  3  amp  fuse— 20151.50 

Columbia  RG  S9v  10G  loil  shield  TV  type—  faffi.  Gould  9V  Nicad— £4,86 
Berk  Tek  Grey  96%  PG  8X^i4*m  Gould  1.2v  500  mAh  AA  Nfecad 

US  made  PL  259-1Q/$5.5G  10/514.50         100/5125.00 


Call  for  Quantity  Quotes 


oeMrdMn 


Universal  Dist. 
RAYMOND  RICHARD 

RT.  1.  BOX25E 
CLERMONT.  FL3271t 


(904)394-2511 
(313)278-8217 


^'55 


satellite  will  take  place  next  January  and  not  this  summer,  as  had 
been  hoped,  The  delay  comes  as  a  result  of  problems  with  the 
government  and  scientific  satellites  which  are  the  primary  payloads 
for  the  European  Space  Agency's  Ariane  rocket. 

Phase  IIIB  is  now  scheduled  to  fly  aboard  the  seventh  flight  of 
Anane,  but  until  the  problems  with  the  other  satellites  are  solved,  no 
launches  can  take  place.  Meanwhile,  the  amateur  Phase  fllB  bird  is 
ready  to  go. 

Thanks  to  AMSAT Satellite  Report 

THAT  BIG  TABLE 

Our  monthly  table  of  amateur  satellite  data  this  month  takes  on  a 
new  form,  designed  to  pack  a  lot  more  information  into  only  a  little 
more  space.  Joining  the  usual  data  for  OSCAR  8  are  reference  orbit 
predictions  for  four  of  the  Soviet  Radio  Sputniks,  RS-5  through  RS-S, 
Each  of  these  five  satellites  carries  at  least  one  operating  com- 
munications  transponder  or  robot  (automatic  QSO  device), 

This  table  provides  reference  orbit  data  for  each  day  of  the  month 
on  the  cover  of  this  magazine,  plus  the  first  half  of  the  following 
month.  For  each  day  during  this  period,  two  items  of  information  are 
given  for  each  of  the  five  satellites,  The  first  number  (UTC)  is  the  time 
(Universal  Coordinated  Time— same  as  GMT  for  most  purposes)  of 
the  satellite's  first  northbound  equatorial  crossing  of  the  day.  The 
second  number  (EQX)  is  the  longitude  (degrees  west)  at  which  that 
crossing  occurs.  The  data  in  the  table  is  based  on  the  Project 
OSCAR,  Inc.  orbital  predictions. 

Using  these  two  numbers,  there  area  variety  of  ways  to  determine 
when  any  of  the  satellites  will  be  within  range  of  your  location.  If  you 
have  a  microcomputer  or  programmable  calculator  at  your  disposal, 
you  can  make  use  of  one  of  several  programs  published  in  73  and 
other  amateur  publications.  The  new  AMSAT  Software  Exchange 
has  a  good  selection  of  satellite  tracking  programs.  The 
OSCARLOCATER  package  from  the  ARRL  gets  the  job  done  in  a 
simple  but  effective  manner.  A  completely  manual  method  for  mak- 
ing rough  estimates  of  satellite  accessibility  was  presented  in  the 
October,  1981.  issue  of  73,  page  178, 

Addresses:  AMSAT  Software  Exchange,  Box  338,  Ashmore 
IL  61912.  ARRL,  225  Main  Street,  Newington  CT  06111.— Jeff 
DeTray  WB8BTH. 


Aug 


Sep 


Afflateui 

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OSCAR 

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138     73  Magazine  *  August,  1982 


W2NSD/1 

NEVER  SAY  DIE 

ed/tor/a/  t>y  Wayne  Green 


from  page  8 

hibit  had  a  nice  restaurant  with 
no  wait  at  all,  right  in  the  middle 
of  the  lunch  hour. 

Sherry  and  I  went  to  the  res- 
taurant in  the  Chinese  exhibit 
for  dinner-  Tom  Salvetti,  of  Ten- 
Tec,  was  with  us  and  we  went 
right  in  with  no  wait  at  all.  The 
food  was  real  Chinese.  It  was 
good,  but  not  outstanding. 
Sherry  prefers  to  use  chopsticks 
when  eating  Asian  food  and  this 
was  a  bit  of  a  problem.  The 
waiter,  a  Chinese  lad  from  the 
Knoxville  area*  explained  that 
they  only  had  three  sets  of  chop- 
sticks for  the  whole  restaurant! 
He  managed  to  get  one  of  the 
sets  for  her,  but  the  rest  of  us 
had  to  eat  with  forks. 

The  food  prices  are  a  bit 
above  what  I'd  normally  expect, 
but  not  astronomical.  China 
seems  to  be  getting  all  she  can 
out  of  the  fair  (they  need  dollars, 
so  l hat's  not  a  surprise),  wjth 
their  dinners  running  around  $14 
per  person.  That's  as  bad  as  a 
banquet  price.  Belgian  waffles 
were  $2.10  Instead  of  perhaps 
$1.50... and  so  on.  High,  but 
not  prohibitive.  They  have  to  get 
their  $110  million  back  some 
way.  don't  they? 

In  all,  t  would  suggest  that  if 
you  are  going  to  be  anywhere 
near  the  Knoxville  areaT  you 
should  aJlow  a  couple  of  days  to 
see  the  fair.  Never  mind  all  the 
put-downs. ,  .it's  a  good  show 
and  the  people  couldn't  be  more 
friendly. 

ROCHESTER 

The  debacle  of  '61  still  hung 
heavy  over  the  1982  running  of 
the  Rochester  Hamfest;  It's  stitl 
a  shadow  of  former  years,  but 
perhaps  with  the  relaxation  of 
harassment  by  the  tax  people, 
the  exhibitors  and  then  the 
crowds  will  be  back. 

This  year  there  was  but  one 
major  manufacturer  exhibiting: 
Hy-Gain/Telex.  A  few  dealers 
were  there,  hoping  that  the  New 
York  tax  people  would  not  bring 
in  the  police  and  threaten  again 
to  close  down  the  whole  show, 


The  dealers  seemed  to  feel  that 
business  was  okay,  considering 

the  economy. 

There  is  a  plan  to  move  the 
banquet  to  Friday  night  and 
keep  the  show  to  one  day  on 
Saturday,  This  would  allow 
hams  to  arrive  the  night  before, 
attend  the  banquet,  and  then 
spend  the  day  at  the  show.  After 
a  full  day  of  browsing  around 
the  flea  market,  most  hams  are 
too  tired  to  wait  for  the  banquet; 
they  just  drive  home  to  rest.  It 
may  be  better  to  run  it  Friday 
night.  It's  worth  a  try. 

After  all  of  the  fuss  from  CO 
about  attending  hamfests, 
guess  who  was  not  there?  HehT 
heh!  But  then  Ham  Radio  was 
also  conspicuously  absent. 
They  seem  to  have  pulled  in 
their  horns  almost  completely 
and  become  invisible.  73's  Jim 
Gray  was  there  to  keep  'em  hon- 
est , .  .  answer  questions  and  fly 
the  flag. 

Speaktng  of  the  magazines, 
guess  who  was  at  the  ARRL 
booth?  There  were  a  lot  of  rotten 
remarks  about  Harry  being  dead 
and  refusing  to  lie  down.  I  think 
that  sort  of  thing  is  in  poor  taste. 
As  l1ve  written,  I  think  the  least 
the  board  could  have  done  for 
Harry  Is  to  make  him  a  president 
emeritus  like  they  did  the  pre- 
vious president.  And  if  they  have 
any  real  case  against  him  for 
malfeasance.  I  think  they  should 
bring  it  out  in  the  open,  not  just 
make  sly  hints  about  it,  Harry 
should  be  given  the  credit  he 
deserves  for  building  up  the 
League,  for  promoting  satellite 
communications,  and  for  his  en- 
thusiasm for  packet  com  muni* 
cations,  RTTY,  and  so  on.  Let's 
not  have  another  of  those 
crummy  deals  like  they  pulled 
on  Don  Miller. 

Other  than  that,  Rochester 
was  upbeat  this  year1  looking 
better.  But  Harold  Smith  was 
almost  invisible  again  this 
year. ,  .where  are  you,  Harold? 
He's  the  one  who  almost  single- 
handedly  organized  and  built  up 
the  hamfest  over  the  years,  turn- 
ing it  from  a  small  independent 
effort  into  a  genuine  ARRL 
hamfest, 


FCC  NEWS 

The  FCC  has  extended  the  deadline  for  filing  comments  on 
Docket  82-63  to  August  16.  Reply  comments  are  due  Septem- 
ber 16.  Docket  82-83  proposes  wider  phone  bands.  For  more 
information,  see  pages  143-145  of  the  May,  1982r  issue  of  73. 

The  return  time  limit  for  Novice  exams  was  extended  to  60 
days,  effective  May  6T 1982.  This  change  will  be  of  interest  to 
volunteer  examiners  who  previously  had  30  days  to  return  the 
test  papers. 


SADDLE  STITCHING 

In  addition  to  the  cover  design 
change,  we  are  also  changing  to 
what  is  called  "saddle  stitch* 
ingH  of  the  binding.  The  idea  Is 
to  get  back  to  the  way  we  used 
to  be  when  73  was  funning  a  raft 
of  small  construction  projects. 
We  want  to  make  the  magazine 
easy  to  open  up  while  you  are 
working  on  a  project.  With  the 
square  binding,  called  "perfect 
binding,"  the  magazine  may 
look  better,  but  it  is  a  bitch  to 
keep  open  on  the  workbench.  I 
really  hate  it  when  the  magazine 
flips  closed  while  I'm  wiring 
some  chips  together 

We're  going  to  be  concen- 
trating on  publishing  as  many 
relatively  simple  construction 
projects  as  we  can  scare  up  for 
you,  so  get  your  soldering  iron 
out  and  start  shopping  for  parts, 

A  NEW  COVER. .    AGAIN? 

Sure,  why  not?  Every  few 
years  we  get  kind  of  fed  up  with 
everything  being  the  same.  We 
look  around  for  ways  to  make  73 
better. .  .or  worset  depending 
on  your  reactions  to  change. 

The  new  cover  solves  some 
serious  problems  for  us.  First,  it 
will  stop  the  continuous  flack 
we've  been  getting  from  73  read- 
ers who  liked  the  old  contents 
type  of  covers,  ft  is  a  lot  easier  to 
find  things  when  the  table  of 


contents  is  right  there  on  the 
cover,  no  question  about  that. 
And  since  virtually  100%  of  the 
73  readers  save  their  magazines 
religiously  and  use  them  for 
reference,  this  is  a  big  plus. 

Another  problem  was  our 
desire  to  use  color  pictures 
brought  back  from  DXpeditlons 
on  the  cover.  If  you  are  not  Into 
photography,  you  may  not  know 
that  33mm  color  pictures  carft 
be  enlarged  to  the  full  cover  size 
without  getting  fuzzy.  Normally 
we  would  want  to  use  a  larger 
film  format  camera  for  cover 
shots. .  .such  as  a 6x 6cm  or  a 
6  x  7  cm  such  as  the  Hassleblad 
or  Mamiya  RB-67  cameras. 
These  will  enlarge  and  provide 
sharp  cover  pictures.  Just  look 
at  some  of  the  cover  pictures  on 
OSTin  recent  months  and  you'll 
see  what  I  mean, , .  fuzzy. 

By  running  the  pictures  in  a 
smaller  format  on  the  cover, 
they  will  be  nice  and  sharp, .  * 
and  look  better.  Also,  we'll  be 
able  to  run  maybe  two  or  three 
pictures   instead   of  just  one. 

I  realize  that  you  probably  are 
no  more  a  fan  of  change  than  I 
am  and  will  take  a  few  months  to 
get  used  to  the  new  look.  For  all 
my  insistence  on  change  being 
important  in  amateur  radio,  I'm 
as  much  of  a  stick  In  the  mud 
when  it  comes  to  change  as  you 
probably  are.  Let's  try  it  and  see 
how  it  plays. 


MM  HELP 


(  need  help  on  my  code  speed  for  the 
General  ticket. 

Howard  Halperin  WB7WDI 

4122  West  Flower  St. 

Phoenix  A2  6S019 

Wanted:  Information  on  the  Gon&et 
Model  900A  2-meter  Sidewinder.  I  would 
like  to  get  In  touch  with  anyone  with  parte 
for  this  unit  or  who  can  suggest  where 
these  parts  can  be  found. 

Peter  Mitrolf  VE30SW 

0  Martian  Or 
St.  Catharines  OUT  L2H  $CT 

Canada 


I  would  like  any  Information  on  the  Globe 
Electronics  HG  303.  including  manuals  and 
schematics.  I  will  purchase  at  a  reasonable 

price  or  will  make  copies  and  send  an  extra 
set  of  copies  back  to  you  with  the  original. 

At  Wilde  W8JZZ 
5580  E.  Gfllbmilh  Rd. 
Cincinnati  OH  45236 

I  need  a  Johnson  Viking  Model  122  vfo  to 
use  with  a  Johnson  Adventurer. 

Jack  Spier  N1BIC 

70  Florida  Hill  Rd 

Rtdgelietd  CT  06877 

73  Magazine  •  August,  1982     139 


A  2-Meter  Space  Beater! 

DDRR 

The  Repeater  Beater 

•  With  as  htlle  2*  on*  iqul'fr  loot  tA  gttmnd 
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piov'Oes    go  mm  u  meal  ion    front    uttuilly 

•  low  SWfl  mate*  to  *  50  ohm  iifta  across  trie 
entire  band. 

•  Miqne!  c  mounl  included 

•  Space  Sealers  are  available  'c  vrvpt*  ot 
m uth -ba r*d  oper al rt>n  f f  om  1  £  I  *  ft  MHi 


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Call  Collect  NOW 
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35  Ruta  Court 
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SPACE  ELECTRONICS  Co. 
Our  22nd  Year 


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73Magazine  *  August,  1982     141 


•7000-    DiCC    gind/lfode   Count  Mei' 
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ATVSSTV-FAX  RTTYSateltttes  EME 
Mrcfowavo  and  Computers 

Published  J  2  times  per  year  by  Mike  Stone  WB&QCD 
PO  Box  H,  iowden.  towa  52255 0408 


THE    PROFESSIONAL 

TOUCH  TONE 


♦»  • 


An  uttra  high  quality 
encoder  for  professional 
application.  Absolute  reliability  and 
function  makes  the  difference.  There's  a 
Pipo  encoder  for  every  system  and 
application.  Totally  serviceable,  easy  to 
operate  and  install.  Call  or  write  for  free 
catalog  and  information!  (213)  852-1515 
or  P.O.  Box  3435,  Hollywood,  CA  90029. 


PATENTED 


*ATAT 


tpipocGommunications 

Emphasis  ts  on  Quality  A  Reftahtitty    *-*  300 


this  publication 
is  available  in 
microform 


University  Microfilms  International 


300  North  Zeeb  Road 
Dept.  PR. 

Ann  Arbor,  Ml  48106 
U  S  A. 


18  Bedford  Row 
Dept  PR 

London,  WC1R4EJ 
England 


i- 


RIG  TROUBLES 
GOT  YOU  DOWN? 

•YOU  COULD  SHIP  YOUR  RIG  TO 
THE  FACTORY  FOR  REPAIR. 

•YOU  COULD  SHIP  IT  TO  RQ  SER- 
VICE CENTER  FOR  REPAIR. 

•BUT  YOU  STAND  A  GOOD 
CHANCE  OF  FIXING  IT  YOUR- 
SELF WITH  HELP  FROM  YOUR 
OWN  COPY  OF  "OWNER  REPAIR 
OF  RADIO  EQUIPMENT" 

•THIS  BOOK  WILL  BE  SHIPPED 
POSTPAID  FROM  K6RQ  FOR 
$8.95 

RQ  SERVICE  CENTER 

14910  LC  Blvd. 

Los  Galos,  CA  95030 


GO  MOBILE  WITH  YOUR  H.T.!  I 


Modal  I— icom  IC-ZA/T.  Etc, 

Model  K1  r<H  TR2500 

—  slid**  on  bottom  of  radio 


*++**+*  wrm  w  ■w  ■  ■■ 


Guaranteed! 


Model  K— TR  2400; 

—powered  thru  battery  plug 

Model  N— FT-208fl 

Model  T  —  Simple  mod  rof  Tempo 

NOW  FOR  R  208R  &  TR-2500 


■  ihiiiibiinii 


Model  Y— FT-207R. 
—tils  Into  battery  compart menl 

"A  unique  battery  eliminator* 
HANDI  TEK  Regulator  allows 
constant  handheld  opera  I  ion 
from  auto  DC  or  base  supply 
with    no    nicad    drain    and 
WITHOUT  RAOiO  MODIFICA- 
TIONi  £24.95  PPD  in  USA.  CA 
add  $1.50  Sates  Tan. 
^4GO 
HANDt  TEK 
P.O.  BOX  220S.  LA  PUENTE.  CA  91746 


PRESERVE 


13 


BINDERS    & 
FILE  CASES 

Keep  you i  issues  of  73  Magazine  together,  handy 
and  pioiected  to  handsome  and  durable  horary  dies 
or  binders  Both  styles  bound  in  red  teaihorcite  wilh 
the  magazine  logo  stamped  in  gold. 
Files:   Each   lile  holds   12   issues,   spines  visible 

far  easy   reference,  $595  each,  3  for  $17  00. 

6  for  S30.00 
Binders:  Each  binder  hoftis  \2  issues  and  opens 

Hat  lor  easy  reading.  $7  50  each,  3  for  $21.76, 

6  for  14200 
(Postage  paid  m  USA..  Foreign  orders  include  $2.50 
per  iiemt 

Please  stale  years:  1977  to  1983 
Send  check  or  money  order  lo: 
JESSE  JONES  SOX  CORP 
PO  Bon  5120 
Philadelphia,  PA  19141 
Allow  4  lo  6  weeks  lor  delivery 


142     73  Magazine  *  August,  1982 


DISTRIBUTING 

7201  N.W.  12  ST, 

MIAMI,  FLA.  33126 

(305)  592-9685 

(305)  763-8170 

WATTS  800-327 -3364 


-CW  MODE  PORTABLE  RADIOS 

IC-502-A     6  METER 
ST  239.00      N&G  PRICE  185.00 
IC-202-S     2  METER 
LIST  279.00       N&G  PRICE  215.00 


IC-720A  H.F. 
LIST  $1349.00 


IC-25-A 
LIST  $349.00 


*  B  E  C  *  Ballet  Electronics  Corp.  P.O.  Box  401144E  Garland,  TX.  7504O  (2143  278*3553 


-12 


THE  PRESIDENT  SAYS:    "HOG  WASH!!' 


After  taking  one  look  at  the  TRIPUT  POWER  SUPPLY  our  engineer  declared  that  the 
units  were  worth  several  hundred  dollars  each.  He  pointed  out  the  engineering,  high  quality 
construction  and  state-of-the-art  integrated  design  in  support  of  his  position.  The  President 
of  BEC  more  pragmatically  pointed  out  the  already  full  warehouse  and  the  two  trailer  truck 
loads  of  power  supplies  waiting  in  the  parking  lot,  and  set  the  price  to  move  them  QUICKLY! 
We  have  a  large  quantity,  but  the  supply  wont  last  long.  The  only  thing  we  ask  is  please  read 
the  ordering  rules. 


QUALITY  DOUBLE  SIDED  GLASS  BOARD 


-Ti 


Hi 


ft* 


'   »l 


**<!„  ill 

j.JID-f 

■r*  1 


»^i?l£%i<- 


13.6V  @  20A  MODIFICATION 

By  changing  a  few  parts  on  the  beard  (he  Triptrt 
Power  Supply  will  do  11  -  14V  ( adjustable)  at  up  to 
20A.  Perfect  lor  that  2  meter  linear  amp!  Wesand  step 
by  step  instructions  and  necessary  parts.  Mod- 
ification per  instructions  will  not  vqld  Ihe  30  day 
warranty. 


REGULATOR  ASSEMBLY 
(part  of  unit) 


62.50 


Plus  Freight 

21  lbs. 
6  x  5V*  x  12 


COMPLETE  UNIT 
(as  you  receive  it) 

ORDERS  SHIPPED  WITHIN  CONTINENTAL  U.S.  ONLYI 

ORDERING  RULES 

1.  Mail  check  or  MO  for  $62,50  +  $5.00  for  shipping  or  phone  (214)  278-3553 
to  charge  VISA/MC  or  COD  order.  (UPS  COD  only,  add  $2.50  COD  fee) 

2.  Texas  residents  include  5%  sales  tax. 

3.  Orders  for  this  unit  will  be  shipped  within  48  HOURS  or  we  pay  the  freight! 
(weekends  or  holidays  excluded) 

4.  ONE  TIME  OFFER!  LIMIT  TWO  (2)  SUPPLIES  PER  CUSTOMER. 


+12V  @  7  A;  +5V  @  10A:  -12V  @  5A 

•  UNIT  IS  COMPLETELY  ASSEMBLED* 

•  Fused  primary  and  OC  sections 

•  HUGE  SHIELDED  TRANSFORMER 

•  2%  Load  &  Line  Regulation 

•  Low  Ripple  (     100m v) 

•  Short  Circuit  Protection 

i  Overvoltage  Protection  on  all  three 
outputs 

•  2SA  Bridge  Rectifier 

•  Over  60,000  mfd  of  fitters 

•  High  Efficiency  Switching  Regulator 
reduces  healsink  area 

•  Schematics  and  service  guide  included 

•  Thermal  Shutdown 

•  Statis  LED's  (3) 


See  list  of  Advertisers  on  page  TT4 


73  Magazine  *  August,  1982     143 


gM^ 


electronic* 


242 
(602)  242-8916 

2111  W.  CAMELBACK  ROAD 
PHOENIX,  ARIZONA  85015 


Introducing 


TVRO  CIRCUIT  BOARDS 


Satellite  Receiver  Boards— Now  in  Stock 


DUAL  CONVERSION  BOARD. $25.00 

This  i>oard  provides  conversion  from  the  3.7-4.2  band  first  to 
900  MHz  where  gain  and  bandpass  filtering  are  provided  andt 
second,  to  70  MHz.  The  board  contains  both  local  oscillators, 
one  fixed  and  the  other  variable,  and  the  second  mixer.  Con- 
struction is  greatly  simplified  by  the  use  of  Hybrid  IC  amplifiers 
for  the  gain  stages. 


SIX  47pF  CHIP  CAPACITORS 

For  use  with  dual  conversion  board . 


,  S6.00 


70  MHz  IF  BOARD $25.00 

This  circuit  provides  about  43dB  gain  with  50  ohm  input  and 
output  impedance,  It  is  designed  to  drive  the  HOWARD/ 
COLEMAN  TVRO  Demodulator.  The  on-board  bandpass  filter 
can  be  tuned  for  baadwidths  between  20  and  35  Mhte  with  a 
passband  ripple  of  less  than  Va  dB.  Hybrid  ICTs  are  used  for 
the  gain  stages. 

SEVEN  .01  pF  CHIP  CAPACITORS 

For  use  with  the  70  MHz  IF  board $7.00 


DEMODULATOR  BOARD $40.00 

This  circuit  takes  the  70  MHz  center  frequency  satellite  TV  sig- 
nals in  the  10  to  200  millivolt  range,  detects  them  using  a  phase 
locked  loop,  de  emphasizes  and  filters  the  result  and  ampli- 
fies the  result  to  produce  standard  NTSC  video.  Other  outputs 
include  the  audio  subcarrier,  a  DC  voltage  proportional  to  the 
strength  of  the  70  MHz  signal,  and  AFC  voltage  centered  at 
about  2  volts  DC, 

SINGLE  AUDIO $15-00 

This  circuit  recovers  the  audio  signals  from  the  6.8  MHz  fre- 
quency, The  Miller  9051  coils  are  tuned  to  pass  the  6,8  MHz 
subcarrier  and  the  Miller  9052  coil  tunes  for  recovery  of 
the  audio, 

DUAL  AUDIO . .... $25.00 

Duplicate  of  the  single  audio  but  also  covers  the  6.2  range, 


DC  CONTROL 


*      *       *«§*!-■ 


$15.00 


SPECIAL  SET  OF  FIVE  BOARDS $100.00 

INCLUDING  DUAL  AUDIO  |2  single  audio  boards) 


1900  to  2500  MHz  MICROWAVE  DOWNCONVERTER 

MICROWAVE  RECEIVER  This  receiver  is  tunable  over  a  range  of  1900  to  2500  MHz  approximately,  and 
is  intended  for  amateur  use.  The  local  oscillator  is  voltage  controlled,  making  the  I.F.  range  approximate- 
ly 54  to  88  MHz  for  standard  TV  set  channels  2  thru  7. 

P.C.  BOARD  with  DATA         1to5     $15.00         6  to  11     $13.00         12  to  26         $11.00         27 -up     $9.00 

P.C.  Board  with  all  parts  for  assembly $49.99     P.C.  Board  with  all  chip  caps  soldered  on. .  .$30.00 

P.C.  Board  with  all  parts  for  assembly  P.C.  Board  assembled  &  tested $69.99 

plus  2N6603 $69.99     P.C.  Board  assembled  &  tested  with  2N6603$79.99 

HMR II  DOWNCONVERTER  with  Power  Supply,  Antenna  (Dish)  &  all  Cables  for  installation.  180  Day  Warranty. 

1to5         $150.00  6  to  11         $140.00  12- up         $125.00 

YAGI  DOWNCONVERTER  with  Power  Supply,  Antenna  (Yagi)  &  all  Cables  for  installation.  90  Day  Warranty. 

110  5         $150.00  6  to  11  $140.00  12 -up         $125.00 

YAGI  DOWNCONVERTER  as  above  but  Kit.  (NO  CABLES)  With  Box. 

1to5         $125.00  6  to  11  $115.00  12 -up         $100.00 

HMR  II  DOWNCONVERTER  as  above  but  Kit.  (NO  CABLES)  With  PVC. 

1to5         $125.00  6  to  11         $115.00  12- up         $100.00 


»•*••**«**■«  *««>•«••«.<■•«**■«■«■>■■  >■■•*■«*■■■■■■■««■■■«■■*■■■•.»■  m  ■■■■■»«■■<■ 


SPECIAL  NEW  STOCK  OF  CARBIDE  DRILL  BITS- YOUR  CHOICE  $1.99 


1 ,25mm 

1 .45mm 

3,2mm 

3.3mm 

1/8 

3/16 

5/32 

7/32 


13/64 

19 

20 

24 

26 

29 

30 

31 


36 
37 
38 
39 
40 
44 
45 
46 


47 
48 

49 
50 
51 
52 
53 
54 


55 
56 
57 
58 
59 
60 
61 
62 


63 
64 
65 
67 

68 
69 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


144     73 Magazine  •  August.  1982 


Start  taking  calls  in  curious  places  with  the 

ft)  £-   ® 

revolutionary,  new  Cordless  (bbcow    Phone 

Special  Purchase — The  S&cct/®  Cordless  Telephone! 

We  are  pleased  to  announce  the  Escort  Mark  III  is  now  available 
at  special  pricing.  We  bought  the  manufacturer's  entire  inventory— 

and  we  are  passing  the  savings  on  to  you! 

The  Escort  Mark  III  was  originally  designed  to  retail  for  $199.95.  Now,  we 

suggest  a  retail  price  of  S169.95  to  S 1 89.95.  Or,  yon  can  move  them 

out  at  $149*95.  In  any  event,  you1  II  like  the  profit  margins. 


QUANTITY 

1 — 2  units 
-5  units 
II  units 
-23  unfts 


3 
6 
12 


DEALER  PRICE 

69,75  each 
64*50  each 
62.50  each 
60.75  each 


GROSS  PROFIT  A  T  $149. 95 

53% 
57% 
58% 
59% 


On  all  orders  of  12  or  more,  we  pay  the  freight!  This  is  your  opportunity 
to  stock  up  for  the  Christmas  buying  season.  These  are  ideal  gift 

items,  that  will  really  move  out! 


ESCORT  MARK  III  SPECIFIC  A  TIONS 


VHFDUPLEXERS 

This  duplexer  was  made  for  RF  Harris  Mobile 
Phones  and  Two  Way  Radios.  These  duplex* 
ers  can  be  used  in  any  mobile  phone  or  two 
way  radio  system,  along  with  having  the  ca* 
pabililies  to  be  modified  for  UHF  use.  The 
physical  dimensions  are  3  3/5"  Long,  4  2/5" 
Wide,  and  1  1/10"  Deep.  The  approximate 
weight  is  18  ozil  lb.  2  oz..  PRICE  $74.99 


^ 


# 


* 


.••• 


! 


•  Operates  as  a  regular  telephone  on  touch -tone  or 
rotary  dial  systems 

•  Range  up  to  300  feet 

•  Ni-Cad  rechargeable  batteries  included 
in  telephone 

•  Charger  built  into  base  transmitter 
■  Simple  plug-in  installation! 

•  High-performance  antenna 

•  Full  duplex,  answer  and  dial  out 

•  Futl  FCC  approval 

Exactly  As  Shown 


HOW  WE  CUT  THE  CORD. 

The  new  Cordless  Phone 
works  on  a  simple, 
highly  sophisticated  principle. 
A  small  base  station  plugs  into 
your  regular  phone  jack,  and 
an  electrical  wall  outlet.   The 
base  station  then  transmits 
any  in-  or  out-going  call  to  the 
handheld  receiver,  anywhere 
up  to  300  feet. 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


Toll  Free  Number 
800-528-0180 
(For  orders  only) 


(fJW^iljE  elect roi|ic§ 


73Magazine  *  August,  1982     145 


GaAs,  TUNNEL  DIODES,  ETC. 


PART 


PRICE 


PART 


PRICE 


PART 


PRICE 


MA471O0 

S   3.05 

MRF503 

$  6. 00 

PT4186B          S 

POR 

MA47202 

30.80 

MRF504 

7-00 

PT4209 

POR 

MA47771 

POR 

MRF509 

5,00 

PT4209C 

POR 

MA47852 

POR 

MRF511 

8.65 

PT4566 

POR 

MA49558 

POR 

MRF605 

20-00 

PT4570 

POR 

HB4021 

POR 

MRF629 

3.47 

PT4571 

POR 

MBD101 

1.00 

MRF644 

23.00 

FT4571A 

POR 

MD0513 

POR 

MRF816 

15-00 

PT4577 

POR 

MHWL171 

42.50 

MRF823 

20.00 

PT4590 

POR 

HHW1182 

48.60 

MRF901 

3.00 

PT4612 

POR 

MHW4I71 

49.35 

MRF8004 

2.10 

PT4628 

POR 

MHW4172 

51-90 

MS261F 

POR 

PT4640 

POR 

MHW4342 

68.75 

MT4150  Fair, 

POR 

FT  4642 

POR 

MLP102 

25-00 

MT5126  Fair. 

POR 

PT5632 

FOR 

MM1500 

32 .  32 

MT5481  Fair. 

POR 

PT5749 

POR 

^1550 

POR 

MT5482  Fair. 

POR 

PT6612 

POR 

MM1552 

50,00 

MT5483  Fair. 

POR 

PT6626 

POR 

MM1553 

50.00 

MT5596  Fair, 

POR 

PT6709 

POR 

MM1614 

10.00 

MT5764  Fair. 

POR 

PT6720 

POR 

MM2  608 

5*00 

MT8762  Fair. 

POR 

PT8510 

POR 

MM3375A 

11.50 

MV109 

-77 

PT8524 

POR 

MM4429 

10,00 

MV1401 

8,75 

PT8609 

POR 

MM8000 

1.15 

MV1624 

1.42 

PT8633 

POR 

MM8006 

2.30 

MV1805 

15.00 

PT8639 

POR 

M0277L 

POR 

MV1808 

10.00 

PT8659 

POR 

M0283L 

POR 

MV1817B 

10.00 

PT8679 

POR 

M03757 

POR 

MV1863B 

10,00 

PT8708 

POR 

MP102 

POR 

MV1864A 

10.00 

FT8709 

POR 

MFN3202 

10.00 

MV1864B 

10-00 

PT8727 

POR 

MPN3401 

,52 

MV1864D 

10.00 

PT8731 

POR 

MPN3412 

1.00 

MV1868D 

10.00 

PT8742 

POR 

MPSU31 

KOI 

MV2101 

.90 

PT8787 

POR 

MRA2023-1.5 

TRW    42.50 

MV2111 

-90 

PT9790 

41.70 

MRF212/208 

16.10 

MV2115 

1.55 

PT31962 

POR 

MRF223 

13*25 

HV2201 

.53 

PT3I963 

POR 

MRF224 

15.50 

MV2203 

,53 

PT31983 

POR 

MRF237 

3.15 

MV2209 

2.00 

PTX6680 

POR 

MRF238 

12.65 

MV2215 

2.00 

RAY-3 

24.99 

MRF243 

25,00 

MWA110 

7-45 

40081 

POR 

MRF245 

34.50 

MWA120 

7-80 

40281 

POR 

MRF247 

34.50 

MWA130 

8.25 

40282 

POR 

MRF3G4 

43.45 

MWA210 

7.80 

40290 

POR 

MRF315 

23.00 

MMA220 

8.25 

RF110 

25.00 

MRF420 

20.00 

MWA230 

8.  65 

SCA3522 

POR 

MRF421 

36,80 

MWA310 

8.25 

SCA3523 

POR 

MRF422 

41*40 

MWA320 

8.65 

SD1065 

POR 

MRF427 

16.10 

MWA330 

9-50 

SS43 

POR 

MRF428 

46.00 

NEC57835 

5.30 

TP1014 

POR 

MRF450/A 

13.80 

ON  382 

5.00 

TP1028 

POR 

MRF453/A 

17.25 

PPT515-20-3 

FOR 

TRW- 3 

POR 

MRF454/A 

19.90 

PRT8637 

POR 

UT0504  Avantek 

70.00 

MRF455/A 

16*00 

PSCQ2-160 

POR 

UT0511  Avantek 

75.00 

MRF458 

19,90 

PT3190 

POR 

V15 

4.00 

MRF463 

25.00 

PT3194 

POR 

V33B 

4.00 

MRF472 

1,00 

PT3195 

POR 

V100B 

4,00 

MRF475 

2.90 

PT3537 

POR 

VAB801EC 

25 .  00 

MRF477 

11.50 

PT4166E 

POR 

VAB804EC 

25,00 

MRF502 

1.04 

PT4176D 

POR 

VAS21AN20 

25.00 

Toll  Free  Number 
600-528-0160 

(For  orders  only) 


Q^iG^x  electronic* 

PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


146     73Magazine  •  August,  1982 


RF  TRANSISTORS,  MICROWAVE  DIODES 


PART 


PRICE 


PART 


PRICE 


PART 


PRICE 


1S2199 

$   7.50 

2N6083 

§ 

13.25 

CA2612   (TRW) 

$   25.00 

1S2200 

7.50 

2N6084 

15.00 

CA2674   (TRW) 

25.00 

2NI561 

25.00 

2N6094 

/M9622 

11.00 

CA2881-KTRW) 

25.00 

2N1562 

25.00 

2N6095 

/M9623 

12.00 

CA4101   (TRW) 

25.00 

2N2857 

1.55 

2N6096 

/M9624 

15.50 

CA4201   (TRW) 

25.00 

2N2857JAN 

2.55 

2N6097 

17.25 

CA4600   (TRW) 

25.00 

2N2876 

11.00 

2N6136 

21.85 

CD 1889 

20.00 

2N2947 

18.35 

2N6166 

40.25 

CD2545 

20.00 

2N2948 

15.50 

2N6201 

50.00 

CMD5I4AB 

20.00 

2N2949 

3.90 

2N6459 

18.00 

D4959 

10.00 

2N2950 

4.60 

2N6603 

12.00 

D4987M 

20.00 

2N3375 

8.00 

2N6680 

80.00 

D5147D 

10.00 

2N3553 

1.57 

2SC756A 

7.50 

D5506 

10.00 

2N3632 

13.80 

2SC781 

2,80 

D5827AM 

20.00 

2N38I8 

5.00 

2SC1018 

1.00 

DMD6022 

30.00 

2N3866 

1.30 

2SC1042 

1 2 .  00 

DMS-2A-25Q 

40.00 

2N3924 

3.35 

2SC1070 

2,50 

HEP76 

4.95 

2N392  7 

17.75 

2SC1239 

2,50 

HEPS 3002 

11.30 

2N3950 

25.00 

2SC1251 

12.00 

HEPS 3003 

30,00 

2N4072 

1-80 

2SC1306 

2.90 

HEPS3005 

10,00 

2N4127 

21.00 

2SC1307 

5.50 

HEPS 3006 

19,90 

2N4427 

1.30 

2SC1760 

1.50 

HEPS 3007 

25.00 

2N4428 

1.85 

2SC1970 

2.50 

HEPS 30 10 

11.34 

2N4957 

3.45 

2SC2166 

5.50 

HTEF2204  H.P. 

112.00 

2N4958 

2.90 

8B1087 

(M.A.) 

25.00 

5082-0112  H.P. 

14,20 

2N4959 

2.30 

A50-12 

20.00 

5082-0253  H.P. 

105.00 

2N5090 

13.90 

A283B 

5-00 

5082-0320  H.P. 

58.00 

2N5108 

4.00 

ALD4200N  (AVANTEK) 

395.00 

5082-0386  H.P. 

POR 

2N5109 

1.70 

AM123 

97-35 

5082-0401  H.P. 

POR 

2N5160 

3.45 

AM688 

100.00 

5082-0438  H.P. 

POR 

2N5177 

21.62 

BB1058 

.52 

5082-1028  H.P. 

POR 

2N5179 

1.00 

BD4/4JFBD4  (G.E.) 

10.00 

5082-2711  H.P. 

23.15 

2N5583 

4.00 

BFQ85 

1,50 

5082-3080  H.P. 

2.00 

2N5589 

8.65 

BFR90 

1.30 

5082-3188  H.P. 

1.00 

2N5590 

10,35 

BFR91 

1.65 

5082-6459  H.P. 

FOR 

2N5591 

13.80 

BFW92 

1.50 

5082-8323  H.P. 

FOR 

2N5635 

10.95 

BFX89 

1.00 

35826E  H.P. 

FOR 

2N5637 

15.50 

BFY90 

1.00 

35831E  H.P, 

29.99 

2N5641 

9.20 

BGY54 

25*00 

35853E  H.P. 

71.50 

2N5642 

10.95 

BGY55 

25-00 

35854E  H.P, 

75.00 

2N5643 

15.50 

BGY74 

25.00 

HPA0241  H.P. 

75.60 

2N5645 

13.80 

BGY75 

25.00 

HXTR3101  H.P. 

7.00 

2N5646 

20.70 

BL161 

10.  00 

HXTR3102  H.P. 

8.75 

2N5691 

18.00 

BLX67 

11.00 

HXTR6101/2N6617 

H.P. 55. 00 

2N5764 

27.00 

BLY568CF 

25.00 

HXTR6104  H.P. 

68-00 

2N5836 

5.45 

BLY87 

13.00 

HXTR6105  H.P. 

31.00 

2N5842 

8.00 

BLY88 

14.00 

HXTR6106  H.P. 

33.00 

2N5849 

20.00 

BLY89 

15.00 

QSCH1995  H.P. 

POR 

2N5913 

3.25 

BLY90 

20.00 

JO 2000  TRW 

10.00 

2N5922 

10.00 

ELY 351 

10-00 

J02001  TRW 

25.00 

2N5923 

25.00 

C4005 

20.  00 

JO4045  TRW 

25.00 

2N5941 

23.00 

CA402 

(TRW) 

25,00 

K3A 

10.00 

2N5942 

40.00 

CA405 

(TRW) 

25.00 

MA4  50A 

10.00 

2N5944 

9.20 

CA612B 

(TRW) 

25.00 

MA41487 

POR 

2N5945 

11.50 

CA2100 

(TRW) 

25.00 

MA41765 

POR 

2N5946 

19.00 

CA2113 

(TRW) 

25.00 

MA43589 

FOR 

2N6080 

9,20 

CA2200 

(TRW) 

25.00 

MA43636 

POR 

2N6081 

10.35 

CA2213 

(TRW) 

25.00 

MA47044 

FOR 

2N6082 

11.50 

CA2418 

(TRW) 

25.00 

MA47651 

25.50 

Toll  Free  Number 
800-528-01 80 
(For  orders  only) 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 

Q^/iGi\x  elect roi\ic§ 


73  Magazine  ■  August.1982     147 


"TRANSISTORS" 


WATKINS  JOHNSON  WJ-M62  3.7  to  4.2GHz  Communication  Band  Double  Balanced  Mixer 

SSB  Conversion  Loss  4.9dB  Typ.  6dB  Max.  fR  3.7  to  4.2GHz 

5.5dB  Typ.  6.5dB  Max.  fl  DC  to  1125MHz  fL  fR 

f 1  880MHz  fL  fR 
fR  3.7  to  4.2GHz 


$100. DO 


SSB  Noise  Fiqure 


Isolation 

fL  at  R 
fL  at  I 


4.9dB  Typ.  6dB  Max. 
5.5dB  Typ.  6.5dB  Max 

3DdB  Min.  40dB  Typ. 
25dB  Min.  30dB  Typ. 
20dB  Min.  30dB  Typ. 
15dB  Min.  25dB  Typ. 
ldB  Max. 


fl  30  to  1125MHz  fL  fR 
fl  880MHz  fL  fR 

fL  2.8  to  5.35GHz 
fL  4.5  to  5.35GHz 
fL  3.6  to  4.5GHz 
fL  2.8  to  3.6GHz 
fR  Level  +2dBm 


Conversion  Compression 

Flatness  -2dB  Peak  to  Peak  Over  any  40MHz  Segment  of  fR=3.7  to  4.2GHz 

Third  Order  Input  Intercept  +lldBm       fRl=4GHz  fR2=4.01GHz  Both  at  -5dBm  fL=4.5GHz 


Group  Time  Delay 

.5ns  Typ. 

.75ns  Max.  fR3.7  to 

4.2GHz 

fL  3480MHz         G  +13dBm 

VSWR 

L-Port 

1.25:1  Typ.   2.0:1 

fL 

2.8  to  5.35GHz 

R-Port 

1.25:1  Typ.   2.0:1 

fR 

3.7  to  4.2GHz  fL  fR 

1.4  :1  Typ.   2.0:1 

fR  3.7  to  4.2GHz  fL  fR 

I-Port 

1.5  :1  Typ.   2.0:1 

fl= 

^lOOMHz 

1.3  :1  Typ.   2.0:1 

fl= 

=500MHz 

1.8  :1  Typ.   2.5:1 

fl  = 

=1125MHz 

SGS/ATES  RF  Transistors 

Motorola  RF  Transistor 

Type. 

BFQ85 

BFW92 

MRF901           2N6603 

Collector  Base  V 

20v 

25v 

25v             25v 

Collector  Emitter 

V  15v 

15v 

15v              15v 

Emitter  Base  V 

3v 

2.5v 

3v              3v 

Collector  Current 

40ma 

25ma 

30ma            30ma 

Power  Dissipation 

200mw 

190mw 

375mw           400mw 

HFE 

40min.  200max.     20min.  150max. 

30min.  200max.     30min.  200max. 

FT 

4GHZ  min. 

5GHz  max.l.6GHz  Typ. 

4.5GHz  typ.       2GHz  min. 

Noise  Fiqure 

1GHz  3dB 

Max.      500MHz  4dB 

Typ. 

1GHz  2dB  Typ.     2GHz  2.9dB  Typ. 

Price 

$1.50 

$1.50 

$2.00           $10.00 

National  Semiconductor  Variable  Voltage  Regulator 

Sale  !!!!!!!!! 

LM317K 

LM350K 

LM723G/L 

LM7805/06/08/ 12/15/ 18/24 

1.2  to  37vdc 

1.2  to  33vdc      2  to  37vdc 

5,  6,  8,12,15, 18,24vdc 

1 . 5Amps 

3  Amps 

150ma. 

lAmp 

TO-3 

T0-3 

T0-100/T0-] 

116 

T0-220/T0-3 

$4.50 

^Dw  i b 

$1.00  $1.25 

$1.17  $2.00 

P  &  B  Solid  State  Relays  Type  ECT1DB72 


*May  Be  Other  Brand  Equivalent 

Toll  Free  Number 
800-528-0180 
(For  orders  only) 


5VDC  Turn  On    120VAC  Contact      7Amps 
20Amps  on  10"xlO"x.062"  Alum.Heatsink  with 
Silicon  Grease  $5.00 


cfM^Ijz  elect roiyc* 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


148     73Magazine  *  August.  1982 


=1 


"MIXERS" 


rtATKINS  JOHNSON  WJ-M6  Double  Balanced  Mixer 


LO  and  RF  0.2  to  300MHz 
Conversion  Loss  (SSB) 

Noise  Figure  (SSB) 

Conversion  Compression 


IF  DC  to  300MHz 
6.5dB  Max.  1  to  50MHz 
8.5dB  Max.  ,2  to  300MHz 
same  as  above 
8.5dB  Max.  50  to  300MHz 
.3dB  Typ. 


$21.00 

WITH  DATA  SHEET 


NEC  (NIPPON  ELECTRIC  CO.  LTD.  NE57835/2SC2150  Microwave  Transistor 
NF  Min  F=2GHz     dB  2.4  Typ. 


F=36H2 
F=4GHz 


dB  3.4  Typ. 
dB  4.3  Typ. 


MAG  F=2GHz 

dB  12  Typ. 

F=3GHz 

dB  9  Typ. 

F=4GHz 

dB  6.5  Typ 

$5.30 


Ft  Gain  Bandwidth  Product  at  Vce=8v,  Ic=10ma.   GHz  4  Min.  6  Typ. 
Vcbo    25v    Vceo    llv    Vebo    3v    Ic   50ma.  Pt.     250mw 


UNELCO  RF  Power  and  Linear  Amplifier  Capacitors 

These  are  the  famous  capacitors  used  by  all  the  RF  Power  and  Linear  Amplifier 
roanuf acturers ,  and  described  in  the  RF  Data  Book. 


5pf 

5.1pf 
6.8pf 
7pf 
8.2pf 


lOpf 
12pf 
13pf 

14pf 
15pf 


18pf 
22pf 
25pf 
27pf 
27 . 5pf 


30pf 
32pf 
33pf 
34pf 
40pf 


43pf 
51pf 
60pf 
80pf 
82pf 


lOOpf 
HOpf 
120pf 

130pf 
140pf 


200pf    1  to 

220pf  1 1  to 

470pf  51  up 
500pf 

loobpf 


lOpcs . 

50pcs. 

pes . 


$1.00  ea 
$  .90  ea 
$    .80   ea 


NIPPON  ELECTRIC  COMPANY  TUNNEL  DIODES 





Peak  Pt.  Current  ma. 
Valley  Pt.  Current  ma. 
Peak  Pt.  Voltage  mv. 
Projected  Peak  Pt.  Voltage  mv. 
Series  Res.  Ohms 
Terminal  Cap.  pf. 
Valley  Pt.  Voltage  mv. 


Ip 

Iv 

Vp 

Vpp 

rS 

Ct 

VV 


Vf=Ip 


MODEL  1S2199 
9inin.  lOTyp.  Umax. 
1.2Typ.  1.5max. 
95Typ.  120max. 
480min.  550Typ.  630max 
2.5Typ.  4max. 
1.7Typ.  2max. 
370Typ. 


1S2200   *7*50 

9min.  lOTyp.  Umax. 

1.2Typ.  l,5max. 

75Typ.  90max. 

440min.  520Typ.  600max. 

2Typ.  3max. 

5Typ.  8max. 

350Typ. 


FAIRCHILD  /  DUMQNT  Oscilloscope  Probes  Model  4290B 

Input  Impedance  10  meg.,  Input  Capacity  5.5  to  12pf.,  Division  Ration  (Volts/Div  Factor) 

10:1,  Cable  Length  4Ft.  ,  Frequency  Range  Over  100MHz. 

These  Probes  will  work  on  all  Tektronix,  Hewlett  Packard,  and  other  Oscilloscopes. 

PRICE   $45.00 


MOTOROLA  RF  DATA  BOOK 

List  all  Motorola  RF  Transistors  /  RF  Power  Amplifiers,  Varactor  Diodes  and  much  much 
more. 


PRICE   $7.50 


Toll  Free  Number 
000-528-0160 
(For  orders  only) 


q^L^\x  electronic* 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


73 Magazine  •  August,  1982     149 


"SOCKETS  AND  CHIMNEYS 


5J 


EI MAC  TUBE  SOCKETS  AND  CHIMNEYS 


SK110     Socket 

$  POR 

SK406     Chimney 

35.00 

SK416     Chimney 

22.00 

SK500     Socket 

330.00 

SK506     Chimney 

47.00 

SK600     Socket 

39.50 

SK602     Socket 

56.00 

SK606     Chimney 

8.80 

SK607     Socket 

43.00 

SK610     Socket 

44.00 

SK620     Socket 

45.00 

SK62QA     Socket 

50.50 

JOHNSON  TU8E  SOCKETS 

124-115-2/SK620A  Socket 

$  30.00 

124-116/SK630A   Socket 

40.00 

SK626 

SK630 

SK636B 

SK640 

SK646 

SK711A 

SK740 

SK770 

SK800A 

SK806 

SK900 

SK9Q6 


Chimney 

$  7.70 

Socket 

45.00 

Chimney 

26.40 

Socket 

27.50 

Chimney 

55.00 

Socket 

192.50 

Socket 

66.00 

Socket 

66.00 

Socket 

150.00 

Chimney 

30.80 

Socket 

253.00 

Chimney 

44.00 

124-113    Bypass  Cap. 
122-0275-001  Socket 
(For  4-250A,4-400A,3-400Z, 
3-500Z) 


$  10.00 

10.00 
2/$15.00 


CHIP  CAPACITORS 


.8pf 

lOpf 

lpf 

12pf 

l.lpf 

15pf 

1.4pf 

I8pf 

1.5pf 

20pf 

l.Spf 

22pf 

2.2pf 

24pf 

2.7pf 

27pf 

3.3pf 

33pf 

3.6pf 

39pf 

3.9pf 

47  pf 

4.7pf 

51pf 

5.6pf 

56pf 

6.8pf 

68pf 

8.2pf 

82pf 

lOOpf* 

llOpf 

120pf 

I30pf 

150pf 

160pf 

180pf 

200pf 

220pf* 

240pf 

270pf 

300pf 

330pf 

360pf 

390pf 


430pf 
470pf 
BlOpf 

560pf 

620pf 

680pf 

820pf 

1000pf/,001uf* 

1800pf/.0018uf 

2700pf/.0027uf 

10,000pf/.01uf 

I2,000pf/.0l2uf 

15,000pf/.015uf 

18,000pf/.018uf 


PRICES: 


I  to  10  -   .99c 

II  to  50  -  .90c 
51  to  100  -  .80c 


101  to  1000  .60c 
1001  &  UP    ,35c 


*  IS  A  SPECIAL  PRICE: 


10  for  $7.50 
100  for  $65.00 
1000  for  $350.00 


MTKINS  JOHNSON  WJ-V9Q7:  Voltage  Controlled  Microwave  Oscillator 


$110.00 


Frequency  range  3.6  to  4.2GHz,  Power  ouput,  Min.  lOdBm  typical,  8dBm  Guaranteed. 
Spurious  output  suppression  Harmonic  (nfo).  min.  20dB  typical,  In-Band  Non-Harmonic,  min. 
60dB  typical,  Residual  FM,  pk  to  pk,  Max.  5KHz,  pushing  factor,  Max.  8KHz/V,  Pulling  figure 
(1.5:1  VSWR),  Max.  60MHz,  Tuning  voltage  range  +1  to  +15volts,  Tuning  current,  Max.  -0.1mA, 
modulation  sensitivity  range,  Max.  120  to  30MHz/V,  Input  capacitance,  Max.  lOOpf,  Oscillator 
Bias  +15  +-0.05  volts  @  55mA,  Max. 


Toll  Free  Number 
800-528-01 80 

(For  orders  only) 


JVIGIJz  elect roqic$ 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


150     73 Magazine  •  August,  1982 


TYPE 


6BK4C 
6DQ5 

6FW5 

6GE5 

6GJ5 

6HS5 

6JB5/6HE5 

6JB6A 


TUBES 


PRICE 


TYPE 


PRICE 


TYPE 


6.00 

5.00 
6-00 
6.00 
6.00 
6.00 
6.00 
6.00 


6JM6 

6JN6 

6JS6B 

6KG6/EL505 

6KM6 

6KN6 

6LF6 

6LQ6    (GE) 


6,00 

6*00 
6,00 
6.00 
6.00 
6.00 
6»00 
6.00 


6LQ6  (Sylvanla) 

6LU8 

6LX6 

6ME6 

12BY7A 

12JB6A 

6KD6 

6JT6A 

6KD6 


PRICE 


2E26 

$   5. 69 

KT88 

$  20.00 

6562/6974A 

$  50.00 

2K28 

100,00 

DX362 

50,00 

6832 

22.00 

2X1000A 

300.00 

DX415 

50.00 

6883/8032A/8552 

7.00 

3B22 

19-75 

572B/T160L 

49.00 

6897 

110.00 

3B28/866A 

7.50 

592/3-200A3 

144,00 

6907A 

75.00 

3-500Z 

102.00 

807 

7.50 

6939 

15.00 

3-1000Z 

400.00 

811 

10.00 

7094 

125.00 

3CX1000A/8283 

428.00 

811A 

15,00 

7117 

17.00 

3CXI500A7/887 

533.00 

812A 

35.00 

7211 

60.00 

3X25O0A3 

200.00 

813 

50,00 

7289/3CX100A5 

34.00 

3CX3000A7 

490.00 

82  9B 

38,00 

7360 

11.00 

4-65A/8165 

45.00 

832A 

28 ,  00 

7377 

67.00 

4-125A/4D21 

58,00 

4624 

310.00 

7408 

4 .  00 

4-250A/5D22 

75.00 

4662 

80.00 

7650 

250.00 

4-400A/8432 

90.00 

4665 

585,00 

7695 

8.00 

4-400C/6775 

95.00 

5675/A 

25.00 

7843 

58.00 

4-1000A/8166 

300.00 

5721 

200.00 

7854 

83.00 

4B32 

22.00 

5768 

85.00 

7868 

5.00 

4E27A/5-125B 

155.00 

5836 

100.00 

7894 

12,00 

4CS250R 

146.00 

5837 

100.00 

8072 

65.00 

4X150A/7034 

30.00 

5861/EC55 

110.00 

8117A 

130.00 

4X150D/7035 

40.00 

5876A 

25.00 

8121 

60,00 

4X150G/8172 

100,00 

5881/6L6W 

6.00 

8122 

100.00 

4X2501 

30.00 

5893 

45.00 

8236 

30.00 

4CX250B/7203 

45.00 

5894/A 

50.00 

8295/PL172 

506.00 

4CX250F/G/8621 

55.00 

5894/B 

60.00 

8462 

100.00 

4CX250K/8245 

100.00 

5946 

258.00 

8505A 

73.50 

4CX250R/7580W 

69.00 

6080 

10.00 

8533W 

92.00 

4CX30OA/8167 

140.00 

6083/AX9909 

89.00 

8560/A 

65.00 

4CX350A/8321 

83.00 

6098/6AK6 

14.00 

8560AS 

90.00 

4CX350F/J/8904 

95.00 

6115/A 

110.00 

8608 

34,00 

4X500A 

282,00 

6146 

7.00 

8637 

38.00 

4CX600J/8809 

607.00 

6146A 

7.50 

8643 

100.00 

4CW800F 

625.00 

6146B/8298A 

8.50 

8647 

123,00 

4CX1000A/8168 

340.00 

6146W 

14.00 

8737/5894B 

60.00 

4CX1500B/866Q 

397.00 

6156 

66.00 

8873 

260,00 

4CX5000A/8170 

932 . 00 

6159 

15.00 

8874 

260.00 

4CX10000D/8171 

990.00 

6161 

233.00 

8875 

260,00 

4CX150QQA/8281 

1260.00 

6291 

125.  00 

8877 

533,00 

4PR60A 

100,00 

6293 

12,00 

8908 

12.00 

4PR60B/8252 

175.00 

6360 

5.00 

8930/651Z 

71.00 

4PR400A/8188 

192.00 

6524 

53.00 

8950 

12,00 

5CX1500A 

569.00 

6550 

10,00 

7.50 
6.00 
6.00 
6.00 
A.  00 
6.00 
6.00 
6.00 
6.00 


NOTICE  ALL  PRICES  ARE  SUBJECT  TO  CHANGE  WITHOUT  NOTICE  !  I  M  !  I  I  I  !  I  I  I!  I  !  !  tl  1  !  !  I  U  1 1 1  M  !  I  !  I  t  !  t  1 1 1 
TUBES  KAY  EITHER  BE  NEW  OR  SURPLUS  CONDITION  I  !!!!!!!!!!!!!!!!!  M  !!!!!!!!!!!!!!!  M  !!!!!!!  !l  !!  ! 


Toll  Free  Number 
800-528-0180 
(For  orders  only) 


oJVf Gljz  elect roqic$ 


PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


73 Magazine  ■  August,  1982     151 


TEKTRONIX  OSCILLOSCOPES 

MODEL  453  Porltbl*  SO  MHz 

Dual  Trace 

MODEL  4S3A  Porttblt  60  MHz 

Dual  Trace. 

MODEL  454  Porlibl*  150  MHz 

Dual  Trace. 

MODEL  454 A  Portable  150  MHz 
Dual  Trace. 

MODEL  455  Portable  SO  MHz 

Dual  Trace 

MODEL  475  Portable  200  MHz 
Dual  Trace 

MODEL  475A  Portable  250  MHz 
Dual  Trace 

MODEL  7514  Storage  Oscilloscope 
with  a  7A15A  and  a  7A15ANT1  Amplify 
and  a  7B50  Time  Base 

MODEL  577D1  Storage  Curve  Tracer 
with  a  177  adapter. 

MODEL  57702  Curve  Tracer 
with  a  177  adapter 

Tektronix  Lab  Cart  Modal  3 


PRICE 


SI 200.00 
$1400.00 

$1800.00 
$2000-00 
$1800,00 
$2640.00 
$2940.00 

$3500.00 

$3233.00 

$2796.00 
S  31600 


MODEL  547  50  MHz  Bench  Scope. 

With  a  1A1  Dual  Trace 

With  a  1A2  Dual  Trace 

With  a  1 A4  Quad  Trace 

With  a  1A5  Differential 

With  a  1A6  Differential 

or  with  1  of  each  above 

MODEL  545  30  MHz  Bench  Scope 
with  a  CA  Dual  Trace 
MODEL  545 A  30  MH*  Bench  Scope 
with  a  CA  Dual  Trace 


$  722.50 
$  637  50 
$  872,50 
1  72250 
$  612.50 
$1667  50 

$   412.50 

$  437  50 


MODEL  544  50  MHz  Bench  Scope 
with  a  CA  Dual  Trace. 

MODEL  543A  33  MHz  Bench  Scope 

wtlh  a  CA  Dual  Trace 

HEWLETT  PACKARD  OSCILLOSCOPES 

MODEL  160A  Main  Frame. 

MODEL  1B0E  Main  Frame, 

MODEL  181 A  Main  Frame. 

MODEL  182A  Main  Frame, 

MODEL  183A  Main  Frame. 

MODEL  160  SERIES  PLUG-INS 
1801 A  Dual  Trace  50  MHz. 

1803A  Dif  ferenhai 

1 804A  Quad  Trace  50  MHz 

1807 A  Dual  Trace  50  MHz 

1615A  TDR'Sampier  with  a  1616A  DC  lo  4 
GHz 

1821  ATime  Base  &  Delay  Generator 

l022ATime  Base  &  Delay  Generator 

1B31A  Direct  Access  600  MHz* 

i840ATime  Base  A  Delay  Generator  * 

1841 A  Time  Base  &  Delay  Generator  ■ 
*FoM83AOnly  >.! 

TELEQUIPMENT  MODEL  D83  Oscilloscope 

Dual  Trace  For iaD<e  50  MHz  With  a  V4  and  S2A  Pi ug-tn 

DUMONT  MODEL  1062  Oscilloscope 

Dual  Trace  65  MHz  portable. 

TEKTRONIX 

MODEL  RM565  Dual  Beam  Oscilloscope 

10  MHz  with  a  3A6  Dual  Trace  and  a  3A72  Dual  Trace  S1107.SQ 

MODEL  549  Storage  Oscilloscope 

Bench  50  MHz  witn  a  CA  Dual  Tface  $1000,00 

MODEL  647A  Oscilloscope 

Bench  100  MHz  with  a  T0A2  Dual  Trace 

and  a  1 1 B2A  Time  Base  S1 200,00 


I 


S  65O.S0 

%  47&.50 

PRICE 
S  675.00 
S  750,00 
SI  000,00 
S  900,00 
11000,00 

S  495.00 
S  775.00 
S  795.00 
$  375.00 

S1 500.00 
S  495.00 
S25.00 
20000 
450.00 


s 
s 

s 


S  575.00 


51200.00 


S  750.00 


ORDERING  INSTRUCTIONS 
DEFECTIVE  MATERIAL:  All  claims  for  defective  material  must  be  made  within  sixty  (60)  days  after  receipt  of 
parcel.  All  claims  must  include  the  defective  material  (for  testing  purposes),  our  invoice  number,  and  the  date 
of  purchase.  All  returns  must  be  packed  properly  or  it  will  void  all  warranties. 

DELIVERY:  Orders  are  normally  shipped  within  48  hours  after  receipt  of  customer's  order.  If  a  part  has  to  be 
backordered  the  customer  is  notified.  Our  normal  shipping  method  is  via  First  Class  Mail  or  UPS  depending  on 
size  and  weight  of  the  package-  On  test  equipment  it  is  by  Air  only,  FOB  shipping  point. 

FOREIGN  ORDERS:  All  foreign  orders  must  be  prepaid  with  cashier's  check  or  money  order  made  out  rn  U.S. 
Funds,  We  are  sorry  but  C.O.D.  is  not  available  to  foreign  countries  and  Letters  of  Credit  are  not  an  acceptable 
form  of  payment  either.  Further  information  is  available  on  request. 

HOURS:  Monday  thru  Saturday:  8:30  a.m.  to  5:00  p.m. 

INSURANCE:  Please  include  25«  for  each  additional  $100.00  over$10a00T  United  Parcel  only. 

ORDER  FORMS:  New  order  forms  are  included  with  each  order  for  your  convenience.  Additional  forms  are 
available  on  request, 

POSTAGE:  Minimum  shipping  and  handling  In  the  US,  Canada,  and  Mexico  is  $2.50  all  other  countries  is  $5.00. 
On  foreign  orders  include  20%  shipping  and  handling, 

PREPAID  ORDERS:  Order  must  be  accompanied  by  a  check. 

PRICES:  Prices  are  subject  to  change  without  notice. 

RESTOCK  CHARGE:  If  parts  are  returned  to  MHZ  Electronics  due  to  customer  error,  customer  will  be  held 
responsible  for  all  extra  fees,  will  be  charged  a  15%  restocking  fee,  with  the  remainder  in  credit  only.  All  returns 
must  have  approval. 

SALES  TAX:  Arizona  must  add  5%  sales  tax,  unless  a  signed  Arizona  resale  tax  card  is  currently  on  file  with 
MHZ  Electronics.  All  orders  placed  by  persons  outside  of  Arizona,  but  delivered  to  persons  in  Arizona  are  sub- 
ject to  the  5%  sales  tax. 

SHORTAGE  OR  DAMAGE:  All  claims  for  shortages  or  damages  must  be  made  within  5  days  after  receipt  of 
parcel.  Claims  must  include  our  invoice  number  and  the  date  of  purchase.  Customers  which  do  not  notify  us 
within  this  time  period  will  be  held  responsible  for  the  entire  order  as  we  will  consider  the  order  complete. 

OUR  800  NUMBER  rS  STRICTLY  FOR  ORDERS  ONLY 
NO  INFORMATION  WILL  BE  GIVEN.  1-800-528-0180. 


152     73 Magazine  •  August,  1982 


FAIRCHJLD 

95H90DC 

95H91DC 

11C90DC 

11C91DC 

11C06DC 

11  COS  DC 

11C01FC 
B2S90 


11C24DC 


11G44DC 


VHF  AND  UHF  PRESCALER  CHIPS 
350MC  Presca  ler  divide  by  10M 1 
350MC  Prescaier  divide  by  5/6 
650MC  Prescaler  divide  by  10/11 
650MCPrescaler divide  by  5/6 
UHF  Prescaler 750MC  D  Type  Flip  Flop 
1GHz  Counter  Divide  by  4 
(Regular  price  $75-00) 
High  Speed  Dual  5/4  input  NO/NOR  Gate 
PresettaDle  High  Speed  DecadeiBmary 
Counter  used  with  the  HC90/91  or  the 
95H90/91  Prescaler  can  divide  by  100, 
(Signeticsj 

This  chip  is  the  same  as  a  Motorola 
MC4024/4324  Dual  TTL  Voltage  Control 
Multivibrator. 

This  chip  is  the  same  as  a  Motorola 
MC4044J4344  Phase  Frequency  Detector 


PRICE 

S  8.50 

8.50 

15.50 

15.50 

12,30 

50.00 
15.40 


5,00 

3.37 
3.37 


GENERAL  ELECTRIC  CO,  GUNN  DIODE  MODEL  Y  2167 
Freq.  Gap  (GHZ)  12  to  18,  Output  (Win,)  l0QmvV\  Duty  (%) 
CW,  Typ,  Bias  (Vdc)  8.0,  Type.  Oper.  (MAdc)  550,  Max.  Thres. 
{mAdc)  1000,  Max,  Bias  (Vdc)  10.0,  $39.99 

VARIAN  GALLIUM  ARSENIDE  GUNN  DIODES  MODEL  VSX  9201 S5 
Freq.  Coverage  8  to  12  4GHz,  Output  {Mm  j  lOOmW,  Bias 
Voltage  (Max.}  I4vdc,  Bias  current  (mAdc)  Operating  550  Typ. 
750  Max..  Threshold  850  Tup.  1000  Max.  $39.99 

VARI-L  CO.  Inc.  MODEL  SS-43  AM  MODULATOR 

Freq  Range  60  10  f50MC.  Insertion  Loss  13dB  Nommal, 
S'gnaf  Port  imp.  50onms  Nominal,  Signal  Port  RF  Power 
+  tOdBm  Max.,  Modulation  Port  BW  DC  to  1KH2.  Modulation 
Port  Bias  1  ma.  Nominal.  124-99 


AVANTEKCASCADABLE 
MODULAR  AMPLIFIERS 


Model  UTO-504      UT0  511 


Frequency  Range 

5  to  500  MHz 

5  to  500  MHz 

Gain 

6dB 

15d8 

Norse  Figure 

11dB 

2  3dB  to  3dB 

Power  Output 

+  17dB 

*  2dB  to 
-3dB 

Gain  Flatness 

1dB 

tdB 

Input  Power  Vdc 

+  24 

+  15 

mA 

100 

10 

PRICE     170,00 

PRICE 

S75.00 

HEWLETT  PACKARD 
MIXERS  MODELS 

Frequency  Range 

Input/Output  Frequency  L  &  R 


Mixer  Conversion  Loss  {A) 

Noise  Performance  (SSB)  (A} 

(B) 
PRICE 


10514A 

2MHzto500MC 

200KHZ  to 

500MC 

DC  to  500MC 

7dB 

9dB 

?dB 

9dB 

$49.99       PRICE 


10514B 

2MHz  to 

500MC 

200KHZ  to 

500MC 

DC  to  500MC 

7dB 

9dB 

7dB 

9dB 

$39.99 


FREQUENCY  SOURCES.  INC  MODEL  MS  74X 

MICROWAVE  SIGNAL  SOURCE 

MS-74X:  Mechanically  Tunable  Frequency  Range  {MHz)  10630  to 

11230  (10.63  to  11.23GHz!  Minimum  Output  Power  (mW)  10,  Overall 

Multiplier  Ratio  108,  Internal  Crystal  Oscillator  Frequency  Range 

lMHz)9S4  to  104,0,  Maximum  Input  Current  (mA)  400. 

The  signal  source  are  designed  for  applications  where  h*gh  stability 
and  low  noise  are  of  prime  concern  these  sources  utilize  fundamen- 
tal transrstor  oscillators  with  high  O  coaxial  cavities,  followed  by 
broadband  stable  step  recovery  diode  multipliers,  Thrs  design 
allows  single  screw  mechanical  adjustment  of  frequency  over  stan- 
dard communications  bands.  Broadband  sampling  circuits  are  used 
to  phase  lock  the  oscillator  to  a  high  stability  reference  which  may 
be  either  an  internal  self-contained  crystal  oscillator,  external 
primary  standard  or  VHF  synthesizer  This  unique  technique  allows 
for  optimization  o'  both  FM  noise  and  long  term  stability  List  Price 
is  $1 158.00  iTHESE  ARE  NEW)  Our  Price— $289. 


HEWLETT  PACKARD  1N5712  MICROWAVE  DIODE 

This  diode  will  replace  the  MBD101,  1N5711,  50B2  2800, 

5082-2835  ect.  This  will  work  like  a  champ  in  all  those 

Down  Converter  projects  S1.50  or  10/S1CL00 

MOTOROLA  MHW1172R  LOW  DISTORTION 

WIDEBAND  AMPLIFIER  MODULE. 

Frequency  Range:  40  to  300  MHz..  Power  Gam  at  50MHz 

l6.6min.  to  17,4ma*.,  Gain  Flatness  ±0.1  Typ.  ±0.2 

Max.  dB    DC  Supply  Voltage  -  28 vdc,  RF  Voltage  Input 

+  70dBmV  PRICE  $29.99 

GENERAL  ELECTRIC  AA  NICAD5 

Model  #41B90SHD11-G1 

Pack  of  6  for  $5.00  or 60  Cells,  10  Packs  for  $4500 

These  may  be  broken  down  to  individual  cells 


ORDERING  INSTRUCTIONS 
TERMS:  DOMESTIC:  Prepaid,  COD.  or  Credit  Card 

FOREIGN:  Prepaid  only,  U,S,  Funds  — money  order  or  cashier's  check  only. 

C.CXD.:  Acceptable  by  telephone  or  mail.  Payment  from  customer  will  be  by  cash,  money  order  or  cashier's 
check.  We  are  sorry  but  we  cannot  accept  personal  checks  for  C.O.D.'s. 

CONFIRMING  ORDERS:  We  would  prefer  that  confirming  orders  not  be  sent  after  a  telephone  order  has  been 
placed,  If  company  policy  necessitates  a  confirming  order,  please  mark  "CONFIRMING"  boldly  on  the  order, 
If  problems  or  duplicate  shipments  occur  due  to  an  order  which  is  not  properly  marked,  customers  will  be 
held  responsible  for  any  charges  incurred,  plus  a  15%  restock  charge  on  returned  parts. 

CREDIT  CARDS:    WE  ACCEPT  MASTERCARD  VISA  AND  AMERICAN  EXPRESS- 
DATA  SHEETS:  When  we  have  data  sheets  in  stock  on  devices  we  do  supply  them  with  the  order. 


gM^ 


master  charge 


THE  Ml  f  MUM.  C*«0 


' 


VISA 


electronic*, 


f  48 


(602)  242-3037 
(602)  242-8916 

2111  W.  CAMELBACK  ROAD 
PHOENIX.  ARIZONA  85015 


Toll  Free  Number 
800-528-0180 

(For  orders  only) 

PRICES  SUBJECT  TO  CHANGE  WITHOUT  NOTICE 


— ^ 


*-S«  Ust  of  Advertisers  on  page  7 14 


73 Magazine  •  August,  1982     153 


r.  ii-^ij    the  first  name  in  Counters ! 


«lfp5 

CT«  mrad  1  tf  if  *  irnmf* 

ll.'H' 

CT-W  Kit  «0  d*t  pwli  »«f 

wiry 

|(M  M 

AC  1  AC  tdipiH 

.1  <*5 

BP  1   Nu-id  pick   -  M 

Adipiar.'  Chiljet 

u»s 

OV  I    h4icit>po*tf  finn 

Ultir  hilt 

4¥^ 

tilcmil  Urn  bin  iwpnf 

i*i»i 

9  DIGITS  600  MHz 


The  CT-90  it  the  most  vers  auk.  feature  packed  counter  Available  for  less 
than  $300.00"  Advanced  design  features  include  three  selectable  gate  timet, 
nine?  digits,  gale  indicator  and  a  unique  display  bold  function  which  holds  the 
displayed  count  after  the  inpm  signal  is  removed!  Also,  a  lOmHz  TC  XO  lime 
hase  is  used  which  enables  easy  zero  beat  calibration  checks  against  WWV. 
Op! junotly.  on  internal  niend  battery  pack  eMernal  time  base  input  and  Micro 
power  high  inability  crystal  over)  time  base  are  available  The  CT  **0. 
performance  you  can  count  on! 


$129^ 

^     "^  WIRED 


SPECIFICATIONS 


Rar-itc 
Sensiiivity. 

Resolution 


Display: 
Time  baser 

Power 


20  Hz  to  600  MHz 

Less  than  10  MV  to  1  50  MHz 

Less  than  50  MV  to  500  MHt 

0.1  Hi  (10  MHz  range* 

10  HUGO  MHz,  range) 

10.0  Hz  (600  MHz  range) 

9  digits  0.4"  LED 

Slandard-IOfJOO  mH?,  1,0  ppm  10-40*C. 

Optional  Micro- power  ovcn-0.1  ppm  20-4OaC 

8-15  VACtf  250  ma 


7  DIGITS  525  MHz  $99 


SPECIFICATION 


Range: 
Sensitivity" 

ResolutioTt 


Display: 
Time  baser 
Power 


20  Hi  to  525  MH* 

Less  than  50  MV  to  150  MHz 

Less  than  150  MV  to  500  MHz 

t.O  HH$  MHz  range) 

10.0  H*(50  M*f*  range) 

100.0  Hi  (500  MHz  range) 

7  digits  0  4    LED 

JO  ppm  TCXO20-40BC 

12  VACi«   250  ma 


WIRED 


The  CT-70  break  t  the  price  barrier  on  Lab  quality  frequency  counters 
Deluxe  features  such  ax  three  frequency  ranges  -  each  with  pre-  amplification, 
dual  selectable  gate  times,  and  gale  activity  indication  make  measurements  a 
snap.  The  wide  frequency  range  enables  you  to  accurately  measure  signals 
from  audio  thru  UKF  with  1 .0  ppm  accuracy  -  that's  000 1%\  The  CT-70  is 
the  answer  to  all  your  measurement  needs,  in  the  field,  lab  or  ham  shack. 


PRICES: 

CT-70  wired  1  year  warranty 
U  Kit,  90  day  ports  war- 
ranty 

AC  I  AC  adapter 
BP- 1  Nicad  pack  +  AC 
adapter/  charger 


S99.95 


7  DIGITS  500  MHz  $7955 


PRICESc 

MINI- 100  wired  I    year 

warranty  $79  95 

AC-Z  Ac  adapter  fc*  MINI- 

100  395 

BP  Z  Nicad  pack  and  AC 

adapter  t  charger  12  95 


Here  s  a  handy.  generaJ  purpose  counter  thai  provides  most  counter 
Functions  at  an  unbelievable  price.  The  MINI  100  doesht  h*>e  the  Full 
frequency  range  or  input  impedance  qualities  found  in  higher  price  units,  bul 
|br  basic  RF  signal  measurements,  n  can  t  be  beat?  Accurate  measurements 
can  be  made  from  1  MHt  all  the  way  up  to  5  00  MHi  with  excellent  sensitrvity 
throughout  the  range,  and  the  two  gale  times  let  you  select  the  resolution 
desired  Add  the  nicad  peck  option  and  the  MINI- 100  makes  an  idea]  addition 
so  your  tool  box  for  "in- the- fie  Jo"  frequency  cheeks  and  repaint 


WIRED 

SPECIFICATIONS: 

Range 

1  MHz  to  500  MHz 

Sonitrrity 

Less  than  25  MV 

Resolution: 

100  Hz  1  slow  gale) 

J  0  ILrfz  i  fast  gate) 

Display 

7  digiti*  0.4"  LED 

Time  base 

:0  ppm20-4gfC 

Power: 

5  VDC  *  200  ma 

8  DIGITS  600  MHz  $159 


WIRED 


SPECIFICATIONS: 


Range: 
Sensitivity 

Resolution 

Display 
Time  base 


20  Hi  to  600  MHz 

Less  than  25  rnv  to  150  MHz 

Less  than  150  mv  to  600  MHz 

1.0  Hi  (60  MHz  range) 

10  0  He  (600  MHz  range) 

8  dipts  0  4    LED 

2.0  ppm  2Q  40  C 

110  VAC  cell  VDC 


The  CT-50  is  a  versatile  lab  bench  counter  that  will  measure  up  to 600  MHz 
with  8  digit  precision.  And  one  of  its  best  features  is  the  Receive  Frequency 
Adapter  which  turns  the  CT-50  into  a  digital  readout  for  any  receiver  The 
adapter  is  easily  programmed  Tor  any  receiver  and  a  simple  connection  10  the 
receiver' t  VFO  is  all  that  is  required  for  use,  Adding  the  receiver  adapter  tn  no 
way  limits  the  operation  of  the  CT-50,  the  adapter  can  be  conveniently 
switched  on  or  ocT  The  CT- 5 0.  a  counter  that  can  wort  double-  duty* 


PRICES; 


CT-50  wired,  I  year  warranty 
CT-50  Kit  90  day  parts 
warranty 

RA-lr  receiver  adapter  kit 
RA-1  wired  and  pre-  program- 
med ( send  copy  of  receiver 
schemaiicJ 


Si  59,95 

119.95 

14.95 


DIGITAL  MULTIMETER  $99^IRED 


PRICES: 

DM-700  wired  1  year  warranty 

S99.95 

DM-700  Kit,  90  day  parts 

warranty 

79.95 

AC-L  AC  adaptor 

3.95 

BP-3.  Nicad  pack  +AC 

adapter/ cFiarger 

19.95 

MF-1.  Probe  sit 

2.95 

The  DM-700  offer*  pmfesatonal  quality  performance  at  a  huhbytft  price 
f  rarurea  include:  26  dtfrtrfru  ratajea  sod  5  finsntfCHit;  afi  stiasnajuJ  m  I 
umvrniirnt,  easy  To  use  formal  Measurements  arc  displayed  on  a  I arjje  3W 
ilifiti  Vi  inch  LED  readout  wirh  automatic  decimal  placement,  autnmatir 
palarirv.  ^verronge  indication  and  over  load  protect  ion  up  to  l25C3voLtson  all 
ranges,  making  ir  virtually  goof-proo I1  The  DM-700  Look*  ureal,  u  handsome, 
jet  Hack,  rugged  ARS  case  with  convenient  retractable  tilt  bait  makes  it  an 
ideal  addition  to  anv  sh^r 


SPECIFICATIONS: 

DC/ AC  volts. 

IOOuV  to  1  KV.  5  ranges 

DC/AC 

current 

0. 1  uA  to  2.0  Amps,  5  ranges 

Resistance 

0. 1  ohms  to  20  Megohms*  6  ranges 

Tnpui 

impedance 

10  Megohms.  DO  AC  volts 

Accuracy 

0.1%  basic  DC  volts 

Potter 

4  *C  ceils 

AUDIO  SCALER 

For  high  resolution  audio  measurements,  multiplier 
UP  in     Frequency 
■   Great  for  PL  tones 

•  Multiplies  by  10  or  100 

•  0,0)  Hz  resolution? 

$29  95  Kit       S39.95  Wired 


ACCESSORIES 

Telescopic  whip  antenna  ■  BNC  plug. . 
High  impedance  probe,  light  loading . 
Low  pass  probe,  for  audio  measurements 
Direct  probe,  general  purpose  usage 

Tih  bail  for  CT  70.  90.  MINT-IOO 

Color  burst  calibration  unit,  calibrates  counter 
against  color  TV  ugna! 


1  7  95 

15.95 

15,95 

12.95 

.      3  9$ 


COUNTER  PREAMP 


For  mraaurtna]  esiretnelv  weak  lignals  From  10  to  l.OOC 
MH:     Small  sere,  powered  b\  ptatf  transformer- in  eluded 

•  Fiat  25  db  gain 

•  BNC  Connectors 

•  Great  for  maffmg  RF  with  pick-up  loop 

13495  Kit      S44  95  Wired 


ramsey  electronic^,  inc.  i 

2575  Baird  Rd.  Penfield,  NY  14526     **62 


PHONE  ORDERS 

CALL  716-586-3W0 


I  H  M  S       So*iilot'  o«  gu^a^lfttf     uoiiimi  tin*  •  ©  rio*t     •■not  pleased 
*•*!* i«   in    afi^mnl  lerr*f  iw   »*Fu^d    Add  ** '      la'   *t*ipp.ng 

miurann  ffi  o  ">ni  mutri  o'  ( <  0  0**f|«Bt  add  k  h       COD  add 

11    O'diiiuidi'VlD     add  1  i   50    N  *  ■•.d.«rv  udd  T      «o, 


154     73  Magazine  •  August,  1982 


FOR  THE  BEST  DEAL 

WITH  OR  WITHOUT  TRADE-IN 


ON: 


•  KENW 

•  TEN-TEC 

•  HAL 

•  DRAKE 


•  ICOM 

•  INFO-TECH 

•  COLLINS 


DIAL  YOUR  DEAL  TOLL-FREE 


ALSO  CALL  FOR  PRICES  ON  AVAILABLE 

USED  EQUIPMENT 

WE  TRADE  ON  NEW  OR  USED 

->HAMRADIOXENI 

8340  42  Ohve  Blvd  »   P.O.  Box  28271  •  St.  Louis.  MO  63132 


IN  MISSOURI  CALL 


1-314-993-6060 


MasterCard 


ftJCif 

ELECTRONICS 


FULL  LINE  ALL  PARTS  &  COMPUTER  PRODUCTS 


60  P.O.  Box  4430M 

Santa  Clara,  CA  95G54 

Will  calls:  2322  Walsh  Ave. 
(408)  933-1640 

Same  day  shipment.  First  line  parts  only.  Factory  tested.  Guaranteed 
money  hack,  Quality  IC's  and  other  components  at  factory  prices. 

INTEGRATED  CIRCUITS  Phone  orders  only  (800)  538-B196 


JtDDTTl 

MMN  tg 

7*39N  19 

ft-\m  55 

7MDN  19 

T45DN  19 

r«3Kl  49 

?«5N  BE 

7WN  BS 

74+aN  &S 

^MH  35 

WSN  49 

F«8fl  1.7D 

WON  35 

74B6H  55 

741DON  T  :n 

74!ffFK  39 

M23N  55 

74125N  .*5 

741*Sh  ,tf 

■■ilMN  1.20 

741S1N  .85 

741  SIN  l.» 

7415?U  .a 

74 161 N  7D 

741KN  B5 

745S3H  B5 

74J7+I*  H9 

T4t75lg  .15 

7^90W  1.15 

mm  fi 

7*123 'N  1.25 

742601  .45 

/43H4  .65 

TWW  65 

T43S7N  .84 

M.SOON  » 

74L&02N  2S 

74L5WN  .25 

ML5WH  K 

,'as&su  35 

74L&HH  25 

74I.MJ*  45 

74LS.S4JJ  gy 

74LS20M  .25 

7tl.SJ?N  25 

74LSSSN  .3i 

74LS3CW  .25 

7*L55JH  55 

74L53&9  35 

T41S74W  i?5 

/4LS7S9)  M 

74139*  .50 

745.593*  55 

74t5HT7«  40 

74LSIT2W  M 

74LS1fW  « 

74L512W  FS 

74i5t3&M  .45 

f4LS15lN  ?-: 

74LS155N  .79 

^LS15?N  R 

T4L$in2N  .K 

7*1.51  fi]N  94 

MLSl7*N  85 

;tL&l3DN  I  DC: 

74L&2J1N  t.r9 

.'4LB25BN  .89 

74LS357M  BJ 

-  h.#t- 

Cr£0*5  .Bfl 

CAJWfl  1  10 

CA3Q61  I.Bfl 

CA3062  l.atl 

CAJOM  3  40 
lM-wiavah  .3* 

I  mow  a? 

LteJWN  .35 

WORN  88 

li-j^wk  t  as 

LIM11H-N  54 


LW31ZT  155 

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Apple  Pe  rich  era  I  Kits 

SERIAL  I/O  INTERFACE     0  to  30,000  baud, 

D.T.R.r  input  &  QUtput  from  monitor  or  basic,  or 

use  Ap pie  as  intelligent  terminal.  Bd  only  (P/N  2) 

$14.95,  Kit  fP/N  2AJ  S&tzs,  Assembled  {P/N 

ZC)  *62J5, 

PflOTOTYPiMG  BOARD    (P/N  7907)  $21.35, 

PARALLEL  TRIAC  OUTPUT  BOARD    a  triacs. 

each  tan  switch  110V,  6 A  loads h  Bd  only  (P/N 

210)  $13.20,  Kit  (P/N  21  DAI  S119.&5. 

APPLE  II  GAME  PADDLES  Adam  and  Eve  $38,00, 

SERIAUPARALLEL  INTERFACE  Bidirectional, 
Baud  rates  from  HO  to  19. 2K,  sw  selectalile 
polarity  of  input  and  output  sirohe,  5  to  8  data 
hits,  1  or  2  stop  bits,  parity  odd  or  even  or  rone, 
all  characters  contain  a  start  bit,  +5  &  -12V 
reqifircd.Bd  only  (P/N  101)  SlU5r  Kit  (P/N 
I01A)S42,69. 

RS-23Z/TTL  INTERFACE    Bidirectional,   re- 
quires ±12V,  Kit  (P/N  232AJ  $9.95. 
RS-232/20mA  JNTEREAGE    Bidirectional.   2 
passive  opto-isolatad  circuits,  Kit  (P/N  7901  A) 
S14.W, 

PROM  Eraser 

Will  erase  Z5  PROMsin  15  mmut&s.  Ulti-aviDlet. 
assembled.  25  PROM  capacity  $37.50  (with 
timer  S59.5D).  6  PROM  Capacity  QSHA/'UL  ver- 
sion $63.00  (with  timer  5119,00) 

Z3Q  MicroProfessor  S149.00 

Single  board  computer.  Learning,  teaching,  pro- 
totyping. 2K  RAM,  keyboard,  displays;  cassette 
interface  Tiny  BASIC  $19.00.  All  fully 
assembled. 


Z80  Microcomputer  Kit  $69. DO 

16  bit  l/CL  2  MHz  dock,  2K  RAM.  ROM  Bread- 
board space.  Excellent  for  control.  Bare  Board 
$28.50,  Full  Kit  $79.00,  Monitor  $20.00.  Power 
Supply  Kit  $35,00,  Tiny  Basic  S3HO0, 

Modem  Kit  £60.00 

Slate  of  the  art,  orig. ,  an&wer.  No  tuning  neces- 
sary. 103  compatible  300  baud.  Inexpensive 
acoustic  coupler  plans  included.  8tf  only 
$17.00,  Article  in  June,  July,  Aug.  Radio 
Electronics,  19B1. 

60  Hz  Crystal  Time  Base  Kit  $4.40 

Converts  digital  clocks  from  AC  line  frequency  to 
crystal  lime  base  Outstanding  accuracy. 

Video  Modulator  Kit  $9.95 

Convert  TV  set  into  a  high  quality  monitor  w«'o 
affecting  usage.  Comp  kit  w/full  tnstruc. 

Multi-volt  Computer  Power  Supply 

6v  5  amp,  ±1Bv  5  ampH  5v  1.5  amp,  -  5v 
5  amp,  12v  .5  amp,  -12v  notion,  ^5v,  x12v 
are  regulated  Basic  Kit  $35.95.  Kit  with  diassis 
and  all  hardware $51.95.  Add  IS.  00 shipping.  Kit 
of  hardware  $16,00,  Woodgrain  case  S1D.DD. 
SI  50  shipping. 

Type-N-Talk  by  Votrax 

Text  to  speech  synthesijerwith  unfimitedvocab-u- 
lary,  built-in  text  to  speech  algorithm.  70  to  100 
nits  per  second  speech  synthesizer,  RS232C 
interface  $359.00.  Speech  I C  $72.00. 

Direct  Connect  Modem  $99  JO 

Fully  assembled  in  case  with  RS232  cable. 
Ortg/answer,  103  compatible.  9V  battery  or 
wall  pi  ug 


INTRODUCING  A  BRAND  NEW  MICROCOMPUTER 


BfttrtftK4> 


VENTURE  is  a  single 
board  computer  that  Is  an 
adventure  for  the  hobbyist.  It 
is  a  learning,  training  com- 
puter as  well  as  just  plain  fun 
for  anyone  wno  wants  to  get 
Kito  a  state-of-the-art  com- 
puter at  reasonable  cost. 

VENTURE  comes  in  kit 
form  or  hilly  assemhled  and 
tested.  >bu  can  get  It  in  its 
minimum  configuration  tor 
as  little  as  $1%.00  or  take  it  all  the  way  to  floppy 
disks  and  voice.  It  can  be  expanded  as  a  kit  or  fully 
assembled,  at  your  own  pace  and  choice 

VENTURE  Is  a  16"  by  20"  main  board  with 
separate  ASCII  and  HEX  keyboards,  tt  runs  fast. 
almost  4  MHz,  and  has  the  capability  of  putting 
almost  1  megabyte  of  RAM  and  ROM  on  the  board 
along  wifli  a  variety  of  inexpensive  options. 

A  16-channel  analog-to-dtgitai  converter  aliows 
use  of  joysticks,  control  functions.,  instrumenta- 
tion, temperature  sensing,  etc.  T1  sound 
generator,  software  controlled  music,  Votrax 
voice  synthesizer  and  real  lime  clock  calendar  add 
to  its  versatility. 

A  standard  &0-pin  bus  with  5  slots,  parallel 
ports  and  2  serial  ports  witfi  full  handshaking  [75 
to  9600  BAUD)  allow  expansion  into  floppy  disks, 
calor.EPROM  programmer  printer,  modem  of  your 
choice.  Later  expansion  will  add  a  light  pen,  a 
universal  user  programmable  music  sound  board. 
General  Purpose  Instrument  Bus,  and  a  high 
resolution  color/grayscale  pixel  mapped  video 
board. 

VENTURE  connects  directly  to  a  monitor  or  to 
your  TV  set  through  an  RF  modulator.  And  now  for 
tne  heart  of  VENTURE  .  .  .  its  video  display.  VEN- 
TURE bas  a  high  resolution  programmable  video 
display  with  up  to  4096  user-defined  characters, 
alphanumeric  symbnlsr  special  graphics  or  ob- 
jects, sucn  as  space  ships,  etc  Each  character  is 
8  pixels  wide  by  15  pixels  high,  with  2  grayscale 


WUt'MHurt* 


maps;  it  bgs  64  levels  of 
grayscale  plus  video  in- 
vert/co-mpliment  end  hidden 
screen  update  for  a  "sriow" 
tree  display.  Tbe  display  is 
512x512  pixel  mapped  with 
2  planes  of  video  RAM  per 
display.  VENTURE  video  is  in 
short    .  .  astounding! 

VENTURE  has  complete 
software  support  with  full 
BASIC,  3  ROM  monitors, 
disassernbier/assem bier/editor,  It  will  run  real- 
time video  names,  all  RCA  chip  8  programs  and  all 
current  Quest  1602  software.  VENTURE  DOE  will 
accommodate  up  to  three  SVr  double  density 
floppies.  A  complete  1602  programming  book  is 
available.  All  versions  of  VENTURE  are  snipped 
with  a  set  of  manuals  wrrtten  to  be  understood  by 
the  inexperienced  as  well  as  experienced  user. 
On-Buard  Options 

16  channel  A  to  D;  5  slot  60  pin  hus,  2  serial 
ports,  parallel  ports;  3  video  options,  4BK  RAM, 
Votrax  voice  synthesizer,  sound  generator. 
EPROM;  full  BASIC  disassembler,  editor,  assem- 
bler; metal  cabinet,  additional  power  supply, 
ASCII  keyboard  real  time  clock  calendar. 
Expansion  Options 

Floppy  disk.  EPROM  programmer,  light  pen, 
universal  user  programmable  music,  sound  board 
hicjh  resolution  coloRgrayscale  pixel  mapped 
video  board,  General  Purpose  Instrument  Bus, 
Minimum  VENTURE  System  $195,00 
Kit  includes  CPU  and  control  with  4K  of  RAM.  1K 
of  scratchpad.  2K  monitor,  1861  video  graphics, 
cassette  interface  and  separate  HEX  keyboard 
with  LEO  displays  for  address  and  output.  Power 
supply  h  included  along  with  2  game  cassettes. 
The  main  board  is  16"  x  20"  and  includes  space  for 
all  of  the  previously  discussed  on-board  options. 
Full  on-board  expansion  can  be  completed  for 
under  S1&D0  00.  Gall  for  rurtner  details,  option 
prices,  etc. 


RCA  Cosmae  1802  Super  Elf  Computer  $106.95 


The  Super  Elf  is  a  tremendous  value  as  rt  combines 
video,  digital  displays,  LED  displays,  and  music, 
all  on  a  single  board  for  $106.95 

The  Super  Erf  expansion  capability  is  virtually  un- 
limited and  you  can  do  it  inexpensively  one  step  at 
a  time.  Expansion  includes  casstte  interface,  addi- 
tional memory,  color  video,  Basic,  ASCII  key- 
board, printer,  floppy,  S-iOO  bus,  RS232,  etc 

The  Super  Elf  comes  complete  with  power  supply 
and  detailed  127  page  instruction  manual  which 
includes  over  40  pages  of  software,  including  a 
series  of  lessons  to  help  get  you  started  and  a 
music  program  and  graphics  target  game.  Many 
schools  and  universities  are  using  the  Super  Elf  as 
a  course  of  study.  OEM's  use  il  lor  training  and 


R&D.  A  monthly  newsletter,  Questdata  is  devoted 
exclusively  lo  software  for  the  Super  Erf  and  there 
are  many  software  books  available  at  low  cost 

The  Super  Elf  computer  system  is  now  available  as 

a  series  of  bare  boards  as  weil  as  full  kits  and 

assembled. 

Bare  Boards:  Super  Elf  $35.00.  Super  Expansion 

$35.00.  Power  Supply  $10.00,  S-100  Color 

$35.00.  Dynamic  RAM  $40  00  Manuals  $10. 00. 

Super  Basic  $45.00. 

Free  14  Page  Brochure 

Send  or  call  for  a  free  brochure  on  all 
details  and  pricing  of  the  Super  Elf  and  its 
expansion  We  will  get  it  right  out  to  you! 


Quest  Super  Basic  V5,0 

A  new  enhanced  version  of  Super  Basic  now 

available  Quest  was  the  first  company  worldwide 
to  ship  a  lull  size  Basic  for  1602  Systems.  A 
completf]  function  Super  Basic  by  Ron  Cenker 

including  floating  point  capability  with  scientific 
noMtion  (number  range  t  17E]B).  32  hit  integer 
t2  billion;  multi  dim  arrays,  string  arrays,  siring 
manipulation,  cassette  I/O.  save  and  load,  basic. 


data  and  machine  language  programs;  and  over 
75  statements,  functions  and  operations. 
New  improved  laster  version  m eluding  re- 
number and  essenki  v  unlimited  variables. 
Also,  an  exclusive  usur  expandable  command 
ftbrary 

Serial  and  Parallel  I; a  routines  included 
Super  Basic  an  Cassette  $45.00. 


Rockwell  AIM  65  Computer 

6502  based  single  board  with  full  ASCII  keyboard 
and  20  column  thermal  printer,  20  char,  alphanu- 
meric display  ROM  monitor,,  fully  expandable. 
$419.00.  4K  version  $43B,Q0,  4K  Assembler 
$29.00.  8K  Basic  Interpreter  $59,00. 

Special  small  power  supply  5V  2 A  24V  .5A 
assem.  in  frame  $59,00.  Molded  plastic 
enclosure  to  fit  both  AIM  65  and  powei  supply 
$52.50.  AIM  65  IK  in  cabinet  with  power  supply, 
switch,  fuse,  cord  assem.  $546.00.  4K  $565.00, 
AB& 40-5000  AIM  65/40  w  16K  RAM  and  monitor 
$1295,00.  RAM  Board  Kit  (16K,  $195)  (32K, 
$215).  vD64fl  Video  Interface  Kit  $119,00.  A&T 
$149.00.  Complete  AIM  65  in  thin  briefcase  with 
power  supply  $507 .00.  Special  Package  Price:  4K 
AIM,  9K  Basic,  power  supply,  cabinet  $590.00 

AIM  65/KIM/SYM/Super  Elf  44  pin  expansion 
board;  board  with  3  connectors  $22,95.  'Send 
for  complete  list  of  all  AIM  products. 


fl***^. 


Elf  II  Adapter  Kit  $24.95 

P  lug  s  i  nto  E  If  1 1  provid  in  g  Super  Elf  44  and  50  pin 
plus  S-100  bus  expansion.  (With  Super  E^ 
pansion}.  High  and  low  address  displays,  state 
and  mode  LED's  optional  $10.00. 


Super  Color  S-100  Video  Kit  $99.00 

Expandable  to  256  x  192  high  resolution  color 
graphics.  6647  with  all  display  modes  computer 
controlled.  Memory  mapped.  IK  RAM  expand- 
able to  6K,  S-100  bus  1B02,  BQBO.  80B5,  Z80, 
etc  Dealers:  Send  for  excellent  pricing; margin 
program. 


TERMS:  $5.00  min.  order  U.S.  Funds.  Calif,  residents  add  6%  tax,  prices 

$10.00  min.  VISA  and  MasterCard  accepted.  $1.00  insurance  optional.         subject 
Shipping:  Add.  5%;  orders  under  $25.00 — 10%.  to  change 


FREE:  Send  for  your  copy  ot  our  NEW  1982 
QUEST  CATALOG.  Include  88?  stamp. 


156     73 Magazine  •  August,  1982 


•  LINKS     •  REPEATERS     •  TRANSMITTERS  QUALITY     VHF/UHF     KITS 

RECEIVERS     •  PREAMPS     •  CONVERTERS  AT  A  CCADHADI    C  DDI^CC 

•  TRANSCEIVERS  •  POWER  SUPPLIES  ""    "  *"  "  —  ■•«**      —   UM-.     — ^ 


AT  AFFORDABLE  PRICES 


FM-5  PC  Board  Kit -ONLY  $159.95 
complete  with  controls,  heatsink,  etc. 


SAVE  A  BUNDLE  ON 
VHF  FM  TRANSCEIVERS! 

1 0  watts,  5  Channels,  for  6M,  2M,  or  220 


* 


*6fc 


&!*•  -<*° 


H/GW  QUALITY  FM  MODULES  FOR 
REPEATERS,  LINKS,  TELEMETRY,  ETC. 


R7S  VHF  FM  RECEIVER  for  10M,  6M, 
2M,  220.  or  commercial  bands.  Fantastic 
selectivity  options.  Kits  from  $84.95  to  Si  09,95 

R450  UHF  FM  RECEIVER  for 380-520  MHz 
bands.  Kits  in  selectivity  options  from  $94.95 

R1 1 0  VH  F  AM  RECEIVER  Kit  for  vtif  aircraft 
band  or  ham  bands.  Only  584.95. 


COR  KITS  With  audio  mixer  and  speaker 
amplifier.  Only  S29.95. 

CWID  KITS  158  bits,  field  programmable, 
Clean  audio.  Only  S59.95. 

A1 6  RF  TIG  HT  BOX  Deep  drawn  alum,  case 
with  tight  cover  and  no  seams.  7x8x2  inches. 
Only  S18.00. 

SCANNER  CONVERTERS  Copy  72-76, 
1 35- 1 44, 240-2 70f  400-420t  or S06-894  MHz 
bands  on  any  scanner  Wired/tested  Only  $79.95, 


T51  VHF  FM  EXCITER  for  10M,  6M,  2M, 
220  M  Hz  or  adjacent  bands.  2  Watts  contin- 
uous. Kits  only  S54„95. 

T451  UHFFM  EXCITER  2  to  3  Watts  on  450 
ham  band  or  adjacent.  Kits  only  $64.95. 

VHF  &  UHF  LINEAR  AMPLIFIERS.  Use  on 

either  FM  or  SSB.  Power  levels  from  1 0  to45 
Watts  to  go  with  exciters  &  xmtg  converters. 
Kits  from  $69,95, 


VHF      &      UHF      RECEIVER 

PREAMPS.  Low  noise. 


VHF&UHFTRANSMtTniMG  CONVERTERS      VHF  &    UHF   RECEIVING  CONVERTERS 


For  SSS,  CW,  ATV,  FM,  etc.  Available  for  GM,  2Mt 
220, 440  with  many  IF  input  ranges.  Converter  board 
kit  only  at  £79,95  (VHF)  or  $99.95  (UHR  or  kits 
complete  with  PA  and  cabinet  as  shown. 


20  Models  cover  every  practical  rt  and  if  range  to 
listen  to  SSB,  FMT  A7V,  etc.  on  6M,  2M,  220, 440r  and 
110  aircraft  band.  Even  convert  weather  down  to  2M! 
Kits  from  $39.95  and  wired  units. 


VHF  Kits  from  27  to  300  MHz.  UHF 
Kris  from  300  to65G  MHz.  Broadband 
Kits:  20*650  MHz.  Prices  start  at 
SI 4,95  (VHF)  and  $18.95  (UHF).  AH 
preamps  and  converters  have  notse 
figure  2dB  or  less. 


Call  or  Write  for  FREE  CATALOG 

(Send  $1.00  or  4  IPC's  for  overseas  MAILING) 
Order  by  phone  or  mail  •  Add  $2  S  &  H  per  order 

(Electronic  answering  service  evenings  &  weekends) 
Use  VISA,  MASTERCARD,  Check,  or  UPS  COD. 


S&e  Ltst  of  Advertisers  orr  pjge  1 14 


amiromcs,  inc. 

65-RMOUL  RD.  •  HILTON  NY  14468 

Phone:  716-392-9430  ^33 

Hmmtronics'  is  a  nsislerett  trademark 


73Magazine  *  August,  1982     157 


•  ••GO^MUNICimONS 


•  • 


PHONE  HOURS:  8  am-5  pm  CDT  Mon.-Sat. 

•  SPECIALS  OF  THE  MONTH  * 


a  MIRAGE  £ 
C22 


i:  J  XL.  SX-100  * 

SPECIALLY  PRICED 
AT  ONLY  $199.95 


2W  IN  -  20 W  OUT 

FEATURES: 

•  All-mode  SSB,  FM  and  CW 

•  Small  Size 

•  Automatic  antenna  change  over 


Frequency  Range  , , 220  to  225  MHz 

RF  Power  In  ..,....,,..  200  mu/  to  5  Watts 

RF  Power  Out  30  Watts  (2  in  -  20  out) 

Modes ...*«..*.„  SSB.  FM  and  CW 

DC  Power  >, ......  13,6  VDC  5  Amps 

Warranty  .  *  5  years  (1  year  RF  Power  Trans.) 


-  - 


tc  J.I.L.  SX-200  * 

TYPE:  FM  &  AM 

FREQUENCY  RANGE:  a)  26-57,995  MHz  Freq  Space  5kHz: 
b}  58*88  MHz  Space  12.5  kHz:  d  108*180  MHz  Space  SkHc 
d)  380-514  MHz  Space  12,5  kHz 

SENSITIVITY:  FM  a)  26*180  MHz  0.4  uV  S/N  12  dB 
b)  380-514  MHz  LOuV  S/N  12  dB  AM  a)  26-180  MHz 
l.OuV  S/N  dB  b)  380-514  MHz  2  OuV  S/N  10  dB 
SELECTIVITY:       FM  .  . .  More  than  60  dB  at  +25  kHz 

AM  .  . .  More  than  60  dB  at  + 10  kHz 

SUPER  VALUE  FOR  ONLY  $389.95 


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RAMSEY 

ELECTRONICS 
"V  Inc. 


PARTS  WAREHOUSE 


We  now  have  avaMabfe  a  bunch  of  goodies  too 
good  to  bypass     Items  are  limited  so  order  today 


2575  Baird  Rd. 

Penfield,  NY  14526 

716-586-3950 


MINI  KITS  -  YOU  HAVE  SEEN  THESE  BEFORE  NOW 

HERE  ARE  OLD  FAVORITE  AND  NEW  ONES  TOO. 

GREAT  FOR  THAT  AFTERNOON  HOBBY. 


FM 

MINI 

MIKE 


A  super  htgh  perl q* mane?  FM  wire- 
less mi*e  kit1  Transmits  a  stable 
sign* J  up  to  300  yards  *<im  eieep- 
fional  audio  qua  Fit  y  by  means  of  its 
built  in  elect  re  I  mike  Kil  includes 
Cat*,  mike,  Oft-Cfl  switch.  anlcnna 
battery  and  super  instructions  This 
i?,  iht  finest  urni  Available 

fM-3  Kit  $14  95 

FMO  W"ed  ano  Tested  1».M 


Color  Organ 

See  music  come 
ahvef  3  different 
lights  flicker  with 
music  One  light 
each  for.  high. 
mid-range  and 
lows  Each  indi- 
vidually adjust- 
able and  driven  up 
to  300  W  runs  on 
110  VAC 

Complete  kit. 
ML-1 
$895 


Video  Modulilof  Kll 
Converts  any  TV  10  wideo  monitor    Super 
stable    tunj&l*  over  ch   4  6     flmns  on  5- 
15V.  aeeaou  tld  videosi^nal   BBstunnon 
lbiF  marlM*!1    Compare  kit   VD-1  $7.9S 


Led  Bilnk y  Kit 
A  great  attention  get- 
ter which  alternately 
Bashes  2  jumbo  LEDs 
Use  for  name  badges, 
buttons     warning 
panel  lights,  anything1 
Runs  On  3  to  15  volts 
Complete  kit.  BL-1 
I3.M 


Super  Sieulh 
A  Super  sensitive  ampli- 
fier whrch  will  pick  up  a 
pin  drop  at  i5  feef  Great 

lor  moAJtortno,  oaoy  * 
mom  or  as  general  pur* 
pose  ampi*he*  Fufl  2  W 
mis  Outpul  nuns  on  G  to 
15  volts  uses  6-45  ohm 
speaker 
Complete  kil,  BN-9 

$5.95 


CPO-1 

Runs  on  3*12  Vdc  1  wall  oul   t  KHZ  pood  "or  CPO 

Alarm  Audio  Oscillator     Complete  kil  $2.95 


Call  Your  Phone  Order  in  Toddy 
TERMS-  Satisfaction  guaranteed  or  money 
refunded  C  O.O.  add  S2  00  Minimum  order 
$6.00  Orders  under  $1000  add  Si  50.  Add  5*  s 
for  postage,  insurance,  handling.  Overseas 
add  15%  NY  resKSenrs  add  7%  tax. 


CLOCK  KITS 

Your  old  favorite*  are  here  again.   Over  7,000  Sold  to  Dale, 
Be  one  of  the  gang  and  order  yours  today' 

Try  your  hand  ai  building  the  finest  looking  clock  on  the 
market  Its  satin  finish  anodized  aluminum  case  looks  great 
anywhere,  white  sue  4'"  LED  digits  provide  a  highly  readable 
display  This  is  a  complete  kit.  no  extras  needed,  and  it  only 
takes  1-2  hours  to  assemble  Vour  chojee  of  case  colons 
stiver,  gold,  black  (specify). 

Cloe*  kit,  12/24  hour,  DC-5  $24.95 

Clock  with  10  mm    ID  timer,  T2/24  hour.  DC-10  $29.95 

Alarm  clock,  12  hour  only,  DC-6  $29.95 

12V  DC  car  clock,  DC- 7  $29.95 

For  wired  and  tested  clocks  add  510  00  to  kit  price, 
SPECIFY  12  OR  24  HOUR  FORMAT 


FM  Wlrelei*  Mike  Mil 

Transmits  up  to  300"  to 
any  FM  broadcast  ra- 
dio   uses  any  type  of 

mike    Runs  on  3  to  9V 

has  added   sensitive   nuke   preamp 

stag? 

FM-1  kii    $3  95  FM-2kit     $4  95 


Type  FM-2 


Whisper  Light  Kit 

An  interesting  kit    small  mtke 
picks  up  sounds  and  converts 
them  to  fight     The  louder  the 
sound    the  brighter  the  fight 
Includes  mike,  controls  up  to 
300  W,  runs  on  110  VAC 
Complete  kit.  WL-1 
$6.95 


Univertal  Timer  Kit 

Proves  T^e  basic  parts  and  PC 
board  required  to  provide  a  source 
Of  precision  tirrung  and  pulse 
generation  Uses  555  timer  IC  flnd 
includes  a  range  of  parts  for  most 
Inning  needs 

UTS  Kil  $5  95 


Mad  Blaster  Kit 

Produces  LOUD  ear  ah  altering  and 
attention  getting  siren  like  sound 
Can    supply    up    to    tS    watts    Of 

octnoxious  audio   Runs  on  6-15  VDC 


Tone  Decoder 

A  complete  tone  deco- 
der   on    a    s«ng'e    PC 
ooard    Features    400- 
5000     Hi     adjustable 
range  vie  20  turn  pot.  voltage fegu- 
I  at  ion.  56?  IG     Useful  for  touch- 
tone    burst   detection     FSK.  etc 
Can  also  be  used  as  a  stable  tone 
encoder     Runs  on  5  to  12  volts 
Complete  ktl   TD-1       $5  95 


Car  Clock 

The  UN- KIT.  only  5  Solder  connection! 


Hetei  ■  super  tooting,  nigged  and  accural*  auto  coc*  »**cr>  4  a  snap  id  tui^d  and 
initaJT  ClOCh  mournful  ij  complete^/  Assemhlcd  —  yOu  Oily  SQfate*  3  wi(«  and  5 
switches    taki*i  aboul   15  minu-1**'    Display  it  brtgrri  green  wiin  aNtomsue  orightriess 

ronrrai  photocell  -  assures  vou  el  a  ftigMy  readable  display  &*v  or  mght  Camps  ,ri  a 
isiin  imiih  snndiirefl  aluminum  caia  which  can  bfrntachetj^difterpntways  utinrj?«icr#ti 
\HPB    Cticmcff  of  nlvcr    hlnrh  or  qolrj  case  fipocilyl 


DC-3  kil   l?  hour  formal 

DC- 3  wted  and  i*sted 


12295 
*29  95 


Siren  Kit 
Produces  upward  and  downward 
wail  characteristic  of  a  police 
Siren  5  W  peak  audio  output  runs 
on  3-15  volts,  uses  3-45  ohm 
speaker 
Complete  kit   SM-3  $2.95 


MB -l  Kit 


£4.95 


80  Ht  Time  But 
Hun*  on  5-lSVPC    Low  Cufmm  d?Smai  I 
min-mcrtlh  fttCuric*  Tfi-T  K.|  J5.HJ 


Calendar  Alarm  Clock 

ThectocMfiatsgolitaii  6-5  LEDs 
12*24  hour  snooze  24  hour  alarm.  4 
year  calendar  battery  backup,  and 
lots  mare  Tne  super  7001  Chip  ts 
used  Sue  5*4*2  inches  Complete 
k'l.  less  case  (not  available! 
DC -9  S34  95 


Under  Oaih  Car  Ciock 

*  J  H  'fti'  cVk*  h"  a  »aaubK<i  ptMK  c*t» 

•  *imbc  REO  LEDS   r-^*  Kfincf  I  X»S. 
1  mm*  Npc*  up   **0la» 

•diutlt  ar*t*m<f  Id  amb4«p  hqm  i 
DC- '  1  CfOC*  *•!>•  mla    rvrich-'  %J7  15  HT 

DM  i  d.mmtr  ict»r'i"  i-  SO 

Ago  1 10  00  Aitv  *r.<3  r  f  n 


PARTS  PARADE 


Video  Terminal 

A  ca«nplEH piv  in II  ca^ijuned  iland  jicmti  wideo  lftrmin*lf;i*rl    BpquiT«i  pnl^  H*i  ASCII  N^boiirfljiri(liy 
infiin  h^noiTii*i  i-nmnM<!n  TF<>»iin4i>^oi1    Pp.*Uitr%*\$    i«ftijJf  *V  t*jpi*it  J" T *L c WHtfiHwl i* h*  Jfloftjiua 

f*l«  |IO  WWW^     POmyiBr  CDfWPMHH  i»»0  bpft>U»r<1  r(wnH*l  O'twrsci      Pj)*.f,-  *^ffVf  ccvlr^nnfl  :t,*: 
*rf  rp!4  arifl  Q*fti>r*ip4  i*'jji  i'if  Ip  pint  p#T*»t<  h«Yd(Mr(l  mr^'     TM  M  T-  it  34  2M1Jt    bk  1^«'"n   *>i^ 
if  rcHirvc  vpp^  ana  HHtavf  cfew  lOpfionni  md  hi*  R573?  vhj  ?0m»  mew  *ip!em  <v  fioata    » 

«t  6JT€  irriMkai  caitt  *«»  iaoa  I4C  00  id*  »^«j  «miii  net » 

Lo**»  CaHHCHpt^n  l*]tS 


IC  SPECIALS 


LINEAR 


301 

380 
Mi 
5S6 
565 


1* 


981 

?4t 

usa 

I4'V 

8ii3fl 


S  » 

11  M 
It  » 
S  «5 
It  00 

il « 

tiao 

tt  3S 

10  12  00 

t  so 

I   SO 
12.95 

12  95 


TTL 


74S00 

S   40 

7447 

I    65 

7475 

$   50 

7490 

S    50 

74196 

51  35 

4011 
404« 


4059 
4$11 
4818 

sej9 


CMOS 


flfffi 


50 
.50 

stas 

.50 
$9.00 
S200 
St.35 
11-75 


SPECIAL 


1tC90 

10116 

7206 

7207  A 

72160 

7107C 

5314 

S375AB  G 

7001 


$1500 
S  125 
$1750 
S  5.50 
$21.00 
S12.S0 
*  J-95 
S  295 
S  6.541 


Resistor  Aaai 
Assortment  ot  Popular  values  -  % 
watl    Cut  lead  for  PC  mounlrng  %  ' 
center,   V   leads,   hao,   of  3D0  or 

more. 

S1S0 


Swilchei 
Mini  loggle  SPOT  Si  00 

-  Pujn buttons  N  O         3  Si  00 


3d  leada  A  o*m  good  'o»  amall  tone 
ipeahBft  alarm  ctocht  etc 

SforSl.OO 


Mini  S  ohm  Speaker 

Appro*   ?"■"  riiam  Round 
(ypfl  for  mdioa  mike  ale 
3  lor  12  00 


Cry  i  tali 

3  579545   MHZ  S1  50 

10  00000    MHZ  S5.00 

5  248500    MHZ  SS  00 


Qood  lo»  c«og4i.  mead 
fnargei|s,aii  iiO  VAC  plug 
pna  end 

9  5  vdt  Ci  JO  m*  Si  00 

16  *ae  @  160mA  S2.S0 
32   vat!  -S  250mA  |3  00 


Solid  Stat*  Bujiara 

Email  huiir.t  *SQ  Hz  86  dB  sound 
outpul  on  5-1?  vdc  at  10-30  mA  TTt. 
compalible  11.50 


Audio 
Prescaler 

Make  high  resolution  audio 
measurments,  great  for  musical 
instrument  tuning,  PL  lones.  etc. 
Multiples  audio  UP  in  freouency , 
selectable  x1Q  or  sc.100  gives  01 
HZ  resolution  wrth  1  sec  gate 
time1  High  sensitivity  ot  25  rnv.  i 
rneg  input  i  and  buftt*m  filtering 
gives  great  performance  Runs 
on  9V  battery,  all  CMOS 
PS-2  kit  S29.35 

PS-2  wired  $3B35 


Slug  Tuned  Colts 
Small  3/t6"  He*  Sings  lurnect  coil 
3  turns  10  for  $1.00 


AC  Outlet 

Panel  Mount  wilh  Leads 

4  SI  00 


FERRITE  BEADS 

rti!"  mlo  ind  ipeci        111!  00 

A  i-HQNi  B*lun  Be#0i  9t<  00 


READOUTS 

fMO  )Mi    CC  HM 

FhD  iOT'SMs  rc*  i  » 

w*H  J2'M*T730  ja~c  *     i  m 

MP  TftSt    «}"C  *  2  X 


TRANSISTORS 

:*+J*J*  **PN  C-*  11  tl  UO 

2NT9Me*iPC*F  iill« 

ZNMOSPlNPC^F  1iV|f« 

?NJ4iO  NPN.  C'F  IS -11  00 

?NM0»  PNF»C*f  f/tl  Dd 

?NeoMC*r  4^i  oa 

jNi^t  NP**s^«™n        itse 

'i  uhf  Ni>h        vtiev 

*»M»^*aw     Mia 
t«a  pt4P  «e*       ita* 

»H  Typ*  T-Bi  ta.1l  ft 

«*#•«»  moo  Tvp*  t>p  *bta» 


Sockets 

S  Pin  10/12.00 

14  Pm  10/S2  00 

16  Pill  10/S2QO 

24  P.n  4  |2  00 

28  P.n  4/$2.00 

40  Pm  3/1200 


Diodea 

5  1  V  Zener  20/ St  00 

1N914  Type  50/|1  00 

lKV2Amp  8  il  00 

100V  lAmp  15/S1.00 


25  AMP 

100V  Bridge 

$1.50  each 

Mini-Bndge  50V 
1  AMP 

2  for  $1.00 


capacitors 

TJLMTAXUU 
r>oo*d  EOOit 

1.5uF2SV3/S1  00 
1.6  uF  25V  341. .00 
22uF25V3/$l00 


ALUUIMUM 

tQ/30  U*   *SV 

500  xtf  2QV  A  ■ia>        t  M 

10  u*  ^vB*cJ.^lB't100 


dim  qi  a  aatic 

ot  Tfly  an*    Kii  oa 

■   ^6V  TS  Si  00 

001  TtV  30  Si  00 

tODO*  30  si  oa 

017  iffV  Wt\  00 


DC-DC  Convvrlvr 
'&  vdc  inpul  prod  -9  vtic  ifiT  SOrna 
'9  Mdtpfalucei'lSvdc  (fr35ma  S1.2S 


2SK  %  Turn  Irffi  Pot    f  1  06 
IK   J»  turn  Tmit  PM    156 


CoramiC  JF  Filters 

Mini  ceramic  llHers  7  kH? 

BW  455  kHz  It  50  *a 


IC 


T"mm#r  C»pi 

Sprag^c      3-40  pf 

STablr  Polyprop  j^ort* 


600  MH2 
PRESCALE 


Extend  the  range  of  your 
counter  to  600  MHi  Works 
with  all  counters  Less  than 
150  irw  sensitivity  specify  - 
10  of -100 

Wired,  tested.  PS-1B     S59,95 
Kil,  FS-lB  $44.95 


30  Watl  2  mtr  PWR  AMP 

Simple  Class  C  power  amp  features  8  times  power  gain  1  W  in 
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incredible  value,  complete  with  all  parts,  (ess  case  and  T-R  relay 
PA-1 .  3D  W  pwr  amp  kit  $22.95 

TR-l,  RF  sensed  T-R  relay  kit  6.95 


MRF-23fi  transistor  as  used  m  PA-1 
a-iOdfj  gam    ISO  mnz  I11.9S 


RF  actuated  reJay  senses  RF 

(1W)  and  closes  DPDT  relay 

For  RF  sensed  T-R  relay 

TR-1  K*t     $6.95 


Power  Supply  Kl1 

Compifiie      Iriplc      regulated      power 

Supply  provides  variable  6  to  IS  volts  at 

200  ma  and  *5at  1  Amp  E*celP«r>T  load 

regulation,    good   filtering   and  small 

sJie   Le&&  trans  lo  rm  era .  r eo  u  i  r  as  6  3  V 

ra1  A  and  24  VCT 

Complete  kit  PS-3LT  16  95 


Crystal  Microphone 
Small  J  drameter  v  thick 
crystal  mike  cartridge    J-7S 


Coai  Connector 

Chassis  mount 

BNC  type  »1+fM 


Mini  HG-i'4  Coax 
10  rt  tor  1100 


f  Volt  ieltery  Cllpi 

Nice  qua  My  clips  5  lor  11.00 

W  Rubber  Orommati,        10  for  1 1,00 


iLiI    01  (N>kH    6*%C    C*pf    tanr     FFMilprl, 

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Moiorota  MV  22OT  30  PF  Nominal  cap  20-80  PF  -  Tufl#s%  range 

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OP-AMP  Special 
81-FET  l  F  1374 1  -  Direct  pin  iot  pin  741  compatible,  but  500,000  MEG 
input  i  super  low  50  pa  input  current .  low  power  drain 

SO  for  only         S9  00  10  for  $2,00 


7BMG 
79MG 

723 

309K 

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SI  35 

$1.25 

s.so 

$1.15 
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Regulator* 


7612 

11  00 

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1100 

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7912 

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Nice  precyt  pcet  of  shrink  nze   I"  i  V 

thnnk  to  >"   Gre(-  for  spi.cti       SC  11.00 


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Opio  Isolators  -  4N28  type 
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LED 


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^See  List  of  Advertisers  on  page  i!4 


73Magazine  •  August,  1982     159 


!2  SPCCIflUSTS-  CUSHCRAf  T  •  DRflKC  •  HAM  K€V  •  HUSTlCfi  -  HV-GAIN  ■  ICOM  .  HANTRONICS 


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SONY  ICF-S5W  SUPER-SENSITIVE  AM-FM  PORTABLE 


3 
5 


The  ICF-S5W  offers  outstanding  sensitivity  and 
selectivity,  which  means  better  reception  of  weak, 
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helps  you  tune  major  stations  by  their  call  letters 

You  simply  select  your  broadcast  zone,  then  pick 
the  station  by  name  without  referring  to  dial-scale 


n  C  t    »|   ma,  *h.  Hi,  ft  m  kj  urgi  at 
no  H  m&h.pc  &*4i_Ft.  am  vt  nc  vc 

TH    V*.  (HAH   l&  US   VII   Q*    Tit   (pi  C*  07  4? 

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PRICE  CUT! 

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(Cont'l  U  S .] 


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STOP  BY  AND  VISIT  WHEN  IN  THE  CHICAGOLAND  AREA!! 


O 
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to  Mini  Stereo  AIWFM  Receiver 

WTTH  HEADPHONES  -  FgJtMHKC^JfcO.fcKl'1  I  Sjpm  E»*ws 


FEATURES:  Lightweight  headphones.  Lett/right 
balance  cxsntrot  Full  ftdehty  stereo  sound.  Addi- 
tional clack  son  carrying  ca$a  &  4 houtdar  strap.  Sen 
dip  (hand*  free).  Operates  on  3  A  A  ceH  batteries  {not 
Inch.  Compact  size:  3V  *  *V  *  I*.  wt-  a  «■ 

M Odel  2830  List  Price  S89.95 $04.95 


SPEAKERS 


ZVi"'  Round  —  S  Ohm 

25  Watt  H"  Leads) 
Sl2fl   2%  "a  It" 

P»MNt,  Pnc- 

AB201         ST-2Sor2>l,9B 


ne*^ 


1W  Square  —  16  Ohm 

.25  Watt  {4  mount  holes) 

Largs  Ceramic  Magnet 

Size:  2\"  *  2%"  *  a*" 

F»"l  Mo  PliM 

SF  25016     $1.33  Of  212.9S 


MOTOROLA 

AM/FM  Stereo  Push  Button 
CAR  RADIO 

FOR  VOLKSWAGEN  SClflOCCO.  RABBJT, 
AUDI  5000  ANO  FOX 

ted  iftnur  adjustments  on  be  used  m  any 


f    <*» 


Includes  bozel  trim  and  owory thing  pictured.  Two 
each  4>&  spankers  and  grille  (1  V*  "  deep).  All  cables 
end  Feeds  for  hook-up.  Include*  ell  Instruction 
Manuals  lor  easy  Installation,  Cui  oui  dimensions: 
7*Wx1WHx6VirL. 

Model  5VW3901    $49.95 


UV-EPROM  Eraser 


iTee.im.uT&z7K«ii 
iii^iwmriejphPiJ 

Oi  «M  Ml,  S0K*tl 


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UVS-11EL  Replacement  Bulb 3 16.95 


DE-4 


UV-EPROM  Eraser  . . ■ 


79.95 


JOYSTICKS 


JS-4K 


y 

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■rem 

JS-5K  5K  Linear  Taper  Pelt 

JS-100K  100K  Linear  Taper  Pot* 

JS-150K  1 50K  Linear  T  a  per  Pote 

JVC40  40K  (2J  Video  Con  ir ol  I  m  in  case 


S5.2S 
$4.95 
$4.75 
S4S5 


SVa*1  Mint-Floppy 

FOB  TRSae  MODEL  iL  p* 


FU    f-ngi*, 

5V0C  I  x  W5Vi  q  *  «mc*  «i 
t«f*el  At  Iril  JOqw  not  i«c<  CM.  po«**r  idKH> 
or  cKUmi  30-ptg*  daft  boofe  MrmL 
WMatu  3*   pound!   BU«    5HH«   <  »"D  . 

P.rtN*.        "■*■■- *hr*-*W  p^ 

FD200 $179,95 

Slrtfl4tf-it<l*d.  40  lifrCH.  &6K  Hyita  ejpielty 

rUdufJ  ........  .     f  199.93 

Doublfl-iJd*}.  36  luCka,  *MK  bvti>  £«-p**:l1y 


JE215  Adjustable  Dual  Power  Supply 

General  Description:  The  JE215  11  a  Dual  Power 
Supply  with  independent  ndjuitebia  positive  and  nega- 
tive output  valtayes.  A  separate  adjuitment  for  each 
at  tht  lyppliei  provide*  Hie  user  unlimited  applications 
for  IC  current  voltage  requirements.  The  supply  can 
alio  bi  used  ai  a  general  all-purpaii  variable  power 

W*D|V-  FEATURES 

•  Adiu»tBM*tafui<f«0ao'v«*rt^poii*a. 
pen.    inti    n*f>    1  ?VDC   to   T5VOC 

^  •  Po«tP  Ootjioi  i»»*n  fupfHy): 

S\rt>C  #  SMmA.  10  vOC  * T&Gk-  ^ 
T2V  DC  »  iOOmA    «nG 
1SVOC*  1?ftf*A 

•  T^b,    3  liiP-iiP*!     ftd(      IC    rsfUlatDn 
InT*     m*»m»l     9W9MDM9    DfOIPEl'Qn 

■  Hwiijm  -*fuiptp*  eociUita 

•  i_E  E>  "on  "  Lnd'Catfl' 

•  Printed  Ba»'d  Construct' an 

■  120VAC  inpuT 

•  S«z*    3-1/J"vf  *  S-iyta"L*  3"H 

JE215  Adj.  DuilFg  war  Supply  Kit  (at  in  own}.  .   S24J5 

t  fictuF*  not  pijah  t^r  pfraUlaf  m  conattuciion  :o  *oov«.i 
J€ 200  Rag,  Powir  Supply  Kit  1 5 VPC,  1  amp!  .  .  $14.95 
jeZOSAdipturBrd .{to  JE200>  :5.f0e«  i12V  512  95 
JSaiflvflr  Pwr.Sply  Kit  5  lSVDCjol.Barap     I19.0B 


KEYBOARDS  -  POWER  SUPPLIES 


JE610  ASCII 
Encoded  Keyboard  Kit 


taeaftV0CL*r1 

JE610/DTE-AK  (Aftaf  asaambly  as  ptcturad  above)    *....,..>     $124.95 

JE610  Kit  62-teyKfybkint  PC  Board  4  Cwnpcmenisfnocase^   ••*«#.$   79,95 

K62  62- Key  Kavtward  ( Key Ooard  only)  .«.••■ ..,.....$    34,95 

DTE'AK  (casarjnly-3^"HxtrWn8^,*P] .  .$    49,95 

JE21S  -  Ntgatlv*  12V DC  Adapter  Board  Kit  for  JEB1D  ASCII  KEYBOARD  KtT 

ProvidBS-12VDCfrDmlnccming5V[>C     , $8.95 


BOOKS 

QHOa  Oaii  floc4 


OF1.  0*51000.  053090  OSmBB)  •*= 
LM.  IF,  ASIC.  D-i- 


30006  Above  (3J  30001 .3.5  as  set  $24.95  lot 


AC  and  DC  Wail  Transformers 


JE600  Hexadecimal  Encoder  Kit 

FULL  8-BiT  LATCHED  OUTPUT 
19-KEY  KEYBOARD 


a* 

aaiaj 

JE600/0TE-HK  ,  jme/aawiuir  at  poured  *»■•) 


. .  syy.yo 


JE600  Kit  19-Key ^^  Headacinaj  itaytnard,  PC  Board 4 
K19  i^  Key  Kaytxurd  tKeyOoard  only}  ,..,,,,.. 
DTE'HKicasaonry-3^-H^8'*"Wi8*T3)  .  .  , 


fnausei 


■  --••*» 


$59,95 

S1 4.95 
$44,95 


ew>L-*l^"W*i,JN 


mVi  >4'^'-W-  i\'H 


jruL^^-Wfiiaerw 


nmun,"H 


JUPS  26^KET  C4LCUUTDB  KfYBDARO 
■§f*r  Klip  t»pi  wRi  bkw,  ptM  *nJ  ■Mi  ht*  tup. 

Pirt  No,  HB26 


lZ.«eachorZyii.9& 


MICRO  SWITCH  69-KEV  KEYBOARD 

AiIb  Entiy  KpybH'tl.  fiic^Hl  Oliipvl  fl-IH|  Pti-nlldl  EBL  DlC   S^rtuNng   NflElliDl.  E4  pin  Edgi 
{ard  CninKllDn  [.nmiilnLt  *llh  Pin  Cenufdlvn 

PartNo.KBb9SDlZ-Z  S19.9SM«ll 


DATANETICS  74- KEY  KEYBOAfiD 

ilkSCH  Sntadia  KiytMIl  tHillnri    fHir   PlAf  ASCII.   SilOJt^  -nftlfl   +1.  41  Vttt.   Iwttrt^]. 

Pan  Ho  KB3&4  5Z9  SI  »ch 


MICRO  SWITCH  I54CET  KETtOAHe 
■eaBiaj 


1»*»|*t«4l 


fart  He  $S$P18  1 


139  95 


MICRO  SWITCH  tt^CV  KFYMAflO 


Pari  Na.  H$D» 


*m.tn 


$S9  tSaacfe 


POWER  SUPPLIES 


aifi  No 
DC6912 


Wlih  Uril^iiil  Plug  And 
fV  0*ll«nf  Snip 
SbIemiIIv.,  MnlEngnn  fl,y.l?VDQ, 
Polantv  ■■  l«c Wan  i  *  i'.j  gut-loot 
Ii*1!?  frurn  Milapl«i<i  Id  plugs  —  slx- 
in.-ji  i Mr'  rrriiu  luipler  Id  bullery 
■nap.  1SQVMDK/  .HHJ'rtA 


PjH  Nn 

iripul 

OulDlH 

p*t. 

AC  aU 

nrvjttOKE 

12VAC2MHH* 

txsa 

AC  bOO 

lavACSOOin*, 

.aaas 

AC  1000 

iirvjaottz 

12VAC  i  una 

eui 

AC  WO* 

iirvwoHr 

a.jvAC  as  »mp 

UKarZt*9S 

DC  «00 

isovnoHt 

!VDC40Qw.JL 

IIBftfJlIUH 

Dceeutiea- 

™i     130VWKr 

0JSL1ZVVC  tOOmA 
a!Sraci»wA 

iaj6 

ovuao 

itrwvpftt 

i;ifw2ii^ 

ecata 

tinvtvu 

avDcaaomA 

ties 

dc  tarn 

Taiftaony 

TWDCJaamA 

■aaifliafaus 

?jfo  CONNECTORS 


POWER  SUPPLY  -  SVM  rg  1  AMP  R«UL*TE0  TwucHmTk* 

ft*?*  *  suae  4)HtiAt  *  amsct  fit  «^t  nsvu  aaat  th4«h  (Matt/Wit,  *** 

iliailf  tw  It  ,  j«v4  H»Kt  friMTtadi  laa  f¥r  "W  ■  ?'  D  t  In   N  *i   3Ba. 

PariNa.  PES  11 94  Si 9  9S  each 


POWtfl  SUPPLY  -  9V0C  at  1  AMP  flEGULATEO  *  induing 

Dutpur  *  swDL  ,-!- 1  *mji  v  jmrvnc  jJi  «'jm*  y  mi.  3ov* i;  i«wn  ( nt '  s  imp  iimm  i  s5v*c 

HlHi.  Circ   li4tF   ri  i»i  h,il1un  fll I ,  i-cl-mcl  ctMW^rubbvrM  I  ft, .  }  nind   nil   pa*  e*rd. 

dn.'Qii  iHiicch.  e^  w  i  xv,  ci  ■  i7/i"H  -  *i.  T  hi. 

PartNa.  PS407D 5Z4B5  oacll 


Tower  supply  -svde  @  7  j  amp,  tzvoc  @  1 1  amp  swiTCHme 

Input  1 1SVAC,  hU-MlU  ii7- 1  *me/JMVAC,  SflllJ  n^  1 .6  kmji  f  fin  villi  nuiwiil  eu|it(l^  mloe;  Swll- 
diHjn1i^MVflt;i  Oiilpur- HV<it  ir  7  R  »mji  IBVDt  .;■  1  h  Amp  III  blli  (law  rarri  i"V'Wi 
1i\k'  Pi  3VH   W   Mm 

Part  No.  PS94V0  


MBSSeacfc 


POWEft  PAC  —  ■**»>  uui^  Vkn  v-taii  Nww  bp*tr  -  wrc.  irvoe  jittoc 

CMpof  -svDc  a  ma.  * tnrac  0  w,  tnnc  gai  * hvk  «  u  i*Pai  1  wit.  ta. 
AfiAC  U»  •*■    t  UH  -»  *  ■>-  c-B*  avpi  iwv  pa«k  m  1—*  Ljhvaaitj  Oh 

pahd.:  it.  till   -IJH  Oaffttf  l«*«a  Met  li'n   L  i  i  n  i  ilT/l  »   ff  «Bi 

Hd  ?S5-016  189  95 


DB29P  D-&ubnijnu»tufe  Plug  -  .   .  $235 

DBZSS  D  Stjbrnjr)«tiif*  Socket  $3  50 

D20418  2  Scf*HLftAHrfwr(3)D92!iS/p     2/S.9Q 

DB5l22b  CiwiirforOB2SP'S  SITS 

22  44SE  PC    Ed^  f2Z«4  Pinl    .  .  S2JS 

UGaa/U  BNC  PJufl ,  .  SI  79 

UG99;U  BNC  Jack ■  S3, 79 

UG17S/U  UKF  Adapter  .  .  $  .49 

SOZ39  UHF  Panol  flacp,  .   ,  $1  29 

PL2SB  UHF  Adapter  .  -  *l,6fl 

PL2BB  UHF  Plufl Sl.fiO 

UG2G0/U  BJVC  Plug    .  .  .   ,  Si. 79 

UG1094/U  BMC  Bulhhead  rl«cp.     ......  SI  29 

TRS80  16K  Conversion  Kit 

Expand  yeur  4K  TRS-BO  System  to  16K  or  32K 
*fff  comes  complete  w 

*  8  ea.  MMS290  |UP04lD/41t6)  1GK  Dyn.  Bant  Tns> 

•  Documentation  for  convaralon 

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*>See  L/sf  or"  Advertisers  on  page  J  74 


73  Magazine  •  August,  1982     161 


DEALER  DIRECTORY 


Phoenix  AZ 

[Tie  Soutttwest  s  nwt  progressive'  communica^ 
boos  company  stocking  Kenwood  t  ICOM. 
Ysesu,  MFJ,  B&W.  Aatron,  Linen,  Cushcraft. 
Hy-Gain,  Bearcat*  and  more.  Would  like  lo 
serve  you  I  Power  Com in tinicatians  Corp,.,  1&40 
Wot  CamdWJt  Hd,,  Ffoenbt  AZ  85015. 
Ml-Wutt 

Fontana  CA 

Complete  lines  ICOM,  DenTron,  Ten-Toe, 
Mirage,  Cubic,  Lunar,  over  4000  electronic 
products  for  hobbyist,  trehnkian.  experi- 
menter, Also  CB  radio,  JandrnoMr.  Fontana 
Electronks,  8628  Stem  Ave..  Fontana  CA 
02335,  822-7710. 

San  Diego  C  A 

We  buy  and  sell  Surplus  Anm-  Navy  Elec- 
tronics, also  Terminated  Material.  What  do  you 
want  to  sell?  Write  for  catalogue  Eledrcaiic- 
inwn,  Inc..  440-Tlh  Avoiur.  PO  Box  204S.  San 
CAS21U,23^»37V. 


Amsterdam  NY 
UPSTATE  NEW  YORK 

Kenwood,  ICOM,  Drake,  plus  mam  other 
hrws,  Amateur  Dealer  for  over  35  yean,  Adiron* 
dacfe  Radio  Supply,  Inc.,  185  Wot  Main  Street. 
Amsterdam  NY  12010,  S4JWJ350. 


San  Jose  CA 

Bay  area's  newest  Amateur  Radio  store.  New  & 
used  Amateur  Radio  iaJs&  service.  We  feature 
Kenwood,  ICOM,  Azden.  Yaesut  Ten-Tec, 
Santee  &  manv  more,  SKivrr  Radio,  Inc.,  1378 
So.  fiascom  Aw.t  San  Jose  CA  95128. 098-1103. 

Smyrna  GA 

For  your  Kenwood,  Yacsu,  ICOM.  Drake  and 
other  amateur  needs,  come  to  see  lis.  Drift's 
Two-Wav  Radio,  2506  N,  Atlanta  Rd.,  Smyrna 
GA  30080,  432r8006. 

Preston  ID 

Ross  WB7BYZ  has  the  Largest  Stock  of  Ama- 
teur Gear  in  the  lntrrmountain  Wert  and  the 
Best  Prices-  Call  me  for  all  your  ham  needs. 
Reai  Dbtributme,  78  So,  State,  Preston  ID 
83263,852-0830. 

Terre  Haute  IN 

Your  ham  headquarter*  located  in  the  heart  of 
the  midwest  fiooaer  Electronic-.,  Inc.,  *9 
Meadows  Center,  P.O.  Box  3300.  Terre  Haute 
IN  479003,  23^1456. 

Baltimore  MD 

Always  buying  lab  grade  test  equipment  HF. 
Tek,  Cr,  LAN,  Etc.  Also  buy  microwave  coax- 
ial &  wiveguipe  HP*  fur,  waveHne,  Etc,  Prefer 
"K".  HF"t  "H"  but  will  consider  larger  wg 
too,  Cadisco  $14  Enanr  St.  Salto,  MD  21202, 
085-1803. 



Little  Ion  MA 

The  ham  store  of  N.Et  yon  can  relv  on.  Ken- 
wood. ICOM,  Wilson,  Taesu.  DenTron,  KLM 
amps,  BfrW  switches  £c  wattmeters.  Whistler 
radar  detectors.  Bearcat,  Regency,  antennas  bv 
Lsnen,  Wilson,  Hustler.  GAM.  TEL-COM 
Inc.  Communications  At  Electronic*.  673  Great 
Rd.,  Rt.  119,  Uttktan  MA  01460.  486*3040, 

Ann  Arbor  Ml 


Syracuse- Rome- Utica  NY 

Featuring  Kenwood,  Yaesii,  ICOM,  Drake, 
Ten-Tec,  Swanh  DenTron,  Alpha,  Robot,  MFJ, 
Tempo,  Astron,  KLM,  Hy-Gain,  Motley,  Lar- 
sen.  Cushcraft,  Hustler,  Mini  Products.  You 
won't  be  disappointed  with  equipment/service 
Radio  World,  Oneida  County  Airport  ^Termi- 
nal Building,  Oriskany  NY  J3424,  337-0203. 

Columbus  OH 

The  bifflEst  and  beat  Ham  Store  in  the  midwest 
featuring  quality  Kenwood  products  with 
working  display*.  We  sell  only  the  best. 
Authorized  Kenwood  Service.  Universal 
Amateur  Radio  Ioc,  1S80  Aida  Dr.,  Reynolds' 
burg  (Columbus)  OH  43068.  S6MS6T 

Bend  OR 

Satellite  TV.  Known  brands.  Call  today  for 
more  information  and  inquire  about  our  dealer 
program-  WESFEHCGM,  p,0.  Box  7226, 
Bend  OR  9770ft,  3S8-O90G. 

Philadelphia  FA/ 
Camden  NJ 

Waveguide  &  Coaxial  Microwave  Components 
flr  Equipment.  Laboratory  Grade  Test  In- 
struments, Power  Supplies,  Buy,  Sell  Ac  Trade 
all  papula*  makes— HPT  CB,  FXR,  ESI,  Soren- 
wn.  Singer,  etc.  Lecbrxiic  Research  Labs,  1423 
FfTTy  Ave.,  Camden  NJ  OT104,  541-4200, 


Scran  ton  PA 


See  us  for  products  like  Ten-Tec,  R.  L.  Drake, 
DenTron  and  many  rnore.  Open  Monday 
through  Saturday,  0330  to  imWBSVCR', 
WBSCXO,  WD0OKN  and  W8RP  behind  the 
counter  Purchase  Radio  -Supply.  327  E.  Hoover 
Ave,,  Ann  Arbor  Ml  48104*  8<&S686. 

Hudson  Nil 

New  England'*  Distributor  and  Authorized  Ser- 
vice Center  for  all  Major  Amateur  Lines.  Tufti 
Radio  Electronic*,  Inc. ,  61  I  j  well  Road,  Hud* 
son  NH  03061,  883-5005, 

Somerset  NJ 

New  Jersey's  only  factory-authorized  ICOM 
and  Yaesu  distributor.  Large  Inventory  of  new 
and  and  specials,  Most  major  brands  in  stock. 
Complete  servke  and  facilities  Radios 
Unlimited.  1760  Easton  Avenue,  P.O.  Box  347, 
Somerset  NJ  08873.  469*4599. 

Buffalo  NY 
WESTERN  NEW  YORK 

Niagara  Frontier"!  only  full  ■imping  Amateur 
dealer  Also  Shortwave,  CB,  Scanners,  Marine, 
Operating  displays  featuring 
and  others.  Towers*  Antennas,  Sale 
and  Service.  DX  Communication*,  3214  Tran- 
sit Road,  West  Seneca  NTf,  68WJ&73. 


ICOM.  Bird,  Cushcraft,  Beckman,  Fluke, 
Larsen,  Hustler.  Antenna  Specialists.  Astron, 
AvanrJ,  BeJden,  W2AU/WZVS,  GDE+  AEA. 
Vibmplex.  Ham- Key,  CES,  Am  phenol.  Sony, 
r'anon*' Courier,  B&W,  Amoco,  Shore.  LaRue 
Electronics,  1112  Crandview  St.,  Scranlon  PA 
10500,  343-2124. 

Dallas  TX 

Dealer  In  Used  Computer  Hardware  0c  Elec- 
tronic Parts.  Special  on  Daisy  Wheel  Printers. 
Xerox  Word  Processing  Equipment.  Dunl  Card 
Printnr*  and  Display  Systems.  Catalog  $UK). 
Rondure  Company  (The  Computer  Room) 
Dept.  73,  2522  Butler  St„  Dallas  TX  75235, 
630-4021. 

San  Antonio  TX 

Amateur,  Commercial  2- way,  Selling  Antenna 
Specialists,  Avanfci  Azden*  Bird.  Hy-Gain, 
Standard*  VibropJex,  Midland,  Henry.  Cush- 
craft, Dielectric,  Bustier,  ICOM.  MF],  Nye, 
Shure,  Cubic T  Tempo.  Ten-Tec  and  others.  Ap- 
pliance e*  Equipment  Co,*  inc.  2317  Vance 
Jackson  Road,  San  Antonio  TX  78213, 
734-7793. 

Vienna  VA 

The  Washington  metropolitan  area's  leading 
supplier  of  the  latest  in  Amateur  Radio  and  Test 
Equipment.  On  your  neat  trip  to  the  Nation's 
Capital,  stop  by  and  see  us.  Electronic  Equip- 
ment Bank,  Inc.,  516  Mill  St,  N,E»  Vienna  VA 
22180,  038.3350. 


DEALERS 

Your  company  name  and  message 
can  contain  up  to  25  words  for  as  Ut- 
ile as  $150  yearly  (prepaid)  t  or  $15 
per  month  (prepaid  quarterly).  No 
mention  of  mail-order  business  or 
area  code  permitted.  Directory  text 
and  payment  must  reach  us  60  days 
in  advance  of  publication.  For  exam- 
ple, advertising  for  the  Oct.  *82  issue 
must  be  in  our  hands  by  Aug.  1st. 
Mail  to  73  Magazine,  Peterborough 
NH  Q34S8,  ATTN:  Nancy  Ciampa. 


182     73  Magazine  •  August,  1982 


PROPAGATION 


J.  H.  Nelson 
4  Plymouth  Or. 
Whiting  NJ  08759 


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A  =  Next  higher  frequency  may  also  be  useful 

B  =  Difficult  circuit  this  period. 

First  letter  =  night  waves.  Second  =  day  waves. 
G-Good,  F  =  Fali\  P  =  Poot\  *=  Chance  of  solar  flares. 
#  =  Chance  of  aurora. 

NOTE  THAT  NIGHT  WAVE  LETTER  NOW  COMES  FIRST. 


AUGUST                          1 

SUN                MON               TUE               WED               THU                 FRI                  SAT 

1 

F/F 

2 

F/F 

3 

F/F* 

4 

P/F* 

5 

F/F- 

6       7 

F/G    '     G/G 

8~„ 

G/G 

G/G 

10 

G/G 

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G/G 

12 

F/F 

13      14 

F/F         F/G 

15 

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17„ 

G/G 

18 

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QUITE  A  SIGHT! 

(AND  EASY  TO  SEE,  TOO!!) 


Sporting  an  all-new  Liquid  Crystal  Display,  the  FT-230R  is  Yaesus  high-performance  answer  to 
your  call  for  a  very  affordable  2  meter  mobile  rig  with  an  easy-to-read  frequency  display! 
The  FT-230R  combines  microprocessor  convenience,  a  sensitive  receiver,  a  powerful  yet  clean 
transmitter  strip,  and  the  new  dimension  of  LCD  frequency  readout.  See  your  Authorized  Yaesu 
Dealer  today  —  and  go  home  with  your  new  FT-230R! 


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SALE  SUBJECT 
FCG  CERTIFICATION 


LCD  five-digit  frequency  readout  with  night 
light  for  high  visibility  day  or  night 

Two  VFOs  for  quick  QSY  across  the  band. 

Ten  memory  slots  for  storage  and  recall  of 
favorite  channels. 

Selectable  synthesizer  steps  (5  kHz  or  1 0  kHz) 
in  dial  or  scanning  mode. 

Priority    channel    for    checking    a    favorite 
frequency  for  activity  while  monitoring  another. 

Unique  VFO/Memory  Split  mode  for  covering 
unusual  repeater  splits. 
Up/Down  band  scan  plus  memory  scan  for 
busy  or  clear  channel.  Scanning  microphone 
included  in  purchase  price. 


Full  25  watts  of  RF  power  output  from 
extremely  compact  package. 

Built-in  automatic  or  manual  tone  burst. 
Optional   synthesized   CTCSS   Encode   and 
Encode/Decode  boards  available. 

Lithium  memory  backup  battery  with  estimated 
lifetime  of  five  years. 

Optional  YM-49  Speaker/ Microphone  and 
YM-50  DTMF  Encoding  Microphone  provide 
maximum  operating  versatility. 


FT-208R 
FM  Handheld 
2  Meters 


FT-708R 

FM  Handheld 
70  cm 


And  don't  forget!  Yaesu  has  a  complete  line 
of    VHF    and    UHF    handheld    and    battery 

portable  transceivers  using   LCD  display  tit 


FT-690R  -  6  Meters 

USB/CW/AM/FM  Portable 


W 


Price  and  Specifications  Subject  To 
Change  Without  Notice  or  Obligation 


The  radio. 


X7 


482 


YAESU  ELECTRONICS  CORP.  6851  Walthall  Way.  Paramount,  CA  90723 
Eastern  Service  Ctr..  9812  Princeton-Glendale,  Rd.,  Cincinnati,  OH  45246 


(213)633-4007 
(513)  874-3100 


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VBT,  notch,  IF  shift,  wide  dynamic  range 


Mow  most  Amateurs  can  afford  a  high* 
performance  SSB/CW  transceiver  with 
every  conceivable  operating  feature  built 
in  for  160  through  10  meters  {including 
the  three  new  bands).  The  TS-830S 
combines  a  high  dynamic  range  with 
variable  bandwidth  tuning  (VBT),  IF  shift, 
and  an  IF  notch  filter,  as  well  as  very 
sharp  niters  in  the  455-kHz  second  IF. 
Its  optional  VFO-230  remote  digital  VFO 
provides  Five  memories. 

TS  830S  FEATUF 

160-10  meters,  including  three  new 
bands 

Covers  all  Amateur  bands  from  US  to 
297  MHz  0LSB,  USB,  and  CWh  Jntiudhi 
the  new  10.  18.  and  24  MHz  band 
Receives  WWV  on  10  MHz. 
•  Wide  receiver  dynamic  range 
Junction  FETs  (with  optimum  1MI3  char 
teristics  and  tow  noise  figure)  in  (1 

'*d  mixer,  a  MGSFEf  RF  amplifier 
Operating  at  low  level  for  improved 
dynamic  range  fhiith  amplification  level 
not  needed  because  of  low  noise  jji 
mixer),  dual  resonator  for  each  band,  and 
advanced  overall  receiver  design  result 
in  excellent  dynamic  ran^e, 


Variable  bandwidth  tuning  |VBT) 
Continuous  s  the  IF  filter  passband 

width  to  reduce  Interference.  VBT  and  IF 

shift  can  be  controlled  independently  for 

optimum  interference  rejection  in  any 

condition. 

IF  notch  filter 

Tunable  hi^h-Q  active  circuit  In  45.ri  kHz 

second  \l\  for  sharp,  deep  notch 

characteristics, 

IF  shift 

Shifts  IF  passband  toward  higher  or  lower 

Frequencies  (away  from  interfering 

signals)  while  tuned  receiver  frequency 

remains  unchanged, 

6146B  final  with  RF  NFB 

Two  6l4ftfrs  in  the  final  amplifier  provide 
220  W  PEP  (SSB1/180  W  DC  (CW)  input 
on  all  bands.  RF  negative  feedback  pro- 
vides optimum  IMi         iraeteristh  s  lor 
high ■  quality  t  ra  1 1  s  m  isslon . 

Built-in  digital  display 
Six-digit  large  fluorescent  tube  display, 
backed  up  b>  an  analog  dial  Reads 
actual  receive  and  iransmif  frequency 
on  all  modes  and  all  bands.  Display  Hold 
IDH1  switch. 

Adjustable  noise-blanker  level 

Built-in  rioise  blanker  eliminates 
pulse*  type  [such  as  ignition) 
noise.  Front  panel  threshold 
level  control, 


Matching  accessories  for  fixed-station  operation: 


•  SP  230  external  speaker 
with  selectable  audio  fillers 

•  VFO-230  external  digital 

VFO  with  20-H*  steps. 

five  memories,  diijiial  display 

•  AT-230  antenna  tuner 
SWR  and  power  meter 

•  MC  50  desk  microphone 
Other  accessories  not  shown: 
»  TL-922A  lin<  m  amplifier 

•  SM-220  Station  Monitor 

•  PL  1  phone  patch 


HC  10  digital  world  clock 
YG-455C  1500-Hzl  and 
YG-455CN  (250  Hzl  CW 
filters  for  455-kHz  IF 
YKS8(   (500-HzJand 
YK-88CN  (270-Hz)  < 
filters  for  8.83-MHz  IF 
HS^5  and  HS  4 
headphones 
MO30S  and  MC-35S 
noise  cancelling  hand 
microphones 


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Various  IF  filter  options 
Either  a  500-Hz  (\  or  270-Hz 

(YK-88CN1  CW  filter  mav  hr  installed  in 
ihe  8         lliz  first  IF.  and  a  verv  sbar 
500-Hz  (YG  455CI  or  250  Hz  (\ 

W  filter  is  available  for  the  455-kHz 
set  in  id  IF. 
-  More  flexibility  with  optional  digital  VFO 
VFO-230  operates  in  20- 11/  steps  and 
Includes  five  memories.  Also  allows  split- 

frequency  operation.  Built  In  digital 

display.  Covers  about  100  kHz  above  and 

below  each  500-kHz  banc! 

Built-in  RF  speech  processor 

For  added  audio  punch  and  ln«        ied 

talk  power  in  l)X  pileup 

•  RIT/XIT 
Receiver  incremental  tuning  IRIT)  shi: 
only  the  receiver  frequent  v.  to  tune  in 
Stations  sHghUy  off  frequer         Trans- 
mitter Incremental  tuning  LXITi  shifts  only 
the  transmitter  frequent 

■  SSB  monitor  circuit 
Monitors  IF  stage  while  transmitting,  to 
determine  audio  quality  and  effect  of 
speech  processor. 

More  information  on  (he  !         iOS  is 
available  from  ail  authorized  dealers 
of  Trio  Kenwood  Communications 
llli  vvesi  Walnut  Street  Compton, 
California  H0220, 


KENWOOD 

, , .  fmmtiter  in  amatrur  radio 


Specifications  ami  prices  are  subj^t  to  change  WUhtiUl  notirr  or  Obligation