I
I
#123
One Dollar
December
1970
I
iSB EMPHASIS:
feuiLOYOURDWN SOLID-STATE EXCITER
IVDELTAf'SSB CONTROL
YOUR "SECOND" LINEAR
OFFSET TUNING for HW 100
PLUS
FM •FUN PROJECTS • HUMOR
GIANT 1970 ARTICLE INDEX
'•'v.-Wwi^^ ■**WA=;' 'i,*; ;7:^^ .V .:--•. ■.liV:-
SWAN
270B
SSB TRANSCEIVER
The 5 band deltis:e 270-B, with a power rating of 260 Watts P.E*P,, is a complete self con- tained radio station wifli imHt^in AC power supply and speaker in one compact, portable package. You can take it with you on vaca- tion or business trips, operate from your motel room^ your boat, car, or hide-away cabin. AH you do is connect to an AC power source and antenna^ plug in your mike and y ou^re on the air, with enough power to work the world.
The Swan Cygnet 270B is a world traveler. And the price h a w<Hrld beater! $499
ELECTRONICS
305 Airport Road
Oceanside, California 92054
A Subsidiary of Cubic Corporatron
SWAN 1 200W 1200 WATT LINEAR AMPLIFIER WITH SELF CONTAINED AC POWER SUPPLY
We built this little gem to go with our Cygnet 270B* But when word got around that Swan had a 1200 Watt amp with a built-in AC power supply, for just two hundred and ninety -five bucks, all h— broke loose* Production has finally caught up with sales again, so see your dealer soon.
ELECTRON ICS 305 Airport Road Oceanslde, California 92054 A Subsidiary of Cubic Corporation
#123 December, 1970
Featu res
2 Radio Amateur News Page 8 Caveat Emptor 10 Never Say Die 12 Mr Virgo Himself 14 Leaky Lines 90 New Products 115 Letters 128 Propagation Chart 128 Advertiser Index
Editor*Publisher
Wayne Green W2NSD/1
Managing Editor
Ken Sessions K6MVH/1
STAFF
Associate Editor Jim Kyle K5JKX
WTW Editor
Dave Mann K2AGZ
FM Editor
Mike Van Den Branden
Advertising Diane Shaw Roci Billings Hilary Wye
Advertising Representatives
Bill Fields Manfred Meisels Andrew McCr eight
Art Director
Roger Block
Graphic Arts Nancy Estle Jan Wozmak
Composition Ruthmary Davis Karen Mellor
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I
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16
28
31
32
39
44
48
51
75
94
96
101
107
108
. W4NVK
. K3KM0
WBeBIH
Contents
Solid State Exciters W6YUY
For The build-don't-buy crowd.
Solid State Control for SSB Exciters
For really smooth tuning.
Hams Are A Funny Bunch of People
Except me and thee.
A 2 Meter Minitransmttter . , * . ,
Hand portable for FM repeaters.
Receiver Offset Tuning for the HWlOO WA2EAW
For tuning in oldtjmers who can't stay on frequency.
The Little Gate Dipper .VV5ETT
1.7 - 225 MHz GDO with no G,
Clinks In A Vacuum ...,,,.,..,.• The wife's view of amateur radio.
Your Second Linear » , >
Usfng the fabulous RCA 3-5002.
General Class Study Course ..,,,..
Vacuunn tubes„. remember them?
Yipes, it Talks _ _ , .W2F
Startle your friends.
Regency — An FM Late Starter . . ,
Wow?
Transistor tester, simple.
Two Terminal Current Li miter * .... Most Have three^ so this is a step ahead, right?
Index to Articles in 1970 Ridiculously detatted yearly index»
Derf ler
W4AYI
Staff
. K61V1VH
. .- W6QPF
. . . . Gerald Beene
I
Drafting
R. K. WJIdman W6MOG Wayne Peeler K4MVW T;M. Graham WSFKW
Subscriptions
Dorothy Gibson
Circulation Phil Price
Comptroller
Georgiana Sage
Publications Jeff Parsons Biff Mahoney Hal Flagg
Traffic Taylor Sage
Propagation
John Nelson
73 Ma^aiine is published monthty by 73 Inc., Peterborough New Hampshire 0345S, Subscription rates are $6 for one year in North AmericQ and U.S, Zip Code areas overseas, $7 per one year elsewhere. Two years $10 in ij\S. and S/2 ovei^eas. Three years S/4, and $16 overseas. Second class postage paid at Peterborough, NM, and at additional mailing offices. Printed at Menasha, Wisconsin 5 -J 95 2 U.S. A, Entire contents copyright 1970 bv 73 /ric, Peterborough, NJL 0345H. Phone: 603^924^3813, We could hassle you about subscribing, ^ivin^ gift subscripti€>ns, bunging passible adver- tisers and all that, but we won't, if you want to go through the next month with one of the blackc^^l curses known to man on your head (hen all you have to do ts ignore 73. . .do not subscrilje, . .do not send in ten gift subscriptions for friends (or enemies, dependhig upon how you think of 73). . ,do not lei Collins know Uiai you thought they were out of the ham tjusiness because they have not advertised in 73 in over ten years. Go ahead and risit a curse so powerfui tiial it could wetl tiave a serious effect even upon your family two generations later.
The Cover An impressive shot of the sky through K9JFD's beam. The photo was submitted by Mrs, Gene Markos as a birthday surprise for hubby*
DECEMBER 1970
1
Amatmr
Page
December MCMLXX
Monthly Ham News of the World
73 Magazine
CHICAGO OUTLAWS
RADIO!!
CHICAGO AMATEUR CLUB BRINGS SUIT
Chicago. Under city zoning ordinances,
Chicago has forbidden amateur radio slations to be set up in residential areas. According to information pub- [ished in the Chicago Daily News, the ban can only be waivered on payment of a special $100 fee.
Proceeding on the grounds that such anti-ham legislation is unconstitutional, a group of Chicago amateurs (the Chicago Area Radio Club) filed suit in district court, charging the city with attempting to reeutate a service that is already [>eing regulated by the federal
fovernment. The suit seeks to have the J.S. district court enjoin the city of Chicago from enforcing its ordinance and from collecting fees for waiving such ordinances.
in supplying this information to 73 News, Art Housh older {K9TRG), man- ager of Spectronics, Inc., a Chicago area ham radio firm, said the action of the city and the counteraction on tlie part of the CARC were topics of
%
U.S. Navy Radioman First Ciass Larry HoUingsworth sets up personal phone patches for crew members aboard the frigate Yarnell, reducing the impact of transgiobal separation between family members.
discussion at club meetings around Chicago and on ham radio nets. Most of Ihe comments, he indicated, were directed against the inequitable city ruling. He also expressed concern that •should the court favor the city rather than the amateur operators, other met- ropolitan areas might follow suit, deal- ing u crushing blow to amateur radio.
NO-MONITOR REPEATER
OPERATION PROPOSED
The editor of 73, Ken Sessions (K6MVH), has submitted a proposal to the ICC that calls for toned repeaters to be allowed to operate without the requirement for UHF monitoring. Un- der present rules, no remotely operated repeater may be used unless the speci-^( fied repeater licensee is monitoring from the UHF control point stipulated on his license. The rules make it impossible for the sole owner of a repeater to operate his repeater from a mobile or from any site away from his control point- Sessions* proposal would make it legal for continuous monitoring to be abandoned when certain fail-safe measures and tone control have been incorporated into a repeater system. Tone-burst and whistle-on repeaters, under the proposed ruling, would re- quire no fixed-control-point monitor as long as effective automatic measures have been incorporated into the re* peater design to suspend operation of the repeater when its emissions deviate from the rules of the Commission, Un toned repeaters would continue to fall under existing rules.
Lucius Seneca^ an ancient philosopher, once said, "It is througli the essence of letters that friends are, in a manner, brought together/*
Although Seneca was talking about letters one writes, his thoughts can also be applied to the call letters of ham radio station WB^BDH, aboard the guided missile frigate USS Harry E. YarneH, presently ctrcling South America on Unitas XI operations.
Bringing people together via ham radio and telephone patches is the off-duty "pleasure'* of radioman Larry Hollingsworth, "It is a pleasure to be able to set it up so one of the men on the Yarnell can talk to his wife or girlfriend back in the States," empha^ sizes Hollingsworlh.
Running WBQJBDH is Hollings- worth's hobby. His main job is radio watch supervisor and controller at Yarnell's communications division.
Instrumental in establishing wa^BDH before Yarnell departed her home port at Newport, Rliode Island, HoHingsworth obtained an FCC license and was designated supervisor of the amateur radio activity.
'it has really been fantastic," Larry says. "We have been gone two months and I have completed almost 400 calls. It is a real morale booster when we are 8000 miles from home,"
Unitas is an annual training exercise involving the United States and the major maritime nations of South America. Larry and the Yarnell will circle South America and return to the United States in mid-December,
A real asset of the service has been demonstrated in situations where an emergency is involved. One chief petty officer on Yarnell received a letter from his w^ife saying they had suffered a very serious fire in their home. "The letter lacked many details which were important to the chief so we placed a call home via the ham setup," Rollings- worth stated.
A Navy wife, who is presently living in Norfolk J Virginia, and whose hus- band is on the Yarnell, in a letter to the YarnelPs commanding officer, wrote: ''Larry's efforts have certainly helped bridge the miles between my husband and myself, and those four wonder words, *1 love you - over,* have kept us close in spite of the miles that separate us. It is warming to know there are those who understand the voice of a loved one can make a long separation at least bearable,"
"We really have received out- standing cooperation from ham opera- tors throughout the United States/' the radioman said. "Almost all phone patch stations we contact seem more than willing to help us place our calls.**
He does encounter the humorous aspect also- He was talking to an operator in the midwest one evening and the man agreed to make phone patches for Yarnell men. However, the operator's wife was using the phone and after ten minutes of idle chatter over the airwaves, HoHingsworth final- ly had to thank the man and sign oft
Originally from Albia, Iowa, Hoi- lingsworth presently makes his home in
Middletown, Rhode Island, with his wife Lynda and two children, Lee and Lynette.
Larry is anxious to talk to any operators in the world who w^ould like to contact him on the air or by writing to him in care of the USS Harrv E. Yarnell {DLG-17), Meet Post Office, New York. Phone patches to the States are actively souglu and QSL cards are available.
GALAXY MOVES TO LINCOLN:
Something Big in the Offing?
LincoJn NB. The acquisition of Galaxy by Hy-Gain is now complete, according to R. A, Kobold, spokesman for Hy-Gain Electronics. The company has brought all Galaxy's operations from Council Bluffs, Iowa to Lincoln, Nebraska. Kobold hinted of some sparkling new products to be evolving from the merger, but would not be specific as to detail.
Galaxy watchers seem to think an unveiling of something new could take place at the big SAROC convention in Las Vegas this coming January. Ac- cording to reports from within Hy» Gain's executive offices, the company has reserved six bootlis for the occa- sion. This ^^extravaganza" attitude could point to an announcement of something the company feels spectacu- lar.
Page One
AMATEURS IN ACTION
Coast Guard Commends Ham For Meritorious Service
Washington, D.C. Admiral P. G. Prins Ivds personally expressed tlianks on behalf of the U. S. Coast Guard to J. P. Corrigan, a radio amateur who pro- vided communications with a ship at sea during a personal shipboard emer- gency*
In a letter to Corrigan, the admiraf reported: "On the afternoon of August 26, it was reported that the radio operator on ithe ship) Stella Lykes had apparently suffered a heart attack. This denied normal communications with tlie sliip and required tliat all inforina* tion be passed through the ship's ama- teur radio. From that time through the evening of August 29, when the sdip arrived in Honolulu and transferred the patient ashore, you maintained highly effective communications, passing medical advice for the U. S. Public Health Service, rescue operations infor* ma tion for the Coast Guard, and port arrangements for the ship*s agent, Oahu Railway and Terminal Ware- housing Company."
By way of expressing the apprecia- tion of the Coast Guard, Admiral Prins said, "'Your diligence and constant willingness to help are noted with pleasure. I fee) that this has been an outstanding display of the humani-
tarian spirit of amateur radio operators everywhere/'
Copies of the admiral's letter were sent to the Lykes Brothers Steamship Company, employer of the cited ama- teur, to Oahu Railway and Terminal Ware liou sing Company; and to the U. S. Public Heallh Service in HonoIuhL
KARLY 73 BRINGS $25!
Tlic January 196! issue of 73, good copies of which sold just three years i'^!> for as little as $10, now is bringing ^i:>. This issue, one of the rarest of tlie early 73 issues, was bid to the S25 price at the ham auction at the ARRL National Convention. This issue feat- ured the first published circuit for the RCA Nuvistor and was in wide demand during the early 60s* Now, with JFETs and Ihirigs, the issue is more of value as a collector's item. The article on using the Efco modulator with the Johnson 6N2 also helped make that particular issue rare.
HAM OPERATOR HELPS
BOY GET CRITICAL
OPERATION
tBeprinted from Florida Skip) by WA4ABY
Josef Darmcnto (W4SXX) has won the recognition of his community and the plaudits of the ham radio fraternity for his assistance in helping a small Italian child receive a crucial heart operation. His able use of ham radio paved Ihc way for 4*y ear-old Fabio Piampiani to undergo a heart operation last month by Houston's famed Dr, Michael Deliakey.
On June 9 Joe intercepted an urgent plea on 20 meters from I IBAX, Roger, a doctor in the Adriatic Sea fishing village of Civiianove. Roger outlined to Joe that the ctiild had an atrophied right ventricle and would die if he didn't get an operation within three montiis. Responding, W4SXX then contacted his wife visiting in Austin, Te^M wliu in turn talked with Dr, DeBakey in Houston- The famous pio- neer of heart transplant surgery gave his tentative approval for an operation at no charge, if the child could be brought to Houston.
Da rm en to, a Merritt Island resident and a physicist with the Air Force Eastern Test Range, relayed this infor- mation back to Italy and arrangements were made for the boy's trip to the United States* Concerned Italians do- nated nearly S6,000 so the boy could receive another chance at life. Finally, during early July little I'abio Piampiani made the trip from Rome to New York and on to Houston, W4SXX enlisted the aid of three New York hams
HAMS CITE
IN CONGRESSIONAL RECORD
Washington, D 'C 'The Honorable Emilio Daddario, Connecticut ap- pointee to the house of representatives, pointed to the service of U.S. radio amateurs during a meeting of the house in September. I-roin the Congressional Record c nines the accoimt of Daddario*s speech, which said in part: .
, J rise today to call attention of the House to the valuable services per- formed by amateur radio operators - '*hams" as they are frequently cat led. Operating their own private radio sta- tions, hams render emergency assist- ance in providing communications during disasters such as Hurricane Ceiia. We have all read accounts of such activities and are weii aware of the irivaluabJe help these volunteers provide. What is not so well |cnown is the continuing assistance hams provide in alleviating a most human problem — the loneliness and suffering that comes from the separation and lack of com- munications between our servicemen and their families. Those of us who daily see our wives, children, and close friends forget that there are hundreds of thousands of young people whose contact with their families is limited to letters and occasional photographs. Like the concerned public servants they are, hams have stepped forward to' lend their aid and provide radio com- munications facilities so thai service- men abroad can talk to their loved ones at home. Using '* phone patch''
CNER 2000 ATTEND ARRL NATIONAL IN BOSTON
by W2NSD
The Boston ARRL National Con- vention was an unqualified success this year with well over 2000 amateurs and their families in attendance, setting a record for ARRL National Con- ventions in recent years.
The sad part was the tiny display area, a far cry from a few years back when most of the manufacturers in our hobby supported these National Con- ventions. Outside of a few distributors, the main displays were by Drake, Mosley (Carl himself was ttiere, by gosh!), Cushcrafl (Les Cushman was there!), National, Swan, Signal One, etc., plus a few newcomers such as Ten-Tec, Eiirhorn, Lee, etc. Even the most avid scrounger of data was hard put to spend more than a few minutes in the exhibit area*
As outlined last month, pressure from HQ prevented the convention committee from permitting any 73 personnel from participating in any way in the programs. Fortunately 73 was able to get a small auditorium room for one of the convention days and hold several FM forums, meetings and discussion groups, show slides of Jordan, discuss incentive licensing, and keep conventioneers from starvnig to death with good New Hampshire freshly squeezed cider and homemade donuts. Many thanks were received for the feed from convention goers with either stunned pockcthoLvks or stunned taste buds from eating at the local restaurants.
The proliferation of local hamfests and conventions has put a strain on the larger manufacturers, but perhaps they should make every effort to save enough lime and money to support a national convention, for without their support a convention looks more like a smalMown picnic and is disappointing to amateurs who^have come from afar for the expected gala affair.
(K2JS0, W2I0M, and WB2CBP) to assist the boy's mother in finding the right plance from JFK airport to Houston.
Sorrowfully the child died on the operating table July 12, But at least the boy had a chance at life he wouldn't have had if it weren't for ham radio.
In an editorial entitled Humani- tarian Ham, the newspaper Cocoa To- day said, **We think this is a fine example of man's luimanity to man.*'
For his pivotal role in this out- standing example of the good in our Jiobby, Florida Skip last month saluted Josef Darmento as "Ham of the Month,"
Lele Defiiippis (HB9AMY), at right, poses with two others of his recent all-band DXpedition to Liechtenstein. QSLs are to be mailed to HB9AMY Box 768, Lugano 1, Switzerland.
equipment coupled directly to their own radio receivers and transmitters, hams call friends and parents of ser- vicemen on the telephones and let then] talk to their absent soldier in Vietnam who use military radio facili' ties over there. Acting as the vital link, the ham provides a much needed human contact between individuals separated by the war.
RADIO AMATEURS
"FILL IN" FOR LOST LANDLIIMES
Cuba, NY- When a work crew acci- dentally cut through an underground telephone cable recently^ tlie local civil defense group was alerted immediately, bringing to life an organized commun- ications network revolving around a 2 meter I M repealer.
Gailerd Perkins stations, working
Chaos repeater deployed at key what the Ocean
According to (WB21DQ), eleven through the Mt, (WA2UWT). were positions to plug I imcs Herald referred to as the ''tele- phone gap."
Volunteers manning mobile radios supplied through the CD office's RACES network - and some CB*ers — patched together an emergency net- work by which tlie Cuba Memorial Hospital and the fire, police, and am- bulance services of the community could maintain instant contact.
A local CD official said that no real emergency arose during the phone out- age, but the network was ready and operative '*jus. ^ ^ e/'
Page Two
*™
Swiss Government Okays FM Repeaters
Switzerland, The Swiss Government has given the go-ahead to amateurs who want to put up repeaters on the 2 meter and 450 MHz amateur bands. Due to the narrow operating spectrum in the 2 meter band only the input or output of a repeater can be placed in that band: the other end of the repeater system must be placed in the 450 MHz region.
Swiss amateurs are expected to set up their repeaters with inputs on the 2 meter band where they can make most effective use of mobile range.
MAHS Ops iKik UHF DX Renri
U. S. Hq., Ft. McPherson, Ga.- Bill Byrd (WA4HGN) of Muscle Shoals, Ala., and Paul Wilson (W4HHK), of Collierville, Tenn., set out to break the UHF DX record, and break the world record they did!
Bill and Paul are both amateur radio operators, and members of the Third U- S- Army Military Affiliate Radio System (MARS), as AD4HGN and A4HHKj respectively. Both are inveter- ate experimenters, anxious to advance the ''state of the art" in their avocation
INTERNATIONAL NEWS
From lARU Region 1 News: "AROUND THE REGIONS"
AUSTRALIA:
The Wireless Institute of Australia has secured permission for the use of slow-scan television on all amateur bands as authorized in Australia. The bandwidth of emissions shall not ex- ceed that of an A3 signal. Identifica- tion is to be by call sign in visual form on the televised picture and by tele- graphy on the telephony sound chan- neL
BULGARIA:
The 7th National Convention of the Central Radio Club of Bulgaria was held on 26 April .1970 in Sofia. Dele- gates from amateur clubs approved the methods of development of amateur radio in Bulgaria. The convention cal- led for further development of SSB telephony and VHF/LIHF amateur communications in this country.
DENMARK:
The following information con- cerning reciprocal licensing has been submitted by the Danish Posts and Telegraphs.
The Danish General Directorate of Posts and Telegraphs is prepared to consider applications from aliens pro- vided that they will stay in Denmark for a reasonable period of time and provided that they have a certain firm connection with Denmark.
case whether a license will be granted or not. If a license for operation in Denmark is granted, this will be done without a renewed technical examina- tion and code test
GERMANY:
The Distrikt Njedersachsen has plans to establish another training course in Wolfsburg which is supposed to take place during the Easter holidays of 1971. Talks with the management of the Wolfsburg Youth Hostel have al- ready been opened and it is most likely that the course will materialize.
The training will include lectures on techniques, laws, and regulations for amateur radio, and training in Morse code,
GHANA:
The latest edition of *^9GI News" reports the tenth anniversary of the inauguration of the Ghana Amateur Radio Society. The number of licensed amateurs in Ghana is now shown as 40,
MALTA:
The Malta Amateur Radio Society has obtained the use of a historic building, known as the Zabbar Gate, for use as its headquaxters. The build- ing originally formed part of the forti- fications erected by the Crusaders* The
NIGERIA:
NARS reports considerable interest in amateur radio at the Kaduna Poly- technic from where a station is active under the call 5N2KPT. The licensee of 5N2KPT is David Wilcox, G2FKS. It is hoped that arrangements can be made to acquire, without payment of cus- toms dues, equipment suitable to start a club station. Certainly it seems right that an educational institution should be able to obtain a concession from the authorities.
SWITZERLAND!
In Switzerland there were 917 ama- teur licenses in force at the end of 1969. Membership of USKA at the same date totaled 790 full members and 655 associates*
The regulations governing amateur radio have undergone some slight modifications in 1969, The minimum age for obtaining a license was lowered from 17 to 15 years. Operation of repeater stations is allowed on 450MHz and 2m.
USA:
The Foundation for Amateur Radio
Inc., a nonprofit institution devoted to advancing the interests of ama- teur radio with its headquarters in Washington, D, C-, announces the esta-
CLASSIFIED
^ViiJTi
t^ ty^9*x? Jy V<> iy*
Caveat Emptor?
r/5^iAi^5Hn^^j#>^
Price — $2 per 25 wi*ifds for non- -com m«*tcial adsi SIO per 25 words for business venture. No display ads or agency discount, Include your cheek with order. Deadline for ads is the Ist of tht* month two months prior to pubii cation. For ex- niaple: January tsl is the deadline for the March issue which will bt- mailed on the 10th of February, Type copy. Phrase and punctuate exactly as you wish It to apptNir. No all-capital ads* We will be the iua^e of suitability of ads. Our responstbnitv fnr errors extends only to printing a corrt-cL ad in a later issue. For $1 extra we can mainiain a reply box for you. We cannot cheek into each advertiser, so Caveat Emp- tor. . .
DIGIT ONE CONTROL DEVICES: Decodt^rs, cncoderi;. li^gic processors, autopatch, power supply. Compact* plug'in solid-state modules, Applica tion Notes /Catalog. Write* Digitone, Box Ta-ST, Bellbrook, OH 45505.
ROCll ESTER » N. Y, will again be headquarters for the huge W, N. Y, Ham f est, V. H. F. Conference and Flea
Market, May 15, 197K
CLEGG VENUS 6M SSB TRAN- SCEIVER, miit<!hini> AC 416 suiiply, speaker i excellent, $250. Ai5io NC-1)8, matching speaker; good^ $55. KlEOP, 1234 Ridgebrook Ct, S, E., Grand Rapids Ml 49 5 08. Tel. (616) 455-1594.
FOR SALE OR TRADE: Frequenele
Meters BC221 ; T.Sl 74; 78323. All with Powersupply and Modulation. Lamp- kin 20 5 A be via Li on Meter, Make offer for rash or trade for GriddiposciUator; Distortion Analy/er, RF Volt meter or what have you, KGIDD Walter Tille- man, 351 Furr Drive, San Antonio TX 78201,
EED HOT J 5RK Delta Tri-bander — Sensational breakthrough in Delta Loop design. Proven outstanding DX ant* Highest quality; also heavy duty high performance quads. Check our low prices. Island Electronics 4102 Ave. S., Galveston, Texas 77550.
NOVICE CRYSTALS: 40-1 5M — $l.:m: 80M — S1.B3. Free flyer. Nat Stinnelte Electronics, Umatilla FL 32784.
FABULOUS OLD TIME RADIO SHOWS
on tape. Drama, comedy, mystery. Catalog $1.00 (refundable with order), RADIO RERUNS, P.O.Box 724, Dept, 73, RtHlmond, Wash, 98052.
2M FM - GALAXY FM-210. Complete with power booster for mobile or 115V operation. Used for 73 tests only, $200. less crystals, Wayne Green, 73 Magazine.
FABULOUS CONDITION! SB 301 Re- ceiver with 400 Cycle CW Filter, $265; DX60A Transmitter and HGIOB VFO, $70. Jan WB6VRN, 1201 Grand Vista, Monterey Park CA 91754.
SALE: Super Pro 600 for Rack Mount, J. Modeste WA2LGJ. 615 Casanova St. Apt, 1, Bronx NY 10459. Tel; (212) 329-0147.
SR-2000 AND AC SUPPLY, realigned by Isi, will ship purchaser's expense, best reasonable offer. J, Richeson, Yolo High School, Rt. 1 Box 1900, West Sacramento CA 95691.
15 JOHN F, RIDER PERPETUAL TROUBLE SHOOTER MANUAL for sale ^ $35t) — or would trade for Swan-270-OR-Heath-lOl — OR sim. Trnscvr. L S. Olson (WnGagb) Box 337, Mendocini CA 95460,
THE 20th ANNIVERSARY DAYTON HAMVENTION will be held on April 24, 1971 at Wampler's Dayton Harra Arena, Technical sessions, exhibits, hidden transmitter hunt and an inter- esting program for the XYL. For infor- mation write Dayton Hamvention, Dipt. 7, Box 44, Dayton OH 45401.
SELL APACHE XMTR with SB-IO Adaptor, $100, Also Drake 2B w/Xtal cahbrator & spkr, $180, Paul Reuter, W-9-Rov, Robinson IL 62454. Tel. (618) 644-2234.
EDITORIAL
THE NAURU CURSE
by Dan Whit sett W4BRE
Of the 300 or so countries I have worked the past four years, two or three stand out as being unusually exciting contactti. These stand out not necessarily because they were tlie most rare, but because of the etTort I had to put out to get them - or maybe tho unusual manner in which they were worked. Just recently 1 made what luis to be one of my two most exciting DX contacts. Nauru is certainly not the rarest catch on the band, but for some reason it liad eluded nic througliout my DX chasing. I had seen in the various DX columns and magazines where the fellers were occasionally working Nauru, but never once did I hear him. 1 he main reason was perliaps that his operating hours would have meant for me to be on between 1—4 a.ni,, and I felt confident that someday I would tlnd hfm on during my regular hours. The montlis went by and still no Nauru. The call changed from VK9 to C21, and I continued to look for him. Then my confidence began to fade, as I began to read that the only operator there, C21JW, would be closing down for good verv soon.
Then I saw in Gus' "DX'er" that the iiiiddle of June was the deadline, I had one week to find and work C2UW - a station that I had iiol been able to find for 27 months.
So, with seven days in which to get the job done, I set my alarm clock the first night for 1 a,m- Listening until 4 a.m., I didn*t hear anything of C21J\V,
WA6FYC, one of the guys I had asked for assistance on the first night of this "mission impossible,*' He told me that C21JW was on 14 J 28, and that he would try to break them, and hold him for nie. I leaped out of the bed, and like Jim Ryan setting the world's record four-mil er, I dashed into the ham room^ turning on every switch I could find.
Just knowing that he was on the air, and that I knew what frequency was more than I could handle and stitl keep cook
Just as the receiver warmed up, I heard \VA6rYC on CW on 14.128. Then some Australian came back to him and said, *^Sorry OM, but C2UW just ORT'd, and ORT'd for good, since he's packing up to leave Nauru*"
There i$ no way in the world 1 can explain my feelings upon hearing those words . , ,but I believe every true DXcr w^ill know the emotions I felt.
Rut then, 1 heard a "break," and a voice said, "This is C21JW, Vm stiU listening." Oh Happy Day! My lieart almost leaped out of my chest Even though he stood by for WA6FYC 1 started pounding tlic kcyer, "C21JW DE W4BRE PSli PSE PSH K."
lie came back, he came back . . J've got him! Oh hang on . . ,don*t have a heart attack yet . , .please hang on until we exchange reports.
He turned it to me, I gave him a report and I was in the process of asking him to listen for me in the
of radio communications. They have conducted endless experiments; de- signed, built, and modiricd equipment, much of it furnished by MARS; and tried new techniques in preparation lor their record-breaking communications feat on 2300 MHz this summer. Bill, father of three, works for the Tennes- see Valley Authority as an instructor of student generator plant operators. Paul, also married and the father of two, is a television broadcast engineer for a station in Memphis, Tenn,
On July 9> Bill drove a panel truck to a place called Sunset Rock near Bon Air, Tcnn. Inside the truck was seem- ingly enough exotic radio equipnienl to monitor a space flight, and on a trailer behind, looking not unlike a large mechanical turtle, was a specially tuned and rigged 10-ft. dish antenna*
Working from an elevation of nearly 2000 ft. above sea-level, and using an astrocompass to point his dish antenna in precisely the right direction. Bill first attempted to contact Paul on the morning of July 10, Repeated attempts that flrst day were unsuccessful, but early on July 1 1 another call brought the looked-for response: **This is W4HHK reading you loud and cleari"
The record thus established was for 249 statute miles, as established by aeronautical charts. And the record is now official, having been recognized early in September tiiis year by the American Radio Rchy League.
To the uninitiated, the distance may not seem very astounding in this age of moon voyages and globe-girdling com- munications. But the record set by Byrd and Wilson was at a frequency of 2.3 GHz - approximately four times as high as that of the higliust-frequency UHl' TV stations on the air in must parts of the United States.
At that frequency, and even at those as much as 75 times lower.
Aliens have to adopt the usual procedure when applying for an ama- teur license (submit an application to the general directorate). It will always depend on a decision in each individual
members of MARS plan to restore the building and undertake conversion work, A picture of the Zabbar Gate with members of MARS appeared re- cently in the "Malta Times.'
communication is normally limited to iine-of-sight, or the horizon. And 249 miles is more than 160 miles beyond the horizon in the location used by Bill and PauL
Also, there\s the matter of power- Commercial UHF TV stations routine- ly use more than a milhon watts of power to send an acceptable signal 50 miles or less. Bill and Paul communi- cated over their record-breaking dis- tance using less than 1 kW, the legal limit.
It all Lidds up to a most impressive achievcmenl, especially when one re- members that it was accomplished by
two amateurs using mostly home-built or modified surplus equipment. If the two southern gentlemen who accom- plished it will excuse the expression, their feat stands as a notable example of modern yankee ingenuity.
/ y^
1
^......nient by it of a Hospitality Com- mittee with the objective of providing visiting foreign licensed radio amateurs with an opportunity to meet some of our local active hams and if desired visit a local amateur station.
PauJ M. Wilson of CoUierville, Tenn,
stands beside the antenna used in bis radio nnoon bounce experiment. Wilson is a member of the Third US Army Military Affiliate Radio System which provided most of the parts he modified in order to build his imposing radio station.
(L^R) A4HHK and AD4HGN, Opera- ting as W4HHK and WA4HGN on the amateur 2300 MHz Band^ set a new tropo-scatter distance record on 11 July 1970f when a two-way contact was made between Bon Air, Tenn. and Collierville, Tenn.f a distance of 249 statute miles.
WAR, NSS. NPG,and AIR had a combined total of 8,208 QSOs during the twelve hours and forty-five minutes devoted to the military-to*amateur
crossband portion of the communica- tion tests. Included in this total were 197 air /ground QSOs made by Navy aircraft on the east and west coast. Conirnemorativc QSL cards have been mailed to all contacts that could be identified. Any amateur who has not received a QSL card confirming his contact should address a request for confirmation to the appropriate sta- tion, or Armed 1 orces Day Contest, A iten tion: Headquarters, U^S.Air Force, !MUX)M. Room 5B53t, The Pentagon, Washington, D, C- 20310. This request must include the ama- teur's call sign, the station worked, time of contact, and the frequency utilized by the military station.
73 GOES TO VIEW AM
The 43 MARS stations in Vietnam and Thailand are ijII getting copies of 73 now on a gratis basis through the efforts of Alex Scherer A9EU of Ottawa, Hiinois. It is hoped that this amateur radio magazine will interest liic uKiny operators at these remote stations in getting on the ham bands and in pursuing amateur radio when theV return to the U,S»
Page Three
MERRY XMAS AND HAPPY NEW YEAR from WOCVU, lowa*s most truthful station. Generally on 20 meter SSB. Collins KWS-1 and 75A'4. Telrex Optimum spaced beams, U'OCVU, Chas. W, BoegeU Jr., 1 500 Center Point Road N, E., Cedar Rapids I A,
TR4 & AC3 just factory checked and alined. First Certified check for $450 winner. David Beckwith, W2Qm,M, Box 226, Pompton Lakes NJ 07442.
TECH MANUALS — R'390/URR,
R-390A/URR, TS-1H6D/UP, BC-639A. R-274/FRR, OS<aC/U, $6.50 each; R-274/FRR, 08^C/U, $6.50 each: TS-174/U, TS-175/U, TS-323/UR. $5,50 each. Hundreds more. S. Con- salvo, 4905 Roanne Drive, Washington DC 20021.
HA-460 AND TR-lOB, both hghtly used, $75 each, ppd. D.i^dd Welty, 320 N. Blackstone, Tukre CA.
HAM-M ROTOR AND CONTROL*
$94.95. Ideal Christmas gift for Dad, RG8U foam coax $A0 a foot FOB. Monte Southward, WB8GZQ, Rl, Upper Sandusky OH 43351.
BUY, TRADE* SELL USED RE- CEIVERS* or trade for new general merchandise. Available HQ-200, 51S-1 SX-122 and BC-799B. 1 0-day money- back guarantee. 30-day warranty on parts and labor. Steven Kullmer, Ever- green Hatchery, Dysart, Iowa 51114,
FOR SALE EICO 7 20 xmtr — $45.00;
Johnson 6N2 xmlr — $45.00; HA-1 Kever w/VIBRO Keyer — $65.00 ;ARC-b rcvr w/ll5 VAC p. s. — $20.00; Novice Xtals - $,75; Regency GT-523 mobile CO* xcvrs — $35.00 each; EICO 221 VTVM — $20,00i AC-1 QRP xmfcr - $20.00; P-2 SWR meter — $15.00. Need cash for gradu- ate school. Will ship collect, R. O. Lust, WB9DWG, 320-4 North Tratt St„ Whitewater, Wl 5 3190,
TOLEDO MOBILE RADIO ASSOCIA- TION'S 16th ANNUAL HAMFEST AND AUCTION will be held February 21, 1971, Lucas County Recreation Center, Maumee, Ohio. $1.00 registra- tion. Open table sales. Map and info write: TMRA W8HHF, Box 273, Toledo, Ohio 4 3 GDI.
GREENE Center dipolc Insulator, with .., or ... without balun. See Nov^ember issue 73, page 107.
SAROC, January 7-10, 1971, Flamingo Hotel Convention Center, Las Vegas, Nevada. Sponsored by Southern Nevada .'\RC, Inc, Box 7 3, Boulder City, Nevada. Advance registration +14,50 per person accepted until Jan- uary 4, regular registration at door, includes Flamingo Hotel Late Show and drinks, Sunday breakfast, Cocktail parties, technical seminars and meet- ings, ARRL, DX, FM, MARS, QCWA, WCARS-7255, WPSS-3952 and WSSBA. Ladies program. Flamingo Hotel SAROC room rate $12.00 plus room lax, per nigh I, single or double occupancy January 3 through 12» 1971. Mail accomodations request to Fla- mingo Hotel. Mail advance registration to SAROC, W7PRM, Club president. W7PBV, SAROC Convention cliair- man,
DRAGON FLY .„ antenna, for 20-40-75 meters ... no traps ,,. no compromise •.. eight months in devel- opment ... one feed line ..• SWR one to
one guaranteed. Construction drawings $5.00. Box 423, Wakefield RI 02880.
FOR SALE: Heathkit HW 32, $85.00;
mint condition. M. Kaufman, 36 Har- vard Ave., Brook line MA 02146.
MSI-DTL INTEGRATED CIRCUITS: Guaranteed new — gates $,56, F/F $.72, dual F/F $.92, MSI $2.00, dual Lamp drivers $1*60, Other inexpensive parts, Mitch^Lan Electronics Co., Dept, 7370, P. O, Box 4822, Panorama City CA 91412.
CAPACITORS. 100 MFD at 3 kv. Aerovox or Sprague, 6" x 8*' x 14", Single terminal welded steel cans. 2 for $35,00, FOB. W5DAU. Box 1443, Hobbs NM 88240.
FOR SALE — MAKE OFFER: Gonset GSB-100, SSB XMTR; Hammarlund HQ-llOC; Homebrew 800 watt linear. John McLean, 5603 N* 12th Ave. Phoenix, AZ 85013
FM CRYSTALS FM-210. They're ac- curate, by International, Transmit: 146 22, 146.25, 146.28, 146,31, 146,34, 146.46, 146.76* 146.94. Receive: 146.76, 146.88, 146,94, $5 each, singly or in lots, Wayne Green, 73 Magazine.
WEST COAST HAMS buy their gear from .4mrad Supply Inc. Send for flyer. 1025 Harrison St.^ Oakland CA
but I did talk with several Calif ornians who had worked him, 1 told them of my plight, and asked them to call me if they should hear him.
The next night when I heard some- one mention his call, my hopes got up and I called in , . .but he had just left a few minutes before. Knowing he was around somewhere, J frantically searched the band that night, but absolutely nothing.
The fourth night my clock again went off at 1 a.m. Bear in mind that I would only have been asleep for an hour or so, and when the clock would go off, it would scare me half to death. Again 1 found a QSO where C21JW had just signed out to go look for a friend. 1 searched the band and found his friend, but no Nauru.
Again the fifth night . . , nothing. The sixth night, same story - and 1 was beginning to believe I had the Nauru curse.
On the seven til night, whicli was going to be my last try since he was due to leave in a day or so, and since there was no way in the world I could survive this ordeal any longer, 1 tuned the band for two hours ,. .all in vain. Finally giving up, admitting that the Great White Father didn't have in his plan for W4BRE to work C21J\V, 1 staggered off to bed,
T must have only been in bed for 10 minutes or so when the phone rang, scaring me out of my wits; it was
phone band, when, forgetting that my amplifier was tuned up around 14*275, Blam! FUSES BLEW! OH NO! I've lost him. Pve LOST NAURU. WE HAVEN'T YET EXCHANGED REPORTS.
If I thought 1 was panicked when 6FYC first phoned me, thai was nothing compared with now. I WAS OUT OF MY MIND. Well, I must have set a workPs speed record because when 1 got back on the air C21JW was telling me that he couldn't go to the phone band because he had to leave. Good enough, I was plenty happy just to get tlic contact.
WA6FYC and I moved up to the phone band, and 1 was tlianking him . . .offering to send him money, my car, my house, anything in appreci- ation, and mopping the sweat off my brow, trying to regain a little com- posure, when "Break, Break, this is C21JW/'
He had a change in plans, didn't have to leave just that minute, and came up and ragchewed with 61''YC and me for 30 minutes!
What an experience . * J was dying to tell the people at the onicc and my other friends about it.*. but no one , . .absolutely no one but an honest- to^goodness true DXer could under- stand and appreciate this absolutely absurd, insane, and ridiculous under- taking, and why, after it was all over, I would say to myself.,, it was well worth it
SELL HEATH DX'60A» 5 crystals. Used very little Guaranteed to be in good working condition. Make offer. Arris Sigle, 543 N. 2nd, Osborne, Kansas 6747 3,
VARIAC, 120 volt J 20 amp., uncased, new $25.00 each plus shipping (25 lbs. each). Brian Sherrett, TUSLOGj Dept. 6 Box 557, APO New York 09254.
TFRED OF ^^MICKEY MOUSE'* TRANSCEIVERS? Immaculate KWS-1, 75A4 (.800 MHz, 2 A MHz filters) aU factory modifications* Corn- del, Shore 444, WiD demonstrate/ guarantee. Top-notch, $1,000, (813) 646-5349, nights.
WANTED: Heathkit HA 14 Linear Amplifier with or without tubes, HL9KQ American Embassy, APO San Francisco CA 9S301*
Page Four
Q^e/9^u ^^r^J^m^J
Sage, who is celebrating her first birthday on Decennber 31, my wife Lm, and I at I wish every one of you a
very merry Christmas. We're sitting on one of those Heath Boonie Bikes, by the way, and we have lots of fun bouncing around the New Hampshire hills and forest trails on them.
Director Green?
Many readers ask why 1 don't run for ARRL director since I know the organization so well and have proposed so many ways of improving it. Frankly, I somehow doubt tlial the executive committee would waive the bylaw prohibiting ham publishers from running for director, even though they have tn the case of ARRL stalwart KONL.
It would be nice to be able to run for the job and I think I could be a considerable help in bringing the League into the 1970s if 1 were elected. What, you ask, would I do as a director of the ARRL to improve that conservative old institution?
Better Directors
Probably the first thing I would do would be to try to encourage amateurs to run for director in other divisions of the ARRL who are inter- ested in improving amateur radio to replace those directors who are there for the prestige of the office rather than as true representatives of their constituents. Little can be done to improve the League until at least nine of the 16 directors want to improve it Right now it seems hopeless.
Sound Financial Basis
There is no excuse for the League losing money every year! There are many ways to increase income and to cut expenses. By reducing
10
the size of QST by a fraction of an inch so it would fit on modern web offset presses and by using more modem paper a saving of thousands of dollars a month can be achieved. There are many other areas where substantial savings can be nrade without losing any valuable services. We can see that the League investments are bringing in a maximum return. We can plan ahead for continued nonprofit operation, but an eventual end to the tax-free status.
Washington Lobby
Only wlien tlie ARRL has a registered lobby in Washington can it truthfully say that it represents amateur radio. Such a lobby would put an end to the double talk excuses from HQ and would give amateur rndio the first real opportunity to protect itself in Washington. A monthly newsletter to congress would be invalu- able in laying the groundwork for a lobby. Amateurs are making news all over the world, but few outside of our hobby hear about it. We need to beat our drum. It is entirely possible that much or all of the cost of a lobby in Washington could be financed entirely separate from the ARRL, thus keeping League expenses down.
Emerging Nations
The key to the future of amateur radio lies entirely with the votes of member nations of the International Telecommunications Union at Geneva. It would behoove us to keep this in mind and devote some time and energy towards pro- tecting our frequencies internationally- The ITU is presently controlled by the emerging nations of Africa and Asia and the League could be of great help to many of these countries at little cost. It could offer custom-made amateur radio regula- tions for individual countries, complete with amateur license exams. It could organize expedi- tions to these countries to explain the value of amateur radio to the heads of the countries and their top officials. Club stations could be organ* ized in the countries, probably in high schools. If equipment is not available it could be arranged to be donated by interested amateurs and manufact- urers. Every effort should be made to assure amateur radio votes at the ITU,
A Modern QST
The club magazine would interest many more amateurs if it were written in a warmer and more friendly tone. It would look more like 1970 with modern type and better layout design. Readers miglii have more confidence in the League if both sides of controversial problems were openly discussed in QST, Some of the departments which fill up so much of the space in QST could be shortened or eliminated in the interests of bringing information of interest to the most readers.
Directors Meetings
The inability of management to get decisions from the directors more than once a year has
(conu on p. 102)
73 MAGAZINE
For The Experimenter !
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SAX'1
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A small signal amplifier to drive MXX-1 mixer; Single tuned input and link output. Lo Kit 3 to 20 MHz
Hi Kit 20 to 170 MHz (Specify when ordering)
PAX-1 Transistor RF Power Amplifier $3.75 A single tuned output amplifier designed to follow the OX oscillator. Outputs up to 200 mw can be obtained depending on the frequency and voltage. Amplifier can be amplitude modu- lated for low power communication. Frequency range 3,000 to 30,000 KHz.
BAX-1 Broadband Amplifier $3.75
General purpose unit which may be used as a tuned or untuned amplifier in RF and audio applications 20 Hz to 150 MHz, Provides 6 to 30 db gain. Ideal for SWL, Experimenter or Amateur.
Write tor comptete c&tahg.
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Last Chance for SAROC Flight!
From early indications, the upcoming "fun" convention in Las Vegas (January 1971") will be the biggest success of any ham conventioii ever held anywhere -bar none. If you've got a vacation comings or if you would just Uke to take the wife and get away for a weekend, by aU means attend! Even if your wife doesn't like conventions, sheUl want to go to this one - because Las Vegas is a magicland - probably the only place in the world where you routinely bump into TV personalities, movie stars, and other famous personages. (Last year I poked Don Rickles with a Motorola telescoping antenna,)
If youVe planning a West Coast vacation anyway, here's your chance to be really sneaky. You can fty on one of SAROC's two chartered *'champagne*' planes (from New York or Chicago)* stay a full 3-njght weekend at the Flamingo* enjoy a couple of stage shows, and buddy it up with hams from every where - all for less than conventional airline rates.
As if that weren't enough, additional free *'flings" are being sponsored by public-spirited groups and organizations. For example, Ham Radio magazine is footing the bill for an all-you- can-drink cocktail party on Thursday night; the next evening, Sw^an Electronics is picking up the tab for tlie same kind of arrangement. And the FM boys in Las Vegas are planning a head-busting three-night open house, with free haidj soft, and hot stuff to drink.
The round-trip "everything included" plane fare from New York is $229 (from Chicago, it's $199) J and there's a full-page ad in this issue that tells exactly all that the price includes. But the ad doesn*t tell you that SAROC is the Western convention, where the accent is on fun and the emphasis is on ham radio. This January will mark the Sixth Annual Radio Operators Convention and the fourth (and by far the biggest and best) national FM convention.
With the August FM lineup (practically all the big names in repeaters) and the unprecedented current popularity of VHF FM, a turnout of more than a thousand FM*ers is expected- This, coupled with the already well established popu- larity of the other aspects of SAROC, should make it a convention to top all others in ham history.
If you^re going, better make plans now. If you don't reserve a seat on one of the charter flights before November 25, you'll have to get there under your own steam - and that could get expensive.
Discrimination. . .
Wayne Green used to mention occasionally that the League wouldn^t let him speak at this convention or that — that the League wouldn't let him set up a booth for 73 at various League-sponsored affairs, and other seemingly unfriendly or discriminatory actions on the part of the ARRL, To be quite blunt, I only half-
beheved him because his charges all seemed to be so fantastic.
But at the recent Boston convention, I found out for myself. 1 was invited to speak on repeaters, and accepted. But the League said no. I saw a letter Huntoon had written saying that I wasn't fit to speak at any League convention.
A few of the fellows protested to the League, even to the extent of offering mild threats of ^'breaking off with ARRL affiliation. But Robert York Chapman, New England Division's director, answered one of the protestors with a counterthreat. It is never too late, he said, for the League to back out of backing the convention. Clearly, the convention planners had to make a choice between the League and the staff of 73.
Working almost surreptitiously, but closely with the convention planners, 73 rented an auditorium in the hotel where the convention was being staged, then held its own programs with its own speakers. And the whole thing went off extremely well.
The next convention was Tarry town, another League-sponsored affair taking place within the Hudson division- I suggested to Wayne that we set np a booth there.
"Go ahead and try," Wayne told me. ''But I can teU you now that they^ll tell you their booth space has already been sold out."
Well, I tried anyway, 1 contacted Harry Dannals, who told me in a very friendly and congenial manner that there would never be any space for 73 in any convention that he is involved with.
Now, fellow readers, I have just told you the truth. There is not one ounce of exaggeration in the foregoing- And if Harry Dannals is an honest man, he will certainly admit that what transpired between us was exactly as I have related -
1 charge Harry Dannals with discriminatory practices, and I charge the ARRL with sanction- ing such practices. I don*t want to make an enemy of Dannals, because, quite frankly, he is a personable and congenial fellow. But he must learn that his acts are not those of a responsible director.
Those of you in the Hudson division who agree with me could probably carry a great deal of weight if you^d drop Harry a line letting him know how you feeL
- . ,K6MVH/1»
12
73 MAGAZINE
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1
M
Ed. Note:
Last month (or the month before), Having Dave took on the Technicians in the country, and after three rounds went down for the count. This month, as "Dave the Brave/' it's Conditionals. Watch for his subsequent attacks on Novices, premarital sex, Mexican food, the electoral college, and motherhood.
In previous issues 1 have mentioned phone patches* usually Latin-American in origin, which have been QRM'ing the DX frequencies, especially the !ow end of the 20 meter phone band, in ever growing numbers. The response of the readership has not been particularly encouraging; there seems to be a feeling that nothing can be done about the situation because^ in the words of one of my correspon- dents, ". - .foreign operations cannot be regula- ted or conliQlled." While this is partially true, let me assure you that it is not completely impossible to effect changes. There is no basis for the total frustration which has been expressed.
There are certain actions which can be taken that may prove to be effective; for example, a large per- centage of these patches are being run by stations iri Florida and Puerto Rico, both of which are indeol subject to the regulations of our own licensing author- ity. The FCC - while many U.S. hams may consider it unsympa* thetic to the needs and desires of the amateur fraternity - is quite responsive and sensitive to reasonable requests, when they are made in a responsible and constructive manner. It is far from an impossibility to envision the establishment of an officially designated frequency allocation which would limit the patches to sequestered portions, as is presently done with RTTY, thus going a long way toward eliminating the annoyance.
But there is another side to this coin. The phone patch stations are also entitled to a fair measure of consideration. There is no founda- tion, either in the regulations or by operating precedent, for DX'ers to feel that they are entitled to a preemptive *iock" on those por- tions of the bands which they regard as desira- ble, and that they are perforce within their rights in bludgeoning the opposition into sub- mission by their sheer weight of numbers, by using power amplifiers, extravagant antenna systems, or by any other means. There is still a right and wrong, after all.
The problem is a knotty one. Both groups have raised legitimate complaints. Both have valid grievances. And somewhere along the tinef
accommodations must be found so as to create order out of chaos.
A tangential point is being raised by the General class operators. Many DX stations seem to restrict their listening frequencies solely to our U.S. Advanced and Extra class subbands, making it virtually impossible for the Generals to compete for DX on an equitable basis. Of course, it must be acknowledged that it is awfully simple for anyone to master the rela- tively elementary material covered in the single examination element which upgrades them to
the Advanced class. Anyone who is at all serious about work- ing DX would be more than willing to devote a small por- tion of his time toward accomplishing this simple task.
The Conditional class ham, however, is faced with a genu- ine crisis. He must qualify in aU ele- ments, both CW and theory . * Js given absolutely no credit for any elements in any of the exams . . .hence must pass the 13 wpm code test plus the General and Advanced theory elements. Many of us are prone to forget that there are vast numbers of people who hold this pade. If you will examine the figures (they may be found in recent issues of the callbook), you will learn that of the total ham population, more than 10% fall into this category. There are 10 states in which Conditionals outnumber Generals! In a few of these states the examination points are truly beyond a reasonably convenient traveling radius. But in several of the states referred to, this is not the case, and I fear tJiat the Condi- tional ticket has been acquired under terms which could not be regarded as completely justified by the circumstances. The regulations have been applied, in all too many instances, to circumvent the qualifying requirements, and some persons who could easily be expected to get to the examination points have simply exaggerated the hardship angle of the physical infirmity excuse. 1 am personally acquainted with several self-styled "invalids" who eat like horses, work like mules, and climb up and over ridges like mountain goats during the deer
fcont on p. 104)
T4
73 MAGAZINE
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SB-220 2-kW Linear AmpMfier,„the hottest perform- ing, lowest cost final avaifabie. Delivers 2 kW PEP SSB. 1 kW CW & RTTY on the 80 thru 10 meter bands. Built*in solid-state power supply, 120 or 240 VAC. Pre-tuned broadband pi-input for maximum efficiency, low distortion. Two front panel meters for continuous monitoring of plate current, plus switch- selected monitoring of grid current, relative power & plate HV,
NEW 16-101 Frequency Counter., .a must item for every shack — and now at a price you can afford. De- livers accurate counting from 1 Hz to over 15 MHz. All integrated circuitry for top performance, high re- liability. Automatic trigger level for wide range input without adjustment. Five digit readout with Hz/ kHz ranges & overrange indicators give eight digit capa- bility. Input impedance 1 megohm shunted by less than 20 pF for low circuit loading.
NEW HM-102 Wattmeter/ SWR Bridge,.. the most use- ful station accessory you'll ever own. Measures RF power to 2000 watts in 10-200 & 100-2000 W ranges. Modern low- loss torrodial circuitry. Built-in calibra- tor permits 10% accuracy throughout the 80-10 meter bands. Built-in SWR capability permits proper tun- ing, correct matching,,, ideal for antenna experi- menters. Remote detector permits placement of meter in any convenient location.
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descendant of the world-famous HW-100. Includes all the features that made the HW-lOO the choice of thousands..* plus: improved receiver circuitry for 0.35 uV sensitivity? new 36-to-l ball-bearing dial drive for smoother, more responsive tuning; new front panel switch-selection of built-in 2,1 kHz SSB crystal filter or optional 400 Hz CW crystal filter; new front panel styling. It all adds up to the only truly low cost, high performance rig around-.* the new HW-101, Kit HW-101, 23 lbs, f 249,95*
«' •
HW^fG Novice CW Transceiver,., a high performance 3-faand CW transceiver. Covers the lower 250 kHz of 80, 40 & 15 meters, 75 watts input for novice class, 90 watts for general. True break-in CW with solid- state TR switching. Less than 1 uV sensitivity? 500 Hz selectivity with high quality crystal lattice filter^ Provisions for VFO transmit with Heathkit HG-lOB VFO.
Kit HW-1G, 25 lbs,
.#■••*
* * * * ^ * *
$109.95*
1^1 |
||
j!^ fW i^vin*^ |
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111 ■-'^1 |
pill 1 |
FREE 71 CATALOG
Describes these and over 300 other Heath- kits. Save up to 50% by byildtng them your- self. Use coupon and send for your FREE copy!
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I I I
I I I I I I I 1 t I -J
SOLID
STATE
Robert R Bloom W6YUY 8622 Rubio Avenue Sepulveda CA 91343
My original thoughts about under- taking a design project of this magni* lude were brought about tlirough a chal- lenge by W6EGZ, after having just com- pleted a three-year design of a solid-state receiver. This was early in 1966. Based upon the complexity of the receiver it was anticipated that about one year would be required to complete the transmitter. This would mean using all available evenings and weekends, abandoning all on-the-air oper- ation and all other aspects of ham radio. As with the receiver, it took a similar three- year period.
The big hangup in progress was encoun- tered in designing a satisfactory third-mixer stage, free of parasitics, I tried many mixer configurations initially without success.
It wasn't until the advent of a magical *'black box" concept that appeared on the industrial electronic market, cloaked in secrecy and at a price of just under $200 that progress once again was under way. This started a frantic search for literature and information as to how this thing called a **double-balanced mixer" was operated. I say ^'magical" as this circuitry is so versa-
tile that it can be used as a phase detector, frequency doubler, current-controlled attenuator, balanced modulator, pulse modulator, phase detector, etc. But let's start at the beginning.
Were it not for the availability of all commercial test equipment this project would not have been attempted. Such items as a Hewlett-Packard counter, gener- ators, and meters; Tektronix oscilloscopes: Measurement Q meter and grid dip oscilla- tors; temperature-controlled oven; sheet- metal cutting and bending equipment: and a Heliarc welder were some of the items used. For those who wish to duplicate all or part of this system, all pert men t dc and signal voltages are called out and all perti- nent coil data can be found listed iji Table L All circuits other than the bulk elements of the power supply and the final are of modular construction; in today's teelv nology of miniature construction this is the easiest and neatest, and lends itself readily to circuit change.
The mdividual circuits were first bread- boarded, checked out, and then made into modules using single-sided 5/16 in, copper-
16
73 MAGAZINE
Table !. ^ |
Coil and Transformer Data. |
||||||
CofI or Trans. identify |
Core Material |
Primary Turns |
Secondary Turns |
Tap from bottom |
Wire type |
Motes |
Transmitter Stage |
T |
Ferrox-Cube cup core tSIIP AT00-3D3 |
SO (700/iH) |
16 |
Pri. 7/41 Sec. 15/41 |
Unloaded "Q" 2B0 Resonant at 453 VWz with 170 pF |
Balanced modulator |
|
Tl |
Ferrox-Cube cup core I408P At00~3D3 |
70 (500JUH) |
7 |
7/41 Litz. |
''Q"UnL 230 |
453 kHz LF ampL |
|
T2 |
Ferrox-Cube cup core 1408P A-40-4C4 |
30 (40 /iH) |
2 1 |
4 |
30/44 Litz. |
^'Q"Un . T70 |
1st nyixer 2045 kH; |
13 |
Powdered-iron slug- tuned ceraniic form Vi" dia both coils |
40 |
5% |
7/44 Lit£. |
^'Q"Unl. 55 ^'Q* Loaded 5 |
Broad band, 2nd mixer |
|
T4 |
Ferrox-Cube toroid 266T-125-4C4 |
13 Tr if liar |
13 26 tota wound |
26 solid Teflon cov. |
Sec tap is the end of one winding St start of another. |
Double- balanced mixer |
|
T5 |
Ferrox-Cube toroid 266T-125-4C4 |
9 Trifilar |
wound |
26 solid Tef ton cou. |
Pri tap is the end of one 9-turn wind- ing Si start of other 9-turn winding, |
Double- balanced mixer |
|
L6 |
Powdered-iron slug- tuned ceramic 'A dia |
25 |
28 solid enameled |
Trim with 8 35 pF miniature trimmer 8i fixed 75 pF silv mica capacitors |
7.0 MHz transistor rf ampI |
||
3/8" ceramic, brass, slug-tuned |
lOV. |
24 solid enameled |
No trtmmer |
14.0 MHz |
|||
Powdered -iron sfug- tuned V*" cerarTiicform |
\VU |
26 solid enameled |
Trim with 8-35 pF miniature trirnmer |
21 MHz |
|||
Powdered- iron slug- tuned y^" ceramic form |
to |
20 solid enameled |
No trimmer |
28.0 MHz |
|||
L7 |
Powdered-iron slug- tuned]^' ceramic form |
15 |
2^/4 & 9 turns |
26 solid enameled |
' |
Band selec- tion osc 3rd mixer |
|
T8 |
Ferrox-Cube cup core t40SP A-40-4C4 |
50 |
2 |
Pri 32 Sec 28 |
Resonant with 22 pF silver mica at 24.5 MHz |
1st mixer, osci lator |
|
T9 |
Powdered-iron slug- tuned 3/S' ceramic |
80 |
20 |
Pri24 Sec 9 & 15 |
32 so id enameled |
See text |
Vfo output transformer |
L10 |
Powdered' iron s ug- tuned Va"' ceramic form |
25 |
28 solid enameled |
Trim with 8-35 pF miniature trtmmer & 75 pF fix. silv mica |
1 28 Y7 driver plate, 7 MHz |
||
Brass, slug -tuned 3/8" ceramic form |
15 |
24 solid enameled |
Trim with 7 25 pF miniature trimmer |
12BY7 driver plate, 14 MHz |
|||
Brass, slug-tuned 3/8'' ceramic form |
10 |
26 so id enameled |
Trim with 8-35 pF miniature trimmer |
12BY7 driver plate, 21 MHz |
|||
Powdered" iron slug- tuned y*" ceramic form |
9 |
20 solid enameled |
Resonate with 10 pF fixed silver mica |
12BY7 driver plate, 28 MHz |
|||
L11 |
T* dia AirDux 1606T coil stock |
15 |
3&8 |
14 plated |
Tune with 200 pF 2kV split-stator, Johnson 200FD20/ 155-505 C- 11 midget air-tuned 300 pF (Han marlund MC'325-MI |
M ultiba nd coupler, final |
ctad board, (Printed circuits could have been used; however^ the construction about to be described was preferred as it lends itself to change where printed cir- cuitry does not.)
It was first necessary to redraw the schematics, keeping all symbols to actual size and positioned exactly as they would appear on the finished board (according to the overall block diagram, Fig. 1), A dot
DECEMBER 1970
17
ICO vf
ji — :tr
ON injLHSJuir
SWITCH
9- f 0'>0
1
Tl I F MiPL ♦J3 KH*
liJKt«
T^
j»
Figr. 3* Audio, balanced moduiaior, mechanical filter, i-f amplifier, carrier oscillator, and carrier buffer amplifier.
for linearity monitoring and testing. The mechanical filter is one of the higher quality Collins multi-element 3J kHz variety with steep skirts down to 90 dB. The input is series tuned while the output is series-parallel tuned using capacitors in a divider configuration. The loss introduced
by the filter is only 9 dB and the gain of the following i-f amplifier had to be severely limited by tapping the coil of TI near the bottom end and inserting degener- ation in the emitter of Q5.
Overall gain measurements for this board were made using a 10/1 divider scope probe connected at the collector Q4 of the i-f amplifier. Using a single tone signal and no carrier, the 50012 pot in the audio amplifier input circuit is set for a 2.5V p-p indication measured at the base of QL inserting carrier to produce a 100% modulated sideband signal, the amphtude
will increase to 4-8V p-p. Turning off the carrier and switching to a two-tone audio signal the indication will be 3.8 V p-p.
The next board, which is located in the lower left-hand corner on the bottom of the chassis, contains the 2045 kHz first mixer and 2,5 kHz crystal oscillator* The major problem encountered with this stage was in designing a mixer transformer, T2, with a 0 high enough to reject the 2.5 kHz oscillator signal from its output. Tills was finally accomplished using the core material and data as furnished in Table L
The L8 kO series resistor from the 453 kHz i-f to the base of the second mixer was selected to limit the signal to the mixer. With a two-tone signal, the mixer output amplitude at the collector of Q6 is 1.9V p-p, A voltage divider network consisting
Powder supplies and compiete final amplifier.
Vfo with lid removed: also shows selectable sideband crystals and balanced modulator
20
73 MAGAZINE
,1 1, |
|
-^H^^ |
Important
E&E Books from SAMS
Beam /imf Antenras
Dipote and
Long-Wire Antennas
^it*«!»
Single SIdebanif: Theory and Practloo
by HABRY D, HOOTON, W6TYH. This one-souTce
guide emphasizes basic principles and cir- cuitry of ssb. Covers the origin of ssb, the derivation of ssb signals, carrier-soppression techniques^ sideband selection, and a com- plete analysis of all types of ssb equipment. Order 24014| on^.,*^ , $635
73 DIpole and long -Wire Antennas
by EDWARD M, NOix, W3FQJ. The first com- pendium of virtually every type of wire an- tenna used by anaateurs. Includes dimensions, configurations, and detailed construction data for 73 diflferent types. Appendices describe construction of noise bridges, line tuners, and data on measuring resonant frequency, velocity factor, and SWR- Order 24006, only $4.50
73 Vertical^ Beanii and Triangle Antennas
by EDWARD M. NOix, W3FQJ. Describe the
design and construction of 73 different an- tennas used by amateurs. Each has actually been built and air- tested by the author. Ap- pendices coyer construction of noise bridges aiid anteiiiia line tuners, as well as measure- ment methods. Order 2402 1, only , , . . $4*95
Electronics for the Amateur
by LOUIS M, DEZETTEL, W5REZ, This IS one of the few books on the theory of electronics and radio that programs the material for the ama- teur. Discusses radio-wave propagation as it applies to amateur band frequencies, recep- tion and transmission pertaining to ham equipment, and the specM field of antennas and now to feed them. Contains all the infor- mation required to pass the theory sections of the FCC exams. Order 24022, only $7.95
18th Edition of the famous E&E
RADIO HANDBOOK
by WILLIAM I. ORE. W6SAL Completely updated editioiitybf the famous cianmunications book that is the electronics industry standard for engineers, technicians, and advanced ama- teurs. Explains in authoritative detail how to design and build aU types of radiocommuni- cations equipment. Includes ssb design and equipment, RTTY circuits, lat^t semicon* due tor circuits^ IC'Sj and special circuitry. Order 24020^0^ .^ . - , . . $13,S0
Radio Amateur's F-MAapoater Handbook
by KBN SESSIONS, JR„ K6MVH. The definitive work on the vital and virtually undocumented subject of amateur f-m repeaters. Chapters include: Preparing and obtaining sites for re- peaters; How to build a repeater; and Re- peater applications. Includes an f-m repeater directory. Order 24008, q^^fy . ,,.... $6,95
Amateur Tests and Measurements
by Loma M. dezettel, w^kez* Shows how to accomplish virtually all performance tests on amateur transmitters, receivers, and anten- nas, and how to make required adjustments. Order 24007, only $5.50
Ham and CB Antenna pimenslon Charts
by EDWARD M. NOLL, wSfqj. Tabulates (di- mension data in feet and inches for all the popular antenna configurations. Charts are so subdivided that an antenna can be dimen- sioned for a specific frequency range accord- ing to license class and mode of operation. Order 24023p only $1,95
Order from your electronic parts distributor or send coufion below^
EDITORS and ENGINEERS
Howard W* Sams & Co-, inc., Dept, 73-110 4300 W- 62nd SL, Indianapolis, Ind. 46268
Send me the fodowing books: Nos,_, .
.enet«
n Send Free 1970 Sams Book Catalofl
Name
FLLASE PJtIfiT
Address.
L
Cfty_
State.
^ip.
Left — band select switch and 6146 sockets. Middle — band select crystal oscillators, 2nd and 3rd mixerSf and rf amplifier. Right — Mike ampli- fier, mechanical filter, and i-f amplifier. Back — 2.5 MHz crystal oscillator and 1st mixer; two- tone oscillator.
of a 220 and a 150X1 resistor shunts the secondary of T2, setting the first mixer output signal level at 300 mV p-p. This measurement is made with transistor Q7 removed from its socket, A voltage dividing network optimizes the 2.5 kHz oscillator signal to the mixer T8, limiting the drive to 550 mV p-p. Both T2 and T8 coil data is critical and is listed in the coil data chart. Table I.
In the chassis compartment just to the right of the audio and 453 kHz board are a total of 3 modules. Toward the panel is the band selector crystal oscillator stages, Q14 and Q15. To the rear of the band selector is the broad band second mixer Q7 and emitter follower Q8, Mounted on top of this board is the third mixer, the double balanced mixer using the latest techniques, and the rf amplifier QIO.
The second mixer has a fixed frequency input of 2045 kHz and a vfo input of 2900—3550 kHz, making the usable output frequencies 4945—5595 kHz, The problem encountered here was to develop a coupling circuit with a flat response over 650 kHz, The coils were wound on Vi in, ceramic slug tuned forms, resistive loaded to a Q of about 5 , The coils are spaced %
in. on centers. The coupling capacitor value is very critical; the calculated value is 10 pF but in practice optimized out at 8pF. The circuit has a frequency response flat to better than 2 dB. Coil data can be found in Table L Unloaded Q of each coU is about 55. The collector Q7 is tuned for the low frequency end of the bandpass while the emitter of QS is tuned for the high end.
T4 and T5 are wound on 4C4 ferrite toroids, 3/8 in, diameter. Ferrox cube 266T125 or equivalent may be used. I must have wound 40 coUs of four different diameters and Vi doz. materials before coming up with a final design. Most of the materials tried seemed satisfactory except for the problem of driving their low input impedance. The key was to select a material with high enough permeability to obtain an input of something over 50n using a smaU number of turns and setting the emitter follower current to 10 or 15 mA, All of the information I received from engineering contacts advised designing both input and output coils with identical number of turns but I found this only to be true if a very wide frequency range was desired.
Bottom view of power supply and final amplifier.
My final design emerged with coils T4 and T5 with 13 and 9 turns respectively. These coils must be trifilar wound. It is recommended that the three lengths of 26-gage wire be of different color so that they may be easily identified. This is not an absolute necessity as identification can be made using a continuity meter. Twist the three lengths of wire around each other and then wind onto the toroid cores, spacing the turns evenly over the entire circumference and then tacking into place
22
73 MAGAZINE
Vfo, 12BY7 driver, 6146s, tuning capacitor for 3rd mixer and driver, and function switch.
using a small quantity of Polystyrene cement. Use the cement sparingly as the capacity effect is critical.
Actually, the mixer has a bandpass much wider than needed - possibly as great as 200 MHz — and should the cement spoil the higher frequency end, you will never know it as frequency interest ceases beyond 30 MHz.
The diodes used in the balanced mixer are Hewlett-Packard Schottky hot carrier type 2900. The type 2800 was found equally good. Experiments with IN269, 1N270, and 1N277 types were found to operate satisfactorily in this frequency range also. The driving signal level into transformer T4 is 700 mV (p-p) and is
measured using a two-tone audio signal source with no carrier inserted* Examina- tion of the schematic for the balanced mixer and rf amplifier (Fig. 4) reveals many components, yet all are contained on a board I % x 1% in.
The only other circuits in this compart- ment are the band selector oscillator module and coil switch assembly. The rf coils are mounted on a metal disk-shape shield which is assembled as part of the bandswitch. (See ARRL sideband manual, page 66 for ideas on this subject.) Both the rf amplifier and the 12BY7 driver stages are panel-tuned by a miniature 8 — 108 pF two-gang capacitor. The tuning knob for this is located just to the left of center on the panel.
The function selector switch (Fig. 5) is also panel mounted. This allows selection of operate, zero-beat, CW, single-tone test^ and two-tone test- The problem posed by the band selector stage (Fig, 6) was in obtaining an equal output amplitude from each crystal. This section had over three designs before the final one. This may not have been a problem at all if similar type crystals had been used but it turned out for the best since the selection of crystal types ceases to be criticaL It is to be noted that for 80 and 20 meter operation the same 9 MHz crystal would be used. Although the final will tune from 80 through 10 meters, no coils were made for the rf amplifier and driver stages for the 80 meter band. Switch
noH
HP \ I
ta*0 — v^p — i\ — f
^F. mx.
flSPUT ClilTTEit
GftlD
TO rvMCTlOM SWJTCH
14-EOO 2 GAMS
Fig, 4- Balanced mixer and rfamplifiet.
DECEMBER 1970
23
TO 1000 CYCLE_ TONE OSC*
TO 4O0 CYCLE^ TONE OSC
U^
N
I
\ \ \
\ i^
9
%
40qO
1' "
O ^ O
N
#|SV |
SUPPLIES |
RtOM |
+r5V TO |
n |
0»0 RF |
AMPL |
SUPPLES +15V TO
TWO TONE TEST OSC
SUPfi.CS
+rsv TO
MIKE AMPL WHEH Xli^T SWITCH IS ENGAGED
♦ ISV
PROM
PS
TO 6V0C ON POWE^
SUPPLY
V
\
TO CUT OFF
SIAS ON t28Y7 STAGE
TO -28 VDC
ANTENNA l?ELAY SUPPLY
TO FIELD ,
TERMINAL X*
OH HIGH
VOLTAGE
RELAY
Fig. 5. Function switch.
positions are provided and 80 meter coils can be incorporated at a later date if desired.
Because of the 650 MHz maximum frequency coverage of the vfo it will require three crystals to completely cover the 10 meter band, A 23 MHz crystal covering 27.945-28.595, a 23.6 MHz crystal covering 28.545 —29 J 95 and 24,2 MHz for 29.145^29.795. Other combina- tions can be used of course. In that these cannot be switched, one must decide what third of the band is desired at a time, changing crystals in order to move to any other third of the band. It would be possible to design a board and switching arrangement containing all crystals, making it possible to switch to any portion. My interests in this band do not go to this extent and I am satisfied to pick mine a third at a time.
The largest board on the bottom of the chassis is the one containing the mike amplifier, mechanical filter and i-f ampli- fier 6 X P/iJ in. Actually the entire exciter portion takes up only one third of the chassis space.
The vfo module is contained in its own shielded box and is located on top of the
chassis and in front of the box containing the crystal carrier oscillator, buffer, and balanced modulator. Incidentally, these two modules were completed about a year before other modules of the transmitter, including construction of the basic chassis. The vfo (Fig. 7) was designed using a tuning capacitor out of an ARC-5. As you know, this capacitor is considered as fine in quality and stability as any obtainable. The oscUlator coil is wound on a ribbed ceramic form % in. in diameter. The big problem with this stage was developing a pure sine
II 1 W**i
-tk*
Fig. 6. Fixed crystal oscillBtor to third mixer (double-balanced mixer).
24
73 MAGAZINE
SR-2000 thaf s what, the Hallicraf ters SR-2000 trans- ceiver is packed with watts. 2000 watts, that's WATTS of power, you can buy it today.
FEATURES: < 1 KG readout • ex- clusive RIT (Receiver Incremental Tuning) • AALC Amplifred Auto- matic Level Control • built-in Noise Blanker • 100 kHz crystal calibrator, VOX, PTT, Break-in CW • < 1 uv sensitivity for 20 db S: N/N • compact rugged cabinet • 2000 watts SSB, 1000 watts CW in a package only 7% x 161^ x 15 inches • P-2000 AC power supply including built-in speaker, final amplifier plate metering, 110/220 VAC • See WATTS UP at your lo^ cal Hallicrafters distributor today.
fhm hafficrafh
A Sobsidiafy of Northrop Corporafion
600 HICKS ROAD ROLLfNG MEADOWS, ILLINOIS 60008
I
I
:3,€<<
<«oo
GI3
^^
1^ i ♦ 4 •- — ♦ 1
TO Q7
Fig. 7. Variable frequency osciUator (2.9—3.5S kHz).
wave (undistorted) rf output signal across the band. This was finally obtained after designing an amplifier (Q12) and emitter follower (Q13) that reduced the loading on the tunable oscillator.
An HP counter and temperature- controlled oven were used for the process of stabilizing the oscillator. Critical com- ponents are CI, C2j and C3. CI and C3 are silver mica dogbones while C2 comprises four separate capacitors (2 ea. 68 pF N-750S, a 21 pF N-330, and a 63 pF NPO all in parallel). Looking back over my data, the temperature tests were run for over two weeks. Frequency drift is 1 1 Hz for a change of IS'^F over the vfo frequency range of 2.9—3*5 kHz, Once this module was completed, the unit was closed com- pletely and not opened again until pictures were recently taken of the entire trans- mitter- At that time, only the top cover was removed.
At the time this unit was designed I did not know what output voltage would be required to drive the second mixer as plans for this stage were still quite a way down the road. Hence, a multi tapped coil with output from 1*0 to 2,5V p-p was made. This turned out to be a bad guess as the output from the lowest tap was more than optimum. Rather than go back and redesign the coil (T9), a 22J2 series resistor to tiie emitter of Ql was incorporated, thus optimizing the second mixer for the best output waveshape. It is suggested that anyone duplicating this design use a secondary winding on the 3/8 in, diameter ceramic slug-tuned T9 form of 12 turns tapped at 4 and 8 turns, rather than the
information as given in the coil table. No series resistor is needed if this winding data is used.
The two-tone oscillator (Fig. 8) is located in the same compartment with the 2,5 MHz oscillator and buffer module and is mounted to the back side of the chassis in a vertical position.
♦15V
.002
TO ARM OF 500 a pot \H AUDIO INPUT CKT
10)C
.002
+J5V
Fig. 8. Two-tone oscillator schematic.
The vswr indicator circuit was con- structed so that all components could be mounted in the space below the rf tuning capacitor. The right-hand portion of the chassis contains the regulated power sup- plies (Fig. 9). A module containing all of the rectifier diodes as well as the complete
26
73 MAGAZINE
iTfcfiPif^ itrntQ
TO iiF niiM
iiTV
l|| 14 m*. WTH ?M m* FIN*L CUIWENT *iOOV
a pj_*T£
30 n* <IF1TH ri*rlL OFF
<9 *av TD All rHMititmt rrjrics
F^, 9. Power supplies for SSB tran^iutter.
component circuitry for the low-voltage and antenna relay supply mounts on the side of the chassis.
The high-voltage transformer is hermeti- cally sealed, containing three centertapped secondary windings. The 63V winding serves three functions: furnishes the 6,3V needed for tube heaters, it operates the high-voltage relay , and it furnishes 3J5V primary power to operate a separate trans- former for the bias supply. The high- voltage rectifier string is made up of 8 1N2684, 600 PIV- diodes, each shunted with 390 kQ resistors and 0.002 mF (1 kV) capacitors for transient suppression.
The ac, line switch has a configuration that turns on the low voltage dc supply in its center position and adds line power to the high-voltage supply in its up position. The function switch is a three-deck, five- position, seven-circuit affair made up from an Oak switch kit.
Function Selector
Function positions are as follows; Side- band, tune, CW, single-tone, and two-tone.
Positions 1 and 2 are similar except that in position 1 there is no supply voltage on the third mixer until the transmit switch is activated. In position 2, voltage is supplied to the mixer and by inserting carrier; the vfo can be set to zero beat in the receiver at the desired frequency. This condition is not desired on position 1 as it may interfere with the reception of the station being worked -
In the CW position, voltage is removed from the audio stages, and B+ is suppUed to the driver and final. The telegraph key interrupts B+ to both the second and third mixers as well as the transistor rf amplifier stages. Positions 4 and 5 provide voltage to one or both of the tone generators, respec- tively.
The transmit switch is the multileaved telephone switchboard type, and in the transmit mode controls the following: cuts the bias voltage to the 12BY7 driver, energizes the high-voltage and antenna relays, supphes voltage to the audio ampli* fier and third mixer, and switches the standby and on the air panel lights.
. . . W6YUY ■
DECEMBER 1970
state
Control
Exciters
The conventional approach to solving the critical problem of tuning a side- band receiver is to use lots of bandspread and a very good mechanical knob linkage to give very fine tuning adjustment capa- bility with little backlash. Sometimes, though, even the best knobs get jerky and develop some backlash after a hundred hours use or so. The only difference betv^een very good knobs and not-so-good knobs is the amount of this jerkiness.
To forever remove this backlash prob- lem and give you a degree of tuning fineness such as no mechanical dial can approach, you need only add a simple diode variable capacitor for precision fre- quency shifting, or *'delta frequency" con- trol.
The best amount of delta frequency {^f) for amateur use appears to lie between 200 and 400 Hz, The fellows with separate transmit and receive controls have an awful time staying on frequency in a roundtable, and I frequently have to shift the full 400 Hz from the operating frequency to reach the worst of them. This control is especi- ally necessary to tune in a feminine voice, since the exactness of tuning SSB gets very critical as the voice pitch gets higher* 1 have never been able to get clear reception on female ops with my mechanical dial, but
with the vernier ^ there is one critical frequency where their voices clear up noticeably.
This control is a must for the serious ^ phone-patch operator, too, since hams who develop a facility for understanding a
TEST f^OtNT
? M0-13VREG
180K
irt29S
^^
TO ROTOR (VFOJ
CI .06
C3
if h; 3K >
1
TO STATOB iVFOJ
&p^
C2
.05
T
♦ TO ROTOR (VFOJ
/77
Fig. 1. Schematic diagram of ''delta frequency vernier control for SSB receivers.
ft
highly garbled SSB voice forget that the layman does not have this tolerance, and can't understand even a slightly garbled voice. In receiving an off-tune patch, they will be polite, but they may be, in reality, missing much of it.
28
73 MAGAZINE
This critical nature of SSB has to do with the harmonics and overtones of the
voice, all being shifted the same number of hertz instead of being shifted the same percentage of frequency. You wlio have tape recorders are probably aware of the fact that the voice doesn^t appear to suffer much if the tape speed is slightly wrong, although music does protest some. With the same degree of error in frequencies, applied as a frequency offset (which is the same number of hertz regardless of fre- quency), even voices become seriously gar- bled, and music comes out as total non- sense. If you doubt how critical thisis^ try to tune in music on one of the foreign BC stations with your sound just right unlil you get zero frequency error and the proper phase, within about 90 degrees of the station carrier- Even with this vernier control J you won't find it easy to tune to music, since a phase-lock receiver and resi- dual carrier must be used to get phone com- pany quality out of SSB.
The circuit for the ^f control is shown in Fig, K As indicated, the only adjustment device added to the existing receiver is the tuning pot, which can be mounted any- where you please. A shielded line of a three-wire twisted line can feed it. Since onJy dc is present on these lines, their length is of no consequence. However, this is a moderately high impedance circuit of up to about 3 kn, so keep the pot leads
The entire cu^cuit can be placed neatly within the existing space of n^ost transceivers. This photo shows the components mounted near the vfo capacitor in a Galaxy.
DECEMBER 1970
Barker & Williamson
Now Offering TVaters Pretax^ "
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WITH AUTOMATIC GROUNDIIMG
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See your local dealer or write dep t. D for descriptive literature.
' '
I
29
1
away from ac lines or you might induce enough ac to FM your vfo a small amount.
Placement of parts is not critical, but keep the components attached to the vfo tuning capacitor rigid, or the whole thing will be microphonic- Keeping reasonably short leads on the components wUl ac- complish this objective just fine.
The pot I used was a used 3 kl2 TV pot. I drilled a 3/8 in. hole in the front panel, and mounted it as shown in the photo. Whatever pot you decide to use, make the hole in the panel far enough away from the calibrated dial to keep the pot from rub- bing the dial after it's installed, A small diameter pot makes things a lot easier.
Tunetip Procedure
Before connecting capacitor C3 to the vfo St a tor, tune in a carrier and zero-beat the signal on your SSB receiver. Use your oystal calibrator if it is of the 100 kHz marker type, or use a commercial BC station that is easily identifiable , Pick a low vfo frequency so that your vfo tuning capacitor is almost completely meshed. This minimizes the frequency shift when you connect C3. Set the 3 kO pot to its center of range and connegt the free end of capacitor C3 to the stator of the vfo tuning capacitor. The carrier that was zero-beat will shift frequency as you do this because you just added a couple pF capacitance in parallel with the vfo tuning capacitor. You will have to remove an equal amount from the trimmer on the vfo to bring back the zerO'beat on the same carrier you had before. (Be careful not to zero-beat an- other carrier!)
To remove the capacitance, unmesh the vfo trimmer just enough to zero-beat the carrier like it was before you attached C3,
That's all there is to it: your vfo is now back in perfect alignment, and you will be able to shift the frequency up and down about 300 Hz with the pot.
Diodes to Use
I used a 1N925 TV video detector dlode^ but just about any type will work. Since we are only using a couple of picofarads of the diode in parallel with 30 pF or more of vfo tuning capacitance, it
matters little whether the diode is a low-Q computer diode, a detector diode, or a high-Q varicap. If the diode you use doesn't give you enough shift, just reduce the value of R2 some (not below 10 kO, though) or increase the value of C3 (not above about 10 pF).
This ^ control shifts both transmitter and receiver frequencies; therefore, in a round table discussion, if you tune off to hear a station, go back to the original pot setting before transmitting. If the other feUow has a transceiver, leave the pot where you hear him best, since this auto- matically makes him hear you best also.
More elaborate circuits can be designed which automaticaEy return your vfo to the center range of the pot when you transmit, by using a contact on your transmit relay and putting a fixed bias on the diode when
If you don't mind boring a small hole in the face of your transceiver you are sure to find a handy spot for the adjustment shaft. This one was placed in the upper left corner^ right above the vfo dial
you transmit- The desu-ability of this is questionable, however. With this circuit, simplicity is foremost, and in a regular QSO, you just adjust the pot to hear the other party and leave it- Should you tremble at the thought of poking a hole in your *'store-bought" rig^ bring the pot wires out to a little handy box, so you can remove every trace of your modification later if you desire, I per- sonally would pay more for a used rig with this control, but to each his own. You can also calibrate the pot in hertz if you have a calibrated af generator to compare its shift with.
. . , W4NVK ■
30
73 MAGAZINE
HAMS
area
PuNnY BuNcH
o
f
PEoPle!
AI Brogdon, K3KM0 RFD 1 Box 390A State College PA 16801
Hams are a funny bunch of people. They will work for days with their beam antenna orientation to make sure it is pointed to within one -half degree of the indicated direction - never considering the fact that the beamwidth of the antenna is 40 degrees.
They will overload their transmitters by factors of 50% or more* and milk that last watt out of it — when it takes a power increase of four times to make one S-unit difference.
They will stay oul of a ham club and complain until the cows come home about how poorly it is run. But they never want to join and work to straighten out the club's problems.
They will spend five hours and more a day building and installing ham equipment, telling the wife all the while that they just don't have time to put a new line cord on her iron.
Some of them will crank their final amplifiers up a little and run 3 kW PEP, never thinking about the fact that they would have to run more than 5 kW to make a significant difference in signal strength above 2 kW PEP. A few of these hams have time to think this over during their license suspension period.
They will spend hours every day talking with people all over the world, but never say hello to their next door neighbor.
They will tell their wives they can't afford a new chair for the living room while they are writing out the order for a new S700 mobile installation.
They will buy surplus equipment to save money, and then spend an amount of money on it^s conversion that would have bought good commercial gear that would have done the same job better.
They will set up stations with which they could communicate their ideas, but they they will give a signal report, a brief weather report, a description of their station, and run out of things to talk about.
They will spend an entire 48-hour contest period at the rig, leaving it only to catch short naps and take care of necessary bodily functions, but during the week they can't spare 1 0 minutes of their time to play with their kids.
They will buy complex and expensive electronic keyers so the extra dots and dashes their sloppy keying causes will be well-formed and correctly spaced.
They use Q signals on voice, and then have to use phonetics to get the letters across, since voice is better suited for communicating words than for trans- mitting individual letters.
They will apply for every ham award they can qualify for to document their accomplishments^ when many of the certi- ficates are for a level of accomplishment roughly equivalent to being able to cross the street without getting run over.
They will load half a ton of amateur gear and antennas into the car and take off for Field Day, but then have to suspend operation halfway tlirough the contest because the didn't bring a spare fuse*
They will take great pride in being a ham radio operator, and tell all their nonham friends of the many accomplish- ments of ham operators, and of the advances in the state of the art brought about by hams, when they themselves haven't been on the air in three years.
But one of the funniest things of all about hams is the typically human short- sightedness of most hams. They see all the faults of their fellow hams, and they are quick to criticize, but they are not aware of their own shortcomings. Aren't you glad that you and I aren't that way?
. , . K3KMO ■
DECEMaER 1970
3T
Clifford Klinert WB6BIH 520 Division St National City CA
A2M
For Repeater Use
When an FM repeater finally came to San Diego last summer it was soon obvious that new possibilities and require- ments were placed on 2 meter FM equip- ment. First of all, high transmitter power was no longer required nor desirable. In many cases output power in the milliwatt level was adequate to activate the repeater since it is virtually line-of-sight to most parts of the county. Also, high power on 146.34 MHz would cause interference with Los Angeles area remote stations that are similarly located on high mountain tops. This would add further strain to already deUcate relations with the Los Angeles groups who can (and do) jam San Diego just as easily.*
Secondly, a large number of RCA CPCR2D pocket receivers had become available for portable use, but the trans- mitters available with them were not transistorized and the batteries were heavy and expensive. With this arrangement, and with the repeater, it became possible to have full use of the repeater while walking around on the ground in most parts of the area. This is probably the most fascinating part of repeater operation, approaching the science-fiction TV shows by being able to
* Ed. Note: Author is making reference to L.A/s R-0-B.LN- (Remotes Operated By Insociable Nets) problem.
talk to someone a hundred miles or more away while walking around on the streets of a city with a handrheld transceiver. However, the idea of having to carry tubes and batteries while doing tiiis was still quite revolting. Solid-state transceivers are becoming available, but are still in the $250 to $350 price range. In view of this, it was finally decided to continue work on a solid-state transmitter. This article describes the first successful results of that project.
Design
Figure 1 shows the schematic of the transmitter as it is now. The most signifi- cant part is the oscillator, which offers maximum simplicity and reliability. The crystal frequency is 18.29250 MHz, and is multiplied eight times to get the 14634 output frequency. Amateur designs of about a year ago used oscillator frequencies in the 8 MHz or lower range. With the sloppy interstage selectivity as used in this transmitter, lower frequency crystals cause more spurious multiples because they are closer together in frequency. With a crystal trequency of 18.0 MHz, the multiples will be at least 18 MHz; apart, and it is easier for the tuned circuits to select the proper multiple and reject others. A Motorola varicap is used to modulate the oscillator. With an audio input of about 22.5V
32
73 MAGAZINE
peak-to-peak (maximum bias on the diode from the power supply), the deviation is a little more than the 5 kHz at the output frequency. Two varicaps might be used in parallel if more deviation is desired — if it doesn't lower the frequency too much to compensate by lowering other capaci- tances.
A few notes about the crystal should be made: The crystal must be a "funda- mental" cut to work in this circuit. An overtone crystal will oscillate on its fun- damental frequency, and will be different
the transistors increases at lower frequen- cies, it i^ possible to have low-frequency feedback paths that have been overlooked while concentrating on the VHF circuitry.
Using the coil in each stage for the dc return to the collector not only simplifies design, but provides a low-impedance col- lector return for lower frequencies that would not be possible if choke-and- capacitor coupUng were used.
The final transistor can be driven to as much as 2W dc input in this circuit, but was held to one watt to reduce heat
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from its marked frequency. The crystal load capacitance in this circuit is about 20 pF and this should be noted in the crystal order. A general-purpose type crystal (0,01% error) might be satisfactory, but a commercial-standard 0.00 1 % crystal was ordered by maiL and quickly tweaked down on frequency with the 15 pF trim- mer.
The three stages following the oscillatoT are all conventional common-emitter, LC-coupled doublers. While operating, they are driven into class C. Interstage matching is accomplished by trial-and-error tapping of the coils.
The use of ordinary resistors in the base bias circuit was found to be most success- ful, TMs avoids the resonance problems when chokes are used, and probably helps stability by lowering circuit Q. Large capacitance (0,01 juF) bypass capacitors were used to minimize the chances of low-frequency oscillation. Since the gain of
DECEMBER 1970
dissipation problems and battery require- ments. Power can be adjusted by changing the value of the emitter resistors in the multiplier stages, and changing interstage couphng- (Ed. Note: This unit can be used to drive the DyComm 15\V FM power amplifier described in 73 review, Septem- ber 1970J
05 2N3e66
ANT.
Fiq, 2. AlXQvnale Oulpui Circuit. L can be five or six turns 3/8 inch diameter ^ ^18 wire. Try to make it work.
33
A more popular output tuned circuit is iuciuded in Fig, 2^ but it was not tried in the transmitter because the circuit used in Fig. 1 was considered satisfactory.
Construction and Tuning
Simply having a schematic available does not mean that it will be easy to build a transmitter. Construction is very simple, but making it work will occupy the major- ity of the time. Since all transistors are different and any two transistors with the same number can have widely different impedance and gain parameters, the tuned and coupling circuits will require extensive adjustment. Many of the values in the schematic will probably be a little different in different transmitters.
Considerable experience as well as appropriate test equipment is required for the tuning and tweaking- A grid dip oscil- lator is a must, and a general-coverage receiver that cuw cover all the frequencies between the oscillator and final output is always handy. An swr bridge or power meter that works at VHF is necessary for tuning for output power, as well as all the other tools and test equipment that are usually available in the average shack.
his own pet methods and parts available to work with. As a final resort, industrial parts catalogs will list all the components necessary.
Speaking of parts, half-watt resistors can be used, but quarter- watt resistors will be easier to work with because of size. In the case of the driver and final emitter resis- tors, power considerations will necessitate the use of half- watt resistors. Small dipped mica capacitors are used for interstage coupling. Other than the feed thro ugh bypasses, disc ceramic capacitors were used for bypassing. Indeed they are not the best, but seemed to work in this case. Just make sure that all parts are as small as possible, JFD makes good ceramic bypass capacitors as well as small disk variable capacitors. The crystal holder is the HC-18/U type and is soldered into the circuit.
The transmitter should be built one stage at a time, starting with the oscillator. Each stage should be checked and tuned as it is built. The oscillator will be easy because- there is nothing to t-une but frequency adjustments and the circuit, is very easy to get working. Check for output while listening to a receiver tuned to the
Pbotograpb of the complete minitransmitter strip^ Note how stages are shielded into '^compartments.
ft
The circuit was laid out on a double clad printed circuit board that makes a very simple arrangement. Small Teflon standoffs were glued to the board with epoxy to provide a place to solder the transistors. Details of the construction and parts to be used will mostly be left to the individual builder. Anyone who would build this transmitter probably would have
crystal frequency. Adjust the two resistors that provide the bias to the varicap to put the diode voltage at about lOV measured at the diode— crystal connection with a VTVM or oscilloscope.
An audio signal voltage can be applied at the "audio in" point in the schematic. Make sure that the audio source is isolated with a series capacitor to prevent affecting
34
73 MAGAZfNE
IF YOU'VE
If you haven't
already received
a copy of our NEW
1970 Catalog of Precision
Quartz Crystais ^ Electronics for the Communications Industry,
SEND FOR YOUR COPY TODAY!
SENTRY
Somewhere along the line, in vir- tually every ham repeater in the world, you'll find a coupfe of Sentry crystals.
Repeater owners and FM "old- timers" don't take chances with frequency— they can't afford to. A lot of repeater users depend on a receiver to be on frequency, rock stable.. Jn the dead of winter or the middle of July, The repeater crowd took a tip from the commercial "pros" 3 long time ago—and went the Sentry Route,
That's one of the reasons you can depend on your local repeater to be there (precisely there) when you're ready to use it, FM'ers use the repeater output as a frequency stan- dard. And for accuracy, crystals by Sentry are THE standard.
IF YOU WANT THE BEST, SPECIFY SENTRY CRYSTALS.
Ask the Hams and Pros
Who Buifd Repeaters!
jr#
USED A SENTRY CRYSTAL
SENTRY MANUFACTURING COMPANY
Crystal Park, Chickasha, Oklahoma 73018
PHONE: (405) 224-6780
TWX-91 0-830-6425
GUNSMOKE?
Blow your mind on our back tssue bargam bunch, 30 (count 'em) assorted (we hope) back issues, all before 1968, for the incredibly low price of S6 post- paid (hardly pays for the post- ageK These are packed by slave fabor (to cut costs) so please ig- nore notes calling for help, etc. that may be slipped into the bundles. 73 Gunsmoke, Peter* borough NH 03458. Send cash, check or negotiable securities.
the diode bias. A maxiniiim of about 20V peak-to-peak can be applied here. A pre- assembled imported audio amplifier can be used for modulation, or an amplifier can be buill to fit individual requirements. If the amplifier is designed for driving a speaker, a transformer may be necessary to step up the output voltage. It should be possible to detect FM from the oscillator by listening to a general-coverage AM receiver and slope^detecting the signal.
Tuning tlie multiplier stages can be iccomplished by measuring the emlLler voltage of the following stage while tuning the preceding one. Voltage across the emitter resistor measures emitter current, which is a measure of rf drive. To deter- mine that the stage is operating class C, compare the emitter and base voltage, as measured with a VOM, The emitter should show more voltage than the base. The base never really has more bias voltage than the emitter, but when the VOM probe touches the base, it partially shorts out the rf there and reduces or eliminates drive. Since the emitter is bypassed, measuring emitter volt- age has no effect on the rf drive, A grid dip meter must be used for the final tuning to be sure that the state is operating on the right frequency, and to check for para- sitics.
The resistors across the coUs in the schematic were used as a cure for parasitic oscillations. The stage shoidd be built without the resistor first, and then resistors
can be added when instability occurs. A grid dip meter can be used to detect parasitics and oscillation, but an AM general-coverage receiver is much more sensitive.
Adjusting the output stages is just a matter of changing taps on the coils while watching for transistor overheating, check- ing for parasitics and oscillation, and retuning each time for resonance. Also be sure to check that the right harmonic is being tuned for on the grid dip meter used as a wavemeter.
Leave a TV set turned on; it will let you know when oscillation breaks out and give a little entertainment while you're work- ing. Watch channel eight; the 36 MHz signal tends to come through the 72 MHz doubler, and multiply five times in the 144 MHz doubler to cause TVI on channel eight. This has been the major source of TVI after the transmitter was operating prop- erly, A 36 MHz series-tuned trap might be used at the collector of Q3 as a last resort, but witli proper tuning this should not be necessary.
The final results will take a considerable amount of time depending on the intuition or "feel" tliat the builder has for what is happening in the circuit.
Conclusions
This transmitter has provided good results in the final analysis, but there are problems and changes that could be worked out. The thing is quite difficult to tune and clean up^ and some kind of standard chassis, housing, shield, board, or whatever should be designed to provide ease of mechanical construction and dupli- cation, rf shielding, and mechanical strength. D o u b le - 1 u n ed, induct ively coupled interstage circuits might be used to provide better selectivity. Tapped iron slugs are available, but I haven't located a source. Supposedly, this would be much less expensive than using the ceramic vari- able capacitors, and much smaller.
Other variations of this same theme might include a low-power 100 mW version for short range use with an absolute mini- mum of size and power consumption. Be creative.
. . . WB6BIH ■
36
73 MAGAZINE
The DRAKE
LINE
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RECE I V
TUNING FOR THE HW 100
ant transceiver offset tuning with- out costing a cent? Without altering your rig? Give this a try:
The introduction of the transceiver to ham radio has brought many advantages. But the one disadvantage that will force a fellow not to select a transceiver is its inability to follow the drift of a CW signal without altering the output frequency. This separation of frequencies was realized by a very simple method which can be employed in many other rigs. It has two good things going for it: no modiiication and no money required.
Theory
The theory behind this method of offset tuning is simple when you recall some of the laws we all knew to get our ticket (and then promptly forgot as they were of no practical value). Inductive coupling is the first order. This is the method by which we will get the change into the rig without altering or soldering. This method will allow you to introduce a change in the frequency of the main vfo. You'll also want to be able to remove the change at will, as on transmit. Figure 1 shows that the inductive coupling links the main vfo with the added tuned circuit. It is with this outboard tuned circuit that we can change the received frequency. The capacitance of the variable capacitor should be iow. Try and keep it in the area of the tuning capacitor of the vfo. In my rig, the HW*100, this is 63 pF, so anything near that will do. The vfo coil in my rig is 5 juH so 1 kept the inductor of the remote circuit as near to this as possible. None of the
values are too critical as to demand adher- ence to strict values. By keeping close to the values of your rig you will have better tracking and zero beating of the received CW signal. And youMl know that when the remote tuner is switched out of the circuit you are still near enough to be hearing the same signal you were listening to on the offset tuning. The greater the change in the offset tuning circuit values, then the greater the coverage up and down fre- quency from the zero beat. I felt that in CW a great range of offset tuning was not of any use and it also would make tuning more difficult. I just about use the full rotation of my capacitor and keep within the passband of my rig, the tuning rate is slow enough that 1 can move it around in the 400 Hz CW filter 1 have added to my HW-100. It is this simple remote tunable circuit that allows the offset tuning.
Construction and Circuit
The variable capacitor 1 used is a BC tuning variable with only the rear section in use. If you have any old variable in the
> I
VFO ENCLOSURE
VFO COIL
M^
^2 Ci , If /^
eOllTACTS 2 6 10
Fig* 1
DECEMBER 1970
junkbox, then that's the one you use. I reduced the high capacitance of this section by putting a 100 pF Mylar capaci- tor in series with it, (You can fool around with values until you get what goes best with your rig.)
The coil for the remote tuner was made after looking in the ARRL handbook; I found that a I V2 in, long coil by ^i in. wide (36 turns per inch) would give me close to 5 juH, which is good enough. The coil was made by winding 24-gage magnet wire, enameled, around one of those fat penciis used for advertising gags. The size of the wire is not important just so you can get about 36 turns to the inch on a half-inch diameter
If you have spent any money up to this point you need a new junkbox. Now for the hookup.
The vfo of the HW*100 is removed according to the Heath manual instruc- tions. Reference will be made to my HW-lOO, but any transceiver that allows you to get at the vfo and its coil can be used with this offset tuner. The vfo is turned bottom-side-up so the inside of the enclosure is accessible. Be careful not to damugc the screened diah One end of the pickup wire has its insulation scraped away and it is soldered to ground on the inside of the vfo, as close to the coil as you can manage. This is the only soldering and modification to the rig. In my rig, the ground for I lie coax feed through into the vfo was used as ground. With tension on the ground connection, make one full turn around the vfo coil and while still keeping tension bring the wire to the nearest spade bolt. Wrap the hookup wire around the bolt 2 or 3 times Just for anchorage. Make these turns just at the base of the spade bolt where it meets the edge of the vfo enclosure and tuck the turns down into the little space between the shaft portion of the spade bolt and the edge of the enclo- sure.
By tucking the turns of wire into these spaces you will keep them from being cut or grounded by compression from the edge of the vfo enclosure when it is remounted and the nuts tightened. It is most impor- tant that the turn of wire around the vfo
coil stay in place without the least move- ment. Movement of any kind no matter how slight, even from vibration, can alter your received signal a few hertz up or down the band. A drop of some kind of glue will do the job of keeping the wire turn in place.
Remount the vfo as directed in the Heath manual. Make sure the remaining free end of wire is not caught under the edge of the vfo and is outside the vfo enclosure. The wire is now fed to SI, from Si to CU to rotor of C2, then to ground from C2.
ff automatic switching is desired, place RLl contacts 2-6-10 before SI, The home- brew coil is placed across the variable capacitor to ground, placing it in parallel with C2. Keep all leads as short as possible. TMs completes the wiring of the remote offset tuner.
Alignment
The transceiver must now be adjusted
only because the loop of wire aroujid the vfo coil has moved the vfo frequency and it will not be the same as the readout frequency of the dial This alignment is simple because the vj'o Is not udjuKtetL This is the pari Ihut can be frustrating at first because you do not know where the frequency has shifted to, I found the turn of wire dropped my vfo down 30 kHz. This meant nothing had changed as far as function of my vfo except that there now was a 30 kHz shift down the band. This was corrected by *'slipping" the dial on the rig until the frequency coming from my vfo and the readout frequency on my dial were the same, i used CHU, 7335 kHz, as my locating frequency. I used this instead of my signal generator only because my trans- ceiver receives CHU (and besides. I was too iazy to set up my signal generator). Any method of obtaining a locating frequency IS fme.
For alignment with the offset tuner in the circuit, tune in a CW signal on any band with the offset tuner out of the circuit. I found RTTY signals to be of longer duration and more dependable. Adjust the vfo for the highest meter reading of the locator signal. Place the
40
73 MAGAZINE
variable capacitor of the offset tuner in the fully unmeshed position. Put the offset tuner into operation by closing SI. When SI is closed you should still receive the same locator signal if your capacitor and coil vahies are close to the values in your rig. One thing you may notice is a change in pitch of the locator signal due to a slight frequency shift (but don^t worry about it), I am only interested in following the drift of a CW signal — not in how much fre- quency spectrum my offset tuner ranges over or in how many hertz the CW signal drifts. (Though this can be done if you care to take the time to calibrate for it.)
Adjust the variable capacitor so that wlicn the remote tuner is removed from the circuit by SI, the pitch (frequency) will be close to the pitch of the signal from the rig alone. What you will be doing here is getting a zero beat for the offset tuner against the rig. Try to get this position of the offset tuner as close as you can to the rig's signal. Mark this zero beat position on the variable so you can return to it at any time. Now when you're receiving and the offset is placed at zero beat you can tune
up or down frequency as a CW signal drifts. I found that my zero beat on the offset did not change from band to band- It would appear that alignment for one band takes care of all the bands. This completes the adjustment and alignment of offset tuner and the transceiver.
Placement
My offset tuner at present is outboard.
It can be mounted in the HW- 100 without making holes in the front panel. The screws in the upper right and left corners of the front panel are replaced by the variable capacitor and the on -off switch (SI). The components in this case will have to be of the miniature type to use the holes as they are now. To use what comes out of the junkbox, in my case, meant enlarging the holes. But f think this is one case where modification will add to the worth of a rig and should not be a deterring factor. The shame of it all would be spending money for miniature parts after having come this far for free,
. . , WA2EAW ■
FM'ers!
GET THESE
EARLY ISSUES
OF FM
BULLETIN,
BOUND INTO A
SINGLE
VOLUME
WHILE THEY LAST
Only 500 copies of this collector's edition have been printed. The material consists of FM bulletin's rarest issues, and is reproduced in its original form by lithography. Contains FM Bulletin, Volume I (Feb. 1967 to Feb. 1968).
a
DECEMBER 1970
41
The Most Powerful Signals Under the Sun!
PICK YOUR PERFORMANCE
-210 2 Meter Transceiver
A^..-v
/*\ gtduMy ftectFonics
FM2tO
CapabUity... That's what you purchase from Hy-Gain/Galaxy. Top performance from the first mass produced 2 meter transceiver. Fixed or mobile, the FM-210 will provide maximum pleas- ure with minimum investment. And all American made too! No parts problems and backed by Hy*Gain*s famous Customer Service!
Top performing transceivers coupled with your choice of the wortd's best 2 meter antennas means a winning combination with capability.,.
SPECIFICATIONS:
Transmitter*
• Frequency Range: 143-149 MHz
• Antenna ImpedanGe: 50 ohms nominal
• Power Requirements: 12-t4v DC
• Transmitter: 5 watts (10w with AC-210 pow- er booster)
^ Microphone: High 2
• Deviation: Adjustable narrow or wide band with clipper filter also adjustable for opti- mum clipping lever
Receiver:
• Sensitivity: SINAD ,5 uv for 12 db
Quieting: 1 uv provides 20 db
Squelch: Continuousty adjustable Modulation Acceptance; FM wide band (nar- row band available on special request) RF Circuitry: FET front end and duo con* version for minimum cross modulation and overload
IF Frequency: 10.7 MHz and 455 KHz, Frequency Control: 3 channel transmit. 3 channel receive. (146.94 MHz furnished) Transmit and receive frequencies independ- ent of each other
Audio Output: 3 watts from internal 3.2" speaker
Order #813. Price $229.50 AC-210 POWER BOOSTER
Use the AC-210 on 11 5v AC or 12v DC to provide AC operation and 10 watts input. Supplied with mounting brackets for permanent mo- bile installation. Order #814, Price $49.00-
ia
MMB MOBILE MOUNTING BRACKET
Mounting bracket provides positive mounting and quick disconnect for easy removal. Between
half of the mount is removable when not being used to conserve space.
Order #816. Price $5.95
PURCHASE yOUfl FM-aiO AND PA-210 DURiNG THE
COMBINATION
PA-210 2 Meter 35 Wan Mobile Amplifier
;s
SOLID STATE
rrr^
This all new ruggedized solid state two meter mobile amplifier provides 35 watts output to greatly increase your communication range. The PA-210 is a must for areas where no repeater Is available. The PA-210 is designed as a companion for the FM-210. (When used as a system, the AC-210 power booster is not required.) A unique circuit protects the output transistor from voltage spikes and surges. All change over relay functions are internal and controlled by f M-2t 0 circuitry through a connecting cable.
SPECIFICATiONS:
• Input Voltage: 12vDC. negative ground only
• Power Input: 60 watts
• Power Output: 35 watts
• Frequency Range: 143 MHz to 149 MHz
• Operation: Class C
Order #815. Price $149.95
Drive Requirements: SVz watts required for 35 watts output (the PA-210 provides oper- ating voltages to the FM-210 for high power operation)
Antenna Requirements: 50 ohms unbal* anced
HY-GAIN 764 ^ WAVE GAIN ANTENNA FOR TWO METER MOBILE
Model 764 % wave antenna with 3 db gain professional mobile antenna for two meters provides the highest gain and best matched performance (52 ohms) than any other mobile antenna on the market. Handles 110 watts and is constructed of 17-7 ph stainless steel with chrome plated hardware. It features an etched copper matching coif on a G10 epoxy fiberglass board. Exclu- sive claw mount fits any size hole %% to %". Easy installation and high power capability. Sup- plied with 22' of RG-58/U coax and PL-259 connector.
Order #764. Price $26.50
Hy-Gain 764 Gain Antenna for 2 Meter Mobile
GALAXY ELECTRONICS DIVISION
-GAIN QECTRONICS CORPORATION
P.O. Box 5407-GL , Lincoln. Nebraska 68505
MONTH OF DECEMBER AND RECEIVE THE 764 FREE
Mi
John Aggers W5ETT
1509 Desoto
Ponco City OK 74601
The
Little
GATE DIPPER
Covering f .7—225 MHz, tt ts simple, inexpensive, and eaSy to build.
Possibly you now own a grid dipper, but is it small, easy to handle, and cordless, making it completely portable? If not, you will want to build this gate dip meter. The cost is extremely low — only about $7. AU parts are readily obtainable and construction is simple. The plug-in coil forms, using battery plugs and polystyrene tubing, are easy to make.
The Circuit
An MPF 102 FET is used in a modified Colpitts circuit. Except for the #1 coil, where a choke is used, the B+ is fed to the centertap of the coil. This is necessary to obtain a fairly constant gate current as the oscillator is tuned to its end frequencies. Drain current varies from 4 to 1 mA proceeding from 225 to 1.7 MHz. At the same time the gate current varies from 20 to well over 50 juA,
From this 5 it is apparent that the stronger the oscillations the smaller the drain current and the larger the gate current. In gate dip operation^ as power is drawn from the oscillator the drain current will increase and the gate current will decrease or dip,
Limited wavemeter operation, obtained by switching off the B+j is accompanied by a slight sliift in calibration. When the circuit picks up rf, the FET suddenly goes
into oscillation using the rf as its battery. Thus, the amount of rf picked up must be large enough or there will be no oscillation and no meter indication. However, despite these deficiencies, it is still considered a useful mode of operation and for that reason has been included • It is only neces- sary to wire the sensitivity control so that the resistance is maximum when the switch is in the off position .
Construction
A natural finish aluminum minibox (4 x 2-f/8 X 1-5/8 in-) is used for the meter case. The variable capacitor came from an old transistor radio and measured 1 3/8 x 1/2x1 in. The shaft was already squared and tapped for a small screw. Since those listed in the catalogs have a plain or flat shaft, you wiU have to use a collar with setscrew, or drill and tap the shaft. The trimmer capacitors are not used and should be removed.
To make the coil socket you will need three pin receptacles from an octal socket, two pieces of 1/8 in* Plexiglas approxi- mately 7/8 X 3/4 in., and one battery plug for a pattern. The pins of the battery plug form a triangle, I shall refer to the holes at the base as the outside holes. Drill holes in one piece of plastic to match the pins of the battery plug. Match the two pieces of
44
73 MAGAZINE
i
The little gate dipper with spm^e coils.
001 iiF
2 PLUG -W
COILS
SOURCE
DRAINV« * VGATE
SWITCH
OFF POSITION
BAMYTHmG Fm)li 5K TO K>K
eOTTOM VIEW liPFI02 FET
Fig. 1. Schematic diagram of the little gate dipper.
plastic, clamp in a vise, and drill the two outside holes in the second piece. Bend the lug part of each socket pin to a right angle. Slip one over each outside pin of the
battery plug. Using this as a jig, soider the lug portions to the stators of the variable capacitor. Remove the plug, and the pieces of plastic should fit down over the variable capacitor. The lug part of the center socket pin is brought out between the two layers of plastic.
File a small notch in the bottom piece to accommodate the lug. Before cementing the two pieces together and to the frame, make each hole slightly larger than the diameter of the socket pins. This will allow for expansion when the plug is inserted.
The dial is made of 2-1/4 in. diameter 1/8 in, Plexiglas, To give the dial a rough edge, for good thumb traction, I heated an old gear wheel and rigged up an arrangement to rotate the dial against it. The gear should have rather coarse teeth and rotate with the dial, or you will create flat spots.
The variable capacitor can now be mounted in the case. Position it so that the top and sides of the dial will be just about even with the edges of the case.
DECEMBER 1970
45
The dial marker is mounted on square aluminum posts. The top post (2 in. long) has I ^h in. of its length filed down to a 1/8 in, thickness to reduce its bulky appear- ance. To make the hairline, scribe a line in a !4 in. wide piece of plastic and fUi in with a ballpoint pen.
The sensitivity control I used was already prepared for the knob shown. If you don't have one like it, use a dime-size pot and a setscrew knob. Any resistance from 5 to 10 \Xl will be fine.
Keystone light meters are available from Olson Electronics in a package of five ($3-99) or Transistors Unlimited Co, (75^ each). Some modification of the meter is necessary- Remove the light ceil and series
resistor- Drill two holes, spaced 14 in, apart in the back of the case to pass 4 --40 machine screws for easy soldering, make sure the heads and nuts are clean and free of any nickel plating. The screws should be filed even with nuts in order to make room for the battery. Solder the leads from the
meter movement to the terminals, but be quick because the plastic case tends to melt in a hurry •
Wiring is just a here-to-there proposi- tion, requiring no terminal boards or ter- minal lugs. The FET is soldered in place supported by its own leads. With reason- able care you should not damage it. A battery holder was found unnecessary; however, it is a good idea to wrap a layer of tape or stiff fiber paper around the battery to prevent the metal case from shorting out the meter terminals.
Coil Construction
Figure 2 and the photo give the neces- sary dimensions and show the parts needed to make the coil forms. The battery plugs are listed in the catalogs to fit #482 and M3 batteries. The center pin should be fUed slightly shorter to make the plug seat evenly in the socket. While you are at it, file the nickel plating from the ends of all plug prongs. This will make for easier soldering-
MelBT is held against the front panel by a small bracket. The FET is the small black object in the center.
46
73 MAGAZINE
l-3/e in LG COf*P£R STRIP a 1/^ in. WDE
CLEAR PLASTIC
5/e Dm
RFC; JOT 20 mm
CLOSE WOUND ON t/B ill LO.
MO BATT PLUG
-I SOT CT CLOSE WOUND as AWG
J IK ^ — WS^ —
<:
G CT D 6-15 MHi
CTu
\K ^ '^
6ATE DRAIN CT
32-85 MMi
J8T CT CLOSEWOUNO 2eAWG
(SPACED 1/4 tfj. BETWEEN TWO WINDINGS)
POWDERED -IRON SLUS
(1/4 It f/Z mj
(5/8 X \/Z m FOR 1.7-3 MHi)
60T fllOT FOR f 7-3 MHx) CLOSE WOUft© 30 AWrtS SILK
SOT (HOT FOR IJ-3 MHl)
e 0 CT
3 13-32 MHz
G CT O 2.9-6 MHi {(.7-5 MHil
Fig. 2. Coii configurations for various frequencies of resonance.
Complete coiJ information is given in Fig. 2. However a little explanation may be in order. The irregular method of winding the §2 coil is necessary to reach 85 MHz and still maintain oscUlation. With 4 turns dose-wound the highest was too low. With the 4 turns spaced ^ oscillation ceased at the highest frequency. The 30 AWG silk wire was taken from a TV flyback transformer. The resistors in the centertap of the last three coils improve the meter*s sensitivity slightly. They are mounted right next to the coil winding. With a slight groove filed inside the insulating sleeve, it should slip over the resistor.
The #6 coil is layer-wound as space permits and scrambled wound the rest of the necessary turns. The top winding of all coiJs should end near the very edge of the coil form. This will make for easier coupling to a tuned circuit. After the coils are checked out the insulating sleeves may be glued to the plug base-
Allow the glue to dry for several days before plugging the open ends of each coil with a small cardboard disk. The coils are painted with colored lacquers. Colored paper between the coU and the insulating sleeve will probably work just as well. Calibration
For calibration purposes^ you will need another indicating oscillator or dip meter. Operate it in the diode or wavemeter mode and loosely coupled to the gate dipper, I calibrated only 5 points on each scale plus any ham bands which appeared. Remember the dipper is not a frequency meter but something to get you in the ballpark.
Conclusion
The little gate dipper was checked against a well known commercial tube equivalent and, as near as 1 could tell, they were just about even. The battery should last for a long time because the current drain is extremely low.
. W5ETT ■
, I
* •
DECEMBER 1970
47
Marlene F. Derfler 804 48th St. S. Great Falls MT S9401
CLINKS IN A Va'
(A LOW PRESSURE ARTICLE FOR WIVES)
My husband is a builder: No, he doesn't build coffee tables or book- shelves or breakfast nooks. Instead he builds important things like linear ampli- fiers, grid dippers, calibrators, and all those other things you need around the average American home.
They say that Nature abhors a vacuum. Well, my husband does too. Most of the time 1 understand his drilliiig and pound- ing, his screams when he grabs the wrong end of a hot soldering iron, and the horrible whistle that wakes up the baby and indicates he is getting ''zero beat," Our day of trial comes, however, when all too frequently it becomes necessary to vacuum the house.
We have a shaggy dog that sheds and you have to really keep after the clumps that surround him whenever he stops to scratch. This means toting out the vacuum nearly every day.
My part of the great vacuum debate comes when I start hearing the pings, clanks, and pows of ^'things" being sucked into my little vacuum *s innards. It sounds disturbingly like bullets ricocheting among the rocks in a "B'' western movie and it certainly can*t be doing my vacuum any good. Investigation long ago showed these ""tilings" to be various little pieces of plastic stripped off the ends of wires, bits of wire, melted glops of solder, small nuts and bolts, and other little indescribable things of Ham Husband origin. We have agreed that he should keep his activities confined to the spare room that is his *'shack," but these things come out on his
shoes, follow like a dust storm in his wake, and 1 think roll out by themselves in the niglit. Once, when 1 shoved a handful of '*clinks" that 1 had gathered out of the vacuum bag under his nose, he peered at it, carefully picked out the little nuts and screws, and ran back to his shack mumbling something about precious hard- ware.
There is another side to the story to be sure. 1 usually just get the vacuum started and have suffered through the initial ten or twenty internal ricochets when he comes tearing out of that dark hole, often with headphones strung around his neck, striving to be heard over the combmed noise of the vacuum motor and a sound like ball-bearing Ping Pong, After pulling the plug out of the wall (a move which someday may be fatal because he wired it himself), lie finally gets across the point that my vacuum is making a horrible noise in his radio. I suppress the urge to ask him why he doesn't talk to this horrible noise just like he does to all the others and instead 1 ask. the same question that I always ask him.
*is there any way to cure our mutual noises without my giving up vacuuming and you giving up ham radio?'' At the mention of the latter sacrilege he usually turns paler and retreats a few feet toward the comforting smell of burning solder. It is hard for him to turn any paler because the only sun he ever gets is when he works on antennas during the winter and at an occasional hamfest in the summer, but the burning solder smell is always around.
48
73 MAGAZINE
r
Normally then, we just stare at each other, both of us silently remembering the time he did try to do something about his noise. On thai occasion he had grabbed up my vacuum and carried it off to his lair where he gutted it and added little round things to its insides with his ever-ready soldering iron. In a way he did temporarily solve both of our problems because when he plugged it in lie l>lew the last fuse we had in the house. I wouldn't let him replace the fuse with a piece of solder, so he tramped out to the store muttering someLliing about "ac working voltages."
I havcMiH let him touch my vacuum since, of course, but I ask him the same question each time just to bring him back to liis senses. He usually is torn for a moment or two, contemplating an ocean of ' dog hair on the one hand and a normal hfe on the other. Remembering that dog hair gets into the fan on his linear amplifier, he usually compromises at this point and says, "QRX one ..." I take the minute to pick up whatever bits and pieces and "things" 1 can see that he carried out with him on his last excursion. When i start vacuuming again after this mysterious ritual of *'QRX" I know 111 be greeted by a sound worse than a trio of two-year-olds let loose to play with all the kitchen pots and pans.
All this that 1 have been telling you was true until just the other day. On that particular fateful day we had gone through our usual routine and 1 had asked him the usual question. This time to my amaze- ment he said, **You know, sweetie, maybe you're right. 1 should spend more time with you instead of with my projects and radio. I could help you around the house. We could go out more, meet new people. 1 couldn't get much money for all that homebrew gear, but 1 could give it to somebody who could use it and then you wouldn't have any more clinks in your vacuum cleaner.**
That day 1 was so happy! We closed the hamshack door and right then he started to help me around the house. The first Ihiiig he did to help was to shake out the rugs. The same eyes that can spot the latest transistor in a radio store window from a moving car at six hundred feet didn't see
r
Feature
' \
Signal/One's |
|
CX7 gives you |
|
More |
performance than any |
transmitter /receiver com- |
|
bination |
|
More |
convenience than any |
transceiver |
|
More |
versatility |
Comparethe CX7 with any receiver for sensitivity, selectivity options, dynamic range, AGC merit, VFO smooth- ness, interference rejec- tion,
Comparethe CX7 with any trans- mitter for continuous power output in all modes, P-A. rugged ness, crisp audio punch, low distortion, instant CW break-in and spotting, quick band -change.
Comparethe CX7 with any trans- ceiver for total size and we
Consider the best at an amateur retail price of S2195-
Write
for all the details of the magnificent CX7 from
Signal/One, Box 12ST
"ft Speaks for Itself
#/
A Divfsion of ECl (An NCR Subsidiary)
2200 Anvil Street No, St. Petersburg, Fla. 33710
1
I
DECEMBER 1970
49
THE BEST
2 METER
CONVERTER
Model 407 $39.95
144-146 MHi rn. 28-30 MHi 9ut or 146-148 MHz with o socond crystal Available at $4.95 each.
A full description of this fantastic converter would fill this page, but you can take our word for it (or those of thousands of satisfied users) that it^s the best. The reason is simple — we use three RCA dual gate MOSFETs, one bipolar, and 3 diodes in tne best circuit ever. Still not convinced?Then send for our free catalog and get the full description, plus photos and even the schematic.
Can't waitTThen send us a postal money order for $39 .9& and we'll rush the 407 out to you, NOTE: The Model 407 is also available in any frequency combination up to 450 MHz (some at higher prices) as listed in our catalog.
*New York City and State retidents Add hcM SAltf tasCn
VANGUARD LABS
D«pt. H, 196-23 Jamarea Av«., H«lltt, N.Y. 11423
Digita I Frequency Meter
> Monitors your "transmitted" signal ^ Measures Khz and Mhz
> Operates with any exciter-transmitter
(1 to 600 watts-up to 30 Mhz)
> Large-bright "IMi^cie" display
> 100 Hz Readout
FM^ Kit . ., .$139.50
Box 2426 Rolling Hills, Calif. 90274
I
my hand washables hanging on the line upwind, but he was helping! The second thing he did to help was to put the dark things in the washer for me. He even included the skirt to my dark wool suit which was in the pile going to the cleaners. He said he wanted to make a full load.
That night we got a babysitter and went out to dinner. He paid ten dollars, for our steak dinner, and then my reformed hus- band suggested that we go somewhere else for an after-dinner drink. Dazzled by all the attention, 1 happily agreed. We had just gotten settled with our dollar-fifty after- dinner drinks when who should pass by but his old high school girlfriend and her heavy-handed, shifty -eyed husband.
After we had paid the babysitter her ransom and my husband was taking her lionic, I began to tiiink. ''It would be nice to have help with the housework, but the experience might take years off my life. What would he do when he found that doing chores together really isn't much fun? Would he go to the bur wiUi the boys and maybe run into that floozie without her heavy-handed husband? The ham friends that come over now are really quite polite, even when they are loaded down with all that stuff they carry in and out. At least now he's around if 1 need him. That smile on his face when he shows me his latest contraption does bring a lot of joy into the house - . •*'
The next day we agreed that we should go into the hamshack together and start to clean it out. It was just by chance, of course, that I bumped against the receiver and turned it on. When that station came on calling CQ I was only curious when 1 asked, "Can he hear you as well as you hear him?" It was with a great deal of pleasure that I saw his eyes flash with an inner determination not to weaken, which died when flooded out by the desire to get just one more signal report.
The smell of burning solder fills the air around our house. The clinks in the
vacuum cleaner are still there, but some- how they mean something different to me now than before. They mean I have a ham at home that loves me.
. . . Derfler ■
50
73 MAGAZINE
YOUR
Norman Ralph W4AYI/5
124 Teresa Drive Greenville MS 38701
After building a grounded-grid linear using four 811 As and modifying it, improving it^ ctc.^ I decided to build a linear that would perhaps reflect some of the knowledge and experience I had learned.
Much thought was given to what type of tube or tubes would be used. The new 3-5 00 Z was chosen for several reasons. First, a tube requiring plate voltages in the 2—3 kV range was to be desired to keep the plate tuning capacitor to a reasonable size (250 pF). Secondly, a tube with a large plate dissipation was wanted to give a much larger margin of safety than was available with the 81 lAs. The 3-5 OOZ has a plate dissipation of almost twice that of four 81 1 As, Third, the low output capaci- tance of the 3-5 OOZ enables it to be used at higher frequencies much easier. Fourth, the 3-5 OOZ efficiency range makes it very versatile. Output ranges from 7 SOW out with IJ kW input at 3 kV to 500W out with 800W input at 2 kV, And finally, the intermodulation products are very low with the 3-500Z as with other zero-bias triodes designed for grounded-grid class B service. Here is a table showing typical operation of the 3-500Z.
Dc plate voltage Zero $pg. p(, current single tons pi. current singfe tone grid cur, PEP input povver PEP useful output pwr Resonant load imped Cathode mput imped I ntermodu Nation prod.
The schematic diagram of the amplifier (Fig, 1) is pretty much self-explanatory
3.0 |
23 3,0kV |
|
160 |
130 |
95 mA |
370 |
400 |
400 mA |
115 |
120 |
130 mA |
1110 |
1000 |
800 W |
750 |
600 |
500 W |
5000 |
3450 |
2750 fl |
115 |
100 |
fOO U |
-30 |
-33 |
-38 dB C3rd order) |
and there is not very much new about the design. It follows what is in the handboolc and other publications. A high-capacitance tuned input circuit was used to obtain greatest linearity. Without the tuned input circuit the exciter sees a low load imped- ance over part of the rf cycle and a very high impedance over the remainder of the cycle. Consequently, the waveform suffers. Also with an untuned input the rf plate current return path to the cathode must travel the outside shield of the coax to the exciter plate circuit and then back the center conductor to the cathode. This can result in high intermodulation distortion. With the tuned input circuit these prob- lems are solved as the tank circuit provides
Inside the 3'SOOZ linear amplifier,
a **flywheel effect" for good waveform and a short rf return to the cathode.
Many of the components used were obtained from suppliers advertising in 73. Relay Kl in the rf section is included to enable the linear to be switched in and out of the circuit with the plate voltage switch S2.
I
DECEMBER 1970
51
9T NO 14
500
^
tj
L3
30 llV
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3 kV
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WlNf^M KERAWfC «gD
ZO-30T NO lO 1» "rfl. OlA 1 9 ifl
FORMVAfiE mm^
FERRm 1*00 '^^■'^'
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HF our
Al HA. OlA 1 9 -J— OOI
1
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4 rfn TAPPED P<W? EACH SAND
FILM
Hg>i»
cti;
/TT
_L^ Af4D L a. eg AMO CB
nCACTANCE OF S5Q^^ -CI riEACMMCt OF 30r-^C2 RCACTANCf OF Z?3[2-L2. Ll
C£ ' teO ||F AT a 5 HHf W (*F AT T.a NWt 49 Df AT L4 MHt 30 pF AT 21 IMv 2? if" AT £9 l«if
LS-tZj9 »H «T 3 5 iMi «29 VH AT 7 2 HHi
312 j^ AT 14 ie4t
2 ft ^ AT ?i HHii
C3- IfiOO pF AT 3.5 MHi 790 pF AT t 2 Mrti: JTft pf AT t* WHi 250 pF AT 21 UHi 190 pFAT M UHI
L2-tA l#4 AT 28 MHt
/W
01
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9 feV
RFC
2J3 mH 900 ifeA
PIMHMI
20M
torn
HT^A
li
./-p-Oi
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tt£
PLATE
o
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P$A
ORLO
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1LAI««(lT
TO
lis. VAC l-PWl?
SUP COMMON
13 V*C
Fig. I. Schematic of the 3-500Z linear amplifier. Coil data is shown on the table insert.
\
Tube Socket
The tithe socket is home-made. I cut a 3 in. round hole in the chassis for the tube socket. The socket consists of a 4 in, piece of Plexiglas with a 2 in, hole cut in it (Fig. 2). Five large tinned forked terminal lugs were purchased from a local automotive store. These could be made to fit the pins of the 3-500Z by springing the part of the Uig where the wire normally would be inserted. J bent the forked part at a right angle and bolted to the Plexiglas in posi- tion to take the pins of the tube.
The part of the terminal lug taking the tube pins protrudes out and down into the 2 in* hole and air can flow freely around all the pins. Short wide copper straps were run from the forked part of the terminal lugs to the chassis on the three grid pins of the tube when the Plexiglas Is mounted under the 3 in. hole in the chassis. This not only effectively grounds the grid pins, but also provides a heatsink for them.
I used an SK-406 chimney, but you could use a chimney from a Coleman double mantle lantern. The lantern chim- ney sells for under $2, which is quite a savings over the SK-406, However, as the sides of the lantern chimney are straiglit, they do not deflect the air flow past the plate heat dissipating connector, so the
tube should be observed closely that it doesn't overheat. A suggested remedy for this disadvantage of the lantern chimney would be to cement a ring-shaped piece of Plexiglas to one end of the chimney. The diameter would be slightly larger than the diameter of the chimney and the center hole would be 2.5 in.
The HR-6 plate heat dissipating con- nector must be purchased separately and lists for $2.20, but a supplier that adver- tises in 73 has them listed in his current catalog for less than a dollar.
PUE^ItLAS SQUAI^
4 in
3 is. CMA HOLf ftCOaJR^ m CHASSIS
TMKI CHA&&4 STRAP
S^PADE LLi(* BENT U3* AT >0'
COPPErt STftAP
Fig. 2, Layout and plans for the do-it-yourself
tube socket.
52
73 MAGAZINE
n
AMERICAN MADE
Mobile 2 Meter FM Transceiver
Here is what the 2 meter, FM Ham World has been asking for.
Specifications: 90 day warranty
RECEIVER
The HR-2 receiver is a double conversion, superhetrodyne with highly selective ce- ramic filter.
Fr^uency Range... 144-14^ MHz Sensitivity,.„*«.«__J).35/iv (nom.) 20DB Quieting
Selectivity ,..^_.
Audio Output {3-4 ii Speaker)
,6DB Down ± 16 KC 50 DB Down ± 32KC
Channels..„<„»„,
. .3 Watts 10% Distortion 5 Watts l\^3ximum
„_6 Crystal controlled with provision for adding an additional 6 channefs
f.F. Frequencfes..-^I0.7 MHz & 455KH2
TRANSMITTER
The HR-2 transmitter uses phase modula- tion for the ultimate in carrier stabiltty. Built in SWR load mismatch circuitry provides protection ajgainst open and shorted antenna conditions.
Frequency Ra Power Output Modulation...
Deviation*.,
Microphone. Channels,,.,,,
nge„„144-148 MHz
...„„,. 10 Watts (min*) @ 13.6 VOC
.phase Modulation with automatic deviation limiting
..Automatic Limiting with in- ternal adjustments from O-^ISKC deviation
„Plug-in, hand held, high Z Ceramic supplied
.,6 Crystal controfied with Individual trimmer capacj'- tors for Frequency netting
tA
O
m i(/i
I
to
a
m o
m
m
n
CD
P.
GENERAL
Power Requirements 13,6 Volts (nominal)
Receive (Squelched), 180 MA-
Receive (Max. audio output) . 800 MA.
Transmit„*««,.,» .2*5 Amps (max,)
STANDARD EQUIPMENT
Built-rn 4'' Speaker Mobile Mounting Bracket SO-239 Antenna Connector Socket T & R Crystals for 146.94 MHz PTT Ceramic Mike
^
only «22900
Amateur Net
C^-C^Cy ELECTRONICS, INC.
i 7900 Pendleton Pike, Indianapolis, Indiana 46226
CO
o
o
o
3
'a o
I
1
02
4000 PIV t.5 AMR
T4QO0 PIV ^1.5 AMP
ALL FILTER CAPAClTOftS 50O |4^/ 3IO VOC EACH
ALL BLEEOER RESISTORS 2-IOOK, 2W CAftSON IN SERES
500K
^.0-1 ITT A
*)CAL(BRATED 0-5000 VOLTS
P29
r
B- 115 VAC
COMMON
Fig, 3. High voltage power supply.
Power Supply
For the power supply (Fig, 3) I used the filament transformer from an old TV. I removed the shell from the transformer and discovered the filament windings wound on top of the primary with the secondary HV wound on the bottom next to the core. I removed the filament wind- ings, counting the 5V windings, end then wound a new filament winding using the 10-gage wire 1 used on the filament choke, I taped up the HV secondary leads and they are not being used. The voltage checked out at 5 -25V without the tube in the socket and 5V with the tube in the socket and Ut. The shell was replaced on the transformer for maximum shielding. In use, the transformer stays cool at all times.
The pi-network is designed around a reactance of 275n in the coil, 25012 in the tuning capacitor, and 300 in the loading capacitor. This will give you a Q of 20 if
you use a plate voltage of 3 kV, If your plate voltage should only be 2 kV or you should later add a second tube your Q would still be a respectable 10. At 2.5 kV the Q is almost 14. Actual values of L and C are given in the chart on the schematic.
All the metering is done in the negative lead of the cathode circuit. This keeps high voltage off them and allows the grids to be grounded direct. The panel meters axe small imported ones that sell for less than $5 each. The voltmeter in the power supply could be mounted in the rf section if desired.
The power supply is of standard design with a full-wave voltage doubler system that gives an approximate no load voltage of 2,8 times the secondary. Voltage regula- tion will depend on transformer capabili- ties and house line voltage regulation as well as the output capacitance of the filter. The filter capacitors used here were pur-
54
73 MAGAZINE
chased from an ad in 73 for $1 each and provide over 40 ^F of filtering.
A relay and 250 20W resistor was put in the primary circuit of the transformer as shown in the schematic to protect the rectifiers from the high surge of current that occurs when the large filter capacitors are charging. The other relay was installed in the power supply to keep the control wiring to the rf section in a small cable of 20-gage wire.
The power supply is a separate unit. It is in a well ventilated , completely enclosed box that is kept under the operating bench.
Finishing Touches
The rf section is enclosed in a home- made cabinet. I had a local sheet-metal
shop cut and bend the aluminum to my specifications. I painted the panel a light gray and the bottom and top cover are painted black. The tube and input circuit are moainted on one side of the cabinet, and the pi-network and filament trans- former are in the other half of the cabinet. An access panel was cut in the bottom plate under the chassis and a Roton muffin fan mounted on the cover plate. Rubber feet were mounted on the bottom to let air under the cabinet- There you have it — a linear that no longer looks like a "Rube Goldberg" special and is pleasing enough to the eye to be placed alongside your exciter. There is, by the way, enough room in the rf section for a second 3-5 OOZ if you have power supply enougli to handle it.
, . . W4AYI/5 ■
^«.
JVIANUFACTURERS,
SPEC SHEETS ^ INSTRUCTION BOOKS
While our typesetting and art departments are not exactly underburdened, they are not all that flat out either- Neither is our printing departnnent, so if you need any spec sheets made up or instruction booklets for your equipment, why not get in touch with us for a quote. We have the technical department to write it, edit it, set it in type, take pictures of the equipment, lay out the booklet or spec sheet, paste it up, and print it. After aM, we turn out two rather good sized magazines a month plus a lot of brochures, letters, pro- motions, and even a fair amount of job work for our locaHty.
Perhaps you need counter cards, posters, bumper stickers, or almost anything else that is printed or silk-screened?
73 Magazine •Peterborough NH 03458
NOW!
from
ROSS AND WHITE COMPANY
ELECTRONICS
SOLID STATE
TONE BURST ENCODERS
(TO THE FREQUENCIES OF YOUR CHOICE)
MODEL TE2 2 tone
Factory preset, only S29-95 postage paid.
MODEL TE-5 5 channel model Factory preset, only S39.95 postage paid.
GUARANTEED FOR ONE YEAR!
Use it for 10 days, if not completely
satisfied return for a full refund.
• Easy to install, 3 wire hookup, attaching bracket included for car or home.
• Operates from a single factory supplied internaf 9 volt battery.
• All frequencies factory preset. Can be field adjusted from 1600 to 2800 cycles. Other frequencies on special order.
• Nominaf 0.5 sec- tone burst length.
• American made commercial grade components on glass epoxy PC board for maximum
reliability.
ROSS AND WHITE CO., Electronics Dept, 73-12
50 West Dundee Rd., Wheeling, ML 60090
Gentlemen: Send me model.
Xcvr make
.tone burst encoder
Model.
Check or money order enclosed. Please set frequencies for
Send additional information. Check Q Name
Address
City
State
Zip
DECEMBER 1970
55
The HT-2 Mark II, now with a new and improved transmitter, is the only 2 meter FM walkie-talkie built for the amateur. It features an extra-sensitive receiver with crystal and mechanical filters for excellent selectivity, and 1.6- 2 watts out with very good audio quality. The ideal rig for re- peater operation — in town or hilltopprng! Comes with many i6xxr3s«
Amateur Net $269.95
One year warranty — atl products.
It's undoubtedly the finest amateur 2 meter FM transceiver on the market. This unit has better than 0.4 fiM sensitivity, uses FETs, ICs, and ceramic fil- ters and, as a result, the receiver audio is superb. Rated at 10+ watts out (often delivers 12-15). Has 6 channels, transmit and receive.* The APC (auto- matic protection circuit] prevents PA failure due to open, shorted or mismatched antenna. Great for mobile applications — it's so small and compact. The IC-2F is a beauty!
Amateur Net $349.95 IC-3P 49.95
^Available soon — concentric 6 position switch alfowing
36 channel combinations!
I
8ut if fie doesn't, surprise him with one of our fine 2 meter all solid-state FM transceivers or that exciting new "REDHEAD "
the AS-2HG 2 meter gain antenna.
'I
You've gotta see THE REDHEAD
The AS-2HG two meter FM 3.4 db gain groundplane antenna is the newest addition to the Varitronlcs quality line. This commercial quality antenna is built of heavy gauge aluminum tubing and is adjust- able for minimum VSWR over the entire 2 meter band. Rated at 500 watts, it's easy to assemble and all mounting hardware Is included.
Amateur Net $18.95
A very happy holiday season to all of you from all of us.
Varitronics Incorporated
Arizona Interstate Industrial Center 2321 East University Drive, P.O. Box 20665 • Phoenix, Arizona 85036
Amateur radio enthusiasts have been using surplus V.H.F. - FM equipment
for years, but until recently most of this equipment was not specifically
designed for amateur use, and was very expensive. Standard Radio
Corporation,* one of the largest manufacturers of electronic equipment in
the world, has applied solid state technology to develop a professional
quality 2-meter system specifically for amateur use.
The SR-C806MA is most frequently used as a mobile unit; however, it also makes an ideal, low cost base station unit when used in conj unction
with the A.C. power supply accessory.
The popularity of 2-meter FM amateur communications is rapidly growing. In most metropolitan areas of the country 146.94 MHz is extensively
monitored, and open repeaters make it possible to maintain
communications over wide areas of the country. Standard's new
professional quality 2-meter system now makes it possible for you to enjoy
the fun of amateur mobile communication in your car for just $335,00,
* Manufacturing division of Standard Communications Corp.
Dealer Inquiries Invited :
Erickson Electronics
4657 N. Ravenswood
Chicago, III 60640
312-334-3200
Artie Specialty
2252 Dixie Highway
Ponliac, Mich. 48055
313-335-4505
Henry Radio
11240 W.Olympic Blvd.
Los Angeles, Ca. 90064
213-272-0871
L. A. Amateur Radio Sales
23004 Crenshaw
Torrance, Ca. 90505
213-534-4456
Export Agents:
Mint home International, 2200 Shames Drive West bury Long Island,
N,Y- 11590 516-334-3304
^
GENERAL
Freq, Range — 143 to 149
MHz
12 channels in 2 MHz spread
Supply voltage — 11 to 16
VDC,
1 3. 8VDC nominal
Current Consumption — ^.15 amp receive standby, 2.4 amp transmit
Polarity of supply voltage — Negative ground
Number of channels^ 12- S applied with 4 channels
1) 146.94 MHzTx and Rx (national calling channel)
2) 146.34 Tx— 146.76 Rx (repeater channel)
146.20 Tx— 146.80
3)
4)
(repeater channel)
146 J4Tx— 146.94 Rx (repeater channel)
Microphone — Dynamic type with retractable neoprene cord
Dimensions — 6% "w x 2^^"h X 9^8 "d
Weight — 4¥i lbs, max.
Frequency stability ^ — .001% (— 10to+60°C)
TRANSMITTER
RF power output — .8 or 10 watts
Audio response hi — 3
dB of 6 dB /octave pre-emphasis
Output impedance — 50 ohms nominal
Deviation — Internally
adjustable to ± 10 kHz min,
factory set to ±7 kHz
Spurious and harmonic
attenuation — 50dB below
the carrier power level
Audio roll off above 3 kHz — 12 dB/octave
Type of modulator — Phase
STANDARD COMMUNICATION CORR
P.O.Box 325. Wflmington, Calif. 90744 (213) 775-6284
RECEIVER
Sensitivity — .35 or less microvolts for 20 dB quieting
Squelch sensitivity — Threshold ~ ,2 microvolts
or less
Maximum (tight) —
Between 20 dB quieting
sensitivity and 20 dB quieting
plus 10 dB
Deviation acceptance — Up to ± 1 5 kHz deviation
Spurious and image attenuation — 50 dB below the desired signal threshold
sensitivity
Adjacent channel selectivity
(30 kHz channels) — 60 dB
attenuation of adjacent
channel
Type of receiver —
Dual conversion
superhetrodyne
Audio output — 2 watts
minimum
Audio distortion — 10% maximum at 1 watt output
$335.00 (complete as shown with microphone and built-in
speaker)
-1
SWITCH
SOLID
^ F ET front end Por low noise and low cross mod. ^0,5U V for20dbof quieting or better
► rf Power output 10 WATTS rnini mum ^2channela installed CH.1 34/94 CIH.2 94/94
AMATEUR NET $249.96
RECEIVER PC BOARD 0.5u V I 20db quieting )
94 installed 3.5X 7"x 1 "
« 68.50
PC BD.
TELECOMM
TRANSMITTER O.BWmin.
34, 94 installed
3 b'x 7"x 1"
♦ 79.10
POWER AMPLIFIER Q5Win lOWoutmin. 1.6x2"x7r
#86.00
ELECTRONICS
ROBOX4ei CUPERTINO, CA. 95014
The new 2K
6^
IT'S EVEN BETTER THAN THE 2K-3.
JJ
STILL all the famous 2K-3 features:
Rugged Construction — Built to last a lifetime.
Reliable Performance — When you call you QSO.
Heavy Duty Components — Our power transformer alone weighs more than
some amplifiers.
Conservatively Rated — Loafs at full
legal power.
Floor Console or Desk Model.
PLUS these additional features;
Modern Styling — Keyed to a new decade.
Tilted RF Deck for Easier Operation — Looks you right in the eye. Mechanically Refined — Pride of own- ership is part of the package. Brushed Aluminum Panel and — Mod- ern Square Meters (Amplifiers can be beautiful). Recessed Power Supply Pedestal.
/
/
11240 W. Olympic Blvd., Los Angeles, Calif. 90064
213/4776701 931 N. Euclid, Anaheim, Calif. 92801 714/772-9200 Butler, Missouri 64730 816/679-3127
STILL a superb value at . . * $795.00
If you are one of the more than 3000 happy 2K owners, trade up to the new 2K-4, If you are not one of the group now is the time to join. For full information write:
Henry Radio has representatives in different areas of ttie U.S. to simplify ordering for
those living near one. Or you can order direct and we will ship . , . across the street or around the world. CatI or write for specifications and terms.
New York area: John Richardt, W2W1Y (201) 637-4107 Houston area: Jan Carman W5SBX (713) 464 0419
>4//^«j^#^». AA*f*t^^A, ^^J ^^*«*«^*^;^/ *.r^^r The 3K amplifier IS now available for continuous
Attention. Military and commercial users, ^^^^ ^-^^ ^^^^^ pttty and extra power ssB
operation. $895.00 F.O.B. Los Angeles, Calif.
i
w^
IV
CiflJ'iS
UNHlttWV
rt^tnor
our unFistmas Shopping with 73 Gift Subscriptions. . . You'll be giving something that will be appreciated and
^used al( year long.PLUS: 73 will send a special Christmas gift card in your name along with the January issue - in plenty of time for Christmas. And the Special Christmas Price will make it easier than
g ever for you to remember all your ham friends. The first
Wbscription is $6. The sec-4
V ond is $5. Additional gifts aiV m only $4 each.
^
k
01? out
I 4
JT^:
ir
lT* >"
^>
v
\-\
i¥ i I
hmu
Sent by.
.Call
Address
City/State
Enclosed $. Bill me..
-ZIP.
.for
_subscriptions. New Renew (in-
clude address label)
Vi
Name/Ca
Address
1
lV;
A
Ctty/Stata
Renewal
ZIP.
Don't know
T -
I
iV^
$6 for this gift
fc:*
Name/Call,
Address
City/State.
ZIP.
New.
Renewal Don't know
$5 for this gift when accompanied by the first six dollar sub.
\V
A
^^PJ^
Name/Call.
Address.
City /State.
New_
ZIP.
Renewal
Don't knoy\i [^^-'^
$4 for this gift accompanied by the first and second gift subs.
j^
Name/Call.
Address
City/State. New.
2IP_
Renewal Don't know
i^
$4 for this gift accompanied by the first, second, and perhaps third gift subs*
Helpful Hanna says:
If you don't Want to cut up your nnagazine, Make a reasonable fac- imife of a coupon , filf out and nnaiL
y^^^
Send to 73 Magazine, Pine St.
Peterborough, IM. H. 03458
1
SPECTRONICS
the FM supplier
Professional gear at less-than-amateur prices!
U43GGT $150.00
T51GGV $ 80.00
— All prices complete with accessories! —
L/KE NEW: 450 MHz BLOWER MOTORS $10.00 (motors orriyl
CALL OR WRITE FOR OUR UNBELIEVABLE SPECIALS ON HT200 NICADS, "EXTENDED LOCAL-REMOTE" PHONES, OUTDOOR SUBMERGENCE-PROOF 25W SPEAKERS, HZ3DCN (BRICK) TRANSMITTER BOARDS, AND OTHER HAM FM GOODIES!
REMEMBER-AMATEURS ONLY and FOR AMATEUR USE ONLY
PLEASE SUPPLY YOUR CALL LETTER WITH CORRESPONDENCE
OPEN-9;30 to 6;00 FRIDAY NIGHT till 8:00 CLOSED-SUNDAY, MONDAY and HOLIDAYS
PHONE; Area Code 312-848 6778
SPECTRONICS
k^
The FM People
11
1009 GARFIELD AVE.
OAK PARK, ILL. 60304
JMH *J^*
2 Meter
6 Meter
GENERAL ELECTRIC . . . RCA . . . MOTOROLA
When it comes to great used mobile communications equipment, we wrote the book" . . . Send for a free copy of "the book" (our new catalog).
Here are only a few of our LOW PRtCES: 2 METERS
4i
$148.00
GENERAL ELECTRrC MA/E33 6 or 12 volts, 30 watts Vibrator Power Supply with accessories
MOTOROLA X43GGV, New Low Price, Specia! Model in 10" case, 30 watt, transmitter narrow band, receiver wide band, vibrator powered, 2 freq. transmitter, and transistor powered 2 freq. "Private Line" receiver (single squelch), less reeds, complete accessories $108* '" quantities often .... $88.
6 METERS
MOTOROLA FMTR140D,6 or 12 volts, 60 watt, wide band, ^-j, Dynamotor Power Supply $4u.
Transmitter Narrow Band $aO.
Fully Narrow Band $68.
cpmplete with accessories (less accessories deduct $15)
GENERAL ELECTRIC PRE-PROGRESS 4ER6 RECEIVER, ET5 OR ET6 TRANSMITTER
30 or 60 watts (as available), 6 or 12 volts, aoo
including all accessories $28>
UHF
MOTOROLA . . . T44A6A with accessories $38.
T44AAV with accessories $48.
RCA CMU15A ...15 watts minus accessories $18.
For Your Convenience SCHEMATIC DIGESTS. (Postpaid)
G.E. SCHEMATIC OUTLINE AND INTERCONNECTION DIAGRAMS FOR GE 2- WAY FM RADIOS.
Voi 1 Pre-Progress Line ('49 - '55) 25-50 MHz 72-76 MHz
Vol. 2 Pre-Progress Line ('49 - '55) a ii en
150-170, 405-425 MHz, 450-570 MHz each volume $4.50
MOTOROLA FM SCHEMATIC DIGEST
revised edition to 1960 $6.50
I
GREGORY ELECTRONICS CORP.
249 Route 46, Saddle Brook, N. J. Phone (201) 773-7550
Dept. 73
^^C^m
ann
for the best in USED FM communications equipment
Two-Way FM Units • Walkies
Mobile Phone
Bases
Repeaters Mobiles
Here are some of the great buys at Mann
Motorola Models
X53GAD
ME 36
T43GGV
2 Meter Motorola Mobile Unit with Accessories, 2 Separate BOW Transmitters with single rcvr. 6/12 Volt Dynamotor Powered in 20 inch
2 Meter General Electric Mobile Unit with Ace. 50 Watt Vibrator Powered 6/12 Volt in 17 inch Housing $150
2 Meter Motorola Mobile Unit with Accessories 25 Watt Vibrator Powered 6/12 Volt in 10 inch Housing $115
WRITE FOR FREE CATALOG
Mann Guarantee
Money refunded without question if equip- ment is returned within seven days from shipment, undamagedp freight prepaid.
Conditions of Sale
Unless otherwise specified, equipment is used, and is sold as-is* All items shipped FOB Tarzana, California. Crystals, ovens, antennas not included unless specifically stated in catalog. AH equipment is sold or, a first-come, first-served basis.
ann communicatiohs
RO. Box 138, 18669 Ventura Blvd., Tarzana, Calif. 91356
Phone: (213) 342-8297
htroduces theFMer's Most Useful Tool!
Integra t ed-Circu it Freq u ency-Standard Oscilla tot- Generates a WW V— Zeroed Signal at 30 kHz Increments on 2 Meters!
If the .94 in your city seems different from the .94 they have in other parts of the State, you need a standard. The PEP oscillator is that standa rd...as a single WWV-compared oscillator, it will generate a solid and sta- ble rf signal on alt narrow- band and wideband channels of the 2 meter band.
$19.95 (kit)
wired & tested: $23.95
The circuit is a 3 MHz oscillator divided down to 30kHz with an output at 15 MHz to zero with WWV and another output that provides 30 kHz markers on 2 meters. The unit requires only a 4V power supply (3 penllght cells are adequate). Short-term stability: within 50 Hz at 150 MHz; long-term stability: within 100 Hz at 150 MHz. Wired and tested: $23.95 - Complete Kit: $19.95 - Board & Schematic only: $4.25.
CORR
PERFECTION ELECTRONIC PRODUCTS CORP.
404 E. HARRISON
ROYAL OAK, MICHIGAN 48067
J
1
RADIO RECEIVERS AND TRANSMITTERS:
R-390/URR Receiver, digital tuning BOOkhz to 32 mhz . , , . . . ,
Hammarlund SP-600JX 500khz to 54mhz , . , * • • »
URR-13 UHF Receiver, tunable 200— 400mhz, ideal for UHF ham bands and monitoring Air
Force and astronaut frequencies *.*.,,.,... , • • • ,
Collins R-389/URR VLF Receiver, tunes 15khz to ISOOkhz, the best in VLF ...._.
R-444/APR-4Y (ALR-5) Receiver, less ptug-in converters, CV-253/ALR or TN plug-ins . . . , .
ARC R-19 Receiver, 1 18— 148mhz, late version Command set ,_,..__.
ARC R-1 1 A Receiver, 190— 550khz, late Q-5er Command version
BC-348 Receiver, tunes 200— 500khz and 1 .5— 18mhz . . , , *...••■
NEIVIS Clarke Model 1671 Receiver, 175— 260mhz * . . ..*••••.•,••
CV-1 57/U R R SSB Converter, 455khz i-f input, used on all military receivers for SSB reception . ARN-5 GItdepath Receiver, 332— 335mhz, uses 90/150 cycle tone transformers plus alot of
good components and tubes or use it in an aircraft
TCS-12 Transmitter type 52245, 1 .5mhz to 12mhz ,
URC-11 Emergency Handle Talkie, 243mhz, less 1.5 and 135V battery, ideal for aircraft,
marine or 220mhz conversion, see May 69 CQ , , ,
R-48B/TRC-8 UHF FM Receiver, 230-250mhz, 115V/60cy _._.__
T-30B/TRC-8 UHF FM Transmitter, 230-250mhz, 1 15V/60cy . . ,
R-316/ARR-26 FM Receiver, 500khz through 30.5mhz , . . . ,,.....•,..,,..
TEST EQUIPMENT!
TS-186D/U Frequency Meter, 100 to 10,000mhz, ,01% accuracy, 1 15V/60cy .,-...
TS-535/U Signal Generator, made by H.P., VLF Type 7-'100khz, 1 15V/60cy
TS-318/UP Field Intensity Meter, range 1550khz to 2500khz .,...,,,
H.P. 3358 FM Monitor, Has two panel meters to show carrier deviation and percentage of
modulation with lamp to indicate peak modulation ..........,-.,.• ,.,....,..
TS-583B/U Square Wave Generator, range 20cy to 1 0Okhz .-,,....,*......
AIM/UPM-2 Wavemeter Test Set, range 80— 1220mh2, absorption type ,.....,. * . .
TS-226A/AP Power Meter, range 405— 425mhz, 0— 1000W . .
0S-34/USM-32 Oscilloscope, 3WP1 tube, portable, genera! purpo^, lOcy to 4mhz . .
Motorola Model TU*546 Portable Test Set for Motorola FM equipment * *
LM Freq Meter 125khz to 20mhz, .01%, AM/CW, original calibration book ,
SG*85/URM-25D Signal Generator, lOkhz thru 50 mhz, 0.25%, portable type in case
TS-155/UP Signal Generator, 2400 to 3750mhz ...........,...•*,
A.R.F. Products Model A R-1 A FM Deviation Meter, quad scale, 0^500khz deviation,
0 — 220mhz, nice to check FM equipment - # * • ,
URM-26 Signal Generator, 3— 405mhz, portable type in case, replaced Model 80 with military. . IE -19 Test Set for SCR -522, has signal generator, field strength meter, VHF 100-156mhz,
complete in case •*.,...-..,,.,..,
Motorola F4MV-24B{B)1C, 152— 174mhz, FM modulation and carrier station monitor, used
for FM alignment ,
UPM-6B Transponder Test Set, used to check aircraft transponders. A popular set ........ .
H.P. 4608 Wide Band Amplifier, 19" rackmount , , .
Ballantine Model 302 AC Voltmeter, range 100/iV to 1000V , • • . ,
Measurements Model 11 IB Crystal Calibrator .,.,,.,* * * . , *
Tektronix RM-IBI Time Mark Generator . . . • * - . .
Tektronix Type 162 Waveform Generator ^ ,.,,.....
ZM-11A/U R-C-L Bridge, 1 0jHUF - 1 00/iF , lOOjUH-IIOH, 1 ohm to 11 meg
Western Electric Model 19C Audio Oscillator, SOcy to 150,000cy . , . .
Measurements Model 79B Pulse Generator, 60 to 100,000cps , , , .
Ballantine Model 350 Precision rms vtvm, range .IV— 300V, digital readout
M99 Dynamotor Test Set, checks dynamotor output ..,,.....
TS-382/U Audio Oscillator, 20— 200,000cy, one of the best ,,.,..,......... • . .
G.R* Type 544-B Megohm Bridge, A to 1000 megohms *..,.. ............*
$495.00
$295.00
$119.00 $345.00 $ 37.50 $ 19.50 $ 12.50 $ 65.00 $ 95.00 $185.00
$ 4,95 $ 19.50
$ 14.50 $ 18.50 $ 18.50 $375,00
$ 69,00 $125.00 $ 45.00
$225.00 $ 49.00 $ 37.50 $ 18.50 $ 85.00 $ 69.00 $ 45.00 $265.00 S 65.00
S 85.00 $225.00
$ 18.50
$125.00 $175,00 $ 35.00 $ 29.50 $ 45.00 $ 27.50 $ 27.50 $ 65.00 $ 18.50 $ 21.50 $135.00 $ 27.50 ^ / o »o\j $ 60.00
TELETYPE EQUIPMENT:
0-5B/FR Exciter Unit
TT-56/IVIGC Reperferator Teletype Machine with keyboard ..,....,.
AISI/UGC-40 Mitey-Mite RTTY Page Printers
CV-89A/URA-8 Frequency Shift Converter, audio type, built In scope, a popular converter . ,
TT-63A/FGC RTTY Repeater, used with FGC-7A
Northern type 115 Variable Master Oscillator, 2— 32mhz
RA-87 Teletype Power Supply, converts ac to dc for operating RTTY line circuits .
Test Set TS-2/TG Teletypewriter Signal Distortion Test Set. Transmits four test signals, R, Y,
space or standard test message. A needed item for all RTTY operations
CV-57/URR Frequency Shift Converter, 455kc i-f type input, built-in scope
TH-5/TG Telegraph Terminal with TA-182/U telephone-telegraph converter and F-98 filter . .
Western Electric Model 161A1 Telegraph Station Test Set ,
Kleinschmidt TT -76/000 Reperferator— Transmitter with keyboard
$ 13.50 $ 65.00 $119.00 $125.00 $ 21.50 $ 65.00 $ 18.50
$ 35.00
$ 75.00
$ 50.00
$ 17.50
$ 85.00
ALL EQUIPMENT EXCELLENT CONDITION, F.O.B. ELLENTON. FL. SATISFACTION GUAR- ANTEED OR MONEY REFUNDED. IMMEDIATE SHIPMENT, WRITE OR PHONE (813) 722-1843.
SLEP ELECTRONICS C0MPAIMY«2412 Highway 301 N.,«Ellenton, FL 33532
NEW G&G CATALOG!
MILITARY ELECTRONICS
24 PAGIS, crommed wJrh Gov*! Surpl^ Et«ctrofiic Geor - t*^e Big^eir Borgaiini Bu/ih in America t \f will pay you to fSEMP ^^Z^ tor tFOuf copy - Refunded with ytujr Firif ofdfcf ♦
BC-645 TtANSaiVet 15 fuhm, 42b to 5GQ Ni^. Eotity odapied for 2 woy voice dr code on Ham, Mobile, Televiiiofi EKperimenhil, ond CtHi«n$. Bpndti Wirh rubes, leas power lupply ^ *»^
r«i factory cortan, SRAND MEW^,,,, $16«95
TRANSMITTIR hos 4 mKw: WE-316A, 2-6F6, 7F7
RECEIVER has 1 1 rubes: 2-953, 4-7H7, 2-7E6, 3-7F7
RECEIVER LF-: 40 Megacycle*
SIZE: 10-1/2" K 13-1/2" x 4-1/2". Shpg wt 25 lbs.
SPECIAL PACKAGE OFFER: 6C-645 Trofuceiver, Dynomofor and all QQceaoTie^r including mounHng, UHf AnNnno Assemblies, control box, coniplefe teF of connectors and plug) « *#fc* ^^m
Bfand New $26*95
AN /APR * 4Y FM & AM RECEIVER "FB'^ for SoreMife Tracking]
High prircHfon lob inafryment, for morlttof ing and
meoiyring frequency ond relotwe fignol itrengfh,
3fl (o 4000 Mc. *n 5 timing tangvl.. For tlO v 60 Cy- ^^»^^^pr-^^^^
deAC. EbHr- in power supply. Original circuit mKmXu9BSKi
diogram TfiHciuded, Checked ouf, ^^MI^SiJP^^^^
Perfect. LIKE NEW*,^..., ,, $S8.50 lpl0l|
All luning units orvtailable for above.
TG*34A CODE KEYER, Klf-con^oine^, oviormiMc, repri^ucei^ode proctice ligiwll from poper tope* 5 lo 12 WPM Builr-tn speoker. frond new with tech monuoU tokeup r«ck ond AC line cord. •••S24*50 Code prdCitrce tapej for above P.U.R,
WllLARD 2-VQLT STORAGE BAHERY
Ra red ot 20 Amp- -Hours. Model 20-2. iechiaf^obte, Coitipoct r>an$pill conslruction. Lightweight polytty- rene conramer, 3x4x3 1/2*'* Shipped dry, uses itondord electrolyte. Shipping Weight 3 Ibt^ NEW, eoch* •••«•**•
. $2.79
HEADSET
Low inipedonce^ With large chomoii oor cushions. 4-ft, cord one
plug. Reg. il2.50* OUR SPECIAL PRICE,, .,. $2*95
High Impedortce ladoptor for above » , ^^C
SCR-274-N, ARC-S COMMAND SET HQ!
Freq. RECCIVEflS,
B ■ 9 T * M'C . . . 4 . '
4f S ■ S Mc ■
7^9. 1 *«C ^ . . .
t^pe Oied
Cam0irte vrltti Tube*
ec 4S3 tl£.9£
BC-4S4. tie-50
eC-4 5S $14.93 «-25
LlHe 14 ew
it9-50 1 17^95 919. SO
CoTnotrl#
BC-4S7 BC-4SH BC-459
with TLltvl % «.95
BJtAMO NEW
92?. SO 922 94 421. SO
.tri.so
f 1 t .99
911-^4 92 3 $D
ARC-RllA Modern Q-5 Receiver 190 - 550 Khi ,.**• ARC-R22 540 - lAOO Khz Receiver with tvnln^ graph R*4/ARft-2 R««eiver 234-258 Mh£, 11 hibn, NEW ..
- * 4- » ■ w a
S16.S0 „ 124 SO
SCR-625 ARA^Y MINE DETECTOR Complete . • • * * ^32. 50
EE-8 SIGNAL CORPS fJELD PHONIS $16.95
T-30 THROAT MIKE, NEW 59? USED , ... 39?
T-17 MICROPHONE, NEW $8,50 US ED, checked out $4,95
6C-605 INTERPHONE AMPUFIER, NEW $3*45 EXCUSED. .. , $1.95
TELEPHONE HANDSET, W.E. type, ....LIKE NEW $2*95
SCft-522 TRANSMITTER-RECEIVER, wtth 18 tobef - LIKE NEW432.50
AM -200/ Arc PUSHPULl AMPLIFIER
4-tvbe PP power amplifier wlfh dynomotof, worUi on 28 VDC* Automotic gain control- *ji n
SlipQwt15lb* LIKE NEW J4,95
FREQUENCY METER MODEL LM
fifie ger»erol purpoie Navy unit, rangift 125 to 20,000 Kc. Operotes on 12/24 VDC & 200V 10 Mo DC* Complete witfi tgbes, crysta I , co U b * bcxjk.
Checked out, EXCELLENT USED , , $59.50
Aj above, le» book $24.50 AC Power Supply. $19,50
McELROY AUTOMATIC KEYER for keying
tronsmittef or for code proctice, Photoelectric cell & ^emitrve reloy * Voriobie speed mofor 110V 60 cy Complete with tube*, EXC, USED $11.25
BC'733 RECEIVER Receivei radio signqls
being trartsmitted by US Kile Mite on approx, 108 Mc# AM^ crystD I -controlled o#* 6 preset freqs« in 108,3 to 1 10,3 Mc range. Operates on 12/24 V DC & 220 VDC 80 V«, Complete witH 10 tub«* Con be converted to FM Receiver
SO to TOB Mc, bccUsed.. $5,95
BC-732A Control Box for above, NEW. . . 1 ,75
T-41 / APS - 18 TRANSMIHER
ANTENNA UNIT designed for 115 V 600 to 1400 cp(. Tubes irvcluded ore two T5£ ond one 15R, Cofnplete with shock moirnti arwJ bbvyer f7iotor.7xax18\ NEW $7-45
RAOrO SET AN/ APR-21 TRANSMIHER
& RECEIVER . Freq.moduloted 152 to 174 Mc,
Operated on any preset freqi>ency wit4iin VHF
range 152-174 Mc FM. Relioble voice communi-
catto*! over moderate distances. Includes ontenna,
handset H~33 and two carrying slTaps,
Size 12i«8^l/4^5-3/4* Wl 15 lb.
LIKE NEW, complete $69.50
AM-26/A1C PHASE INVERTER AMP.
4 —tube pushpu^ll power amplifier* Corbotf mike input, hi -lo imp* output* Workj on 24 VDC* Eas- ily converted to dor^dy 9'^>watt amplifier* Complete with tubes ond dynomotor UKE NEW $6«95
DUAL AMPLIFIER bos Iwo inpur circuits eoch feeding a single 6SN7GT twin triode dmplifier, Cornplete with 1 15V 60 cy* power supply gssing 6X5 GT rectifier. NEW 95*95
IP-69A/ALA-2 INDICATOR 3" scope* Front porkfll contnols: Vertical Pos*;hori£ontol poi. intensity, locus, gain, width ^ center ffoq. Pan, Operates or^ 1 15 V 380 to TOOO cF»^ Complete wtth tubes. LIKE NEW $24-50
BC-929 US GOVT SCOPE INDICATOR Compact nador display unit uses 3BP1 , A favorite with TTY fans os foundation for converter with cross-Jme scope presenfation, Aiso for Horns s Modulation-monitor foundation. Complete with all tubes, LIKE NEW. . . . $16*95
I I
I
TG-5B TELEGRAPH SET for code commun- ications or code practice* Portable, with hinged lid* Two or more unSti operate up to 25 miles o- parK Bell coll iyitsm, TOOO cycle Howler, key^ headpi ece , co nvos case , book . SJze 5-1/^5-1/2x10-, NEW . _$8*95
TS-100AP TEST OSCILLOSCOPE StmII
portable instrument used to test ond calibrore range meosuring circuits of rodar systems* Ui&i for viewing short video pulses on 3" t(^ee»i, PovAfef supply; ITS or 230 V 50-1200 cps. Complete wItK pi tigs, cobles. . . . . ^** ,*, $59*50
TS-126/AP RANGE CALIBRATOR TEST SCOPE Top quolJty 2" scope with oil position-
ing, focus, gain and intensity cor^trols* Complete wllh tubes ond cobles, NEW. $24. SO Demilitarized, like new. ...... *****.**,, i $ 13,75
TELEPHONE TYPE RELAY
Mode by J.H.Bunnell, hos adjustable sensitivity. 150 ohm coil. NEW $3»45
T-28 / APT TRANSMITTER , rodor jomming covering freq. 140 to 210 Mc, 0$c . Amp p Plate, Grid Plote & Mixer Plate controls on front panel. Complete with tubes, 7-1/2x10x20" Wt40 lbs, NEW $32,50
rFHM;S; 1:^ . l>[|KtMt * tUi oriJi»r, balaiti:* r*U«li. -vr- KcmiUanci? in lull, MinMiium urUrt $b,w\ j^.ti. H, NVt'. Subjt*! U. ifriipf ^ialv and |>riCL' ehvi^i^i^^
G&G RADIO ELECTRONICS COMPANY
47 Warren Sf , '2r%d F! ! New Yorfc. NY. 10007 Ph 212-267-4605
the all
ii
NEW
ft
CRYSTAL . CALIBRATOR
100-50-25- KC Markers
• Zero Beat to WWV
• Uses New 100 KC Crystals
(included in all units)
• Glass Epoxy Boards • Very Compact
rxTxYz" • 3.5 v. Operation
tMTlGRAUD CIRCUITS
FACTORY FRESH - NO REJECTS
W/SPEC. SHEET
FAIRCHILD - MOTOROLA
UL 900 BUFFER 80c— 10/6.00
UL 9U GATE 80c— 10/6.00
UL 923 J K. FLIP-FLOP $1.50—10/900
MC 790P DUAL JK FLIP-FLOP. $2.00— 10/18.95 MC 789P HEX INVERTER i i i« -,
10/9.50
MC 724P QUAD 2 INPUT GATE MC 799P DUAL BUFFER
\
MC 780P DECADE
MC 757P QUAD LATCH
MC 9760P DECODER DftJVER . . .
THREE ABOVE $11.95
V 4 * *
r 1 * « 4
$3.50 $3.50 $S.50
KIT
with 100 ffC
cfty5r4L
Wired and zeroed to WW V $15.95
ARN-30 108-135 mc tunable re- ceivers. High frequency version of the famous command receivers. Lis- ten to local airport frequency or convert to 2 mc. New, with schematic and operating instruc- tions $19.95
Western Union facsimile machines, send and receive pictures and memos. Works on lib v 60 cycles. Shipped with auto-start, auto-phase & pos-4-pos, conversion instruc- tions $19.95 each
Telfax paper 2d each, 1000 for $12.95.
,^^f r
KIT INCLUDES:
1-PC BOARD and CONNECTOR 1-NL 940S READ OUT TUBE
anil SOCKET 1-MC 9760 DECOOER DRIVER 1— MC 780P DECADE 1-MC 767P QUAD UTCH
NIXIE
READ OUT
STAGE
"NEW"
FROM
USES:
• FREQUENCY COUNTER
• DIGITAL VOLTMETER
. TIME INTERVOLTMETER
• DIGITAL CLOCK (has facilities for
dividing by six for clock)
PRICE 1 ta 2 - $21.49 EA. PER 3 to 4 - $20.49 EA. KIT 5 Of more $18.25 EA.
R & R ELEaRONICS, 311 E. SOUTH ST., INDIANAPOLIS, IND. 46225
UP
Professionally Engineered Antenna Systems
Single transmission line "TRI-BAND* ARRAY"
By the onfy test that means anything , . . on the air comparison . . . this array con- tinues to outperform all competition , , , and has for two decades. Here's why , . . Telrex uses a unique trap design employing 20 HiQ 7500V ceramic con* densers per antenna, Telrex uses 3 opti- mum-spaced, optimum-tuned reflectors to provide maximum gain and true F/B Tri-band performance.
ONLY TELREX GIVES YOU ALL THESE FEATURES--.
• Power rating 4 KW PEP . . , rain or shine
• Wind rating survival 110 MPH
• Patented broad-band coaxial Balun
• Heavy-duty steel gusset mounting plate
• Aluminum boom 2 in., 2Vz in. 0*0, X 18 ft.
• Large diameter, .058 wait taper- swaged dural elements for minimum
weight and exceptional strength
to weight ratio
Stainless steel electrical hardware
a Telrex Tri-band Array you get 49 lbs. of educated afuminum engineered and built to provide many, many years of performance unmatched around the world by any other make. Longest ele- ment 36 ft. Turning radius 20 ft. Shipping weight 65 lbs. Shipping container 13 in- x 5 in. X 13 ft
Note: If not available from your dealer, order direct. YouM get fast, personal service.
Telrex Labs are design engineers, inno- vators and manufacturers of the world*s finest % to 160 meter communication systems and accessories priced from $25 to $25,000.
For technicaf data and prices on com- plete Telrex tine, write for Catalog PL 71,
TC99D
BALUN
\
t4
J^ ^.
Elements shortened to show details.
■>
TRAP
L
I
Some thoughts from Mike Ercolino, P,E, — W2BDS, Telrex Chief Engineer . . .
'Tve been in the game over 50 years (pounded brass for 25} and found out a long time ago that an- tennas were the weak link. We changed all that"
*'Good antennas such as those we build can be ruined in two minutes by a tinker. So put 'em up and leave 'em up the way we make 'em/'
''Our Big Bertha' systems cost more than a Rolls Royce, Three of our cus- tomers have bought two of them , . . that's living."
—let
fp V COMMUNICATION ENGINEERING LABORATORIES
■ %^y^ TV And Communications Antennas Since 1921
Asbury Park, New Jersey 07712 201-775-7252
1
ATTRACTIVE PRICES for the R39QA
L.!!'i« QM»
The R390A communications receiver, long used for rniiitary surveillance of discrete frequen- cies between 500 kHz and 32 mUz, is a- vai table now at but a fraction of its worth. Both new and remanufactured sets are in stock each furnished with appropriate Instruction Manuals and necessary ancillary parts.
Providing digital readout with an accuracy to 300
Hz, the R390A is the latest and best made general coverage communications receiver that you can buy. Robustly constructed on sub-assembled units this receiver provides unequaled stability and maximum flexibility of controls. Six degrees of band pass from 100 Hz to 16 kHz and two positions of audio filtering enable this set to be used for the most sophisticated moon bounce conversion purposes all the way down to deluxe short wave listening.
Mechanically this receiver Is a marvel of gears, ratchets^ and cams providing ferrite slug tuning of both the front end and one of the triple conversion IF stages.
There are two audio systems within the set, one intended for feeding a monitored 600 ohm telephone line and the other used for a local loud speaker loop. Two meters are provided, one measuring the incoming RF signal and the other the level of audio set to fit a 600 ohm line.
The balance of this set is impressive, the knobs
for example having been designed for maximum comfort. The controls are not so closely set that any of them are awkwardly adjusted. There is, of course, a dial lock and a means of zero adjusting to the extremely high quality calibrator circuit provided internally. There is, of course, the antenna trim control and the AGC slow, fast, and medium control. The very effective noise I i miter is built in and of course the receiver is designed to be used with associated transmitters and is therefore provided with a muting cirucit.
Both balanced and unbalanced antenna inputs are available, and there is an IF output at 50 ohms to enable the receiver to function with a spectrum analyzer or a panoramic adaptor.
Perhaps one of the most unusua! advantages of the receiver is its extreme stability. It is so good, for example, that you can pretune the receiver to any choice frequency such as the Canadian Time Standard CHU in Ottawa or to our American WWV even while the set is cold and in off position. Turning on the set and then turning up the audio control will reveal the desired signal perfectly tuned in. So accurate is this presentation that you can literally use the receiver as a frequency meter. This unusual stability is achieved by a combination of superb mechanical engineering and very expensive permeability tuned oscillators one of which is used as a VFO control while the main one, of course, is ganged mechanically with a kilocycle change knob.
Thermostatically controlled ovens enclose both PTO's and the crystal oscillator circuitry. The R390A can be used remotely with suitable signal circuit control connections to the terminals of the set.
Although the set was designed for CW, MCW, AM, FSK and SSB, it does not contain a product detector. We can add in our shop a compatibly designed product detector assembly at a small additional cost which will facilitate tuning sideband signals.
This is the ultimate communications receiver priced at a figure that serious-minded individuals can afford. Many professional men or those who have recently retired have purchased these receivers from us to their entire satisfaction. It is the kind of set which will last years and years and years. Indeed there would be no normal reason for ever wanting to replace such a set for the
generally available merchandise made these days tf sufficient numbers are interested, we will
does not begin to approach in quality or prepare an illustrated brochure about this
performance what you can expect from the receiver and make it available without charge. In
RCSOA. Foreign customers should understand the meantime, study the specifications and if you
ttiat the set will also function on 230 volts 50-60 are in the vicmity of Harvard, Mass, do stop in
cycles. Although when packed in its special for a demonstration of this superb
container the shipping weight is 100 lbs, the net communications receiver. weight of the set itself is but 75 lbs. The shipping cube is 3.9 cubic feet
PRICE LIST
R390A new $1495
R390A new fitted with product detector 1565
R390A remanufactured 1 195
R390A remanufactured fitted with product detector 1265
R390 remanufactured 995
R390 remanufactured fitted with product detector 1065
R391 new 1995
R391 new fitted with product detector .2065
R391 used fitted with product detector 1865
?
I
The R390 is the original series Bet, Essentially the same is the R390A with a more complex mechanical tuning system and a voltage regulated power supply^ The 391 is a special series similar to the 390 but intended for servo-con trolled remote operation of up to seven pre-deter mined frequencies. Above prices are FOB Harvard, Alass. Shipments are effected in approximately two weeks after receipt of order and remittance,
TECHNICAL CHARACTERTSTCS OF R390A RECEIVER
Type of circuit: Triple-conversion superheterodyne on eight lowest frequency b^nds;
double-conversion superheterodyne on all other bands. Frequency range: 0.5 to 32 me. Types of signals received: Al,cw; A2, mew; A3, voice; A9, single side-band, Fl, frequency-shift
Keying, Type of tuning: Continuous; frequency read directly on counter-type indicator. Method of calibration: Built-in cry staJ-contr oiled. Calibration points: Every 100 kc.
Audio power output:
60Q-ohxn unbalanced line
600-ohm balanced line
Headphones ...,.,,,.,........
IF selectivity: 100 cps to 16 kc bandwidth in six steps. Intermediate frequencies:
First variable IF (used on eight lowest frequency bands) 17.5 to 25 mc-
Second variable IF (used on all bands) 2,5 to 2 mc on lowest band: 3 to 2 mc on all other bands.
Third (fixed IF) 455 kc, _^
Power source; 115/230 volts ac ±10%, 48 to 62 cps. Power input:
115/230 volts ac; 225 watts total: 140 ^atts with OVENS switch turned OFF. Number of tubes: 26 (including current-regulator tube RT510)* Antennas:
Unbalanced: Straight-wire of random length or vehicular-mounted whip.
Balanced: 125-ohm terminating impedance; matches 50 to 200-ohm balanced or unbalanced
transmission lines by using adapters. Temperature range: — 40oc (--40c*F) to 65^0 {149oF) Altitude: Up to 10,000 ft* above sea leveL Weight: 75 lbs. Range of tuning PTO: 3.455 to 2,455 mc.
# « • • «
n « *
500 mw, minimum. - 10 mw, minimum, . . .Imw, minimum.
HERBERT W: GORDON COMKVNT
HELPING HAMS TO HELP THEMSELVES
T'
PHONE 617 456 3548
PREPUBLICATION SPECIALS!
?^
The Best of FM"
. , . A huge selection of FM Journars finest technical and conversion articles, never before reprinted in any other magazine. . . . The concluding segments of those contra versial "CHH 0 Nl - CLES"! . . .Selected FM editorials to show
a broad view of the problems faced by FMers.
THIS BOOK COMPRISES VOL- UME II OF THE FM ANTHOL- OGY, AND INCLUDES AN "ED- ITOR'S CHOICE" SELECTION OF TOPFLIGHT ARTICLES FROM FM JOURNAL, FROM MARCH 1968 TO MAY 1969. WHEN THIS BOOK COMES OFF THE PRESSES IT WILL SELL FOR $5. ORDER YOURS NOW FOR THE SPECIAL PREPUBLICATION PRICE OF ONLY $3!
for the Amateur"
by Pau Semicon- Thts has
. . . A collection of 73's most popular ham projects, selected by you, the read- ers, and edited Franson (Mr. ductor himself), got to be the best, most authoritative, most univer- sally appealing collection of up-to-date circuits ever published. Not yet off the presses, this great MUST manual can be yours for the prepublication price of only $2. (Or wait a month and have the privilege of being one of the first to buy at the low postpublica- tion price of $3.)
Send to:
73 MAGAZINE, PETERBOROUGH NH 03458
n I enclose $3 for THE BEST OF FM.
EH I enclose $2. Send me the $3 transistor book.
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74
73 MAGAZINE
STUDY GUIDE
ILIKgJl
Partv Something for Nothing
For nearly 50 years, the vacuum tube reigned supreme and virtually unchal- lenged as the amplifier for electronics. From the passing of the spark gap and decoherer in the years following the first world war until the advent of the transistor in 1948, the vacuum tube had no serious competition.
The period of the vacuum tube, not entirely by coincidence, was also the time during which electronic engineering as it now exists made the major part of its growth, and the characteristics of the vacuum tube left their indelible imprint upon the entire field*
And despite the phenomenal growth of semiconductor electronics, some areas yet remain the province of the vacuum tube* UHF amplifiers, cathode-ray tubes such as TV picture tubes, and high-voltage devices are three major regions in which the vacuum tube remains the least expensive device to do the job.
Both because the vacuum tube is still in wide use, and because many other areas of electronics and radio in particular are built upon a foundation derived from vacuum- tube experience, the General class amateur examination contains a number of ques- tions dedicated to determining the appli- cant's knowledge of vacuum tubes and their operation.
The specific questions in the FCC study list are:
5. Describe the operation and usage of a cathode follower,
8, How is the plate circuit efficiency of a vacuum tube determined?
14- What is meant by the maximum plate dissipation of a vacuum tube?
5 1 . Compare the operating features of the grounded-grid and grounded-cathode amplifiers.
Not one of these four questions makes any sense at all, unless you are already familiar with the principles upon which a vacuum tube operates. Before we can get into the details required for the FCC questions, therefore, we must delve into just how tubes do their job. Then we can examine the various ways they are used and the factors which limit their use, to determine answers to the exam questions.
Our first question, then, will be "How does a vacuum tube work?'' When that is out of the way, we can move on to learn **What factors limit a vacuum tube's useful- ness?'*, and finally find out "How are vacuum tubes used?" By the time we get even a brief view of the realms opened up
by our final question, we should have adequate knowledge of tubes and their operation to handle any questions such as those on the study list.
With such a broad set of questions, and limited space in which to explore them, we cannot go into excessive detail about any part of vacuum-tube operation. Here, we're only providing enough to satisfy the General class exam questions.
How Does a Vacuum Tube Work?
Before we can determine how a vacuum tube works, we must first determine just what a vacuum tube amounts to. Even though we know that by "vacuum tube" we mean only those gadgets used in radio transmitters and receivers, that still leaves an almost unbelievable amount of terri- tory — diodes, Iriodes, tetrodes, pentodes.
DECEMBER 1970
75
hexodeSj heptodes, multifunction tubes, klystrons^ magnetrons, , ,The list doesn*t go on forever, but it might as welL
Ail of those special types of tubes share the fact that they consist of electrodes sealed into a tube full of vacuum. Since "vacuum'* is defined as the absence of anything else, that's where our phrase about "something from nothing" derives. Unfortunately as we have just illustrated, that's not precise enough to sort out the kind of * Vacuum tubes" the exam is concerned with.
Rather than try to define .all the differ- ences, let's start with the one common element and see what develops.
We already know that an electrical circuit, to be a circuit, must be complete. That is^ it must have both an input and an output. Even the simplest vacuum tube, then, must have at least two different electrodes sealed into its vacuum, one for input and one for output.
The first recorded vacuum tube was just about that simple. It was built by Thomas A, Edison in 1883, and its operation as a vacuum tube was purely accidental. Edison was trying to improve his newly invented incandescent lamp, and one of his experi- ments was to put a metal plate into the bulb near the filament (Fig. 1). He dis-
FrUAMENT
EVACIJATED
GLASS
ENVELOPE
Fig. J* Vacuum tube owes its existence to Edison effect, discovered by light bulb*s inventor. Circuit which revealed Edison effect is shown here. Metal plate was sealed into hulb^ near filament but electrically insula ted from it. When filament lit, current flowed between plate and filament More current flowed when plate was connected to positive pole of filament battery, than when connected to negative. Edison didn't know why this happened; others followed it up.
covered that when the filament lit* a small electric current flowed between plate and filament. The discovery was duly notedj published, and became known to the world as ''the Edison effect." Since it did nothing either way for the operation of the light bulb, Edison apparently ignored it and went on to other inventions — thereby missing the chance to become known as the inventor of electronics atop all his other laurels!
Serious scientists did, however, sit up and take notice of the Edison effect. As a direct result of it, Sir. J* J. Thomson spent several years in study and experiments, and in 1900 or so announced to the world his "electron theory-" That's the familiar structure of electrons, protons, and neutrons which we accept now as the **true" picture of the way things are made, and the reasons for electric current.
The electron theory explained the cur- rent of the Edison effect as an '^evapora- tion" of electrons from the surface of the filament, caused by the heat energy present in the filament. As these electrons boiled off, some struck the metal plate — and any time we have electrons in motion^ we have to have a current. That's the current Edison observed,
Edison also noticed that when he con- nected the metal plate to the positive side of a battery, the current flow went up, and if the connection was to the negative side, the current went down. This showed that the moving particles had to be negative in polarity, since they were attracted to a positive pole and repelled by a negative one,
A few years later, in 1905, an Engiish- man named Fleming obtained a patent on a device making use of the Edison effect, which he called a "valve." It was intended to detect radio signals by making use of the one-way property inherent in the current flow from a hot filament to a metal plate (anode). It worked in just the same way as today's diode detector circuits, and it established ihe vacuum tube as a part of the growing art of radio communications.
Let's look a little more closely at just what goes on in the simple diode, since it was the first vacuum tube to be discovered.
76
73 MAGAZINE
the first to be used, and is still the basis of all conventional vacuum-tube action ^
We have, as we have mentioned, two elements inside the vacuum for a diode. One is known as the cathode, and the other is called the anode, or piate.
The cathode is normally heated to a rather warm temperature (between 1000 and 3000^ F.) The heating may be done by a separate '*heater'* which is electrically insulated from the cathode itself, or it may be done by forcing a current through a high-resistance cathode materiaL Normally, an Indirectly heated cathode makes use of a "heater," and the word *'filament" is reserved to mean a combination heater and cathode. So far as the basic principle of operation is concerned it doesn't make much difference where the heat comes from so long as it's present, but in practice if ac is used to provide heating power it's better to keep the ac out of the signal circuitSj and so the heater— cathode com- bination is most frequently encountered in ordinary tubes.
At the cathode temperature, some of the electrons of the cathode material liter- ally boil off into the empty space sur- rounding the cathode. This forms a cloud of electrons known as the "space charge*' around the cathode itself.
The plate or anode is separated from the cathode by distance, and it's far enough away that the space charge never quite reaches it.
Under these conditions, with no voltage applied between plate and cathode, the space charge is self-limiting. It always contains all the electrons emitted (boiled off) from the cathode, and so always has a negative charge which just balances the positive charge produced on the cathode by loss of the electrons.
If the temperature of the cathode is raised so that more electrons are emitted, the space charge will increase, but the current flow to the plate will remain essentially zero* Similarly^ if the cathode temperature is lowered, the plate current will remain unchanged at zero.
If we return the cathode to "normal" temperature and put a small positive volt- age on the plate, the picture changes. The
positive voltage on the plate attracts some of the electrons from the space charge, and a current flows between plate and cathode. Not all the emitted electrons reach the plate, though. When we put voltage on the plate, this created a "voltage gradient" from cathode to plate something like a hill in the path of the emitted electrons (Fig. 2), and only those electrons which left the
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Fig* 2. Action of electrons inside simple diode tube is shown here. Difference in voltage between cathode and plate surfaces forms a 'Vo/tage gradient" shown here as a downhill slope. Space charge puts a hump in this hill, near the cathode. Angry ram represents action of heat, boiling electrons off the cathode surface. Those electrons with enough energy to make it over the hump fall down the hill, and hit the plate with a crash, releasing more heat.
cathode with enough energy to "make it up the hill" go to the plate. Some are repelled by others in the space charge, and a few even return to the cathode as a result.
Making the cathode hotter doesn't change things much -- but if we cool it down somewhat, the number of electrons in the space charge is reduced and we find that the "hUl" is not so steep. As the temperature cools, we find one point at which all the emitted electrons go over to the plate.
We can achieve the same effect without changing cathode temperature if we simply increase plate voltage. When plate voltage is high enough, it will pull all the electrons over the hill
In a diode, we have only these two factors available with which to vary the
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plate current. If either stays constant, the other exercises control (so far as it is able). With constant plate voltage, cathode temperature will determine the current up until the increased space charge with increased temperature makes the hill "too high" for the plate voltage to pull electrons over. With constant cathode temperature, plate voltage will be the ruhng factor until it is great enough to pull all the electrons over the hill, at which time temperature again takes over.
This "hiir' effect determines the maxi- mum power dissipation rating for Lhc tube, in a slightly indirect manner. The *'hiir' is hefM^een cathode and pfate, so that elec- trons leaving the cathode must '"chmb up" the hill to get past it^ and those which reach the plate are "falling down" the other side. (The analogy to a hill is not quite real, but if the voltages are plotted on B graph as in Fig. 2 it's close enough for all practical purposes,)
The more electrons that hit the plate, or the harder they fall, the more shaken will be the molecules of the plate material. This shaking up of molecules is what we gener- ally call heat, and a large amount of it goes on in a typical vacuum tube. Plates often run at a dull red glow, and some lubes are designed to operate with their plates white hot - with the heat all coming from the impact of the electrons falling down the '^voltage hill" between cathode and plate.
Any material eventually gets hot enough to melt, and the plates of vacuum tubes are no exceptions to this rule. For this reason, any tube is rated for a "maximum plate dissipation" which is the power in watts tlie plate can safely convert into heat. Power is the rating factor because it includes current (the number of electrons hitting the plate) — and voltage (the hard- ness with which they fall). It^'s also easy to calculate and to measuire, in operation.
While we've explained "power dissipa- tion" ratings in terms of the simple diode, it's the same situation for any kind of tube. Not only the plate is involved, either. Any electrode which is more positive than the cathode (on the ""downhUr* side of the voltage hump) must dissipate the impact energy of the electrons that get to it, and
78
73 IVIAGAZINE
such electrodes are individually rated for maximum power dissipation.
The diode's main usefulness in radio today is as a polarity -sensitive switch (Fig, 3), If the plate is positive to the cathode, it conducts a current, while if the plate is negative, the electrons are repelled and
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Fig. 3, Primary use of diode in electronics today is as a switch. When plate is positive (top) current can flow. When piate is negative (center) no current flows. This action can be used to change ac input into pulsating dc output f bottom), or to detect the envelope of an ampUtude-modulated radio signal, as well as for many more exotic uses not strictly a part of radio.
current flow stops. This makes it useful as a power rectifier to change ac to pulsating dc, and also as a nonlinear device for modulation, mixing, and detection of sig- nals (which we'll explore later).
The first great advance over the diode came about when Lee Deforest sur- rounded the cathode with a coil of wire which he called the "'grid*' (Fig. 4). By applying a negative voltage between the grid and the cathode, it became possible to add a new dimension of control.
For proper operation of a triode, as the three-element tube is known, cathode tem- perature and plate voltage are kept in the range where plate voltage controls cathode current- The plate is kept positive to permit large currents, but the grid is kept negative so that it repels electrons from its neighborhood and so holds down the plate
current.
The effective ''size'' of the grid, as it shows up in its interference with plate
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current, depends upon the voltage applied to it. The more negative the voltage, the more effectively the grid blocks current flow, It*s possible with most tubes to bring plate current down to zero by putting an extremely negative voltage (known as "cut- off voltage") on the grid. If, on the other hand, the grid is allowed to reach a positive voltage, it acts just like another plate, and loses its control of current flow.
For normal amplifier operation, the *'bias" voltage applied to the grid is some- where between the limits of cutoff and positive voltage, and is chosen so that the variation in plate current which results when small changes occur in the grid voltage is a reasonably true repljca of the variations in the grid voltage. Picking the right combination of plate voltage, plate current, and grid bias to achieve this happy effect is one of the fine points of engi- neering design work which we won*t go into deeply right here.
For our purposes, we can think of the tube as something a little different. As we mentioned in our previous installment, either a tube or a transistor can be con- sidered to be just a resistor in the circuit from cathode to plate, with the value of the resistor being controlled by the grid voltage.
This is a somewhat unconventional approach to the matter - and one you won't find in any engineering testbooks — but it works. Keep in mind that the more
PLATE
S04EMATIC
SYM80L
^CATHODE
Fig, 4, Introduction of grid between cathode and plate made it possible to control cathode current by means of a separate isolated electrode j and gave birth to electronic amplification as we know it today. Appearance of simple triode is shown at left; schematic symbol is at right.
negative the grid-to-cathode voltage, the more ohms in the "resistor" presented between plate and cathode connections, and the less negative the grid, the fewer ohms in the ^'resistor.'* As grid voltage goes positive, then, the resistance value goes down and more current flows. If the tube is in series with a fixed resistor, this will reduce the voltage at the plate, and we have a change in plate voltage which is brought about by the change in grid voltage which is 180 degrees out of phase.
When used in this manner as an ampli- fier, the triode vacuum tube operates almost exactly like the transistor except that its resistance is controlled by the voltage on its grid rather than by the current injected into the base, and it uses somewhat higher voltages than do most transistors.
However, both the triode and the tran- sistor share a common problem. The grid and the plate are both conductors, and they are separated by an insulating medium. This makes them form a capa- citor — which permits some of the plate voltage to feed back to the grid. This plate-to*grid capacitance makes the triode tricky to handle as a radio-frequency amplifier (and the transistor too, for that matter, but we're talking about tubes at the moment).
To solve the problem, another grid structure was introduced between the origi- nal grid (now called the "control" grid) and the plate* The new grid, being added to screen the control grid from the plate, was called the "screen" grid. It was, like the plate, connected to a positive voltage so that it had little or no effect upon the electron stream passmg through, but was bypassed through a capacitor to ground to prevent any signal from coupling back through grid -plate capacitance.
The screen grid worked nicely, and the resulting structure is known as a *'tetrode'' because it has four elements. However, it introduced a new problem. Sometimes the plate voltage is driven to a value lower than the screen voltage. Electrons still hit the plate hard - hard enough to knock a few *'secondary** electrons free. These secon- dary electrons then went to the screen
80
73 MAGAZINE
rather than returning to the plate* The result was an effective "negative resis- tance" between plate and screen under certain conditions^ which could cause oscil- lation.
The direct cause o£ this effect was the fact that the screen was the most positive tiling around when secondary electrons were released. A direct cure was instal- lation of still another grid, the third, between screen and plate. This *'suppre- ssor" grid is connected to the cathode, so that it will be more negative than either screen or plate. When secondary electrons leave the plate now, the negative charge on the suppressor grid drives them right back where they came from.
With five elements — a cathode, three grids, and a plate - the resulting tube is known as a pentode. Most present-day rf amplifier tubes are pentodes. Some power tubes are "beam power" tubes; they make use of special beam- forming plates attached to the cathode, which focus the electron beam in such a way as to create a ^'virtual suppressor'' by space-charge effect between screen and plate*
Each of the additional electrodes intro- duces a small amount of noise into the signal. Normally this is of no consequence , but in critical applications such as the first stage of a VHF receiver, triodes are still preferred despite their problems simply because of their low noise.
The many other kinds of tubes you may meet are, for the most part, combinations of the kinds we've examined here. They all start out with the elements of a diode, and all conventional tubes then add grids as necessary to do their job. Often I wo or more separate tubes are combined in the same enveiope for convenience (the 6 USA (Fig, 5) is an example of a triode and a pentode sharing the same chunk of glass), but the essential structure remains unchanged.
What Factors Limit a Vacuum Tube's Usefulness?
The vacuum tube is a most useful gadget, but each individual one is limited in its use by a number of factors. One of these, power dissipation, we've already
met. Some of the others include such tilings as the circuit efficiency, operating frequency limits, and power requirements. The major limits on any specific tube are those set by its power requirements, power dissipation J and operating frequency limits. The power requirements include both the power necessary to heat the cathode and that required to operate the tube's plate circuit (and screen, if any). Power dissipation involves not only the ratings, but the method by which the tube is cooled. Frequency limits are usually one-sided. Almost all tubes will operate at frequencies down to and including zero (or dc), but every tube has an upper frequency hmit beyond wliich it wUl no longer act as a tube should. Let's examine these in reverse order, looking at the frequency limits first.
The absolute frequency limit in any tube is set by the physical distance between its electrodes. The electrons in the
tube do not travel at the speed of light; they take a definite amount of time to make the 'trip from cathode to plate. If the signal frequency is so high that the distance from cathode to plate is an appreciable part of a wavelength, then everything goes sour. For instance, a positive-going signal at the grid should increase plate current — but if it's a half-wave from grid to plate, the plate current will be decreasing at that instant rather than increasing, and cannot increase until a half-cycle later when the grid signal is going negative.
Almost no tubes actually make it up to this limit J though. Other factors impose even lower frequency limits on them. One is the combined effect of the cathode
6U8
PINS l,9,8H/2 6J6 PINS 2/3,6,7 = 6 AG 5
Fig. 5- Combination tube such as type 6U8 is actuaUy two different tubes enclosed in same glass envelope and sharing same heater for con* venience. Triode haff of 6U8 is same as half a 6J6t while pentode portion is same as a 6AG5, Portions can he used independently.
DECEMBER 1970
81
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structure's own inductance and the capaci- tance from cathode to each other element in the tube. Taken all together, these effects add up to a low-pass filter circuit which prevents any signals above the fil- ter's cutoff frequency from flowing through the cathode — and so makes the tube unusable at these higher frequencies.
FILAMENT BUTTONS
PLATE RING
GRID RING CATHODE RING
Fig- 6, In quest for UHF operation, tube design- ers have come up with strange designs. One is this "planar " triode which is made of ceramic, with eiectrode connections coming out as rings around tube body to eliminate lead inductance as much as possible. Tube operates well into UHF region, but still has an upper frequency limit.
Tube designers combal these limits by making tubes intended for VHF operation physically small, and providing multiple connections for all elements. An extreme example is the family of tiny "'planar" iriode tubes made for space use, which have no connector pins as such. Instead, each element is brought through the envel- ope as a ring (Fig, 6). Distance between elements is reduced to thousandths of an inch. The tubes operate far into the UFIF region — but they still do have frequency limitations.
Power dissipation comes about because the electrons which compose the cathode
current have energy, and release it in the form of heat when they get where they're going, as we already saw. The limiting factor here is almost always purely physi- cal; when things get just so hot, they melt. It*s not uncommon to see overloaded power tubes with large dents in their glass envelopes, where lieat has softened the glass to such an extent that anything can change its shape!
The type of cooling provided has a lot to do with the limiting effects of power dissipation. If a stream of cool air blows past a tube, it can handle much more heat
than if it is sealed into an airtight box of
polished aluminum. Very-high-power tubes are often liquid cooled, with water actually flowing through the interior of the plate structure just like an automobile engine's cooHng jacket. Published ratings usually assume good ventilation is provided.
Power requirements limit the usefulness of tubes in a number of ways, most of them indirect. In comparison with a tran- sistor, for instance, a tube requires much more power — so much so that the vacuum-tube portable radio is almost extinct now. More power is necessary for heating the filament of just one radio tube than is used by all the transistors of an average pocket receiver.
Similarly, in the case of mobile radio equipment, those tubes which require extremely high plate voltage supplies, or high current, are usually ruled out because operating power is limit ed.
In some instances^ even when high voltage and high current are available, the comparative danger of high-voltage oper-
82
73 MAGAZilME
ation as compared with low-voltage circuits (transistors, etc.) tends to swing the choice away from the tube.
Circuit efficiency also limits the useful- ness of any circuit, not just those using tubes. In general, the efficiency of any circuit is the ratio between power put into the circuit and power taken out. For vacuum-tube amplifiers, it's sliced a little thinner in the standard definition of plate circuit efficiency,
Plate circuit efficiency, according to this definition, is the ratio of signal power output to supply power input (Fig, 7)< It
SKiNJIL ^ |
AMPLlHEII STAGE |
^SISNAL |
5J6NAL OUT |
|
IN 1 |
OUT |
DC INPUT |
||
1 1 1 1 1 t DC \Hf^ |
UT |
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Fig, 7. Efficiency of an amplifier or a circuit is
figured as shown iiere, by dividing signal output power by dc power put into the stage. Input
signal power is ignored in the calcuiation.
has nothing to do with signal power input. Thus, an rf amplifier which operated on 1 kV plate supply and drew 500 mA current would take 500W from the supply. If it delivers 300W of rf output, its plate circuit efficiency is 60%,
While circuit efficiency up to 95% or better is possible on paper^ almost no working circuit has ever been buOt which gets better than 75 to 80% efficiency. The trouble with the higher efficiencies is that they measure all rf power output, not just that at the signal frequency > In order to get figures above 75%, it's necessary to choose operating conditions which greatly increase the percentage of harmonics in the output — and all the "extra'' output power con- sists of just those harmonics!
Most audio power amplifiers are far less efficient than this. Typical figures are around 20 to 25% for **moderate" distor- tion. We'll get into this a bit more a little later when we look at some of the ways in which tubes are used.
The definition of plate circuit efficiency contains a built-in loophole, and in the early days of SSB operation many oper-
ators took advantage of the same loophole (which was also in the FCC rules at that time). The loophole is this; signal power input is not taken into account.
Some types of amplifier circuits use only a small fraction of the input signal as input, and feed the rest right on through into the output circuit. Such an amplifier can, for instance, accept lOOW of signal input power, amplify 1 OW of it by a factor of 30 to get 300 W, and feed through the remaining 90W of input to the output. The output power will be 390W, yet the ampli- fier produced only 300 of them. If input power were to be reduced to lOW, output would drop only to 300. And in either case the dc supply power taken by the circuit would be the same. This means that the same circuit might produce 300W at an efficiency of 60%, or 390W at an efficiency of 78%^ with no change in the circuit or its adjustments!
For the definition of efficiency, this loophole is closed by requiring that only the power output produced by that circuit be used in calculating efficiency.
The loophole in the rules had to do with the maximum power limit. It was originally stated as "1 kW to the transmitter stage which delivers power to the antenna/* and the fellows who found the loophole went through it by using a 1 kW final of a type which could feed through almost unlimited power, and driving it with a 10 kW "driver/' Most of the 10 kW, of course, would go right on up to the antenna, with apparent efficiency in the final of several hundreds of percent.
The loophole no longer exists. Part 97,67 of the current edition of the Rules and Regulations states that power input shall now be measured to **the tube or tubes" delivering power to the antenna, and the Commission has served notice that in the case of feedthrough amplifiers, this is interpreted to include all driver stages as well*
How Are Vacuum Tubes Used?
Wliile at first glance it would appear that vacuum tubes are used for many purposes, we can compress all the uses for the ordinary garden variety of tube (that is^
DECEMBER 1970
83
■■
all except such special-purpose items as TV picture tubes, oscilloscope CRTs, tuning indicators, and the like) into one, with our **voitage-variable resistance" concept intro- duced in the previous section.
The diode J for instance, when it is being used as a rectifier, changes from being a very high resistance (when cut off) to a relatively low resistance (when turned on). The amplifier simply controls tke flow of current between two terminals in response to the voltage between one of the two and a third. The oscillator is simply an ampli- fier connected in a special circuit. Even the digital logic circuits used in early electronic computers for timing and storage can be viewed as resistances controlled by volt- ages.
The exact characteristics of any indi- vidual type of tube such as, for instance, the 6C4 triodCj depend upon the materials from which it is made^ and primarily upon tlie shape and spacing of its electrodes.
These shape and space factors are gener- ally called the "internal geometry" of the tube type, and they fix the amount of effect the grid voltage will have upon plate current, the maximum plate dissipation, the maximum cathode current^ etc.
If yoii know the geometry of the tube — or what amounts to the same thing, know what its effects are — you can apply the tube in almost any way you like. To make life easier for equipment designers, the people who design and build tubes run measurements upon their products and pubUsh "characteristic curves" which describe the key factors,
A typical characteristic curve for a triode (Fig, 8) graphs plate current against
so
lOO r&O 200 250 300 350 400 450 SOO PLATE VOLTS
Fig. fi. Typical set of plate-voliage/p}ate-current curves for a triode tube shows relation of plate miUiamperes to plate volts for six selected values of grid vohage. Relationships for other grid voltages must be interpolated between these, if they are needed.
plate voltage for various values of grid voltage. A not-so-typical curve might graph plate current against grid voltage, for vari- ous plate-voltage values. For most designers' purposes, though, the plate- current/plate-voltage curve is best, so it's the one most often supplied,
However, if we know plate current and plate voltage at any instant, then by Ohm's Law we can determine the effective plate- to-cathode resistance represented by the tube.
If the tube's plate is working into a reactance rather than a resistance, as for instance the primary of a transformer, or a choke-coupled output circuit, the plate voltage averages out to be constant and the manufacturer's curves can be used as they are. Changes of grid voltage then change only plate current.
If the plate works into a resistor, as in a resistance-coupled amplifier, it's "a bit dif- ferent and the picture gets messier. A "load line*' must be drawn on the curve to determine the dc plate voltage present at any instant.
By using the curves, together with his accumulated training and experience, the equipment designer picks an "operating point" for the tube by proper choice of the plate and grid voltages, so that the change in grid voltage will cause a corresponding change in resistance between plate and cathode. That is, if a 0.5 V increase in grid voltage causes a 10% drop in resistance, a IV increase of grid voltage should cause a 20% resistance drop and a IV decrease at the grid should result in a 20% increase of resistance. These figures are, of course, merely examples and do not correspond to any actual circuit.
When this had been done, the result is a circuit which produces for its output an **amplified'* or stronger version of the input signal. The "linearity" of amplifica- tion is a measure of how accurately the output follows the input; another phrase used for the same effect is "distortion/*
NQtice particularly that this same pro- cess occurs in any kind of amplifier based on tubes or transistors, no matter what the circuit's name may be. Class A, B, or C amplifiers, as well as grounded -grid,
84
73 MAGAZINE
grounded-cathode, and cathode-follower circuits, all act on this same basic process.
The terms "class A," "class B," and "class C** describe the operating point of the circuit. A "class A" circuit is intended to produce low distortion, and to give an output which is a faithful replica of the input. A class B circuit *s operating point is much closer to the cutoff point (a true class B circuit operates exactly at cutoff); output is distorted but efficiency is higher. A class C circuit remains cut off most of the time and passes current only during the peaks of the input signal. Output is dis- torted beyond recognition but efficiency is highest under these conditions. Since the distortion can be removed from a continu- ous (unmodulated) rf signal by a resonant circuit, class C amplifiers are used for rf.
As we have already learned, any circuit requires two conductors to complete it; we can think of one as the "hot" lead and the other as a "return" path for the current. The usual "return" past in most radio equipment i^ the chassis, which we refer to as "ground" or "common" since it h often connected to ground, and provides a common return for all signal paths,
Our vacuum tubes, with their associated components, convert an input signal into an output signaL This means that four conductors are involved, two for each signaL The return for each signal, however, is almost invariably grounded, which reduces the number of conductors to three — an input "hot" lead, an output "hot" lead, and ground. This is fortunate, since a triode tube has only three elements; we have exactly enough conductors to assign one conductor to each element: with neither elements nor conductors left over.
Because of the physical means by which the tube does its job, the input signal must be applied between grid and cathode, and the output signal must be taken from plate
and cathode. However, this does not neces- sarily mean that' the cathode must be connected to ground, input to grid, and output to plate.
While it's true that the most conven- tional use of tubes follows just that assign- ment (called grounded-cathode operation), we can connect our common ground to
any one of the three elements (Fig. 9). If, for instance, we ground the grid, then we must apply the input between cathode and ground. In order to take output with only one wire at the plate, we must pass all the output current through the input circuit- That is, since the input is connected to the cathode, the output signaTs path must go through the input to get to the cathode in order to reach the plate.
Similarly, we could ground the plate* The input signal is now applied between grid and plate, while the output signal is taken from cathode and plate. For the input to get to the cathode, it must travel through the output circuit.
Tliis means that in both the grounded - grid and the grounded-plate (usually called cathode-follower) circuits, the input and output circuits are directly connected. In the grounded-grid circuit, they are in series, so that all the current of one must pass through the other, while in the cathode follower, they are in parallel, so that the voltage of one becomes the voltage of the other.
GROUNDED cathode:
GROUNDED GRID
OUT
SIG OUT
GROUNOED PLATE (CATHODE FOLLOWER)
Fig. 9, Differences between the three ways of connecting tubes in amplifier circuits are shown here. These are simplified schematics and leave out all the necessities such as grid bias, coupling capaciiorSf etc^ to emphasize the similarities and differences of the three different circuit types.
DECEMBER 1970
85
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In the conventional grounded-cathode circuit, the input and output circuits are isolated and do not interact so directly.
The apparent differences between these three different circuits are due primarily to this difference in relationships of input and output signals. In the grounded-grid circuit, a small input voltage causes a large change in plate current — which forces a large change in input current because of the series connection. This makes the circuit look like a low impedance to its input, and a very high impedance to the output. It also permits feedthrough of power from input to output.
Since it's voltage rather than current which interacts in the cathode follower, the effects are reversed. Input impedance is very high, and output impedance is very low. Coupling of signal from input to output is small; voltage gain is always less than 1, which means that a cathode follower actually introduces a voltage loss.
The gain of any individual tube is determined by the internal geometry of the
tube, together with the applied voltages and currents. If voltages and currents are the same, the tube must provide the same gain in any of these three circuits. The stage, however, need not deliver the same gain.
For instance, a conventional ground ed- cathode amplifier has its input and output circuits separated and minimizes inter- action between them- In such a circuit, the stage gain can approach the maximum of which the tube is capable. Both the current and voltage of the input signal can be made larger in the output.
A grounded-grid stage, however, has its input and output circuits in series, so that the output current and input current must always be the same. Its gain can affect only the signal voltage. Thus the current gain of the grounded-grid amplifier cannot exceed 1, but high voltage gain is possible. While the gain of the tube itself remains high, the interaction between input and output signals outside the tube reduces stage gain.
86
73 MAGAZINE
The cathode follower has its input and output circuits effectively in parallel, so that the voltage in an;out must be approxi- mately the same. Its gain can affect only current. Voltage gain cannot be greater than* 1, but high current gain is possible- Again, the tube gain is unchanged, but the input/output interaction outside the tube provides the restricting factor.
Since both the grounded-grid and the cathode-follower circuits produce less gain than does the groundcd-cathode arrange- ment^ and since amplifiers are usually intended to produce gain^ this gives rise to the question "Why use these inefficient circuits?"
Each of them has its own unique properties^ which provide certain advan- tages in special situations. When the properties are not needed, the special circuits aren't used.
The grounded-grid amplifier reduces the stray coupling between input and output circuits inside the tube, because the grid acts as a sliield between cathode and plate. This makes it possible to avoid having to "neutralize" a high-frequency amplifier^ and in some cases makes it possible to operate a given tube at a higher frequency than would otherwise be possible (by modifying the effect of the built-in "low- pass filter" we examined earlier).
In addition, the low input impedance of the grounded-grid circuit is often con- venient for a high-power rf, amplifier, and the capability of feeding througli power from input to output is also nice (although no longer offering a loophole in the FCC regulations).
Contrary to popular opinion, there is no appreciable difference in amplification quality between a grounded -grid amplifier and one using the conventional grounded- cathode circuit. Quality in each case depends upon proper adjustment of oper- ating point and input signal level, not upon the choice of the common electrode.
The cathode follower's special proper- ties depend upon its high input impedance and low output impedance. This makes it ideal for use in transforming impedances from high to low levels. The input capaci- tance is reduced by the same factor that
input resistance is increased, making the cathode follower an excellent device for coupling energy out of critical circuits such as rf oscillators. The low output impedance makes it capable of driving a feedline without any intervening transformer, although other factors make this idea less attractive than it may sound at first.
The cathode follower offers an ideal example of "feedback" in action; this is an important idea iii aU electronics^ and seldom appears so clearly illustrated as in the cathode follower. Let's take a conven- tional grounded-cathode circuit and change it, step by step, into a cathode follower to see how feedback provides all the special characteristics of the cathode follower while the tube itself continues to operate just as it did before.
We'll start with an imaginary triode which operates normally with a plate-to- cathode potential of lOOV, a cathode-to- grid potential of 5 V, and a plate current of 10 mA. Under these conditions, with a 10 klZ resistor as its load, the tube provides a voltage gain of 21 times (Fig. 10). That is, a 0.1 V change In grid voltage will change the plate current by 210 /iA, causing the plate voltage to change by 2.1V* A IV change in grid voltage will change plate current by 2,1 mA, causing a plate voltage change of 2 1 V,
Now let's move 1 kO of the plate load resistor around to the cathode cu-cuit, leaving 9 kf2 in the plate lead (Fig. 1 1 ). This 1 kfi in the cathode circuit is in both the cathode—grid circuit and in the platen- cathode circuit, so that the plate path still sees 10 kn.
If we change the grid voltage by 1 V, the plate current will change by 2,1 mA. This will increase the cathode voltage by 2.1V (if the grid is going positive so that the current increases) and decrease the plate voltage by 18,9V- The plate— cathode volt- age change is still 21 V. The output voltage change would be less than that, however,
Unfortimately, the 2,1V change in cathode voltage is of such a polarity as to
reduce the effect of the IV input signal; were the entire 2J V increase to occur, it would completely cancel the input signal
DECEMBER 1970
87
mi
21 X IN
10 K
+ 200
J^+2J
FtG. 10
+ 102 J
100V>9000
7x IN
+ 200
1000
FIGM1
+ 150
1.83 X IN
+50 +200
0-91 K IN ^^
+200
0.95 X IN
+ 105
FIG. 12
FIG. 13
Figs. JO— 13. These four schematics iilustrate how feedback introduced by resistance in cathode circuit reduces stage gain although tube itself continues to operate unchanged. Voltage applied £o grid maintains grid-to-cathode voltage at 5; as cathode voltage changes, grid voltage is changed to always be 5V less.
which produced it. This, of course, cannot happen. What does happen is this:
The effective input signal is the one between grid and cathode, while the actual Input signal is between grid and ground. When the grid voltage goes up IV, it cannot do so instantly but must increase a few millivolts at a time. As it does so, the cathode voltage comes right along behind to buck it — and at some point they meet and level off so that IV applied between grid and ground produces a grid-to-cathode voltage just right to permit the cathode- to- ground voltage at that instant.
In our example, this wlli happen when the grid -cathode voltage is a little higher than 0.322V. The cathode current increase caused by this voltage is a little more than 0.67 mA, and the rise in cathode voltage is about 0,676V, The two voltages add up to 0:998 — which would have been LO except that we rounded off our figures.
The "feedback** voltage appearing across the cathode resistor^ then, reduced the effective input voltage to a smaller value. This in turn reduces the output
signal voltage, since there is less input signal available to the grid. Stage gain is reduced - but the tube itself is still pro- viding a 2 1-time voltage gain- Input resistance of the stage increases, because resistance is defined as voltage divided by current (Ohm's Law). Only the effective input voltage sees the original stage input resistance, but the entire input signal is affected. Tliis means that the original input resistance must be multiplied by the same value that the voltage is divided by in order to keep current con- stant. In our example^ the effective voltage is about a third of the actual voltage, so the effective input resistance is three times that of the original circuit.
Now let's move some more of the resistance from the plate circuit to the cathode (Fig. 12). This time, let's make it 50/50, with 5 kU in each.
The feedback causes the effective signal input voltage to be smaller than the actual input, just as before, only more so. Where in our first example the cathode voltage rose 2,1 for every volt increase in grid —
88
73 MAGAZINE
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cathode voltage, it will now rise 10.5 because of the greater resistance.
Effective stage gain under these condi- tions is reduced from 21 times to about 1.83 times. That is, a IV input signal frpm
grid to ground will produce an apparent K83V change in plate voltage -- which means a 183 juA change in ptate current.
This means that the increased cathode resistance caused the leveling-off to occur with an effective input voltage of only about 0.087V. The remaining 0.9 13V of the input signal was bucked out by cathode voltage- Input resistance, similarly, is much greater now.
If we move all 10 kH over to the cathode circuit (Fig. 13), we find that effective stage gain is down to 21/22, That is, a 1 V input signal will cause a 0.954V change in cathode voltage. The effective input between grid and cathode, then, is only about 0.05 V. The tube is still pro- ducing its 2I-time gain, because 0.05 times 21 is 1.05 factually the input is a little jess than 0.05. providing 0.95V out). Input resistance is now 21 times larger than originally.
The cathode follower circuit we have just developed can accept much larger input signals than could the grounded- cathode circuit with which we began. For instance, we had a 5V bias on the grid at the beginning, which meant that any input signal more positive than 5V would carry the grid positive (a condition to be avoided in most cases). With the approximate 20-time division of actual input voltage produced by the cathode follower's feed- back, a 5V input signal is effectively
reduced to 0.25V, and even a 20V input signal is effectively cut back to IV from grid to cathode.
Where originally we ran out of the operating range with a 5V signal^ we can now go up to a lOOV signal without exceeding the same operating limits.
This is not the only advantage produced by controlled feedback. The changes in input and output impedance are also due to feedback's modification of effective voltage and current levels. Not so obvious is the fact that any distortion introduced by the tube is reduced, because it is not a part of the original input signal.
The grounded-grid amplifier's character- istics of low input impedance and high oulput impedance are also the result of feedback; in the grounded-grid circuit, it is current that feeds back rather than voltage, and this reverses the effect upon imped- ances.
Feedback also makes oscillation possi- ble, if the feedback voltage boosts the input signal rather than bucking it. We'll go into all this in another chapter, however, when we examine practical amplifiers and transmitter circuits.
A Place to Start
By this time, w^'ve fairly well covered the basic components and ideas upon which electronics and radio theory are built- With our foundation estabhshed, we're ready to begin putting things together into operating circuits. One thing which any circuit must have is a source of power, so the power supply is a good place to begin our study of practical circuit theory* . . . Staff ■
i
DECEMBER 1970
89
NEW PRODUCTS
Crystal-Controlled Microcircuit
A crystal-controlled microcircuit oscil- lator (Model MCO-F), which uses thin-film capacitors and resistors on a single sub- strate, is totally contained within a 4-lead TO-5 Koldweld package. The new unit is designed for application as the local oscUlator or second mixer in dual- conversion receivers, ft is especially suited for use in advanced paging and personal portable receivers where rugged environ- mental conditions may be encountered. TRW Electronics, 1 1 00 Glendon Ave., Los Angeles CA 90024.
IC Breadboard Socket
A new device is now available for bread boarding with 12-Iead, round TO-5 integrated circuits. The device consists of an epoxy glass wafer, 2-3/8 x 1-5/8 in., on which is mounted a 12-pin socket, the tabs of which have been soldered to two adjacent rows of reliable solderless termi- nals.
The device should speed IC breadboard- ing because as many as four solderless connections can be quickly made to any terminal pin with ordinary hook-up wire. If discrete components are required, they may also be easily connected. Vector Electronic Co., 12460 Gladstone Ave,, Svlmar CA 91342.
Power Transistor Line Expanded
Four new transistors have been added to the industry's only line of silicon PNP rf power devices. The transistors, types MM4020 thru MM4023, bring to nine the number of devices in Motorola's PNP rf power family and increase the variety of output powers available to the designer. These now range from 0,5 W to 40 W @ 175 MHz,
Each of the transistors features bal- anced-emitter construction for maximum safe operating area, isothermal design for flat power output versus temperature performance, and low lead inductance striphne packaging.
The transistors are designed for the 12.5V VllF large-signal amplifier amplifica- tions required in military and industrial equipment operating at frequencies up to 250 MHz.
In the unusual construction used for the four new transistors, thin-film Nichrome resistors in series with each of the multiple emitters distribute power evenly through- out the chip. This technique prevents **hot emitters*' and results in maximum safe operating area and a rugged device that
90
73 MAGAZINE
stands up under the high voltage standing wave ratio conditions sometimes occurring in a mistuned rf system.
The MM4020/2 1/22/23 transistors bring another important characteristic to the rf designer — exceptional output power stability versus temperature — through the use of isothermal design. This type of transistor design insures the even genera- tion and flow of heat in and from the chip so that the "power slump" usually encountered in an rf power device operating near its maximum frequency is nearly absent. Motorola Semiconductor Products Inc., Box 20924, Phoenix AZ 85036.
Amplifier Modules in Semi-Kit Line
Eight different special and general- purpose audio amplifier modules are being offered by GC Electronics Division of Hydrometals, Inc., as part of its new Calectro-Amperex line, Basic module shown here is a 20-watt stereo amplifier, which is blister-packed and displayed on a pegboard rack. The line also includes lower-power hobbyists' amplifiers and guitar amplifiers, along with a profession- ally finished universal chassis/ cabinet kit, Ivens Stanton Assoc, 122 East 42nd St., New York NY J 001 7,
Miniature FM Mobile Unit
The Regency solid state Model HR-2 features a lOW of rf power output with operation on any of 12 transmit and receive channels. The receiver section of the new radio is double conversion, super- heterodyne with a highly selective ceramic filter for operation on both wide and narrow band signals. Sensitivity is rated at 0.35 juV, 20 dB quieting. The transmitter features phase modulation for exacting
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We have in stock over six million crystals which include types CRIA/AR, FT243, FT241, MC7, FT249, HC6/U, HC13/U, etc. Send 10^ for our 1970 catalog with oscillator circuits, listing thousands of fre- quencies in stock for immediate delivery.
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Special Quantity Prices to Jobbers and Deaters
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HATRY ELECTRONICS
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203-527-1881
(1 Block East of Wetharsfterd Ave,
off Airport Rd., Rte 61
See CORKY, WIKXM or WARD, WIWRQ
4.95 4.65 , J9 .JO
ANTENNA
In 100 foot rolls only 450 ohm open wire. Per 100 faet ^ , ^ ...*.. $ 300 ohm open wire. Per 100 feet *..,*.....,
Standoff Mdst or Screw-In . , .
Mast straps .>..«.,**>..*.**-**^ -#'
In 100 ft. interconnected coils
18 Copperweld, Per 100 feet ...-,*.$ 1.19
14 Copperweld. Per 100 feet .,,-., * . . 2,95
12 Copperweld, Per 100 feet . ^ * 3.99
14 Copper-Solid. Per 100 fest *••..---***... 4.23
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W2AU Balun. Each 12.95
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AN major lines Of Amateur gear— Rohn #25 towers and accessories — Coaxial switches— Dow Key relays - Greene Baiuns - New-Tronics Hustler Mobile ' All anterina insulators in stock.
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CQNMECTICUTS OLDEST HAM STORE I
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DECEMBER 1970
91
1
carrier stability. Individual trimmer capaci* tors enable frequency netting for optimum performance in point-to-point or repeater applications. Built-in swr load mismatch circuitry protects against open or shorted antenna conditions.
The IVa X 5Vi x IVz in, package comes complete with plug-in ceramic microphone, built-in speaker, and mobile mounting bracket- One pair of factory installed transmit and receive crystals on 146.94 MHz are included in the $229 amateur net price. Regency kicctroiiics, 7900 Pendle- ton Pike, Inifiana polls IN 46226.
High Power on 450 MHz!
Requiring only 8-lOW of rf input power, the Alpha PA-100 UHF amplifier will achieve a power output of lOOW. Designed for fixed base station or repeater use in the 450 MMz band, this compact unit has a self-contained solid-state power supply, no electromechanical moving parts, and requires only 5V^ in, of rack space. The true integrated coaxial plate cavity con- struction assures high plate efficiency and low plate operating temperature, making possible continuous-duty use while assuring long component life. The grid input circuit works to suppress harmonics generated by the input transmitter, thus reducing the problem of inlermod. The PA-100 is said to be easy to install and is ideal to upgrade existing low-power repeaters or base trans- mitters. Alpha Electronic Services. S43! Monroe Ave., Stanton CA 90680.
High Power on 2 FIVI
The new ''22'er FM'' by Clegg features 60W of rf input power plus a highly sensitive TUNABLE receiver- Ten crystal- controlled channels are available for trans- mit. Made in the United States. Clegg Associates, hu\, Littell Road, East Hanover NJ 07936.
Solid State Transmitter-Receiver
Another 2 meter FM transceiver has just been introduced to the amateur scene. The unit sells for S250, has a 5W transmitter, 6-channel receive-transmit, FET front end. The i-Fs and af circuits are IC, ajid the unit comes with two installed channels (.94
direct and J4-.94), A front panel meter indicates signal strength and rf output relative power. Price includes mike, bracket, and dc power cable. Te leva mm. Box 461. Cupertino CA 95014.
PhaseLockedLoop Linear IC
Two new ^*^phase~locked loop*' linear integrated circuits are ideally suited for such applications as accurate multiplication and division of frequencies virtually in any ratio, according to Anliur E, Fur\\ Manager of Linear Product Marketing. Range of operation extends from suhaudio frequencies to VHP,
**These units are unique in the industrJ^" Fury said, "because they are designed to perform mathematical func- tions that are quite impractical with digital circuits. Our devices can multiply, divide, and even fractionalize frequencies virtually in any ratio. For example, they can divide a fundamental trequency by 10/3, if desired, a process which is virtually impossible with digital devices/'
Operating range of the 562, a model of the device fabricaled with a dielectric isolntion process, is 0.1 Hz to more lliim 50 MHz, The 562 chip is 67 by 75 mils in size* Signetics engineers designed the two new phase-locked loop circuits in direct response to comments received on the first PLL linear circuits which were introduced by the company several months ago, *'We have added a number of features," Fury said J ''which makes the phase-locked loop more useful for specific applications. Most important among the features is that we have opened the loop and provided connec- tions that permit the insertion of external devices into the loop circuit,"
Four separate sections comprise each device: a phase comparator that also operates as a multiplier and mixer, a low-pass filter, an error-signal amplifier, and a voltage-controlled oscillator. The loop circuit has been opened between the VCO and the phase comparator.
Additional information is available from Sign erics Corp,, 811 East A rq ues A re. . Sunnyvale CA 94086.
92
73 MAGAZINE
Low-Harmonic High-Povuer Linear
Raytrack Company of Columbus, Ohio is introducing its new lowband linear amplifier, the DX2000L. This amplifier has an input capability of 2 kW PEP SSB, and I kW AM, CW, and RTTY, and is for operation on the 80-10 meter bands. The DX 2000L is the first high-power linear amplifier to use a hybrid tank circuit (Raylrack's unique toroid and air inductor combination). This system gives the DX2000L extraordinarily high efficiency on all of the 80—10 meter bands, and, in combination with the pretuncd toroid input makes this amplifier far less prone to radiate TVI, according to the manufac- turer.
Two zero-bias triodes (EIMAC 3— 500Z) are operated in class B and are preneutral- ized for maximum stability. Other features include: an adjustable ale output (negative feedback) that is compatible with all standard equipment; an exciter feed- tin o ugh that eliminates the need for additional relays to operate the exciter only; precision taut-band meters: and a very handsome case. The DX2000L has a separate power supply that is included in the price. Raytrack Co,, Columbus OIL
Hybrid Povuer Amplifier
TRW Semiconductors announces the addition of the HMD 2000 hybrid power amphfier to their microelectronic product line. This amphfier can be operated in either a linear or switching mode willi capabilities of delivering 3 A peak current for power supplies to ±25 V. Mounted in a TO-3 package, it is ideal for a broad range of appHcations including switching; class B servo; hi-fi audio amplifiers, and motor drivers. Power amplifier is priced at SI 0.50. TRW Semiconductor Diw^ 14520 Aviation Blvd., Lawndale CA 90260.
SERVICE AND FRIENDUNESS
To Radio Amateurs For 32 Years
WE MUST BE DOING SOMETHING RIGHT.
RECEIVER TUNING OPTIONS
PHONE
510-842
8350
In
The Clegg 22'er FM \s now availabte with two RECEIVER TUNER choices:
Series 24: Full 2
meter band coverage
from 143.4 to 148,3
100 kHz increments and
MHz. Calibration is readable to 25 kHz.
Amateur Net Price of the 24 Series units *s $369.95 with Transmit crystal for 146.94 and PTT micro- phone.
Series 2S: Restricted coverage from 145. 9 to 148.2 MHz with the tuning dial calibrated in 30 kHz "channer^ designations.
Amateur Net Price of the 25 Series unit is $384.95 with th# same accessories. The 25 Series units also include a steeper skirt ceramic filter in the IF stages. ADDITIONAL TRANSMIT CRYSTALS can be fur- nished {.0005% tolerance from 1 to 40 degrees C ambient) at $9.00 each. All standard 30 KG increment channels ere available in stock. Alternately, crystals con be supplied by Sentry Mf§. Co., Crystal Park, Chrckasha, Oklahoma 73018. Order their Stock No, 88001 plus desired output frequency.
Just off Exit 27 on Thruway
Distributors of all major lines
of amateur equtpment.
185 WEST MAIN. AMSTERDAM. N.Y, 12010
RANDOIVl WIRE ANTENNA TUNER
All band operation (80*10) with any wire over quarter wavelength- Absolute 1:1 SWR. Full amateur legal power. Turn counting dial on rotary inductor for exact resetability. Ideal for portable or field day operation.
■ ALL BAND OPERATION
■ UNITY STANDING WAVE RATIO
■ IDEAL FOR PORTABLE
■ COMPACT, 5" X 672" x Iff'
■ FULL YEAR MONEYBACK GUARANTEE
SOLD FACTORY DIRECT ONLY — $59.00 W6's add 5% California sales tax. Send check or money order ($15,00 deposit on C.O.D.'s)
to:
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PRODUCTS COMPAraV
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I
DECEMBER 1970
93
Yipes, It Talks
f
i
W. Edmond Hood W2FEZ
116 W.Park Street Albion NY 11411
1 shall never forget one Hallowe'en, long ago when 1 was a neophyte in electronics. My dear old grandmother, God rest her, came into the parlor ready to settle down with a good bloody murder mystery. It was quite late and the whole family, she thought, was sound asleep. She switched on the light.
^*Good evening/*
Grandma jumped back. Then, getting a grip on her nerves^ she quickly checked the closet, looked under the couch and behind the curtains. She was quite alone in the room.
"What 'cha looking for?" It seemed to be coming from the coffee table. An old news- paper lay innocently on the table. Grandma adjusted her glasses, bent over the table and scrutinized the paper. She was breathing rather hard,
"Lady, you really ought to do something about those adenoids/*
Grandma jumped back as if she had seen a rattlesnake. "It talked," she gasped, "The d^ thing talked!''
"So, what^s wrong with that? Do I get all shook up when you talk?"
Grandma was completely befuddled by now. The last remaining black hairs on her head had just turned snow white. Then a strange thing happened. She shrugged her shoulders, set her mystery aside, and began to talk. Of course she never told anybody about the conversation, but she confided with the newspaper that she hadn't had such an enjoyable conversation in ages. The two
of them chatted together until the wee small hours,
I never had the courage to confess to Grandma that I had been the culprit, A few times after that, when she thought she was alone, she tried to strike up a conversation with other newspapers^ but none of them were anywhere near as sociable as that Hallo we *en issue.
Since I've already mentioned that 1 had
been the culprit, you've probably guessed that there was a loudspeaker concealed in
the room. Not exactly. The secret really lay in the newspaper. If grandma had picked it up, she'd have caught on right away. For- tunately for me, she was far too polite to lay hands on her guest.
It's really a pretty simple thing to rig. All you need is a copy of the DaOy Dirt and a package of aluminum foil. Open up a full sheet and spread a strip of the foil inside it. Fold the sheet over and lay another strip of foil on top. When you fold the sheet again, if you've done it right, the foil should be completely concealed and the paper should look the same as it did when it was on the news stand. The two pieces of foil should be insulated from one another by the paper. In other words, the whole business should look like a big capacitor. The next step is to wire it up, but before we do, let*s take a look at how and why it works,
I said before that it is a big capacitor. I can qualify that slightly and say that actual- ly it is an electrostatic loudspeaker. The
94
73 MAGAZINE
audio signal is impressed between the two foils. Since two oppositely charged objects attract each other, and since the audio signal consists of a varying voltage, there is a
o
OPEN VQfQt COrL ^CIRCUIT HEPE
e
3K
\
/77
Fig. L Method of connecting electrostatic speak- er to vacuum tube outpuL
varying attraction between the plates. The plates, in this case the foils, will therefore vibrate and reproduce the sound*
When I first rigged up this demonic device, solid state equipment was virtually unheard of, so I simply connected one foil to the plate of my final amplifier tube, and the other to the chassis. Electrostatic speak- ers work best when the audio is riding on top of a high dc voltage. This polarizing voltage, as it*s called, was neatly provided by the plate supply voltage which was there anyway.
Nowadays most audio equipment is solid- state. Since solid-state operates under very different conditions, you will now have to artificially duplicate vacuum tube condi- tions. An electrostatic speaker, you see, is a very high impedance device, and so it must be fed with a high voltage signal from a high impedance source. You can meet this requirement by connecting a small output transfonner in reverse. That is, the voice coil winding connects to the output terminals of your amplifier. The plate winding connects to the foils, A polarizing voltage of a hundred volts or so can be supplied either from a rectifier or from a battery, the capacitor, C, providing a path for the audio voltage-
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73 MAGAZINE |
Peterborough IMH 03458 |
Tl<^COUMON OLfTPUT TRANSFORMER. Tl varC£ COfL WINDING SHOULD WATCH AMPLIFIER OUTPUT, OTHER WINDIflOS SHOULD Bt AS HIGH IMPEDANCE AS POSSIBLE
AMPLfFIER SPCAKCR TERMINALS 4-^9 OHM OUTPUT
10 II F 400 V
/77
ii
100 TO 900 V
POLARlIlltd VOLTAOC
Fig, 2, Method of connecting electrostatic speak^ er to output of solid state ampHfier.
Even if you do not have a sweet old grandmother to bug with this tomfoolery^ it can still be an excellent party gag, and I know of no better way to have your best friends tag you as an absolute unmitigated nut.
. . . W2FEZ
I *
I
DECEMBER 1970
95
an FM Late Starter
, , could be a front runner!
I have nothing but praise for Regency^'s new HR-2 minialure multichannel all- Iransislor 2 meter FM transceiver. This is far and away the best buy in American- made amateur FM units. It's priced right, it
Ken Sessions K6MVH
output power, and it is one of the smallest units obtainable. And it has some very desirable features that none of the other manufacturers have thought of yet.
Of all the good points, the price itself is
performs right, it 1 |
las a very |
respecta |
ble ttie mos |
it impressive. J |
VL bJiy |
there should |
|
Manufacturer |
Model |
Price (S) |
Channel Combinations Available |
Total Xtals Mfr T R Loc |
Xmtr Pwr Out W) |
Rcvr Sens (^V - 20 dB) |
|
Regency Electronics |
HR-2 |
229 |
12 |
6 6 1 |
U.S. |
10-12 |
0.5 |
Galaxy (Hy-Gain) (w/power booster} |
FM-210 |
230 |
9 |
3 3 |
U.S. |
2.5 |
1.0 |
Telecomm |
FM144-10F |
250 |
6 |
6 6 |
U.S. |
10 |
0.5 |
VariTronics (Inoue) |
FDFM-2S |
270 |
6 |
6 6 |
Jap. |
10 |
0.8 |
Standard |
SR-C806M |
349 |
12 |
12 12 |
Jap, |
10 |
0.5 |
Varitronics (Inoue) |
IC-2F |
349 |
36 |
6 6 |
Jap. |
12-15 |
0.4 |
CI egg Associates |
22er |
400+ |
Tunable |
10 0 |
U.S. |
30 |
0.4 |
RX. Drake Co. |
329 |
12 |
12 12 |
Jap. |
10 |
0.5 |
96
73 MAGAZINE
be no reason at all for any VHF enthusiast to put off going to FM any longer. You're just not going to get on 2 meters FM in style for anything less.
Now let's take a look at what you get for that $229:
How about power? The Regency HR-2 runs between 10 and 12 watts owfpwf /The Motorola transistor that the Regency unit uses in the final rf amplifier is guaranteed to crank out at least 10 watts, and the people at Regency are making sure that each unit produced meets or exceeds that specification.
Deviation level. When the Regency leaves the factory, the deviation is set at 10 kHz. Since this is a little much for the New England repeaters, I had to crank our test model down to about 7 kHz. The deviation can be adjusted anywhere from less than 5 to slightly more than 15 kHz with an easily accessible pot inside the rig. The unit comes with microphone, too, by the
way - and from reports of the local repeater groups^ the audio is exceptionally clean.
What about the receiver? The receiver is a dual-conversion superheterodyne type with six-channel capability. It is relatively broad-banded, requiring no peaking on individual channels in the 2 meter range. A ceramic filter in the second i-f stage gives adequate selectivity for most metropolitan areas^ even where adjacent charmels are active.
If you buy this rig and later decide to add crystals, you've got to be a bit choosy as to where you buy your rocks. The HR-2 has no means of rubbering "receive" crystals onto frequency; if the crystals are off, your receiver wUl be off. The people at Regency say nobody will ever have trouble if they order from Sentry Manufacturing Company (Oklaho ma) , I n ternational Crystals (Oklahoma), or Shepherd Indus- tries (Kansas). To my mind, the lack of
Accessories Included in Purchase Price
Extras You
Must Buy
Comments, Special Features
Problems, disadvantages
Microphone, power cord, mobile mounting bracket, crystals for 146.94.
Power plug.
Mike, mobile mounting bracket, power cord, crystals for 146.34 and 146.94,
Mike, mobile mounting bracket, power cord, crystals for 146.34 and 146.94.
Mike, moinle mounting bracket, power cord, crystals for 146.94.
Mike, mobile mounting bracket, power cord, crystals for 146.34 and 146.94, antenna connector, spare fuse, connector for optional external speaker. Discriminator test socket and plug.
None
ALL
None
None
None
None
See text
Power booster supplies 24V dc to final transistor to bring the rf output up to5W. (costs S50 extra).
Panel meter for rf out & signal strength.
Illuminated panel meter for rf out & signal strength
in.
High/low power switch; illuminated panel meter. Add-on amplifier avail.
Ac/dc power supply, micro- phone, power cords for ac and mobile operation.
Mobile antenna, coax, mobile mount, mike, ac/dc pwr splys.
None
None
Panel meter illuminated white on rev, red during transmit. Meter indicates S'Unitsand rf out. Freq selector switch is concen- tric so xmit and rev chan- nels are independently controlled.
Built-in ac/mobite power supply.
Built-in ac/mobile pwr supply. Extremely selective & stable rcvr*
No meter; no receiver rubbering capacitors.
No accessories, no meter, unstable rubbering capacitors.
Test unit did not meet specs.
Antenna connector makes sloppy fit to VHF connector.
Squelch and volume controls too tiny for easy mobile operation.
Tunable receiver. Too large for mobile use- Tube- type transmitter
final.
Transmitter has vacuum-tube final,
1
DECEMBER 1970
97
Amateur Test and fMssuremtrttf
by W5REZ S6S0
Using VOM, scope, VTVM, dipper, SWfl bridges, •tc. Covers amateur uses of test equipment in the Hmm station, 208 page^, softbound. I nterestrngly written, covers tuning receivers, all kinds of transmittefs, etc. Invaluable for every hamshack,
Ehwtronics for the Amateur by W5REZ , . $7.95
Hardbound book, 212 pages. Cowers entrre theofY needed for passing amateur licenses. Fine book for instructors, and for amateurs wanting a refresher course before exposing thernseWes to the FCC eHaminers. Hardbound books look nice and last.
Handbook of Transislari, Semiconductors, Instruments and Mrcroelectronics
^y Thornas ».,...,.,^. ..<,*.« ^ $14,&0
453 pages, hardbound. For the working engineer, circuft designer and technician. Very thorough. Limited supply. Published at $25.
IBM Electronic Circuit Analysis Program By Jensen, Hardbound, 400 pages, published at $25, limited supply at $9.00,
Radar Detection by DiFranco, Hardbound, 6B4 pages, published at $20, hmSted supply $8,00.
Audio Systems by Crow hurst . ^ $7.95>
Audio for the engineer, the hhfi addict, and the broadcast enginee'r. Every radio station should have this handbook handy.
Eltetronies Ref^refice Han^lbook
Hardbound. ^*,..,*^*,* »*«*,«,,». S7.95
All the charts, tables, formulas, and other refer ence data that you need as a technician, ham or engineer,
TV Servicing Gutdebook, hardbound ..... $6.95
Thfs is a book on isolating the circuit containing the TV defect, nor a theory manual. \t should help you get those sets moving.
Electronic Test & Measurement Handbook Hardbound. . S7.95
Use Qf various test instruments, Testing trans- mitters, receivers, amplifiers, etc. Covers subject thoroughly.
The Man Behind the Mike^ hardbound .... $6.95 Guide to radio announcing for the professional,
Tape Recording for Fun and Profit
Hardbound. ... • • • • $7.95
Complete data on recorders, systems, mixers, microphones, cassettes, etc. Much money to be made in this field.
Single Sideband: Theory and Practice
WSTYH handbook of basics and circuits, plete analysis of an ssb equiprnent.
$6.95 Com-
FM Repeater Handbook, hardbound $6.95
K6MVH. Book IS required for alf repeater operators and must reading for all F^'ers. Only complete book on the subiecf. 1 1 is also one of the bes:t setllng books in amateur radio today.
Editors & Engineers RADIO HANDBOOK
Hardbound S13S0
Latest (iSth edition} by W6SAI. This is the most complete ham handbook ever published. Makes all other handbooks look like comic books. 896 pages.
Editors St Engineers RADIO HANDBOOK
Hardbound. .**•*** S10.00
W6SAI 11 7th edition) reduced for clearance, limited supply available for fest acting amateurs. L««t chance to get this great book before it is gone forever.
How To FiK Transistor Radios Bi Printed Circuits Only. «*«,*«>««............., $7.95
Do you throw those little radios away when they stop? Wasted money 1 Easy to fiK with this manual. Worth many times the low price. No serviceman or amateur should b« without this tremendous book.
f25 One-Transistor Projects, hardbound . » $6.95
Practicai circuits for the eitperimenter end hobbyist. Have fun building the** l-transistor €ircu its, „ test ir>struments, audio amps, osciHe- tors, receivers, transmiiiers^ alarm devices, etc. Never will you have so n^uch fun for to little.
3458 |
||
a. |
NEW HAMPSHIRE 0 |
|
O |
I |
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X |
CD |
|
o |
I BOOKS |
BOROUi |
}~ |
O |
cc |
1- m |
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CO |
IE |
0. |
73 Vertical, Beam and Triangle Antennas, . $4,95 W3FQJ. If you like to build interesting antennas then you will seriously regret passing up this wonderfut book. Also info on noise bridges, other test equipment you can n'^ake and use to advantage.
73 Oipole and Long Wire Antennas
W3FQJ. Better buy both books, dimensions, details.
$4 JO
Includes all
« •* * ♦
Installing 6f Servicing Home Audio Systems $?S5 Hardbound, 256 pages. Worth its weight in gold. Positively the finest book ever written on the subject. Make a fortune in part time audio work. Hi-fi is everywhere and none of them are working right.
64 Hobby Projects for Home and Car Hardbound. ...«...<«..-■* ^ ., p , .... . $6.95
Any one project li worth more than the price of the whole book, Light sensitive garage light, wireless TV commercial kitfer, fire alarms, smoke alarm, etc. If you are having less fun in radio you aren't building enough smalt projects. This book is guaranteed fun.
CB Radio Operator's Guide, hardbound . . $6.95
Most complete book ever published. Lists all equipment and antennas available, all acces- sories...how to use them, how to set up, test, get best action. Contains complete CB rules end regi.
Servicing Modern Hi-Fi Sy^ems
by Crowhurst. , . , , . $7.95
Hardbound^ Paperback is only $4.95, but won't look as nice on your shelf or last as long, Thom solid-state hi-fi's bugging you? Like duck soup with this gem of a book. Why take hours to find miseries when you can take this book mn^ pin-point difficulties imrnedtately. This book will either save you a fortune or make you one.
Basic Electronics Problems Soved; Smith . . $7.95 Hardbound. Paperback is only $4.95 if you don't care how your library looks. Solid state Bn0 tube circuits. This is a "cheat book" which will whiz you through any electronics course by showing you short cuts in solving electronics problems and math.
Modern Electronic Circuit Design by Long $9.95 Hardbound, 286 pages^ McGraw-Hill. Written for professional circuit designers, graduate engineers. Published at $18.95. Looks very impressive on the reference shelf. Worth many times the price as prestige book. Also handy if you happen to be an engineer. Limited quantity on hand. Hurry.
Handbook of Practical Electronic Tests and
Measurements, Lenk. Hardbound $9.95. Pub- lished at $18. A guide to the basic theory and application of every practical electronic test and measurement procedure for technictani Lnd amateurs. Limited supply so act fast.
Pulse and Switching Circuits^ hardbound . . $7.95
Almost ev ery phase of electronics uses switching circuits, .TV, radar, telemetry, computers, etc. About time you read up on every one of these circuits being used, isn't it? 256 pages, over 200 illustrations. Available paperbound (fails apart) for $4.95.
FM Receivers by Cook
Hardbound, 528 pages. ... * . $14.50
Published at $2&. Most comprehensive boolc ever published, absolutely up to date.., ail circuits. Invaluable for professionals and advanced ema-^ teu rs.
Amateur Radio Advanced Class Licen» Study Guide. $6.95
Hardbound book for your library shelf. 193 pages! Absolutely everything you need to know to pass this license exam, written by one of the top radio editors in the business. Written for the simple-minded so they can pass the exam by knowing the answers ipstead of memorizing them. This book is available in softbound for $3.95. Vou ere going to have to get an advanced license so you might as well get this book right now.
Electro mechanical Oeviees for Energy Conversion and Control Systems, by Del Toro Published at $25. Limited supply at $10. Hard- bound, 617 pages.
tweaking ability on the receiver is a distinct disadvantage — but it is overshadowed by a considerable margin when I consider the xmit's sales price.
Special features? The most useful single feature of the HR-2 is its multiplicity of transmit— receive combinations. There are six crystal positions each for the trans- mitter and the receiver, but a twelve position switch is used for selection. The first six positions on the switch (numbered 1 through 6 on the faceplate) select the six crystal positions, and the next six positions on the switch (labeled A through F) can be used to select specific combinations of the various crystal sets. Positions A through F are chosen by jumpering on the switch itself, so that there are a total of 12 available channel sets from only six sets of crystals.
Now does the Regency HR-2 stack up? Probably the best way to determine the relative merits of the HR-2 is to compare the unit with other 2 meter FM trans- ceivers. The chart on the preceding pages will give you an opportunity to make your own comparison and evaluate the features
you consider to be the most important,
. . . K6MVH ■
Buy 73 binders and win the love of a beautiful girl. Now only .00!
L
Radio Amateurs Relerence Library of Maps and Atlas
WORLD PREFtX MAP ~ Full color, 40" x 28 % shows prefixes on each country , , * DX zones^ time zones, cities, cross referenced tables postpaid $L25
RADIO AMATEURS GREAT CIRCLE CHART OF THE
WORLD — from the center of the United States! Full color, 30" X 25", listing Great Circle bearings in de- grees for six major U.S. cities; Boston, Washington, D.C., Miami, Seattle, San Francisco ^ Los Angeles.
postpaid 1125
RADIO AMATEURS MAP OF KORTH AMERICA! Full color^ 30" X 25" — includes Central America and the Caribbean to the equator, showing call areas, zone boundaries, prefixes and time zones, FCC frequency chart, plus informative information on each of the 50 United States and other Countries. . . postpaid |1.25
WORLD ATLAS — Only atlas compiled for radio ama- teurs. Packed with world-wide information — includes 11 maps, in 4 colors with zone boundaries and coun- try prefixes on each map. Also includes a polar pro- jection map of the world plus a map of the Antarctica — a complete set of maps of the world. 20 pages, size 8%" X 12^ - ^ postpaid $2-00
Cornpfete reference library of maps -^ set of 4 as listed
above . , postpaid J3.50
See your favorite dealer or order direct.
W am FOR BROCHUH!
RADIO AMATEUR
lib
oa
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INC.
npnf R 925 Sherwood Drive ^*^^° Lake Bluff, 111.60044
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World's Finest Log Book?
Designed and executed by W2NSD/1, thTs Is the most relevant amateur radio log ever de* sfgned. Th»s is a log for today. It has a column for the date, one for time and off of each contact, a small column to indicate whether you called the station contacted (or CO) or not, a good wide space for the station call con- tacted, little columns for the reports, a good space for his location, a QSL column, and lots of room for notes. The log Is the long way on standard BVk*' x 11" paper and padded into pads of 12B sheets^ with room for 20 contacts per page. The whole book of log sheets will carry you through 2500 contacts. There is a pJace to indicate on each sheet the band being used and the power m case these change now and then. The log pages can be numbered for file card reference. Why use a log book designed in the 1920's? This one was designed for use In the 70's and is exactly right for the DX'er, the rag chewer, or even the round-table denizen. It Is fine for CW or phone, AM or srdeband. It will work for RTTY, ATV or even slow scan television. Never has a log been made available which is as handy as *this gem. Why keep struggling with those ring binders which get all bent out of shape? Get this first really modern (og. 125 Super W2NSD log sheets. . . .only $2 ppd.
73 Magazine, Peterborough NH 03458
DECEMBER 1970
99
fOi^
uM*S
VHF ANTENNAS This handbook fs a complete collection of up-to- date mformation about VHF and UHF antennas, with design hints, construction and theory. If you've been wondering what array you need, this book will give you enough background to make the right decision, $3
ADVANCED CLASS STUDY GUIDE
128 pages of up-to-the-minute simplified theory, written with the beginning radio amateur in mind. This unique book covers all aspects of the theory exam for the Advanced Class license and has helped hundreds of hams to sail through the exam. . .nothing else like it in print, $3
DIODE CIRCUITS HANDBOOK An invaluable reference book. Cavers rectifiers, mixers, detectors, modulators, FM detectors, noise limiters, AGC, BFO/Q-multiplier, AFC. Varicap tuning audio clippers, balanced mods, field- strength meters, RF probes, zeners, control cir- cuits, etc, 111 different circuits, $1
COAX HANDBOOK Invaluable book for the ham or the fab and for everyone else who doesn't want to have to keep a whole Nbrary on hand for reference. . .or even worse, have to write to the manufacturer for coax spec. $3
73 USEFUL TRANSISTOR CIRCUITS If you've been looking for a transistor circuit to do a speciai job, chances are there is a circuit in this book that will give you a head start. It covers circuits for audio, receivers, transmitters and test equipment, $1
INDEX TO SURPLUS Do you have a piece of surplus equipment that you want to convert but can't find an article? If so, this IS the book you need. It lists all of the surplus articles and converstons in popular electronic and amateur magazmesfrom 1945 to 1966, $1,50
DX HANDBOOK
Includes giant world country-zone wafi map. Articles on QSL design secrets, winning DX con- tests, DXCC rules, DXpeditions, reciprocal licen- sing and many more. World postage rates, WAZ record lists, time charts, propagation, etc. Special ham maps and bearing charts, A must for the DXer. $3
SIMPLIFIED MATH Does math scare you? — It shouldn't. This easy-to understand book explains the simplified expo nential system of arithmetic, simple formulas, logarithms, and their appltcation to the ham shack, 50tf
FM ANTHOLOGY
Vol. (. This book is largely a collection from FM 8ulletin; edited by K6MVH and WA8UTB. The material is taken from the editions of February 1967 through February 1968.
NOW AVAILABLE FOR ONLY $3
m^ |
««••#••••«■•«■»«#«•• |
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VH F Antennas |
. $3.00 |
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Advanced Class |
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Diode Circuits Handbook |
.SI. 00 |
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73 Transistor Circuits. . . . |
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Index to Surplus. ....,.' |
.$1,50 |
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DX Handbook |
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Simplified Math ,....,. |
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Coax Handbook. ,*,.,-, |
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Please send me ftie books checked at left:
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City -_„„™ .„.„„„„ State Zip
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73 Magazine
Peterborough, N. H. 03458
*
Of all the various transistor tester pro- jects that have appeared in numerous amateur radio and electronic magazines this past decade, I beheve I have come up with a circuit that will outdate previous articles. Many of these projects have been designed so you may utUize a tester with your scope, VTVM, or some other gear-
This particular circuit, which I named the 'Transi-Test/' is designed with simpli- city and is very accurate in measuring beta, leakage, and shorts. It will test any NPN or PNP transistor (signal or power). 1 also find it great in checking silicon or germanium diodes by using the emitter and collector leads to test for shorts and leakage. The Transi-Test is 100% portable, using a 9V battery for its power supply- Most transistor testers employ a 4pdt switch for polarity, but this one is designed around a dpdt switch, which is easy to find at any parts store. To say the least, all the parts can probably be found in your own junkboxf I used a Premier #SPC-23 meter case to give the Transi-Test a professional appearance. The three test leads should extend 6 to 8 in. from the front of the case. For easy connection to small transis- tors, a micro alligator clip should be used such as the Mueller #34-C. Be sure to use an alligator insulator on the collector lead to prevent the emitter and collector leads from shorting togetlier due to stiff test
Lew Christy WB6QQP 342 E. Second Street Rialto CA 92376
leads. This will save unnecessary battery failure.
If you do transistor servicing quite frequently, it is advisable to use a toggle switch (SI) which will last indefinitely. The only holes that have to be drilled in the case are for the three test leads, using rubber grommets. The SPC'23 meter case is already prepunched for the meter and two switches, which is why I happened to choose tliis particular one. Bud Radio also manufactures a case identical to this one.
p
60K'!
47
31
6
E
Si
6 6
B e
After completion of this small project, you can rummage through your junkbox and start identifying those "lost cause" transistors that have been lying dormant all this time. Vm sure you will find the Transi-Test to be a very valuable test instrument on your workbench- Lew Christy WB6QQP ■
•
DECEMBER 1970
101
^«
Never Say Die (cant, from p. 10} been a strong factor in freezing the League into immobility. We cannot afford this paralysis in the 1970s, if directors were to attend four regional ARRL conventions each year (east, midwest, southwest, west) and consult the membership at open forums at these conventions, they could act immediately upon the wishes of the members. Their way would be paid to the four conventions by HQ.
Public Relations
A competent public relations firm (preferably run by an amateur) should be engaged to promote amateur radio with articles in national magazines such as Life, Look, New^sweek, Play- boy, etc. They could coordinate amateur radio talent such as writers, cartoonists, and performers for maximum effect. They could help to organize ham films for television, for schools, and even shorts for movies. They could prepare strip slide shows for schools and libraries. They could prepare news releases for the papers and news services, thus making sure that amateur accom- plishments reached the television, papers, and radio.
Club Material
In order to increase interest in radio clubs throughout the country the ARRL should have a wide variety of films available, covering all aspects of amateur radio operation. ,xon tests, DXpeditions, moonbounce, television, RTTY, traffic nets, mobile operation, repeater operation, etc. There are many amateurs that would be happy to work to produce films and slide shows on amateur radio subjects if only there were a central organizing effort. ARRL could provide this coordination. Films and slides can do a lot toward building club membership as any member of sports car clubs and skin diving clubs, will tell you. Amateur radio is almost alone in its lack of interesting program material for clubs. This should be a function of the League. Who else is there?
Outgoing QSL Service
Virtually every other national amateur radio society in the world provides an outgoing QSL service for its members sending cards to other countries. There are, as far as I know, no in- surmountable problems stopping the League from providing a simitar service. This should be care- fully investigated from the viewpoint of fmding out how to do it rather than trying to find out why it can't be done.
Legal Fund
The legal problems involved in setting up an emergency fund for helping amateurs fight law- suits which, if lost, could seriously affect the whole amateur radio hobby should be investi- gated and overcome. Is there any real reason why the League should not help beleaguered amateurs in such legal fights?
Amateur Radio's Future
Satellite repeaters for FM and ATV are within the realm of technical feasibility today. The League should take the lead in planning for the future of our hobby. Even the cost of a set of satellite repeaters covering the whole world could be organized by the ARRL. Perhaps the techni- ques of multiplexing can be developed and applied to solve ORM problems on 20m and other crowded bands. Dialog in QST on new ideas should be encouraged.
Radio Clubs
It is possible that the role of amateur radio clubs could be expanded in the administering of exams for the FCC, Certainly the clubs could be a powerful factor toward developing new amateurs with guidance and encouragement from HQ. A monthly newsletter to provide dialog between radio club presidents and the directors might help encourage amateurs to take more interest in their future,
lARU Development
The International Amateur Radio Union, made up of the national amateur radio societies of the world and organized by ARRL could function better and provide better leadership if ARRL were to publish a monthly newsletter for aU member societies. At present all that is provided, 1 understand, is a yearly calendar. Region 1 (Europe and Africa) periodically publishes news- letter. The amateur radio societies in the rest of the world might have more confidence in lARU if it provided some leadership and communica- tions.
The lARU could spearhead a drive to collect older amateur radio equipment and ship it to underdeveloped nations. The shortage of equip- ment is one of the most important deterrents to new amateurs in these countries. India could have thousands of amateurs instead of a few hundred if only gear were available- Unity of the lARU societies would provide unity toward the problems of the ITU and frequency allocations. Communications is the first step towards unity.
New Books
The ARRL book department should be turned upside down and cleaned out. One look at the Editors and Engineers handbook is enough to prove that a major change is needed in the production of books at HQ. The yearly ARRL Handbook changes like a glacier. Not only that, but one of Iife*s more frustrating experiences is to try and learn radio theory from that book. This is not necessary as we showed with our license study courses.
Spend 25^ and buy a copy of the ARRL book on "Operating an Amateur Radio Station." This publication is all too typical of League literature and is beyond description. As a director I would make every effort I could to see that those re-
102
73 MAGAZINE
sponsible for this type of claptiap were trans- ferred to some other job.
The League has a responsibility to produce interesting and up-to-date books on every aspect of amateur radio- They should have thorough study books on each amateur exam, not memo- rization manuals as they do right now. They should have a definitive and continually up- dated book on RTTY, DX, ATV, FM, moon- bounce, traffic, VHF, learning the code, high- speed code, frequency measuring, 160mj antennas, microwaves, etc.
QST can carry information on building gear, on new developments, and such, but books are needed to provide detailed information on speci- fic interests. Obviously these would all pay for themselves.
New General Manager
Few amateurs with whom I have talked have had anything encouraging to say about their visits with the present ARRL manager. Though I donU talk with him often, I must admit that on each occasion I have found him to be as close-minded as the visitors have reported. If he were capable of doing his job we would not have the growing problems here and all over the world which he has brought upon us.
Were I to be elected a director I would try to get the other directors to start looking for a
suitable manager for ARRL,
It would not be simple to find the right man for this difficult job. There are many qualifica- tions that he should have to be worthy of consideration. But you may be sure that such a man exists and that it is important that he be found before it is too late.
What sort of man do we need for this post? As I see him, he should be a man who has devoted a good deal of his life to amateur radio. He certainly should have a record of being interested and active in several branches of the hobby,.. DX, TV, RTTY, VHF, FM, traffic, etc. I would expect that he has done a good deal of building and designing. I would think it strange if he had not had several articles pubhshed.
The ARRL is a $1,500,000 business, so we should expect our man to have experience in running a medium- sized business. One of the problems at HQ is mismanagement of finance. There is no shortcut to business knowhow.
Our manager is also the editor of QST, so some background in publications would be valu- able. He will need this to help cut the present runaway costs of publication of the magazine. Of course he could learn about all this after being hired if you like the idea of on-the-job training at your expense.
Our man should be able to speak well in front of large groups- The general manager is also a front man for ARRL and must attend most ARRL functions as host. He would also be ex- pected to speak for the United States at inter- national gatherings and at the ITU,
One would hope that the manager of the ARRL was highly intelligent- Can we afford to have a mediocre brain at the head of 265,000 U.S. amateurs? And remember that he is the titular head of amateur radio worldwide. This spot calls for all the brains we can muster,
I suspect that we should also be sure that the man we choose is one with a long history of getting things done, A man's history speaks for him. If he is too wealthy he has devoted himself to wealth alone and not to other interests. Has he a wide number of accompHshments? Is he well read? WiU he be interested in working for a modest salary with his major payment in achieve- ment? The answer is simple, of course. If you ask any director of any large corporation how he goes about finding a new general manager, he will tell you that there are a number of organizations that specialize in just that. You consult one and let them find your man.
Most of the directors that I have talked with recognize that it is important for them to locate a new general manager, but they are afraid to take the bull by the horns.
Other Ideas
This is by no means the end of my ideas for improving the ARRL, but I have probably lost 90% of my readers already and should shut up. Now that I've told you some of the things I would try to do if I were elected director of the ARRL, perhaps you can encourage your own director to go ahead with some of them* Or you can work to get a director elected that will do what you want,
73 at Boston
The ARRL' National Convention hit Boston in the fall this year, providing a splendid display of New Hampshire foliage for those interested in beauty.
When f got word from the convention com- mittee that no one from 73 would be permitted to speak at any convention function, I made arrangements to hire an auditorium room in the hotel to provide forum space for those interested in FM, repeaters, ham politics and my slides of Jordan taken just before the civil war there- in 1969 we took along an international Crystal microwave oven and cooked some New Hampshire hotdogs as a feature of our exhibit. This was popular, but I didn't want to repeat so we decided to have some freshly squeezed New Hampshire apple cider along with fresh home- made New Hampshire donuts this time.
On the Friday afternoon before the conven- tion we went up to Hancock (N-HJ and helped
Joe Quinn run off almost 30 gallons of the best apple cider you ever tasted. Early Saturday morning we stopped by Crane's Bakery in Jaffrey (N.H.) and picked up 73 dozen old-time New England donuts. None of those machine-made crullers for us! There wasn't a really round one in the bunch.
I I
DECEMBER 1970
103
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We served the cider and donuts all day Saturday in between slide shows, forums, and talks in our auditorium room. By the way, one leally outstanding show was put on by George Fataki Y02B0* showing slides of visiting DX hams and his recent visit to DX'ers in Europe,
To those who have written to thank us for the feed and the programs, we hereby acknowledge your notes and want you to know we appreciate your thoughtfulness.
A Look Around 73
In looking at last year's staff picture we see several absentees, alas. Two of our gals left to get mairiedj and a third left to work with her husband who started his own business.
We've had some interesting replacements for the dear departed, starting with Nancy, who was with us back in early 1970, but had gone off to seek her fortune in Colorado, and returned, she's not sure why. Nancy puts together most of the ads in each issue as well as laying out many of the articles- Jan, the other gal in the art department, does most of the rest of the articles. In her spare time Jan is an outstanding artist, joining Lin out in the 73 art studio afternoons and weekends.
Ken Sessions (K6MVH) has added a new dimension to the editing of 73, as well as an almost undetectable tendency to favor FM arti- cles. Ken is responsible for the new arty look of the articles in 73.
Taylor Sage joined us recently and does just about everything that we can*t get anyone else to do, from supervising the maintenance of the HQ building to keeping our recalcitrant machinery running. His wife Gigi handles the bookkeeping.
In our print shop we have Jeff Parsons and Biff Mahoney, who run our three offset presses, turning out local job work as well as office forms, advertising letters, and stuff like that. 73 is printed in Wisconsin, not here, but we do have complete facilities for smaller printing jobs and turn out our books right here,
Nixon Letter Reprints
Several clubs have called and written asking for bulk copies of the October 73 Action Coupon addressed to President Nixon, This coupon re- qiiLsts an investigation of the recent increase in license fees for radio amateurs. If you would like reprints of this page just send a sell-addresscd stamped envelope to 73, Peterborough, N-H.03458 and indicate how many reprints are desired.
Ham Bumper Stickers?
Several readers have suggested thai bumper stickers be made available for amateurs. Since wc have dandy facilities for printing up bumper stickers here at 73 we are all for the idea. But what do you want on the stickers? We are open for any clever suggestions. The only sticker we have seen so far is BAN THE HAM, and that doesn't seem appropriate.
73. , -Wayne ■
Leaky Lines fconr, from p, 14)
season, but who lapse into a state of sudden paraplegia when any mention of the FCC examination is made. They remind me of some unnamed soldiers of my acquaintance, who, never having served overseas in World War II, wore some unauthorized ETO, Asiatic Theatre, Persian Gulf Command or Purple Heart ribbons on their tunics when they went out on dates with young and impressionable (or old and impressionable) females.
I know that \ am running the risk of falling into disfavor with the 35,000 odd Conditionals when 1 say this, but I feel strongly that some changes in this situation are long overdue. Perhaps I am being unduly harsh toward the Conditionals, but ever since the implementation of Incentive Licensing, I think most of us tend toward a less permissive and less tolerant atti- tude concerning all '*something-for*nothing" advocates.
I am already considered persona non grata among large numbers of Techs who objected to my published views with respect to the granting of a portion of ten meters on an exam-free basis. They labeled me with ever>' pejorative in the book, and with a few even I had never heard before. And I suspect that this new call to sanity will place me squarely in the path of the ''slings and arrows of outraged Condilion- als." So be it. Might just as well be hanged for a sheep instead of a goat
I truly believe^ and I am confident that many share my view, that all classes must somehow be drawn into the vortex, the main- stream if you wilU of the present context of licensing. Operating i\ ham station is a privilege, not to be taken lightly. Any preferential excep- tions to the standards which are now being demanded (intermediate In difficulty tliough they may be) constitutes a very real disservice to aU those who have been compelled to uppade in order to maintain their allocations. Unless all amateurs are governed by identical rules and regulations, subject only to legitunaiB exceptions for valid reasons, the entire Incentive Licensing structure becomes an empty mockery.
Simply stated, \ am catling for the abolish- ment of the Conditional class license. Now, liold on a minute . , A didn't say I was calling for the delicensing of Conditionals, but merely for the retirement of the category. I have thought for a long time that the designation * 'Condi tional** implies by its very name a type of second claims stutus, carrying a certain stigma with it. Since the privileges of the class are identical witli the General ticket, the onlv reasons why it is maintained are: (1) die holder is physically handicapped, or (2) he lives in an area so far removed from an exam point that a journey thereto would consittute an unreason- able hardship. Iience has not taken the custo- mary FCC administered exam- He has, however, attested to his proficiency in the required tech-
104
73 MAGAZINE
nicaJ elements, by taking an exam by mailj supervised by a volunteer examiner. In all other respects the grade of license is not distinguish- able from the General Hcense, Why then must he be given this appellation "Conditional"?
An apt analogy is that of native born citizens and naturalized citizens. Both are entitled to exactly the same rights and privi- leges. Both are expected to shoulder the same obligations and responsibilities. No one asks a citizen whether he is native born or naturalized. He^s an American citizen, and that's that! Another case which comes to mind, unfor- tunately still not expunged from American life compietely^ is the regrettable holdover from the unspeakably horrid days of Puritanism, when the innocent and blameless offspring of unmarried parents were stigmatized with the label of illegitimacy. Though they were not different in any way from others, they were regarded as inferiors, and because of this bar- baric practice, were denied status in society in an unbelievably broad spectrum of areas . . jobs, education, social acceptance, marriage* civil service, freedom from the mischievous, wagging tongues of the vicious hypocrites who enjoy making others miserable at every oppor- tunity.
Let us grant that tlie mail exams have been on the up and up . - .that not a single Condi- tional was party to any hanky-panky. Despite this concession, there will always be those who will wink, place their fingers alongside of their noses and nod knowingly. So long as someone wears that designation on his sleeve he is fated to be suspected of having cheated. Since we have just finished granting that such is not the case» and since all the Conditionals have applauded my eminent fairness with eathusiasm^ the next logical step would be to require some of them (ju*it a few , , ,75%, for example) to prove that our utter confidence in their inte* grity was well merited. Boy, 1 can hear the gnasiiing of teeth and the blue vitriol ascending into the air right now, really I can.
Why in the name of Tophet cannot some machinery be devised for the purpose of taking the exam to the applicant who cannot come in under his own steam. If a single volunteer examiner is regarded as untrustworthy, why not employ the services of (if you will forgive a Russian term) a * troika* . . .three people are hardly likely to risk any joint dishonesty for fear of subsequent disclosure. They could undertake to administer the test to the truly handicapped person who cannot possibly get to the examining point And the exam should be given the same weight as the regular FCC exarn^ with all credils applicable for higher grades. This should be limited to absolute establishment of the candidates' inability to get to the l-CC office. All others should be required to meet the standards that have been established for the upper three license grades. If necessary, as
seems likely, some of the additional revenues now being reaped from the increases in renewal fees {up 125%) could be apphed to the establishment of additional exam centers, and could be u.sed to help defray the salaries of additional personnel. Then, when the test is taken, either by the troika method or the FCC method, let the appHcant be issued a General class license, completely indistinguishable from othets, destigmatized and totally immune to the jibes and insults of any *Tirst'Class" amateurs who might feel an inclination to accuse them of skullduggery.
The fact is that we cannot, in good con- science, permit a large number of operators^ comprising hterally thousands of individuals, to continue to enjoy a privilege which is earned by the vast majority, simply by feigning physical disabilities which, in far too many instances, exist only in their wishful imaginations. We cannot continue to tolerate equality of partici- pation by those who waltz blithely through the mile-wide loopholes of the law, which conven- iently allow them to take the ticket while ignoring the basic technical requirements. No matter how sorely handicapped an individual might be, he should at least be required to conform to a standard within the limits of his own ability and competence. To offer him a completely free pass, an Annie Oakley, is not only derogatory to the rest of us , . ,it is an insult to the integrity of every single Condition- al with a legitimate reason for holding that grade , , -and there are many, many of them.
I am sure that we all know sightless hams,
amputees, victims of dread disease, shut-ins
- . .who have spurned the Conditional license,
and who have insisted upon being examined in
the standard fashion, just like everyone else, in
order to avoid being deemed cripples or
invalids. We are all mighty proud of them, for
Uiey are a source of inspiration, and their
achievements set an example of courage for all
of us. Within the framework of that type of
pluck and determination, how can we possibly
dare to countenance the flimsy alibis and
"plea-copping" of the indolent, unindustrious,
shallow^ cheats who masquerade behind the
technicalities of legalistic gobbledegook, even
tliough it may be within the definable semantic
terms of the FCC regulations?
Isn't it time some changes were made?
* * *
I never saw^ the beat of it; when you write comment^ many people take it as a persona! point of privilege to challenge you on every* tiling . - .opinion as well as fact It is as though an editorialist had no right to express his own ideas . . .that somehow when he allows his name to appear on the printed page, he must express only til at which coincides with what they think . , .all other ideas become invalid!
Really, you have no idea of the tone of reproof, sometimes downright abusive, which
DECEMBER 1970
105
1
even one's best friends are likely to use in disagreeing with this or that editorial point of view on any given subject. Take the recent growth of lists on the DX bands, for example. This has now become the chief target for the rugged individualist types who keep insisting that they prefer pileups.
1 have no axe to grind either way, I have such a minuscule number of DX credits, that Vm happy to take 'em any way I can get *em. So my views are not subjective . , .not based upon my own needs . , .therefore unprejudiced.
While it is perfectly true that a well opera* ted station using standard power, a medium height tower and an ordinary tri-band antenna, is adequate in the average hurly-burly of a minor or medium-size pileup, it is decidedly at a disadvantage in the prodigious traffic jam which inevitably occurs whenever a rare one turns up. The recent operations at ZA, AC3, ICP6> ZKl, and Gus Browning*s Indian Ocean activities all demonstrated the folly of attempt- ing to compete on an equal basis with the super-kilowatt boys with the sophisticated antenna systems. Those boys stick out like a sore thumb . , .many "dB" stronger than the other hundreds of poor sh nooks calling in the pileup*
In such cases, the list method tends to favor the less powerful stations^ enabling them to make QSOs which they would have very little hope of getting under normal circumstances. Of course, this displeases some of the big noises, who evidently feel that they do not wish to lower themselves by soliciting anyone's aid for the demeaning purpose of standing in line to make a contact , , ,any contact They seem to think that they should not be required to wait in line, but should be accorded instantaneous and undivided attention by whomever they call. They are perfectly willing to have everyone else stand in a long queue, twiddling the thumbs, just so long as it is not they who are made to wait And whenever these certain parties hear a list operation in progress, a couple of them invariably try to break right in and call right on top of everybody, simply because they are just not about to get used to waiting their turn. When they are asked to move off because the DX is working to a list, they commence lecturing all and sundry on the evils of lists, and how this is likely to destroy amatuer radio. Or, they move off about t\%o kilohertz and QRM the frequency with all of their side hash.
If ever there was a sterling reason for me to feel kindly disposed toward the lists, this would be it 1 think that it is high time that some of these super-mouths* oh the bands were made to feel a tittle less secure about their positions on invincibility. lt*s time somebody gave them a comeuppance.
Well, anyway, to get back to the lists . . J decided that maybe I would support a couple of them, not just to get in on the DXj but
because I happen to be a strong advocate of their sponsorship of DX stations by distributing gear to them. So, I sent in a few bucks , . ,not a large amount at all, and I had the unmitigated temerity to announce the fact on the air to a few fellows 1 know. Boy! That*s when the eggs hit the fan! They wouldn't even control them- selves to the extent of waiting their turn to tell me off. They said 1 was stupid, shortsighted, foolish, naive, ignorant, radical, vicious, treason- able, and that 1 was losing my marbles. They doubled, tripled* and quadrupled, drowning each other out in a caca phony of indignant outrage.
Well, if there's one thing IVe learned since beginning this column, it is this: Whenever you get an angry reaction as a result of something youVe written, you can be pretty sure you're on the right track! Nothing gets people who have enjoyed an advantage (particularly an unfair advantage) more upset and riled than a movement toward equalizing the situation.
Of course, even if the edge could be taken away, they would somehow find a way to regain it I know a couple of guys who would do it legally, by developing more efficiency in the antenna system, and that's fine with me* But the answer for many of them * * ,far too many . . •would be an illegal increase in power. Don't ever get the idea that the so-called California kilowatt is confined to the Golden State. The overpowered stations are all over the map, and what's more, everyone knows it And as long as there are people who are willing to sidestep the regulations by running illegal power, then I am solidly in favor of list-taking, because it is just about the best way yet devised for overcoming the overwhelming odds which have been unfairly lengthened by these cheats and chiselers.
MAGNETIC CAR SIGNS
M- "> ' v •'•'<
•>:^
I
$4.00 postpaid!
Put this magnetic caff sign on your car when you are on a trip and meet tfie tiams afong tfie way. Comes rig fit off wfien tfie XYL drives tfie car, if sfie doesn't want to be bottiered by fiams tooting at fier.
Send $4 afong with your caff fetters today. Radio Boofcshop, Peterborough, N.IH. 03458. (USA onfy pfease).
106
73 MAGAZINE
Gerald Beene Greenville TX 75401
Many power supplies wiU not survive a short circuit. The reason for this is that in the low voflige supplies used for
02
Fig, 1, Series current luniter circuit.
transistor circuit work, a series transistor is used to regulate the output voltage. If an unusually large current is demanded from the supply, and there is no current limiting,
UMfTER |
TO |
|||
+ POWER SUPPLY |
||||
1 |
£ |
CKT |
||
± |
Fig. 2. Biock diagram of iimiter in typical applica- tion.
the peak current rating of the regulating transistor may be exceeded.
Other than the sensitivity of some power supplies to overload, experimental circuits are also subject to damage if for some reason excess current is allowed to flow.
A fuse alone will not necessarily provide the needed protection for current setisitive semiconductors.
The simple two-terminal current iimiter shown in Fig, 1 will give instantaneous limiting for those slips of the probe, sudden shorts, etc. The use of a fuse in series with the Iimiter will reduce the need for a heat- sink on the transistor Ql.
The Iimiter is placed in series with the line so the current is from collector to emitter. Though shown polarized in Fig, 2, the Emiter may be used with either polarity supply.
In order to design for a particular maximum current, select Re such that
.6V ^ I (amps)
and make R^ about ten times as large as Rg, CRl and CR2 are silicon diodes
such as 1N4002, 1N645, 1N2070, or just about any diode capable of at least 100 mA. Ql is a sUicon transistor capable of the current to which the Iimiter is designed.
It works like this, Ri, is small enough to keep Ql saturated as long as CRl and CR2 are not conducting. As soon as the voltages drop on R^ reaches 0,6V, CRl and CR2 conduct and regulate the output current by regulating the base voltage on QK
Gerald Beene ■
I
DECEMBER 1970
107
1
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ARTICLE
DIRECTORY
1970
This master article directory lists, by subject, all the major articles featured in 73 Magazine during 1970, Entries are first by subject (alphabetically^ then by article title (chronologically). A brief abstract of each article appears once, though the article itself might be listed under more than one category. When no abstract appears and a subject heading is shown in parentheses between the author's call and the date of publication, refer to the parenthesized sub- ject heading to read the abstract.
Antennas
AAB— AM— FM Modulalion System W2B5P Jan
TonBue-in-che*k technical article about a system th* author actually uses, H* calls it **freqwency apertio'e'" modulalicm. The mait interesting part of Ihc article is ihe Authot\ clever adapialion ol a &5 eallon drum for use as a 10 meter cavity.
Base*Tuned Center- Loaded ARtenittl WZEEY Jan
An antenna can be c*»ntpr-kj*idi*d without hiiving the reactive elemeni physitally prescni ,it the center at the antenna. Transmission line transfer of the reactive element is the: Jiey.
Variable*! mpedauce Mobile Mount WIEMV Frb
A roLan*' twitch with a few capacitcirs can effectivetv change the matching trnpe^-inei- «>£ a mcibile antenna,
Qiiick'Stap and Reverse Antenna Rotator Circuit rV2AUC Feb
A yimple rot4*r itindificatmn in make the antenna stop when yOti w^nt it tt>. A No lets you suddenly rrvtine the antenna's travel without fearing, damage to anythtne too hi^ to reach eamfor- tabiy.
The Glop Will Get You if Vou Oon*t Watch Out! W20LU Ftb
Thi^ effects of Klup (dirl and crud) on antenna connections. Contain;; suggestions. lor mmimi/ine the likelihood of Glop buiId-up.
18*in. Dipole for 15 Meters K9LGH F«b
Rupt-rsmatl Hnirnna for cliffdw**!lrr!>^ incorporates two prinied^cijTcuil radiaUitii elentents.
Loiiy f ransmissDn Lin^^ KH6IJ Feb
A deschptjon of the ef fet'ts of an- ajiienna
tiansniission lme*s losses^ and a discussion as to the insignilicartce of svtr meA$uremenU under con di Lions i>f a lossy line.
How to Megger Your Antenna W2EEY Apr
A simple, pjfoved method for period icajly fht'tk- ine performance of a iransmisBion line iind antenna system. Can uncover fautts not indie -iii'rt by svvr measure men Is.
7 /S -Wave Mobile Antenna for 2 meter FM W2E1UP Apr
An r Xpert describes an antenna of original design, and compares it nfojectively wnh other antennas. of commerciiil m.anufaeture, In the Buffalo tirea, this 7/&'wave antenna has held the FM mobile ^in record sinee 1^67.
5;8 Wavelength Verlicals WAt^NGV May
1 hi'ory and information on 5|ffl'wave verticals of various descriptions. Includes radiatjon^angle data, construction informaiion. and necessary equations for original design.
DECEMBER 1970
109
Vi^
1
TH« LittJr Wondrr: Mark U W5ZBC Jun
Another cliff dweller antenna. ThU ame can br tlt$hioned from an oM po!f> lamp.
The 663 Bpam ZL2ASJ Jun
Six i^l^menls nn tO aJid !5. and 3 elements on 20ni. Canstrucli[»n plains were left out, but w*ri printed in the Aug issue 4 p. S3).
Qtiarter^W^ive Top-Loaded MoblU^ Antenna WSAZE Jun
An effjcienL, ifth«rt quarter-wuveleneth dipuk- antennti for 20 meters.
Eleven -Element 2 meter Circylar Quad W4itAE Jun
A new type tit ^miemna that seems to have a lol ti» offet .
TIm Sly Beam ZL4TAH Jun
21 dB gmn an 2 nueLeTs with a new approach to the constfufrtion of y»gils«
lieasorinc the Difference Between Incident
And Reflected Powrr
vrins Jun
The difference is the differenre Trtrludes circuit for mea^urtng n? fleeted and f^^rwrtrd rf.
The EfrectK nf Temper^itnre und Frequency On Coaxial Call 1 1^ Lo.tsi W9KXJ Jun
As Irdnsmisajon line tempers Lun- inrrtases, so does loi5 — and vice versa. Complieatiiie matters, the losses get worse as the operating frequeney i» raised, includes eharts-
Jmprovxnf the Ferfarmnincc of Trap-Typt
Vertieal AntennaA
W2EEY Jun
The addition of another element can consider- ably improve the performanee of multiband verticals. The added element c^n be automati- eallv band switched aiid a transmission tine system ujed which ^tows ^mple ehanaeovef from an omnidireetional to a directive radiation pat tern «
A Practical DDRH Antenna W6WYQ Jun
Ring-type Inw-prutiW radiator thai i& hard to build. Good for mobile rooftupa^
Two Receivers from One Antenna WA6IIFW Jun
An easy-to-make sjenat splitter that allows niaxi- mum utilization and minimum loss.
Remote SWR Indieator
vnmsY jyti
Concentionallv pUced swr meters iiften do not ir^cate the true swr at the lync^tion of the ttmnfmission bne and antenna. Remote location of the re fleeted -pnwer sensing ^sortion of an s:wr unkt is the key tu true sw^r v^ue IndicaUan.
The Low-Noise Antenna WBGJNJ Jun
B-lasting the theory that an antenna always works aa well receiving as it does transmitting,
MfaSuTioE RF Output WA6CPP Jun
U^ing a cheapie meter to measure wattage.
Raising a Rhombic WflDYF All you really need is space.
Atn
Log Periodic Antenna De^gn* fov VHF/URF W3DUQ Auf
Three Arrays are featured: 21—55 MHz. 50—150 MHz, and 150-450 MHz.
ATV: GettinE a Better Picture WA6BJV Aug
Plani for a lood antenna and suggestions for other station improvements.
Brew I on 2 ^^ a 2 Meter Coaxial Antenna WA9RWQ Sep
The title is alluding to California's '^Brew 102*^' beer. The ^irtiele describes u beer-t^an coaxUil antenna that can be fun to make if you obtain the cans as the author suggests.
Four-Wire Inverted Vee WABCOB Oct
Simple but effective antenna for 4B and BO meters.
Remote Quad Tuning W6AJZ Nov
How lo tune a quad stub from a control bon gat ua ted at the operating console.
CW
The Combo K4FQU Jan
A CW monitor that is installed hetween the key and the traruimittei-. Contains but one transistor. Simple. Effective,
Mobile CW KGRA Jan
A fantasttcallv great way to get yourself killed »n a Los Angeltr:^ Freeway.
Fint Clasa Keyer Key W6BLZ Jan
Quickie article describes a cute modification to fnodernize an mcKpcnsive but readilv available "by|U ■
A CW Monitof WB2GQY Mar
How to get a 08 if oscillatoi module to key on and off w^ith rf. Uies a voltage doubter rf pickup.
Tltmlni the AN/GRC^ Into A
Novice Ria,
W6JTT Mai
A simple converfion puts this surplus unit on 80 and 40 meterit. Converted, the rig will run about I5W. Includes n det^led power supply circuit, Modula tori ess, the transmitter Is intended for CW operation i.
What Will Become of CW? W5TOM May
A di^tfi^rtiiticm on the st^te of hum radio todity^ pod sugge^stions tor possible Improvement. I^fukcs a case — of sorts — for CW, aiKl offers predictions for CWs role in amateur radii^'.s future.
A Mobile CW Transmitter W6BLZ May
For those who donH know what to do with their free hands while drivings
CW Can Be Fun Staff An evaluation of Ord*s DK-I keyer.
Jan
QRF WA3JBN Jun
Two simple rigs for CW opeoition on 40 meters.
How in Biiild a Keyer and Retain Your
Status tts an Appliance Operator
WSKXJ Jul
A couple of guitar picks and »iome relay contacts
can turn nut a pretty nice looking liending key.
Mobile CW Receiver W6BLZ Jul
For people who just can't seem to get enoufh code during the evening at home,
the ICmittef Goldstein Aug
Costs hi tie and do^-sn't run much power, but It will put out a signal — AM ot CW — on 40 through 160 meters.
Integraled Circuit CW ID Generator W7PUG Sep
A device for automatic identification — with CW — of FM repeaters. Author also offers^ to supply PC boards plus computer printout of any call letters, as optiTni?,ed with the author's tiom* puter.
Low-Cost Automatic ICeyer:
A Firsi Project
WB4MYL Nov
Schematic, description, and circutl board layouts for an ine^penvive keye? thai can send from 10 wpm to over 30,
DX
How to Visit Foreign Countriet W2NSEI/I Feb
A few salient hmts for prospective travelers and sometimes DX>rs»
Ham Exchangp WA2ELA Miir
First-hand report of a "^ham ps change" whereby DX visitors slay i^ith U.S. amatt'urs, then recipro- cute later when the U.S. hams visit the DX country,
QSLing: Ham Radio's Own Con Game VK4SS Jul
One ham's negative opinion of the state of DXing today.
Latham Island DXpedition 5HaLV Jul
Problems and iucccs&es Ln a recent DX trip to Zanzibar,
Worldwide ITU Prefix/Call Area List WISWX Jul
Reprinted from DX'er Maga/Jne.
YO — An Interesting DX Y02B0 Oct
A look at Roniitnia and a deKcnption of the h^ms jjnd country^
FM
VHF— FM: A New Involvement K6MVH Jan
The story of FM Maga^ne^s demise and the
promise of 73 to give adeqi^ate attention lo FM. an area alt but neglected by ham joumaJs in the past.
Low-Cost Electronlci:
Japan *s FM Invasion
K6MVH Jan
A brief overview of some of the 2m FM triin^cetvers th^^t lire being inported for sale to the booming VHF hiim market,
Setting Up the Tone-Burft System W6TEE Feb
The little details that are necessary in setting up a toned repeater^ including, a tone-burst timer for the user mobiles.
Tone Decoder for Remota
Switching AppbrptiDns KBMVH Feb
A simple and tested tone decoder that may be used for such repeater control supplications as whistle-on and tone-burst arceKSi systems.
Hitooders for Subaudible, Tone-Burst
or Whistle-On Use
W6CZL Feb
An extremely simple and stable transistor oscil> laior circuit, with adaptations for the varioui modes of repealer controL tncludc:5 PC board
layout and construction plans,
Freqiuency Synthesis: The Modem Way to Control Frequency W2EUP Feb
A complete anti comprehensive article covering theory and techniques of indirect frequency synthesis, plus schematics and u deschpLion of a practical tOO-c'hanne| synthesizer used in a 2 metet FM tF.tnsi eiver» with only one frequency- determining ci y^i^
VHr— FM and You K9STH Mar
A "wh«t*s^t-a^^ilboul'*'' lype article covering everything that's happening in FM tigbl now.
6*tO'12-»volt Filament Conversion
for the -11 V
W6YAN Mar
Changing the cheaper 6V Motojhala FM units to
12V types.
AC Power Supply Conversion
for the Motorola 41 V
K9PKQ Mar
Schematic diagram and helpful hints for con* verting Motorola^! truhk-mounlinf mobile unit to a base station.
Remote Muttjfrequeney Oscillator W2Al,M «.»Sun.lu»FMOml. ^^
Complete plans^ PC layouts, and construction info for a four-frequency osciUator deck thai can be used in the control head of such trunk* mounted units as GE. Motorola. Link.
Converting the Snnoliuoy to a 2W FM Transmit tef WlBYX Mar
Schematic diagram, photo, and instructions for converting the AN/SSQ-23A underwater trans- miller to A 2W 2 meter FM rig. Also tells where to get such transmitters.
Kfli Smiming Receiver Staff Mar
A close look at one of the newest entrants into the hjun radio field,
A Look at Amatem FM Standards WB6DJT Max
A general survey of the VHF revolution with respect lo repeaters over the pat; few years and some sugge«tioni for planning ahead.
A Poor Man's Frequency Meter W6YAN Mar
How to turn a che*ap LM frequent u meter into an extremely accurate piece of ipsit equipment. You'll need the front end from a Sensicon receiver, too.
The Fine Points of FM Operation WB2AEB Apr
Good common sen« for FM befinners. Includes good hints on setting deviation level.
Examining FM Repeater Operation WB6PJT Apt
A state-of-the-art article telling il like it ii, with
sugjg^stioiiB as to how it ought lo be,
A Repeater Controller WA4YND Apr
The myriads of mechantcul contrivances thai repeaters inevitably wind up with can be replneed with transistor cquivalentfi. . .with a resulting increase in system reh^bilitv and decreases in headaches for the repairman. Complete circniu, with timers. COR , keyer control, etc.
Understanding the Carxter^Operatcdt Repeater K6MVH Apr
The complicated repeater is not rvally so com^ p|e:K after all. . .it's only a matter of under- fl*nding the simple op era lions that are taking place when i.»mebody tr^ntmitc on the input fere<juency.
Evaluations Standard 2m FM Transceiver WfiQGN Apr
A cioiii> ItKik at the SR-C-ftOfiM transistor triin* sceiver*
Directory of American Open Repeaters Staff Apr
A comprehensive listing of open repeaters in the United State* and Canada. Includes editorial introductjon and vnjteup afaoiil repeaters in geneiaiL
FM Repeateca Under Fire From FCC Staff Apr
The first pubhshed notice of FCC's infamous Docket IB803. Sketchy but eEsentially accurate.
no
73 MAGAZINE
A Woird AbciuL Repeaurs
WB2AEa AP*
The trend for the future seems to be to use a compaiibie denatiort eif both narrowband and wideband rigs: this is Accomplished with a pe^k devintion of about 8 kH?. at the repeater iran- smitter. Other trends and characteriiiics alio naied. tnclwded with the repeater directory*
7 /B -Wave Mobile Antennft for 2 melef FH W2EUF Ai*'
(Antennai)
FM— AM Transmitter-Receiver AUftnet W3JKl^ May
A fieiial generator that can be used in cofijunc- tion wiih # transmitter to givt m zero beat for frecLuency measurement*, AUo uicfut for alieumg F.M receivers.
The intemgeiit Vam of 2 Meters FM KIZJH May
A eeneral description of the wif it's done un FM (it IS different^ ajid a few word* of wiidom to people who arenH used to working throuftb rrpitaters.
A Low-Band fohce MonlloT W6JTT May
How to modify Motorola** old. no lonfer used 30O type receivers bv buildmc Up a simple supply and diddling with the receiver oscillatof.
Thf Wichita AutopAieh
w«DKu ^^y
Tied in with the local repeaicf , this phone patch receiwed approval from Ma Bell. Include* descrip- tions of the patch and tells ho* Ma BeU was canoed into going along with the idea.
An FM Beit Buy WATCliM May
Bojf to convert the world** rarest FM rig (ComcoJ from commercial service to the ham band.
FET Preamps for VHF FM WA4WDK May
Two good preamps are described — one for S and the other for 2 meters. Complete performance curves, construction data, schematics* etc* are given. Preamps are grounded -gate, which offers high Rain> ease of Lunins, and simpUcjtv of constructioTii
K9STH
Allied Portable FM Hecelveir
Jul
An evaluation of AlUed's A-26e7 pocket FM receiver.
Jul
A Two-ChanneJ Search-Lock for FM Receivers W3DTN
Simple gadget turns a S-channel rig into an automatic scanner type, and provides the added capabUity of locking onto a channel where activity is sensed.
Super Autopatch
K6MVH ;f"*
Why automatic phone patches are important for public service. Includes construction data for a p4itch thai does everything.
Repeater Audio: Time Out for Quality
KfiM VH ^ '^'
Use of a cathode follower to pick audio du-ectly from the repeater*s discriminator can do wonders lor an ailing amateur relay system.
Optimising Antrnna Separation *
in FM Rrpcaters K6HVtl Sep
If the receiving range of your repealer cant match the output capability, the problem could be desensitj/ation. And chances are you cart solve tfve problem by as simple a step as moving the antennas around a little at the repeater site.
DyComm's 15W 2 M«t«r Minl-AmpMfier Staff ^eP
Afl evaluation of a ready-made 15W class C ■mpUlier that can be used for VHF CW or FM applicationsn, requiring only 20 mW of drive.
JmegraUd Circuit CW ID Generator W7PUG Sep
{CW)
Low*Co£t pseiliator it Infintic Attenuat^ir for Tuning VHF Receivers KICLL Sep
A signal generator with A very reliable ^ad repeatable attenuation device for adjusting receiver front ends lo maximiie scnsitivily.
Controlling Hepeatert with Tones K6MVH O"^
Basic repeater control logic, and how to set up a tone control system for tone-burst or whtstle-^n use»
Semiautomatic FM Channel Scanning WA^QFM Nov
Usmfi ordinary flasher module, this unit connects to a lwo*channel FM transceiver to allow moni- toring of both channels bv a scanning setjuence. Does^ not lock onto a signal.
■
2-Meter Mini transmitter
for Repeater Use
WSGSIH Dec
A straightforward, simple transmitter with five
stages using five transistors.
Regency — m FM Late -Starter Staff ***«
A comprehensive comparison of the Regency 2 meter transceiver with other units currently a vd Liable.
General Info
Fascinating Fundamentals; VoiU and His File W2FEZ Jan
The interesting story of Voila and his ex pen- ments in galvanic resifarch. Describe* an early (and easily duplicated) battery.
Fascinating Fundament^Ls* The Terrible Jar at Leyden
¥V2F£Z
Feb
Interesting historical facts about the Leyden Jar; how to duplicate it and make you? own capaci* tor.
How Do Ham Radio Stores Decide Trade-in Frices? W2CEP Apr
The owner of Stellar Industries gave this run- down on the way pnces aJre figured in the amateur radio game. Stellar ii no longer in the ham business, but the article is nonetheless applicable*
fieryllia — The Lethal Refractory WB2PAP Apr
Take another look at those lube bostes on your shelf; tho^e ceramic jobs that are made with beryllia r=>uld be dynamite! I
Inexpensive New Semiconductor!
for the Ham WA7KRE Apr
Descriptions and representative circuits for « whole flock of recently introduced semieon- ductors from Motorola. Includes dual-gate MOS- FETs^ several power amplifiers* thyristorSt recti- fiers, etc. Circuits included: VHF amplifier, audio amplifiers, telephone ampUfier,
London's Science Museum Demonstration Station
Ellison ^^y
A look inside the museum and a description of
the amateur radio facilities there. Includes photos.
Plus Ten dB. . ■ W20LU M*y
A quick way to rcJate power to decibels^ and an easy method for calculating one commodity or the other when one of the commodities Is known.
Selectivity Has Come a Long Way Swan May
The theory of bandpass fillers and a descriptiort of Swan's n&west entry, [ncLudes performance specs.
Science Fairs; Science EducatilHlf Mocking May
A revealing look at the schools* approach to science education these days. Good reading for those who care.
Bigger Knobs for Better Performance WB21CV May
An encapsulated rundown on the findings of a hi^h-cost program to human -engineer consoles. Modt-rn j^ience now says tiny knobs can cramp your style!
Epoxies for Electronics W9ICXJ May
How to steal a trick from the professionals and
use modem epoxies lo perform the bonding that once had to be done with a hot soldering u-on.
Comments on FCC Repeater Froposal
Staff **■*'
A poi»t4iy -point reprint of the FCC*s Docket 1SS03. along with suggested revisaons to make the rules more realistic and easier to live with.
Ground Support for the Powder Puff Derby
W7ZC
Jun
The ins and outs of providing commumcation* ior the most famous ak contest in the world.
WBSJNl
W^KXJ
The Low-Noise Antenna
(Antennas)
The EffecU of Temperature and Frequency on CoRAlal Cable Loss
I Antennas)
Jon
Jun
Government Surplus
Straight Froin the Hor&e's Mouth
WA9ANW Jtm
How to get on the Government's surplus gravy
traln« How to buy: how to bid.
Improving the Performance of Trap-Typ«
Vertical Antennas
W2EEY Jun
The addition o (Antennae I m consider-^
The Club for Blind Amateurs Champagne Aug
Pictorial story of KlTpX, the Perkins Radio Club for the Blind.
Bam Radio Chess W1EMV/©BMW W Au»
Two schemes for annotating chess games for over* the -ait play.
What Really Happened to Hamdom?
W9HBF ^P
The author asks why we are in the sute we are. He advocates QRO and a good beam as opposed to brute force power, and poinu to socne uncomfortable comparisons between ham radio and citizem band.
Y02B0
YO — An Interesting DX CDX)
Oct
AC Switchiog with ^eU -Powered ICc W2FBW Nov
A new approach to pow^er switching of ac circuits: rii is eliminated, power supply diodes are protected, switch contact wear is reduced « and tube heater life extended. iCs switch at the icro current point.
Pioneer Radio on the Frairte W6CXC ^^v
Sentimental remembrances of E, E. Krebsbaeh and the contributions he gave to the field of
amateur radio.
Helpful Hints Proper Use of Silicon Diodes
1WA3ACL J»"
How to use the ratings of diodes in your rectifier projects. Includes suggested applications for such diodes*
Simple Compact 6m Bandpass FiUcr WA5SWD J*'^
A high-performance TVl for 6 meters that costs less than S5 to huild. The filter is to be installed in the transmitter's transmission line.
Using Diodes for Adapting AC Relays to DC WASSWD J«*l
Simple shorty article showing the right way to use diodes for low- voltage rectification where the object is to use dc relays with an ac supply.
The DX-aS Revisited
W2AOO ^^^
A trick or two for updating Heathkit's popular
DX*35 Novice rig.
From Breadboard to Printed CirciilU
the Easy Way KIAOB , Feb
A simple system for making PCs by usmg an Xacto knife to cur around original artwork.
professionalP PCs From Roll-Your^wn Negatives
K6MVH W"'
A means for creating high-quality printed circuits without the time-consuming and expensive dark- room processes*
Easy Diode Testing K4JK Mar
A clever means for nondestructive I y testmg * 'bar- gain** diodes to leam their PI V.
Super Sizer WASAQS ^"
Many little modifications that will cut the resale value of Heath^s Sixer, hut which will surely make the rig work better*
Apr and
Renovating Surplus Meters
WAtABI . ^
A test or two, a dab of w*iiite paiov -
presto!
Keep 'Em C^lO^ to KFO Cajis
G3KFO . ^ , **f^
Construction data for building simple heatstnks for vacuum tubes. The idea is to extend tube life and reduce heat dissipation within the lube envelope^
W9KXJ
Epoxies for Electronics (General Iriforfnation)
May
Bigger Knobs for Better Performance WB21CV
(General Inlormation)
May
DECEMBER 1970
111
1
Educated tdiot Lithlc Holfoitf Mar
Hon to modiFy the tM-t"* "klitii Itght^" wanting ivit«m l>y Ada[)tfT)i a buxi,er to complein^n^ tt,
CoaK Adaptcf - VHF to BNC W9MEV Jun
A "quLehlr*' article ihowE how tp combine fiuines tci gpt a professiorial Look Ins adapter.
UsefuL Cable Clampi
A brask iK<irty tellinc how^ to uw host cSainps to hold cabLci.
De^&r Your VTVM WA0FFi Jun
A quick and crafi^ wav to clean il up.
Two Recrtven Ijom On* Anlrnna WA6UFW Jun
CAnleitnai)
WAGCrr
MeaitETinf RF Output. (ADlennasJi
Jun
InaUUing the Swan 350C Noi«« Stlincer WA6CFP Jun
PiftairiaL itoTy tells how to do it neatly.
A Sotderinf Gun Tip WB€rKA Jul
UiinE silver-plated winr for ^otderina. Mount That Mobile Riaht K4IPV Aug
The rlRhi kind of mobile Initall^tior wlfl retult in bigger sigrub. better operator safety, and more fun m hamming an Ibr road, , T
ATVt Getting a Belter Picrtof* WA6BJV Aiig
CAntcfinaJ^
Converting 24V DC Rt^tays to 116 V AC Douglai Sep
Thr^e circuits and a brief article on how to accomplish this La^.
Reed ReUyc for UHF/VHF Coaxial Switching W7CRV Sep
How to us# reed relayi in plaee of the expensve e««3i rvLays awi get better overall performance.
tnctudei frequency loa and isolation curves.
Neater Cabling With Nylon Cotd WA9ABI Oct
Use o( nylon and he^t to make it neat.
Irnproving Regulation in High Voltage Suppliea KGBW . Oct
Shoriirtg nut the surge resistors with a delay circuit Co improve perrormance of a high -voltage regulated power iupply.
Calibrate that Catibrator W2KPE Nov
Uung WWV to calibrate the receive^r 100 kHz calibrator more accurately than it ha* ever been calibrated before^.
Sotid-State D«tt«-r Control for
SSB EKCiter«
W4KVK Dec
Vernier tuning eliminates dial backlash and other tuning anomalies, and gives precision variable- fre<juen.cy cnntrol of operfttjng slot,
Two-TeTmlnal Cuirent LlmJter Beent Dec
Simple series circuit holds current to tafe leveL
Humor
The Manuicript Game Staff
Every good article gets its due reward.
Jan.
How I Read the Radio Operator*!
Handbook and Found Happinru , , , Johnson Mar
The author's fitoi-y Of ho%v he mastered ham radio theory overnight.
Bob-Bob- Bobbin" Along K1YS0 Mar
titter <rhaot and hilarious confusion from the pen of 7^'5 only in^ne author.
That Contest Craze VK4SS An old tiger bares his fangs.
Aug
Code Frartice a la Baby Tail W90XA Sep
Sometimes there are advantages to becoming a ham that irenH even listed in tne manuals.
Camouflage K99AZG Oct
How to buy lots of ham gear without letting thf* old lady know.
Clinks In a Vacuum Derfler Dec
A )ow-pTf*S!(ure article for wives^ (Or for hubsands to show wives who don't dig radio ,)
Hami are a Wufutf Bunch of People fc3KMO Dec
A few of the paradoicrs that make it emsr for us to Eaugh at ourselves,
T^pm. It Talkal
WSFEZ Dec
Kool vour friends with a newspaper that talk*;. IVs a homebrew electrn static speaker fashioned from paperK and foil.
IC Proiocts
Frequency Synthesis:
The Modem Way to Control FreqiJericy
W2EUP Feb
(FM)
Hew Linear ICs for the Ham WA4KRE Feb
A dowo-to-earth description of Motorola** latest ICs doe amalcurs. along with schematics lifted from Motorola's application notes. Includes Ikower supply and regulator circuits^ amplifiers, modulatori.
A Logical Approach to Surplus Buying K5JKX Mar
How to identify and te^t ICs commonly found in the surplus market. Includes an extremely literate discussion of the principles of logic.
Low Frequency t«F Modules Using ICi K1CLL Mar/ Apr
Description of what the author feels is the ideal hi. This teat includes a very good dis$ertaLton of the ins and ottts of such populaj- i-fs as 455 kHz.
High'PerfDrnuince Power Supply Ufuig an IC Voltage Regulator KdfCF Jul
0-20V at up to KDO mA in a iinv package.
An Impedance Multiplier for the VOM K6DQB Jan
Using an IC to do the trick.
Goldstein
The tCmitt«t CCW Three Versatile IV Testers
AtJg
WA2IKL Sep
This article lists pin diagrams for the common ECs and diescnbcs simple testers for checking digital, linear, and counter ICi^
Understanding and Using Integrated Circuits W6DNS Oct
All the baticsi what, they are, how they're used; why they're used.
The Phaae-Locked Loop Comes of Age K5JKX Oct
A new IC and how it can be used in some pretty snphis^ticated circuitry,
Low-Cost Functton Genermtor
for Expertmrnters
WAJ2EKL Oct
Makes sine, square, and sawtooth with excellent
quality.
tC Marker Generator K4BBC Oct
Simple tC device gives marker signal when you approach the edge of your authori^^d band.
Ptactical IC Regulator Circuits for Hams WB2EGZ Oct
For a 500 mA supply.
ICs for Amateux Use KI CLL Oct
Describes m couple of good rf amplifiers using inexpensive ICs, One for 6 meters, another for 40.
AC Switching with Self-Powered 1C«
Nov (Gen, Info^li
WB4MYL
Low-Cost AtiNimfltic Reyeri A First Project
(CW)
Nov
SoUd^tate Transceiver for 40 Me ten;
the SST'l
W9ZTK Nov
A modulari/ed QRP rig with huJit'in twr bridge, CW monitor. Has ICs in audio and receiver lectio OS.
Solid-Sate ExciUr W6YUY De*
IC'S and transistors makes this SSB exciter modern^ inexpensive, and efficient.
<HR PROJ) W2 FEZ
Yipea, It Talks! (Humor^
D«c
lC«y«rt
Transceiver Companion W^AJZ jaa
This ii a complete control console and accessory for the transceiver that doesrk''t already have everything. It includes ci»m pressor^ preamp. elec- tronic keyer. phone patch, speaker, cloc^, and the kitchen smk all tn one neat package.
SUff
WB4MYL
CW Can Be Fun
<CW)
Low><}ost Automatic Keyer; A First Prole ct
KfiKA
tCW)
Uabile CW {CW>
Jun
Nov
Jan
Base^Tuned Center-Loaded Antenna
WaEEY , Jan
(Antennas)
SSBh>AM*FM Modulation System W3BSP Jan
Tongue-ifi-rliepk techfilcaJ article about a system the author actually uses. He trails il ^'frequency aperture^' modulation. The most inleresiing part of the article i$ the author 'n clever fid^ptiatian of a 53 e^on drum for use as a 10 meter cavity.
The Camper — Mobile and Portable WA9EHE Feb
How to get the most out of a ham station when you own a camper, plenty of radios, and like to travel a lot.
Variable- Impedance Mobile Mount WIEMV Feb
(Antennas)
7/B-WBve Mobile Anietuui lor 2 meter FM W2EUP Apr
(Antenami)
»^«» , ^^ Riviera Style
K9BDJ May
The story of « Buick-owner*i problems and how be traced them down in order to eliminate mobile interference.
WliBLZ
I I
A Mobile CW TransmJttee tCW)
May
WA7EMM
An FM ''Best Buy"
(FM) A Ham-Si ylc Burglar Alarm for the CttT
May
K2JLD May
Description of a scheme for foiling prospective rig thieves-
Hplford
EAO^TGV
Educated Idiot Lights
fHelpftU HinU>
S;a Wavelength Verticals
lAntertnas) The 2 7 -Minute Mobile Limltcr
Mmy
Mar
W7SOH May
How to build an effective noise Jimitpr. As an alternative, the author shnws how to modify an existing Bishop type noise li miter* The modifica- lion takes 27 minutes.
wurYQ
A Practical DDRR Antenna CAntennai)
Jun
Suarter-Wave Top^Loaded Mobile Antenna _ ZE Jun
(Antennas)
Installing the Swan 25 OC Noise Silencer WA6CPP Jun
(Helpful Hints)
K4IPV
Mount That Mobile Right (Helpful Hints)
toV From 12 — The Easy Way
Aug
K3GSY Sep
HijLh cur?«fft tegulator that uses two transislur at^d a zener. Better approach than the ^'dropping RSistor*' tdea«
Semi auto nu tic FM Channel Scanning WAfQPM ijo^
(FM) "***
IMoi5« Clippers
A Noise Blanker That Works WflRHR Apr
it DOES work, but the article somehow got into print utithouit being edited, yind there ^v^ Kome errors. Those who want let build should drop a card to editor of 73 to get straightened out on discrepancies.
WTSOH
The 27-mlnute Mobile Limiter (Mobile)
Mar
Installing the Swan 25C1C Noise Silence^
WA6CPP „, . . , ,., . Jun
(Helpful Hints)
Nova I Ham Radio Proiects
CDnvertind the 4CX1000 into a Lamp K3QKO Jan
A clever lamp for the hatii*t ham. Even has a switch fashioned from a coaxial connector. Bet- ter not to use a new tube f<rtr the lamp, though; it will have somewhat of Mti impact on the total cost of the project.
WGAJS^
Transeeiver Companion
(Keyers)
The l>ip Light
Jan
VE3ECU Mar
A grid -dip ppr that uses lamp int'^nsity tnsLt«ad of a m^eter.
Add Spotting to your VFO KRBYO Mar
Cuti^ and simple technique thut lets you hear the vfo without transtnitting.
He verse-Current Charginc K8YUC Mar
With an almost foolishly simple technique you i^^n successfully recharge ordinary drv^ cells, and make them hold the charge again and agaid.
Single-Side hand on the All-Wave Radio W7CSD Apr
A miniature tunable oscillator provider an Ideal s<»urce for h bt'al.-frequcnrv ^^igna], and Allows you to hear code and SSB on any self.*ctive receiver without making modifications to your store -bought eiM^^
W6JTT
A Low^Band Police Monitor (FM)
May
112
73 MAGAZtNE
A Ham* Style BiusUr AUrm fox the Car K2JLD
(Mobile}
Holford
Hfvw
Educated tdiot Litfhti (Helpful HLntfi)
Mmr
May
Thi Consummate Console WB2FBF Aug
Increasine station efficiency and enjoy m.^ril with « broadcaM-$tyle console. J n elude ^s plans and construe Uon data.
K4B6C
IC Mȣkrr Generatotr (IC Proiecuj
Oct
Solid -Statf lO-Minutc Timef WB4MYL Oct
FlAns, layout^ and PC pattern for a M05FET tkmer for vanous station functions or repeater applicationjl.
Power Supplies
Simple Bench f ower Supply 2L2AMJ Jan
PfOvide^* foKir output voltages* three current- overload Limits. The techniques described can be applied to other power supplies.
Pfopez Use of SiUcoo DiiKies WA3ACL Jul
How to use the rating of diodes in your rectifier
Srojects^ Includes sugsesied a ppli coitions for such lodes.
A IQmiCB Fireamp WA3IIMW Jan
Using $. smrpki^ 10m preamp with a slight amount of conversion* Details Include power supply Instructions^
Usinf Diodes for A dating AC Relays to DC WASSWD Jhtp
Simple shorty article showing the right way to tiM diodes for low-valtage rectificauun where the object is to use dc relays with an ac supply^.
WA4KRE
New Linear ICs for the Haia
(IC Projects)
Feb
Tuiming the AN/GRC-S Into a Kovtee Rig W6JTT Mar
(CWJ
A Simple Bias ReEEUlator tot Linear Ampll/iers ZL2ANG Apr
Shunt ro£ul«tic»n for bias supplies nffers the ad^'antage of low constant current drain, and it can be u5e^i wfih the netleete^ — till now — class B and AB2 linear:^
Va<;ttyiB-Tub« Load Box Aalie Apr
Schema tic«> photos^ and coo^truction details for a power supply test set . . ,
Power Supplies From Surplus Components WB6BIH May
Lots of theory and a few schematics for con- verting old surplus Junk into something usiefuL If you're a muthematiclan, this is certAlnty your bag.
K<PECF
MJjth-Performance Power Supply Umtng, an iC Voita#e Regulator
etc Projects) kkfcc.
More Notes oik Diode Stadu
Ju!
W2BDG Sep
A description of GE*s high-power (5 kV aL 300 mA} rectifier modules.
K3GSY
6V From 12 — The Easy Way (Mobile)
Sep
Simple Regulated Power Source for ICi WIRAN Oct
Regulated power supply uilng series diodes (not xeners) to give precise vMu«t of required voltages.
Practical t€ Regulator Circuits for Hams WB2EGZ Oct
(IC Projects)
improiring Regulation in High Voltage Supplies KSBW 0«^*
(Helpful Hints)
Differential J^FET Preamplifier
W4RAE
Design, construction data, arid performance curves for a low- noise preamp using an tti^A CA^3028 J-FET. Includei separate power suppJy circuit.
Vour Second Linear
H^b^wer linear amplifier "S^ihSmftfc^f^r
vacui^ tube for the fin*!. Includes schematic lor
a kilowatt power aupplF.
QRP"
''Quasar*' QRP 40m DSB Tranfimitter WA5WWN Jan
Good low-power rig for nid^'bnnd or CW; u.ms 4 transistors and an audio umplirjer module.
Postage Stamp Transnattter for Sise KICLL Mar
Complete plans — including part list, layout, srhem^atic. and construction details for a irans- miuer thai is an eighth of an mch thick and oniy '3/4 in, square. This one really works, to-o.
QRP WA3JBN Jun
Two sample rtgi for CW operafJoD on 40 meters.
Goldstein
The iCmttter
(CW)
VHF AM Transmitter Using Low -Co St TranMftors, Btubakcr If it'll work on AM it 11 work on FM.
Aug
Aug
KICLL
Oct
ICs for Amateur Use (IC Project*)
2W S Meter Transmitter Using the Beterodrne VFO KICLL Nor
Breadboard design, tuneup, and performafice of itn rf power stage on 6m using a So trmnfistof and a stable vfo circuit.
Solid-State Transceiver for 40 Meters:
the SST-1
W9ZTK: Nov
(IC Projects)
^-Meter MinilraiisiiiJtter for Repeater Use WB6BIH Dec
<FM)
Receivers
Solid-state Double*Band width Tunabk l-F Converters KICLL Jan
A good tunable converter can get you any frequency or band in the VHP rai^ge you want. This article tells how, and it includes schematics, parts lists, afid completi instructions.
A lOm/CBPreamp WA3HMW Jan
Using a surplus lOm preamp with a slight amount of conversion. Details include power supply iiutructions,
A Simple IC Q^M uH jplier W2EEY Feb
l/sing an IC opamp for a Q-multipiier, Ad vantages include simpiicily, broad r^nsn' of operjitiaii„ xind variable Q and peaking frequency.
High-Performance Con%'erter for 6 WABHES Feb
Tube-type converter uses a Nuvistor. This article may become valuable as the last tube converter circuit ever published.
Low Frequency I-F Ifodutes Using ICs KICLL MariTApdr
CIC Projects)
High Performance i-F Amplilier „. ^ "nd AGC System
Zt2BDB Apr
For C. W or SSB work, you'll find this system hard tti beat with its fast-attack, slow-decuy char- acteristics. A wide blilud^" of slug e ijain is dsiured with both forward-and reversei-acting age ele- ments^
Hot Carrier Diode Mixer Converter for 2 Meters WA6NCT Apr
Low noise, high gain, eKceltent overload reMst- ance, and a very high degree of isolation combine to make the hot carrier dMnJe particularly attrac- tive for applicatiuns in receivers and converters This tut^cie has good PC layouts, photos, schema- tic^.
WA4WDK
FET Fteamp» lor VHF
(FM)
May
I-F Filter, Converter, AVC "Ideal" _,„, Circuits
KICLL May
The second half of Hoisington's two-arttclo series on the ideal i*!'. This one m eludes bread boarding the complete l-f syst^^m.
450 MHz Mighty Mite
A superregenerative receiver for 432 MHz, tn*
K9VXL A supei dudes PC layout.
Mobile CW Receiver
CCW)
Jul
WGBLZ
c
Jttl
Dclune Receiver Gain Control VU2JN Sep
Improving age 'jpformanee In tube-type receivers with the addition of a triinfiislor control circuit. Intludes. charl showing tracking cur^^e.
A Versatile and Stable MOSFFT
CriDverter for 144 MHz
WBCYVT Sep
A low -noise, high performance converter with eiccellent gain.
The Phase'^'Locked Loop Comes of Aie K&JKZ Oct
(IC Projects)
W4KAE
Differential J -FET Preamplifier (priwer Supplies 1
Nov
RF Applications of the Dual-Gate MOSFET Sir Hon
Application suggestions from Ihe engineering desk at Fairchild Semiconductors. Includes re- ceiver circuits and amplifiers for VHF.
W6TEE
Feb
Repeaters Setting Up the Tone- Burst Sy lEtem
Tone Decoder for Remote Switching Applications K6MVH Feb
(FM)
Encoders for Sub audible. Totie-Buirst
or Whistle-On Use
Feb
A Look at Amateur FM Standards WB6DJT Mar
(FMl A Work Session on the Wichita Repeater
WC^D K U ^ P^
Nobody knows any better than the tepeater owner just how religiously Murphy "S law* are followed by Nature ,, . .
FM Repeaters Under Fire From FCC
Stafr Apt
The first published notice of FCC's infamous Docket 18803, Sketchy but essentially accurate*
Examining FM Repeater Operation WBBDJT Apr
<FM)
Understanding the G*rrier*Operat«d Repeater K6MVH Apr
(FMJ
Directory of American Open Repeaters Staff Apr
(FM)
WA4YND
WB2AEB
W9DKtr
A Repeater Controller CFM) A Word About Repeaters
Apr
Apr <FM| iioofc...
The Wichita Autopatdh
St^ff
KIZJH
CFM)
73 Commentjc on FCC Repeater Proposal
(General Information)
(General Information)
The Intelligent Use of 2 Meiers FM
<FM)
May
May
May
A Two^hannel Search'Lodt for FM Receivers W:iDTN Jul
(FM)
K6MVH
Super Autopateh CFM)
Jtil
Repeater Audio: Time Out for Quality KfSMVH Aug
(FM)
Optimizing Antenna Separation in FM Repeaters K6MVH Sep
(FM)
Integrated Circuit CW ID Generator WTFUG Sep
CCW)
Controlling Repeaters with Tones K6MVH Oct
(FM)
WB4MYL
SoUd-State 10«Minute Timer
(Novel HR Projects) 2 -Meter Mini transmitter for Repeater Use
(FM)
Oct
WB6BLH
Dee
Staff
Reviews Kris Scanning Receiver
(FM)
Mar
Evaluation; Standard 2m FM Transceiver WeOGN Apr
(FM)
The GmiMlift "Satellite '"Receiver Staff Jun
An evaluation of a portable receive th^l has every th in g« in cludirkg stable SSB,
Suff
K9STH
CW Can Be Fun
Allied Porta:ble FM Receiver (FM)
JUB
Jul
The Knight'Kit RF Generator W9KXJ Aug
An evaluation of the KG-694i signal generator,
DyComm'^s 15W 2 Me(«r Mini- Amplifier Staff Sep
(CW)
Regency — an FM Late ^S tarter Staff Dec
(FM)
i I
I
DECEMBER 1970
113
SSB
Single^idebajid on the Atl-Wav« Radio ^ W7CSO Apr
(Novel HH ProKcts>
A New Approach to Communications Eqiilpfnent K9ALD Sep
The author describes ft modular concept for ■tandardizing of SSB triLnsceiver desifin. The object U to improve oerforrrtance of each module itk an SSB system, while affording hams the op- portunity of building or repairing their own^
W4AY1
WSYTTY
W4NVK
Touf Second Lineai:
{Power Supplies)
Solid-state Exciter
([€ Projects}
Solid-State Driia-F Control for SSB ExcUezs
CHcJpful Hints)
Dec
Dec
Dec
WAaHMW
Surplus
A lOm/CB Preamp
CPower Supplies)
Jan
UdDf Diode I for Adaptinc AC Relays to DC WA5SWD
Jan
(Power Supplies)
Fac^mlte «nd Ihe Radio Amateuf K€GKX Jul
More on adapting surplus equipment to hftm FAX service; m eludes photos of equipment, block diafiams^ and a cha^i showitt^ tr^msmission frequenciea and times for various stationj.
W^KXJ
The ICnifht-Klt RF Generatof CPtoducl Reviews}
Aug
An Impcdanee Multiplier foi the VOM KDEQ Jan
(IC Projects)
File Box Retittance Decade WB4ITN Sep
The firit in a series of "fUe box" Articles. Here the author ma^eis a precbion decade box and inctudec ic he ma tics for v^rLations of his own de$ifn.
The Indicatlni OsciUaloT RH6AF Sep
\ gnd^pptit without fridi. Uses FETs. Includes A Circuit for amplifying microajnpi to miUiamps, which should be bandy fot other projects as well. But be caj-elul. Fie J ii Imbeled 2 and vice vena.
WA21KL
Three Versatile IV Testcti
(EC Projects)
Sep
Low-Cofi Osicillator & Infinite Attenuator
for Tuning VHF Receiver*
KICLL Sep
(FM)
A Low-Cost RF Wattmetci WAaAJR . Nov
Inexpensive means of using an ordinary meter and i conversion chart lo accurately gage power output from 4 to 4O0O Walts.
W2KPE
Calibrate that CalibratoT (Helpful Hints)
The Tmnd-Tesi
Nov
WB6QQP Dec
Useful but simple device can measure traniiistor beta^ leakage^ and shorts.
The Little Gate Dipper W5ETT Dec
Anotber grid -dip per with no grid: eoveri 1.7 to ZZb MH£« yet is cneap and quick.
Turning the AN/GRC-d Into ■ Novice Rie W6JTT *Mar
(CW)
A Logical Approach to Surplus Buying K5JKX Afar
(IC Projects}
W6YAN
A Poor Man's Freauency Meter (FM)
Mu
Convertirti the Sonobuoy lo a 3W FM Tranimitter WIBYX Mar
tFM)
_„ An Inejcpeniive RF Wattnjeter
WB41fYL Mar
Simple adaptation of a piece of surplus equip- mentc
Power Supplies From Surplus Components- WB6BIH May
(Power Suppties)
Government Surplus Straight from the Horse's Mouth WA9AKW Jun
(General InformAtton)
Converting 24V DC Relays to 115V AC
Douglai Sep
(Helpful HinUI
Test Eiiulpment
Equipment Panoramic Rewlver for VHF IISLO
Feb
A spectrum analyzer of tons. Let's you see on a CRT the whole 2 meter band at once,
Frec|ueney Syntbens:
The Modem Way to Control Frcqtwney
WZ%UW Feb
(FM)
Extra Services from Your Grid Dip OscilUtor WA4UZM Mar
A pltig'in jidiipter turtle a grid-dipper into ii good crystal eaijbrutur.
WB4MYL
An tneacpenffive RF Wattmeter
Mar
W6YAN
A she
(Surplus) A Poor Manx's Frequency Meter
(FM)
Vacuum-Tube Load Box
(Power Supplies}
Apr
How to Megger Your Antenna
W2EEY Apr
(Antennui)
FM-AM Truumitter-Receiver Aligner W3JKL May
(FM)
Measuring the Difference Beiwteti
Incident and Reflected Power
VE7BS Jim
(Antennas)
W2EEY
WA6CPP
Remote SWR Indicator
(Antennas) Measuring RF Output (Aniennai) Amateur Wattmeter for S3.85
Jun
Jun
KICLL Aug
Tells you your power output from about 10 mVV to 5W. over the f^n^^e from 160 meters thcough 450 MHz. Principle is based on cotnpanson of an rf activated lamp with another of same bnlli^ce whose power input is known.
TrBfism (tiers
''QuaiEftr" QEF 40m D SB Transmitter WA5WWN Jaa
(QRP)
Postage Stamp Transmitter for Six KICLL Mmt
(QRP)
VFO Circuit K0HVK Jun
Tube-iype for BO and 40 meters. Em%y to build.
WA3JBH
QRP
CCW)
Cheapie 6-Meter Half Gallon
Jun
KICLL Jul
It works out to $12.&0 a quart, and features low-cost tubes, no screen voltage, no bias require- ment e, and no btower^
Goldstein
The ICmitter (CW)
Aug
VHF AM Transmitter tiling Low'Cost^ Tnosistors, Brubaker Aug^
tQRF)
KICLL
ICs for Amateur Use (IC Projects)
Oct
Solid -State Transceiver for 40 Meters^ the SST-1
W9ZTK Nov
(IC Projects)
W6YUY
W4AY1
So lid -SI ate Exciter (IC Prof ecu)
Your Second Linear (Power Supplies)
Il«c
TV
Slow-Scan Color TV W4UMF Jftn
The principles of color separalion. as applied to slow-scan tele vision $>-tlemf. Includes tpectral charts^ photos of ofl^the^air pix.
Bfbliofrmpbr t»f SSTV W4UMF
Complete directory of «rtie:les.
Jul
Improved Color TransntlHian — SlowScan TV W4UMF Jul
Applying ihe principles of color separation and synthesis.
WA6BJV
ATV: Getting a Better Picture
(Antennas)
Amateur TV is Easy
Aug
IC20JL [>ec
It actually costs no more than flOO to get starteil In the fun hobby of amateur T v.
ctnir>
K20JL
K9VXL
Amateur TV b Easy
(TV)
UHF 4EiOMiIz Mighty Mite (Receivers)
Dec
Jul
Log Periodic Antenna De^siu for VHF/ UHF W3DUQ ^^
WA6BJV
(Antennas)
ATV; Getting a Better Picture
(Antennas)
Atig
Aug
Reed Relayi for UHF/VHF Coaxial Switching W^vtiRY Sep
(Helpful HinU)
VHF
SiQlid^State Double- Band widfli Tunable l-F
„, Conre rtcn
KICLL Jan
(Eecciv. )
IISLO
TuMkfUnle Receivt* forVHF (Te«t Equipme tl)
Feb
High •^Performance Con^ ^rter for B WASHES Feb
(Receiver!)
Super-Sixer WAaAQS Mar
Many little modifications that win cut the resale value of Heath's Sixer, but which will *ur*ly make the rig work better.
Inexpensive New Semiconductors for the Ram
WATECRE Apr
(General Information)
7/B*Wave Mobile Antenna for 2 Meter FM
W2EUP Aps
(Antennas)
Postage Stamp TranimJtler for Six KJCLL May
(QRP}
ZL4TAH
The Sly Beam {Antennas)
Jun
Ele¥en*Element 2 meter Circular Quad
W4KAE Jtin
(Antennas)
KICLL
Cheapie S-Meter Half Gallon
(Transmitters)
Jul
VHF AM Transmitter Using
Low-Cost Tranilittors.
Bru baker Aum
(QRP) Log Periodic Antenna Design for VHF/UHF W3PUQ AtlC
(Antennas)
Low-Cost Oscillator gt Infinite Attenuator
for Tuning VHF Receiver*
KICLL Sep
(FM)
Brew 1 on 2 — a 2 Meter Coaxial Antenna WA0EWQ Sep
(Antennas)
DyComm's 15W 2 Meter Mlni-AmpUfler Staff Sep
(CW)
Differantiftl J -PET PreampEfieir W4KAE Nov
(Power Supplies)
2W 6 Meter Transmitter Using the
Heterodyne VFO
KICLL Nov
IQEP)
Semiautomatic F^ Channel Scanning WAOQPM Nov
(FM)
RF Appllcitlons ol the Dual^Gste MOSFET Sir Nov
(Receivers)
20Meter Mini transmitter for Repeater Use WB6BIH Dec
(FM)
114
73 MAGAZINE
Statement of Ownership^ Management
& Circulation
Date of filing: October 9, 1970. Title of publica- tion: 73 Magazine. Frequency of issue: monthly^ Location of publisher: Peterborough, NM, 0345S, Publisher: Wayne Green, Peterborough^ NM* Editor: same* Managing editor: Ken Ses- sions, Owner: 73 inc.^ Peterborough, N^H. Bond- holder: Wayne Green, Peterborough, N.H, Bond- holders, mortagees, other security holders owning or holding 1% or more of bonds, mortages or other securities: none. Extent and nature of circulation: Average number of copies each issue during preceding 12 months: total number of copies printed 72868, total paid circulation (mail subscriptions) 72251, free distribution 127^ total distribution 72378, of (ice use 490, total 72868, Actual number of copies single issue nearest to filing date: total copies printed 74285, total paid circulation (mail subscriptions) 73649^ free distri- bution 132, total distribution 73781, office use 504, total 74285.
Over 250 of USED EQUIPMENT on SALE
Be sure to check this list— over $20,000 worth of good used Receivers, Transmitters and Trans- ceivers offered at these reduced prices! While the stock lasts — let us serve you?
We have Signal One CX7's
in stock ready to ship
Sandy Jackson mgr — T.T.Freck W4WL
FRECK RADIO & SUPPLY COMPANY 38 BILTMORE AVENUE ASMEVILLE, NORTH CAROLINA 28801
B^E
IC Troubleshooting: A Matter of Temperature?
any hours can be wasted trouble- shooting IC equipment if you over- look one important characteristic. The popular Fairchild epoxy case ICs and the Motorola MC 700 series and HEP (dual in-line package) series are designed to operate between the temperature extremes of +59''F to +131°F (Fairchild) or +167^F (Motorola).
If your shack is in the garage like mine or at least unheated, you may very well be operating these ICs below their design temperature range during the winter months. Therefore, if your keyer, counter, or whatever seems to be operating errati- cally or not at all, take it into the house and give it six or more hours to attain room temperature. Then see if your trouble is still there. You may save yourself alot of time and frustration. (You may also have to buy a heater for your shack.)
Rich McMahon WA6IGU ■
advised by my lawvers that ou goons don't ever orooir
n
ev ov
I Insist that you print should be boiled in oil
Bottomless
I would like to take advantage of your most gracious inoney saving special 3-yeai subscription to 73, I still have a card you gave me at a Hamfest last year so 1 could get 3 years for S10» but I suppose it*s too late to use it now. 73 is still the best ham magazine on the market, and I am tired of having to run down to the dirty book store on Broadway in San Francisco's "Topless- Bottomless'' North Beach night club strip. You would be surprised, though, how many hams from all over I have met standing in that dirty booic store reading 73.
So please accept my check for a 3-year
subscription to 73, and come on out to California again when you can, and maybe you can stop in and meet some hams. They're always in the dirty book store reading 73,
Larry Johnson K7VZH
2051 Fremont Street
Klamath FaUs OR 97^01
Jordan
After attending the ARRL convention, and sitting in on several of your meetings, 1 felt that I should write you. First of all, may I honestly say that 1 found the most interesting part of tiie entire convention to be located in the 73 room on the 4th floor. In particular, 1 was fascinated with the slides of King Hussein and Jordan, and the slides of Y02BO, whom I talked with at Y02KAC in the late 195 Ox. As one of those who spoke with you when you operated JYl in Jordan, I sent my QSL card to Box 1055 in Amman and received a beautiful QSL card personally signed by the king.
I then decided to write again and request an autographed photograph of His Majesty suitable for framing. In the letter I told the king that I was a Social Studies teacher and that I would surely appreciate an autographed photograph that I could not only use for educative purposes, but also could frame for display purposes in my radio room, I really never expected an answer from such a busy and important person. About a
DECEMBER 1970
115
1
New!
Shown above: Model 3, for
10/15/20 meters.
Terminals: SO-239
$29.95 ppd.
MULTI-ANTENNA COUPLER
Eliminates Antenna Switching
Chang© bands without having to switch antennas!
Combme your antennas into a multi band antenna system while retaining optimum
antenna performance on each band! Coupler feeds any combination o^ antennas from a single transmission linet Saves
operaiing timel Saves coax and switches* Coypter isolates the Itne fronn all antennas but the one in usef Works with all types of antennas? Handles full legal power! Models available for any bands^ 2 to 160 meters! Weatherproof I
POST OFFICE BOX 468. OCEAN BLUFF, MASSACHUSETTS 02065
month later, however, the postman brought a large white envelope with ten stamps on iL On the back of the white envelope was a large gold crown.
Upon opening the letter I was amazed to find another QSL card signed by the king along with a personally autographed photograph dated July
k A
#.. -_ .
.•Sa .w ^M >Cj
25, 1970. Both the date and the signature were obviously in tiie king's own handwriting. 1 have framed the card, picture, and stamp section of the envelope and am enclosing a picture of it with thiji letter.
Vernon G. Dameron, Jr. KIDRN
265 Davis Road Bedford MA 01730
You have no doubt kept up with the situation in Jordan in the iast few weeks. According to the
reports I have heard tlie situation is bad, especially in regards to medical help, food sup- plies, and so forth. Perhaps someone else has already made this suggestion but I was thinking it might be helpful if we hams banded together and ail pooled our contributions for some help to the people in Jordan. I don't know who, if anyone, could organize such a program within the ham population but 1 would help if such a program is feasible.
The king was very friendly while you were there and it would be very generous on the part of the hams of the U. S. if we could help him in his time of need. I would appreciate yojar comments on this. Keep up the good work in 73. I am now a lifetime subscriber and am happy to be one.
Richard J. Malby GS9E
537-^44-0619
579th Ordinance Co.
APO New York, N. Y. 09035
Cairtotiflage
I just finished reading K9AZG*s article CAMOUFLAGE, 73, October 1970, and I think I can help him out. He was in a similar position to mine, trying to get a 50 ft mast and tri- bander up without letting the XYL know* I solved the problem by covering the top section of the mast with brown paper, adding" a few branches or so on it, and ''planted" it Every few months or so I added a section to the bqttonj to make it *'grow/' The tribander was painted green and covered with leaves. Next [ ''pruned'* the lower branches off, leaving only the beam. The brown paper eventually falls of, and if the XYL is at ail near-sighted, the system is almost foolproof*
Bin Ames WA9WBJ
1909 Karlin Dr.
St. Louis MO 63131
WAAS
Do you still issue the WAAS certificate? If so, will you please forw^ard the necessary forms so that 1 may make application in the name of the club w^ho sponsored and operated K6SB for the San Diego 200th bicentennial celebration. K6SD operated from October 1968 until October 1969 contacting as many hams as possible while celebrating San Diego's 200th birthday. During that year we were able to contact every state in the union, including Alaska and Hawaii, except Delaware.
So you can see K6SD does trulv qualifv for
"Worked Almost All States."
Robert R* Smith VVB60DR President El Cajon ABC
Yup, still available. Send 49 cards and $1,00 to cover costs of mailing^ etc* * . . Wayne
116
73 MAGAZINE
FM Coverage
I am involved with two repeater groups here in the Denver area, and am in charge of a project to set up a new repeater for the Colorado Civil Air Patrol west of Denver. Colo, Thank you for the excellent coverage your magazine has given during 1970 to FM repeater activities and tech- niques.
CUff Flatiarty WA* CKS
Box 1007 Littleton CO SOI 20
Inflation In a Nutshell
Popular opinion seems to be that the FCC fee hike is an inflationary move. Well let's get things straightened out The fee hike happens to be a noninflationary move. By making amateurs pay more for their licenses this will take money out of circulation giving hams less to spend.
The whole thing that starts inflation rolling in the first place is the fact that people have too much money to spend. This action of spending puts more money into the hands of the business man. When he gets more money, his workers want more money. When the workers get more money this cuts down on the profit margin of the business man. Seeing that he is making less money the business man will raise prices to equal what he was making before. And the cycle goes
on and on. Joseph F. Lutz WB8EAS
2951 S. Moreland Blvd Cleveland OH 44120
Delightful theory, but I don't believe it. I tend to agree with the economists who feel that histori- cally inflation arrives on the heels of the night shift at the Treasury Department when they print more money than is being taken out of the economy in taxes.
. , , Wayne
CBers and Hams
What's going to happen to American Private Citizens' Radio? That's how I refer to all civilian radio communications, chiefly amateur radio and CB, Today we are in the strange and destructive position of having two separate and competing civilian radio services. Competing for members, prestige, and frequencies. How absurd! Under this set-up it*s not only likely, but inevitable that conflicts wilJ arise, and it's not too difficult to see who's been winning the last few years. I don^t know how^ this unfortunate situation developed, completely.
I think Wayne Green came close to the solution a couple of months ago witJi the proposal of the Hobby Class license. This would move tlie CBers and their sliort range com- munications to 220 MHz. the least wanted ham band. Actually it was sort of a compromise, but ■the important point is: it would unite the two services into a single licensing and com- munication structure! 1 support this 100 per cent. But There are problems, 875,000 CBers won't relish the thought of replacing their equip- ment, just so they can call themselves hams. Most people already think they are!!
Anyway, how about a conciliatory approach to CB? They're not dumb. Most are friendly and
some are real sharp ops. If we can assimilate and
unite the two radio services, not abruptly but as fast as possible, then we will be able to provide better total service, and we will have a much more powerful position in the national and international radio structure. It won't be easy, certainly; but it appears to be the only reasonable solution that would not interfere with the distinct but related services we provide.
Mark R. Hansen WA9YEC
1701 West Eighth Street
Maxshfield WI 54449
Boo Boo
I have been receiving a tremendous ajnount of mail concerning two items in the August 1970 73 article on Log Period ics. Perhaps you could print a couple of items to straighten things out for your readers,
In middle columns of Table 1 (p.45), the third longest element length is L404 ft., not 1304.
Also, perhaps you could redraw Fig. 1 with a top view of one boom assembly only. My questioners aren't sure of the element attach- ments which are not clear in the figure. Try this idea:
TOP VIEW (one boom)
4 J'"
8
TO-
12
11
13
I hope you can find room to put this in 73 real soon to straighten people out.
BiU Nagle W3DUQ
RD 1 Box 188A
Honey Brook Pa 19344
Busted
My fictional story, *That Contest Craze/' in August '70 issue of 73 (in w hich I am not too kind to a young cop who slaps on me a $5 parking fine) has prompted members of the police force here and abroad to write and say, ^Wiiy send us up.. .Don't we have enough trouble with the teenagers without an oldie like you getting on the wagon?"
Constable First Class Gerry Letford ( VE3FTV) has added another S5 violation fine (No,l 10932) for illegally parking mv Big Red Kangaroo car in his hometown of St, Catherine, Ontario ^ and if unpaid a warrant follows.
Another Constable ham mate in the north of my home State has invited me up for a few days. He guarantees to land me with something heavier than a parking fine.
In the local village here, the sergeant (who borrows my 73 mags) booked my son and said, ^Vd prefer to give this ticket to your OM.
I
+?
DECEMBER 1970
117
T A GIOBE?
Particularly when these fabulous Hammond globes (the best in the biz) are available at our LOW PRICE.
13" inflatable globe {guaranteed, by the way), regularly selling for $15, now special, while they last, ONLY $10.
13" lighted globes, reflularly $25, now ONLY $15. We have a few of these in stock and when they are gone, that is it.
RADIO BOOKSHOP Peterborough, New Hampshire 03458
DUAL GATE MOSFET
PRE-AMPS
ANGUAR
^
««U«fa.Ai¥ h*l AWAi
Its,!** %■
to 175 MHz. $21.95 ppd. to 300 MHz. $25.95 ppd.
NEW FOR 1970! The above models now have rf gain control.
For 300 to 470 MHz
See Model 202 in our catalog.
• AiraTlabtft from S MHi, to 4S0 MHz, Bdndwldth ts approximately 3% of frequency.
• Volfag« Odin 30 to 40 01 depending on frtqutncy.
• Two Dual Oote MOSFET amplifitr stages with each having a tuned Input and tuned output. Each Dual Gate MOSFET It actually an fntegrated cascode cir- cuit thui giving you 2 catcode circuits equivalent to 4 triodes.
• Except Jona fly low noise (2,5 Dfl at ITSMHx.), great- ly reduced crosi modulation and 10 times the dy* fiamk range (iigna] handling capability) of the best bi-polar traniistori. Alio luperior to preamp$ using junction FETt and Single Gate MOSFETs.
• Internal connections for high Impedance AGC or manual qain control if needed.
m Type BNC input and output receptacles for minimum loii at UHF. Standard impedance is 50-75 ohms.
• Carefully tuned at our laboratory with sweep genera- tor and oscilloscope for the best bandpass character- istic.
• Full wave UHF diodes protect input transistor.
• Operates on 6 to \h volts DC, S to 15 Ma.
New York Cify and State residents add local sales tax.
VANGUARD LABS
Dept. H 196-23 Jamaica Ave., Hollis, NY 11423
Fve already paid the $5 fine that pi nh ended cop put on me in the story. If much more of this keeps up, the check for it will be busted. So please, fellers, lay oft I know when Pm beat, FU
go quietly*
Alan Shawsmith VK4SS
West End
Brisbane
Queensland
AUSTRALIA
Blunders^ Blunders
I still think your magazine is the greatest for the ham; have continued to think so ever since 1 subscribed very early in your magazine^s career. Keep it up.
I want to be an old stinker and point out a couple of technical goofs in Sept 73, First, a little layout problem on page 30. Figures 1 and 2 are obviously interchanged, OthenAise, I have to suspect that it will work fine. FlI soon know; I am in the process of converting my old Heathkit grid dipper, since most of the key parts can be used.
Now, look at page 26 (same issue). That voltage dropper has something goofed up on it. The way it is drawn, 01 will never conduct Either Ql and Q2 must be changed to cor- responding NPN types or the input and output polarities must be switched (with a corresponding reversal of the zener diode). Otherwise, it seems to be a good scheme, within the limitations already mentioned by the author.
HotYy K. Lotie. W7CQK 220 Seneca Ave NW Rentont Washinston 93055
Yoxx'tb right in both cases, Here^s the correction for the p. 26 gooL
>
20A
JN I0-I6V
>
Q2 2N3635
OUT
6.5-T5V Q-ISA
iN;76I9 B.2V
^
. Ken
118
73 MAGAZINE
Objectivity
This letter has a dual purpose. As long as i must write to you, I want to express my deep satisfaction with the policies of the mag* 73 mag has reached a height of editorial freedom 1 have not encountered even in Time or Newsweek. 73 allows each of its editoriaJists complete freedom while it has also opened its pages to critical comment and occasional discussion. Your head- ing to the 'Tetters'' shows that you are inter- ested in the irate and sometimes ignorant views as well as informed, intelligent ones,
Jim Altman WAVUWL/2 Box 6136, River Campus Sta.
Rochester NY
Politics, Religion and Sex
I have been an amateur for 8 years now and have become somewhat sick with the regular routine in which a OSO is supposed to be carried on. A few^ months ago I began to experiment on 40 meters in the way of trying to make a OSO more meaningfuL I have been told by many people on the bands that politics, religion, and sex shouldn't be discussed in a QSO, but my personal feelings on this subject is different from that of the majority of hams. We are a society and almost a big fraternity of people with different interests and thoughts and if we want lo get to know each other better, we should learn by our QSOs how each of us thinks. In the process of my experiment I found many ama- teurs that w^ent along with my ideas. We dis- cussed topics ranging from Vietnam to women's Ube ration. But it seems that whenever we would get into a sticky subject one of the members of our society would come on to the frequency and throw a carrier on, whistle Dixie, or sing the Star Spangled Banner, as the case may be. As other groups on the amateur bands have found, when- ever someone disagreed with what you are doing - no matter if it is in the form of breaking the norms of the frequencies or conducting a net such as the one conducted by the students - choice stations show their inteUigence by throw- ing all sorts of interference on the frequency. These kinds of people don't deserve the privilege of operating amateur radio,
I d like to relate a story to the readers of 73. 1 have a very good friend on 40 meters (K2PJG)< Bob is crippled from .the waist down and is confined to a wheelchair. He is very active on ECARS and does an excellent job as monitor control. He has frequently been the recipient of all kinds of insulting remarks and has almost given up hope on the bands. I happened to be on the frequency one day when one of our fellow hams came on and started to insult Bob- When 1
broke in, the fellow insulted me as well. After the OSO I ran into Bob and he asked me if 1 knew of anyone who wanted to buy his rig, I have also thought about selhng my 40 meter equipment
Going back to my original topic of sex^ religion and politics, I feel that the amateur bands might be more exciting and challenging to hams if some other hams would try my method of learning and discussing the problems of the world today. And maybe if more of us discussed problems and issues of the world and the amateur bands, there might be less conflicts and dissatis- fied hams today.
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If any stations wish to discuss the topics I have mentioned, just drop me a line with a sked and if possible we will have an out*of-the- ordinary QSO- Which is pretty rare to find these
days.
Jim MiUner
116 Comw^aU Ave.
Trenton NJ
Incentive Licensing — Fro and Con
The following letters are representative sam- ples of letters received in response to 73*s incentive licensing questionnaire. Those opposed to IL far outnumbered those for; thus^ we cannot reprint ail of the letters against the principle, even though the 'Tor" ietters reprinted here are the sum total of all letters backing incentive licensing we received from amateurs as of 1 October^
Pro
Anything as worthwhile as amateur radio is worth the time and effort involved in learning the code (20 wpm). My gripe is that you may interpret my responses to your biased advantage, so I have only answered the questions you will have difficulty biasing.
Jerry Poi;>e W4YRY
5112 Cedarwood Dr.
Raleigh NC 27609
1 am for incentive licensing, but I think the principle should be reconsidered, perhaps favor- mg new bands as an incentive.
Jack Petree WB40VX
Box 5175
Roanoke VA 24012
The only answer I can give to anyone op- posing an incentive of any kind is that he must be
classed as too lazy to want to better himself and (improve) his knowledge*
BiU Cooke W3GBB
427 Grain Hwy NE
Glen Burnie MD
I favor IL, but all amateurs who held the original Class A license should be issued the Extra automatically. They earned the top benefits, so why take them away?
Paul Fritich W3HHC
11 Oakleigh Rd.
Allentown PA 18104
I have Extra class,.-took many days of code practice but consider the time well spent. Some people will never pass the Extra, but most have the capability to do so if they really want to.
Bob WB9ABT
Rt 1 Box 269
Lake Zurich IL 60047
Twenty wpm is the speed of the expert and Extra class should be expert. Incentive licensing gives one something to strive for, keeps the mind strong. Without (such an incentive program) some people would tend to grow stale. I think incentive licensing should be as the name implies - an incentive, something extra - not something restored that was previously taken away,
John Mrozinski WB2EX1
155 Eckford Street
Brooklyn NY 11222
120
73 MAGAZINE
Con
*lndian giving" - that is, offering something in exchange for a demonstrated proficiency in certain skills then revoking that something — is a very poor way of creating goodwill,
M* W, Macy W9UM
Rt4 Syracuse NY 46567
I want to see ham radio grow - why not give it a chance? The Generals should be given back all the bands taken from them. If incentive is necessary, lei the Extra have a small part of one band for phone and code. It is not hard to see why so many people say to hell with the FCC and the ARRL and go to CB where they can have almost as much enjoyment and can work the country without all this nonsense!
Roy Gunter K9GNK
1637 Rock Spring Dr.
Alton IL 62002
In spite of the fact that I am against IL, don't get the idea that I do not study and strive to improve my knowledge of amateur radio. It's just that I would rather see us go back to the previous system.
Richard Weiner WA8WMC
Rt 2 2660 Lincoln Ed
Ludington MI 49431
Hams in Alaska are under a particular hard- ship with respect to upgrading because of the tremendous distances involved in getting to Anchorage (where exams are administered). But I am against IL regardless of where I am located. Thanks for standing up for the majority of amateurs, who are against incentive licensing.
Jack Bone KL7GKY Sitka, Alaska
I'm certainly glad the FCC doesn't have
anything to do with my birth certificate, mar- riage license, bachelor's degree, etc., where re- vocation of privileges could really be serious!
C. H- Smith K»ERL
611 Wesley Dr.
Farmington MO 63640
Granting extra privileges to a few at the expense of the majority is hardly justifiable. The ARRL never proved it was speaking for a majority - surely the FCC must know that!
Theron LriOie V\^A2UrG
190 Henrietta St*
Rochester NY 14620
I don't favor IL the way the ARRL presented it and as far as I am concerned they can go to h— with their incentive licensing*
John PerUck WBQADO
3400 Edgewood Ave North
Minneapolis MN 55427
Thanks for giving us hams the opportunity to express our feelings about IL. I do not favor the principle, I can see no useful purpose in knowing how to send and receive CW at 20 wpm unless someone simply wants to be a faster operator. The entire mess has dealt a severe blow Xo amateur radio; I sincerely hope the FCC will reopen the whole matter for reconsideration,
Kenneth Cregar K3KBG 3411 Stoudt's Ferry Bridge Rd
Reading FA 19605
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The wortd of transistors and ICs makes ft possible to have a complete kilowatt all band ham station in one small unitl Not much larger than normal transceiver yets runs solid 1000 watts. Extremely sensitive, processed speech for maximum umph when wanted, everything you need in one Httle package. Only tubes are driver and final.
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73 MAGAZINE
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My low opinion of IL h colored Uy the pcrsonul blight of downgmding after more than a haltWenturv of Eood bchuvjor on the ham bands. It all seems so unnecessary. I would think that old experienced people could be let alone and not subjected to such indignities as have been dreamed up from time lo time by the ARRL. I cdui be mad at tlie I 'XX\ who - I am sure - simply fell that Newjnglon could hardly be wrong. As a matter of fact I recall that the t^CC turned this thing down some years earlier on the basis that it would lead to an elite establishment with a sLtpposedly democratic government put in the anomalous position of enforcing a caste system.
R* A. Hllferty W2HEY
Box 409 Miller Place, Li; NY 11764
I hope that someday this incentive licensing tliiniz can be rehashed,., Now I have a General license which restricts me to certain portions of the amateur bands ...and ihc ironic thing is that EMias seem to operate in the General portion of the band.
John Stagnaro W6MAB 2305 Panorama DrXa Crescenta CA 91214
I don't have any idea how much influence you will be able to swing in your effort to convince I CC that this whole thing was ill- advised, but if 1 can help by sending you my opinions, then it is the least I can do. I am against IL. and would only be for a 20 wpm requirement if use of a typewriter were optional.
BUI GuUedge W9LWG
Rt 3 Box 56
Phillips WI 54555
r'lnally someone uses a magazine to get 3plnions on the IL program on a national scale. I lopc that 60% of votes is not the losing percentage (see p. 9 QST Sep 1970)-
Harris WBSBTV
It's not incentive licensing when the FCC narrows and removes frequencies so as to load the remaining spectrum with nets and phone patches. And cramming ARRL activities into the highly congested remaining portions of the bands is idiotic.
R. W. Daniels K^KYH
Rt2 Box 212
Aitken MN 56431
IL was supposed to be a step above General; instead, the space between Novice and Lxtra was split in three rather than two. And the present Genera! is not up to his predecessor, who knows half the Advanced test from his old General exam. Thus, either increase the exam require* men 15 for Advanced or throw it out! Let those who know the code at high speed get credit for iU but let the chap who doesn^t know it demonstrate some alternate ability. If the FCC insists on restricted privileges, how about power? New Generals to get 150W, maybe Advanced and Lxtras could get the full gallon.
Joel Look WIKCR
Box 25 Claremont NH 03743
122
/3 MAGAZINE
Radio Interference Reduction
Some hams try to purchase new electric razors for neighbors in an attempt to reduce existing razor QRM. However, attempts I have made to find any razor thut is treated to reduce ORM, have not been successful at dealers, rinal- ly, I received a reply from a SEARS buyer who said that their 92737 razor (Austrian) claimed to be so treated. I had read many instruction sheets with new razors without seeing any such com- ment on other products,
[ think that the magazines should be willing to mention this, and to Ust products that have reduced QRM,
Note Public Law 90-379, 90th Congress, which amends the Comm. Act of 1934, permit- ting FCC to regulate the interference potential of devices. QST published a request for letters to FCC suggesting items heading such regulation.
I think that amateurs should encourage FCC to bring out at least a general requirement that household appliances be treated for reduction of QRM, and especially that tiicr mo stats be treated to prevent "hanging" of the contacts in a sparking condition. Also, essentially all light switches could be so treated - which 1 under- stood was required in (ranee 35 years ago. I encourage the magazines to stir op a little thought on the use of the Public Law to reduce QRM.
E, H-Conklin K6KA
402 Olivet a PL Box 1
La Canada CA
Sparkling
Keep up the good work with 73 Magazine. You have a good following at KEYN. We have four active hams on the staff. Our News Director K0WTM has his two young sons hcensed as Novices. Fm now working on the general man- ager and his oldest son and hope to get them tickets. The station supports the W0DKO re- peater with tower space and power. You can imagine the response a CB organization receives when our program director (W5MGC) takes the call. Our weekend disc jockey and engineer WA(JTHQ is a senior at Wichita North High SchooL Oh yes, we also operate a station WA0ZZX on 2 meter FM from the KEYN studios.
Anyway we here at KEYN heavily support Amateur Radio and 73 Magazine. Each copy I receive from my new life subscription is well digested before I safely file it away.
Larrv Waggoner WA9QPM KEYN, 3357 W. Centra]
Wichita KS
Lackluster
I keep reading in the letters column tlie bouquets that come your way regarding the magazine. I started subscribing some time ago and thought the same way - even got the back issue Gunsmoke and enjoyed them all. However, in the last year or so, it seems to me that 73 has lost its sparkle and is becoming a lackluster publication, 'aybe it's me, maybe not. Anyway, it seems to be turning into a specialty-type maga- zine geared for VHF-Novice interests. Of course, maybe this is what you want.
I wonder how much the advertiser influences editorial policy? I have yet to see an article saying that a particular piece of equipment is a piece of junk. These *' reviews" in all the maga- zines claim that anything is the biggest thing
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SAMPLE B'2i 32 transistors - over lOO resistors - capacliori — over 15 t$iQ09% — compiflt^ With board.
GROUP c - Actual Value $50.00 - PEP Pike $4.50
SAMPLE C-1: 22 in-hne KCt - over 75 diodes — 20 trans. — Over 50 resfttors — cap^itors — complete with board.
SAMPLE C 2: 22 m Ime LC.s
Over SO diodes - over SO resist — Cftpecnors - carnpieie with board
LIMITED SUPPLY! Hurry and place your order for the best buys!!!
NO SALES TAX— WE PAY POSTAGE
PARK ELECTRONIC PRODUCTS
P.O. Box 99, N. Salem, N.H. 03073
since ttie ice cream cone. For instance, I had a Swan VHF- antenna, made by the Stockton man, that tlew apart in the wind, mainly because of insLifncicnl hardware, I wrote something about it and sent it in - no responiie. Wrote another and sent it to QST - and got a nice letter from the technical consultant that they only checked the 2 meter, not the 6 meter.
I believe there is a little more than a year to go on my 73 subscription and I frankly don't
intend to renew it for a lack of interest in the contents.
Paul Schuett WA6CPF
A lot can happen in a year
. , , Ken
Easter i&Land
On March 20, 1970< I was licensed to operate my amateur station from Easter Island with the call sign: CE0AE- I have been operating with this sign since May 20, and work all bands, CW and SSn. Only twice have I operated above 21,400 on the 15 meter band. My name is ''Dave", my QSL Manager is WA3HUP, and my QSL card is red and white. I do NOT have an APO address. I have received fewer than one QSL card for every three contacts, and would appreciate more. My usual frequencies are: 28,550 - 21,360 - 14,332 -
7030 - 3530. Fr. David h. Reddy, O. F. M.
Parroquia Isla Be Pascua, Chile
Flamboyant
In my opinion your increasingly flamboyant lieadlines lower the appearance and appeal of 73 to the level of cheap trash like CQ and PE, and waste space that could otherwise be devoted to several more pages of articles.
73 is not Movie Mirror or True Confessions* For examples of proper headlines for a technical
magazine sec July QST.
R- B. Kuehn W(^HKF
St, Paul
MN
The Good . , •
A friend loaned me the June and July copies of 73 magazine- They're the greatest. 1 saw your notice about a bundle of back issues of 73 for $6-00* My check's enclosed, Hope Vm not too late,
Vm in a Code & Theory class. As soon as 1 get my Novice ticket, Vll subscribe to your fine magazine, Can*l see how any amateur can be Without it.
My sentiments are with your point of view on every issue in these two issues of 73. Keep up the good work.
JijTi Edwards Chiilicothe OH
. . . and the Bad!
In your recent letter asking me to renew my subscription you said that you were worried that 1 would not renew my subscription. Well Gentle- men I would like to say tliat you had better start worrying for your publication has become sheer garbage in the past 9 months. If you want to sell your mag, you had belter try the funny farm for they are the only people that might find your magazine of interest!
Lloyd Dotese Jr, WN5ZZF 220 E, Maple Ridge Dr.
Metaire LA
124
73 MAGAZINE
Mideast
Wayne's helping Hussein out was a true gesture of gentlemanllness in the true ham
spirit I guess you just have to remind some people that you are not a discriminating person. To me, Hussein is a person who has same common interest as myself, ham radio, and this ham fellowship (to me anyway) is not affected by either race, creed, color, religion or place of birth. As for those childish kids who say, ''OK, now go to Israel or you're anti", let them go somewhere!
Wayne has befriended a great ham for all of us. May 1 remind some people that Hussein has understandable troubles of his own and he gets on the bands (like most of us, anyway) to relax and take it easy. You must forgive some of us, Hussein, for those pileups, but you're still a rare one for many of us. Take it easy and as long as you are a member of the fellowship of hamdom, I won't yell at you about the Mideast, My feelings remain much the same for Wayne. Keep
up the good work. Times, they are a-changin\
Chip Cohen WAIJHO
Ham Critic
It Strikes me, Wayne, that the technical quality of the articles is slipping. "More Notes On Diode Stacks'"' must have been written for the Novices or the XYLs. Maybe my interests just were not touched - we'll let it go at that.
Brown (W9HBF) must not have listened recently on CB; further, he should keep track of what hams do in emergency communications, I could have enjoyed the Sept. issue a lot more if this article had not been in there! QRP, yes - CB, no!
WB41TN could have something real useful going with his file-box series if he handles it correctly^ and produces some really handy gad- gets for the shack.
One has to question the use of the word "waveguide*' in KICLL's attenuator article. Two coffee cans soldered together will do the same job only it\ called shielding!
There are a lot of pluses in the Sept issue: W7PUG's CW ID Generator, WA2IKL's IC Testers J K6MVH's Antenna Separation, and Douglas's Relay, etc„ The study guide material is always excellent. Too, WB6YVT's 2M Converter looks good.
It is noted that the number of advertisers seems to be picking up, Wayne, Anyway, I guess you know that I read ''It" from cover-to-cover. Thanks.
73's Carl K2IA
10-16 Burbank Street
Fair Lawn NJ
In regard to the letter by Ernest Robarge, who says he would make a good ham except he can't pass the code exam, it really made me laugh. Over 600 hours of code and he still can't pass it. I took 16 hours for my Novice and passed with no trouble. So as far as code goes Pm okay but I can't get enough theory to pass the General. But I'm still going to keep on and not write to 73 to teU the world what a fool 1 am.
Bob Mackey WN9ERZ
Somebody's sure been writing letters over your signature, , . . Ken
Special-Purpose Receivers, Panadapter
RAK-7 complete, w/dwg, 15-600 khz TRF , . . J25.0Q RFI (Noise 8t Field Strength Meters) are basically radio rcvrs. TS 587/U (no ant. accessories) some- what modified as an RFI Meter. OK as rcvr, 15-400 mhz, $195.00, Ferris #32 A, ;15-20 mhz, complete, OHC w/charts & book, $175. #32B is later model, $275'. Navy OF1, .15-17/2 nihz, OHC, with book, $75, MORE PR0FESS10MAL setups, to $4000.00, Stoddart and Empire Devices: ASK! Also ask about SPECTRUM ANALYZERS, if interested,
455 kh^ Panadapter, various models, all 100% ^ ^_«
OK, all with instruction books 3/.DU
\N\NV Comparator Rcvr has meter to zero beat your signal with WWV switched tuning at 2^3/5/10/15/20/25 mhz. Beckman #905R sold for $650. From us -
OHC and with book * /3.UU
Hi Sensitivity Wide-Band AM/FM RCVR
3^_1000 MHz: AN/ALR-5 consists of brand new Tuner/Converter D\/-253/ALR in original factory pack and an exc, used, checked OK &i grtd. main rcvr R-444 modified for 120 v, 50/60 hz. Packed with each tuner is the factory checkout sheet. The one we opened showed SENSITIVITY: T.l uv at 33.3 mhz, 0.9 at 133 mhz, 5 at 538 mhz, A'A at 778 mh2, 7 at 1 ghs; w/book, 8t pwr-input plug, all for .,*,,...,..
275.00
R-390/URR Rcvr: Collins xtl-zero-beating, drifttess receiver, grtd 100% perfect , .
R-390A/URR has mech. filters, grtd perfect , , .
795JD 995.00
ReguL Pwr Sply for Command, LM, Etc.
PP'106/U: Metered, Knob-adjustable 90-270 v up to 80 ma dc; also select an AC of 6-3 v 5A, or 12.6 v 2>iA or 28 V 2/2 A. With mating output plug & all tech. data, Shpg, wt 50 lbs ......
Bargains which the above will power:
LM-{*) Freq. Meter; .125-20 MHz, .01%, CW
w(th serial-matched calib. book, tech, data,
plug,
Shfpplng wt. 16 lbs ,,*«,, . . .
Same, less calib. book ...................... 27.50
A.R.C. R1 1A: Modern Q-5'er rcvr 190-550 khz. . . 2.95 A.R.C. R22: 540 — 1600 khz rcvr w/tuning graph . 17.9& A.R.C. R32; 108-132 mhz rcvr 32.50
19.50
or AM, matmg
.57,50
IF YOU DON'T SEE IT HERE, ASK FOR IT! But don't ask for a general catalog. . .we believe that is nonsense in surplus. . .we get new things in almost every day I WE ALSO BUY! Bo iell us what you have, condition, and your asking price*
R. E. GOODHEART CO., INC,
Box 1220 GC, Beverly HiJIs, Calif. 902 T 3 Phones: Area Code 213, Office 272-5707
Thousands of IWts
NO FLIERS
DOW TRADING CO.JNC.
ELECTRONIC PARTS & EQUIPMENT
1829 E. HUNTINGTON DRIVE DUARTE, CALIFORNIA 91010 357-3763
SCOTT'S QSL SERVICE
1510 Lynnvfew Houston, Texas 77055 USA
Fact! We forward cards anywhere (except betwet^n continental U.S.) for 34 • We offer Stateside and DX roanae^^ service at an unbelievable low price ♦We keep an up to date day to day Ust of QSL managers to which we forward cards along with SASE^ supplied Dy us*
Reason far usine our service: There is no cheaper way to QSL than us • No easier way to QSL than us # You do not have the time or money to keep up with and hunt for QSL managers and QTH's for every station in the world, we do — it's our business.
WRITE FOR FREE INFORMATION TODAY
DECEMBER 1970
125
.>, • •;• -vr. * ; ■■x..:;'
A7000
A7001
A7000
Contains cadmium sulfide photocell, potenti- ometer, relay, lamp & Fairchild 2N2657. 1-5/8" x 1-1/4". Originally used as exposure meter control. Complete circuit diagram & application data . 1.25
A7001
Contains cadmium sulfide photocell, 2— 500J2 vari- able resistors, 8i Fa ire hi Id 2 N 2240. Presence or absence of light changes bias on transistor. Useful for all types of alarm & light sensing devices. Complete with diagram 75 ea.
3 A7000& 3A7001
li > I
.5.00
aniriiEii man specims
Ag082
Honeywell Computer boards, 4%" x 12", Transis* tors, diodes, zeners, capacitor, precision resistors, heat sink, trimmers, etc, 2 different boards , 1,00
A9093
Honeywell Power Board contains 4 2N1137B 80 watt PIMP power transistors, 8 Top Hat diodes, 8 precision resistors & 41 N 642 diodes stock, 1,25 ea.
A2040 Sangamo or Pyramid 4'A*' x 1%" 4000 MFD 50V .50 5/2.00
A4016 FET Field Effect Transistor TO-18 25V Source to Gate N Channel 50 5/2.00
A4017 Tunnel Diode similar to 1N371 7 -50 5/2.00
$1.00 FREE WITH $10.00 ORDER MINIMUM ORDER $3.00
Lots of other items — send for free flier: All mer- chandise fully guaranteed^ Please include post- age: excess will be refunded.
A DELTA ELECTRONICS CO. BOX 1, LYNN, MASSACHUSETTS 01903
SLOW SCAN TV
Now for the first time din S.S, monkor designed for your own custom instaMation. Available m 3 econonay kits.
KIT 1 PC Boards only (2 req.) ea. S 9.95
KIT 2 PC Boards {Both) Ei all parts (unwired) KIT 3 P,C. Boards Wired & tested Power Supply Kit-No chassis Complete Monitor- tn handsome cabinet
All k KS lube lypewith instructions, CRTs^ Pow^r Supplies, av^tl cabinets not included
E.K.Y. VIDEO VISION CO. Box 15, Stockhofm NJ 07460
$ 80,00 $125.00 S 54,95 S298.00
SCHEMATICS AVAILABLE FROM 73
$1.00 each
ARR-1S from June 1965 73, page 78. ARC-27 2M Guard Channel Receiver, SSB Transceiver, N6v- 1961 73, page 23. R508/ARC, June 1965 page 48, before & after. 73 Magazine, Peterborough, N.H. 03468
\ if ^ „ !
.€t?
Q..
©
■rKn — ^^-t-ml f
'®^ ® ^ ^
G:R, Frequency IVleas*
uring Equipment
Type 11 05 A
This primary frequency standard will measure from 1 Hz to over 100 MHz with an accuracy ot one cycle up to 10 IVIHz. This IS a laboratory stan- dard used primarily for calibrating other equip- ment. This is the last word in frequency stan- dards. Send for details. SPECIAL ..,.$1935.00
DGP COMPANY box 431 Jaftrey, N.H. 03452
126
Atlanta Repeater Problem K6MVH's recent editorial on the Atlanta repeater was an accurate description of the situation as it now exists in that area. I lived in Atlanta for over five years and still maintain my **4*' call because of frequent trips to the Atlanta area. The group which originally began construc- tion of the Atlanta repeater consisted of serious amateurs with a desire of promoting the growth of FM activity. This group was gradually over- taken by a group of ex-Army MARS operators who, atter a change in command of the MARS group, became dissatisfied with the Army MARS FM repeater program. This group then used its political and financial contacts to establish the Stone Mountain repeater. This group has never liked to have its inner circle questioned, even while affiliated with MARS.
There still remain a few stations who will work transient mobiles. However, the control station will not work anyone with what he calls a "Yankee Brogue," which includes anyone who does not come from the 4th call area. I have been called down by that station because he cannot understand anything but deep southern drawl!! On my last visit I made the statement on the repeater that the Atlanta area was getting a bad reputation in FM circles. This stirred up some comments, both pro and con. However, it did serve to wake up some of the operators in the Atlanta area, and, for several days every transient operator was worked by several stations, Thus^ I hope that Ken's editorial did some good.
Glen Zook K9STH
818 Brentwood Lane
Richardson TX 75080
73 MAGAZINE
HIGH VOLTAGE
1 AMP ifO«<
PtV
D 2000* D 3000 D 4000 O 5000
aeooo
D8000 □ 10000
SALE
SILICON RECTIFIERS
1 AMP 800 P IV
SILICON RECTIFIERS
ir Avotanche Type i^ Micro Mtniafur^ * Up to 2 Amp%
for
3 AMP
1000 PIV
SILICOH RECTIFIERS
4 ^or $2
RAYTHEON I 5U4 SILICON I
$J98
1 AMP 5$1
lOOOPIVfor I
SILICON RECTIFIERS
FAIRCHILD LINEAR IC AMPLIFIER SALE
An>f 3 - 10% Diicountl
D«tcripljon Each
Wide Band DC 1.49 RF-IF Amp 1 .25
Operational Amp 1 .49 Hi-Sp«ed Diff I.19 Dual Comparator T.49 Freq. Comp. 709 2.50
6 AMP SILICON FULL WAVE BRIDGES
GIANT SALE ON NEW TTL TEXAS & NATIONAL ICs
*^/Spec SheeH Any 3 ^ 10% DhcoonN
Typ#
□ SN7400N n 5N7402N 3 SN7404N U Sf^74lON 3 SH742QH 3 SN7430N H SN7440N U SN7440F J SN7441N J SN7442N J SN7447N
n SN7470F
n SN7472N G SN74r3n
n SN7474N
n SN7475N n SN7476N
D SN7483N n SN7490N D SN7492N J SN7493N ~2 SN749SN Code: F
I ■«*#'A-«^« i'-a ■'«
■i^iPfPi
D«scrtptton
Quad 2 Input Nand Gate ,
Quad 2 Input NOR Gate .««... Hex Inverter
Triple 3 In. NAND Gate
Dual 4 In, NAND Gate ,„.,„.
8 Input NAND Gate
Dual 4 In. Nand BUFFER
Dual 4 In. Nand BUFFER
BCD to DeciTnal Driver
BCD to Decimal Decoder
BCD to 7-Seff.
Decoder-Driver
J-K Flip Flop .
J-K Master Slave Flip Flop
Dual J-K Master Slave
Flip-Flop
Dual **D'* Type Edffe Triggered Flip Flop ...
4 Bit BisUble Latch
Dual J-K Master Slave
Flip Flop -
4 Bit Binary Full Adder Decade Counter Divide-by-twelve Counter .»»** 4 Bit Binary (divide by 16) „ 4 Bit Right & Left Register .. — Flat Pak, N — Dual Inline
SALE
■*-><■-« ra V4«B#i! ■■■■ « Bi^tf ^
h«d^4VB i ■■■-l-»l-l-...v*t*#l-W-l-V
k * 4 HA i^%44#«»i, ,fl _ .
■ i-«*qM44«*BaH
iihklllhiR.q|.
■ PII-1-" ■! P-l #*«*■■■■
1.49
1.49 2.95
D lot Catalog on Fiber Optics, MPs', Semis, Parts
Terms: mid post;ige. Rated: nel 30, cod's 2^*^/r Phone Orders: Wake/ield. Mass. (617) 243^3820 RefaiU 211 Albion, St., Wt^kpfieid, Mass.
POLY PAKS
P.O. BOX 942 A lynnfield, Mass.
01940
WORLD QSL BUREAU
5200 Panama Ave., Richmond CA USA 94804
PLAN I. We foTtvvard yotur Q^Lii (please arrange aiphab^'ti- caliy) to any place jn Worlds including all forefen counuries^ and to or wtthui USA, Canjjtda, cind M«;xico, for 4V euch.
PLAN 2. Ydu usfr our ip^cuJ t^g form and send us a copy. We supply QSh—mmkc out QSL^a^bver QSL, aU for 8^ each.
HHb
EVICES
Hot C«rTii* Diodn: HP^8O0 90i. 12/SlO.OO Maichnd by HAI 4/M.^5
ICj: f ^ L 900. 914. .„ , 60^ f ^ L 923 90^
MRTU MC790P. MCS90P S2.00, 10/$19,50
MC734P. MC7e9P. MC792P, MC7Z5P Si 05. 10/S9.50
AlsoA^aMabler MC7g8P, MCS80P. MC7e7P, MC97^P OP AMf^ SH72713m (DlPl. SN7270eL itOBJ . . . $1.B0. 7/SlO.OCi
TOROJOS; Indiina OBfwnlCF 102-06, CF 102^1. Cf10t<»2 Gtk
CINCH iCiCH*iti,14^Dir.riCS. Md HAL DEVICES
AfM Poftagt, wnd for aim(ti«t« iret. Box 365 L. Urbana, Illinois 61601
PROFESSIONAL REPAIR AND CALIBRATION SERVICE
SpeciaJut in the maintenance and calibration of school 'i electfonic -laboratory ffquipmentp teit equipment and amateur equipment Prompt fenricf by holders of amateur and commercial FCC Licenses. Wri(e for shipping inttmctions.
PANTRONICS OF VIRGINIA, INC-
&e08 Ed»li Rd,
Alexandria, Virginia 22312
VHF-UHF
CRYSTAL CONTROLLED CONVERTERS Model 432CA — *64<S5 -^
• Silicon • BuiLt in
Available for 50 through 432 MHz FET Clrcuftrv • Silver Plated Circuits ac Pouver Supply * Wfite for detailed Data I A (U F I Shirats or order direct, fpecrfying i-f frequency.
ACij^OATr\ c P.O. Son 112,Sycca5yiina, rtfJ07876
LABORATORIES teiephon* ?a 1584^521 1
LARGEST ASSORTMENT of BRAND NAMES
You can save enormous amounts of money while choosing from a complete fine of trans- ceivers, receivers, transmitters, etc, WE HAVE EVERYTHING IN HAM GEAR
SAVE MONEY ORDER BY MAIL CB Radio Co,, Inc. se Aspen Rd.
Swampscott, Mass. 01901 617-598 97 QQ
l^l^^ CONTROL CENTER
FOR SWirCHlHG SYSTEMS IN PUT /OUTPUT
3-ChitnneIat Vs0, push switches to aeiftit TV camernst monitors, RF antenna systems. "M" type connectors on reur side. No impe* diiLnce worries^ Mitny audio model* too. LawrenceV Ma. 0i842S>i*PP^d postpaid.
A I m^''^^^' ^"^ 134SS
WE PAY HIGHEST CASH PRICE
for Electron Tubes & Semiconductors
Immediate Payment on Unused Tubes
H & L ASSOCIATES
Elizab^thport Industrial Park
Elizabeth, New Jersey 07206
(201) 351 4200
VibropleX
ENJOY lASY, RESTFUL KEYING
$21 .95 fo $43.95 THt VfBltOPLEX
CO.. INC, 833 Broadway, New York, NY 10003
DECEMBER 1970
127
h
No on© likes to go into a store without buying somethmg, right? It Is the same with these information requests. You will be *ixpected to buy something. Oh, it doesn't have to be a $50,000 antenna system, but It should be something modest ... a transceiver • • . a linear . , , you know- Ws'll leave the decision up to you, knowing that we can trust you to do the right thtng.
And we are definitely not saying that the use of this service coupon has any curative powers, but we cannot but notice that many readers report remarkable relief from simple backache, headaches, lumbago^ and acid indigestion after sending in their coupon. Why take any chances?
AOVERTISEfl INDEX
J Adirondack 93 |
Perfection Products 68 |
|
Arco 127 |
Poly Palti 127 |
|
AmateLir Electronic 37 |
t J |
Regency 53 |
« .' Antenna Labs 116 |
a |
Ross a Whrte 55 |
a Antennas Inc. 32 |
p |
BP Electronics 79 |
LI ATV 119 |
□ |
R&R 70 |
o saw 29 |
a |
Sams 21 |
= Calibook 78,99,121 |
O Stones aSL 12B |
|
M CB Radio 127 |
r |
Sentry 35 |
Cfvstck 78 |
1 |
Signal One 49 |
D^Kl 122 |
u |
Siep 67 |
n Delta 126 |
n |
Spectronics 64 |
i ' Dow Trading 12& |
o |
Standard 58. 59 |
n Drgke IV |
□ |
Swan \ 1 |
1 J EKV Video Vision 126 |
II |
Telecom 60 |
LJ Electra 89 |
n |
Telre>t 71 |
O Epsilon 119 |
D |
Tower 124 |
O Flammgo 90 |
n |
Tristao 120 |
DFreck 115 |
u |
Two Way 123 |
Gateway 123 |
n |
unique Products 93 |
1 1 GgfG 69 |
I.; |
Vanguard 50, 118 |
11 Goodheart 125 |
n |
Varitronics 56, 57 |
M Gordon 72 |
n |
Vibroplt!i< 127 |
; Gregory G5 |
i |
World QSL 127 |
! Hal 127 |
U 73 Stuff |
|
Mallicrafters 2B |
Gunsmoke 36 |
|
Ham Buerger 38 |
FM Anthology 41 |
|
Hatry 91 |
Spec SheetB 55 |
|
1.! Heath 15 |
73 Subscriptions 63 |
|
t:i Henry 13,61 |
Tech Manual 95 |
|
n HBiL 127 |
73 Binders 95 |
|
■1 Hy Gain 42,43 |
Extra Class Handbook 9£ |
|
n International Crystal 11 |
OX Logbook 99 |
|
J Jan 91 |
73 Books 100 |
|
Jan«l 127 |
M^nettc Signs 106 |
|
1 Jefftronics 122 |
Repeater Handbook 108 |
|
U Lswispaut 123 |
OX Map 119 |
|
r 1 Mann 66 |
OX Charts 120 |
|
: 1 Micro-Z 50 |
Ivjational TranscoiveT 121 |
|
< ] Mosley 86 |
Lapel Badges 122 |
|
I i National III |
Oesk Plates 122 |
|
QPal 120 |
73 Schematics 126 |
|
D Pantronlcs 127 |
DGP 126 |
|
OPark 124 |
73 Globe 118 |
Name«
Call
Address.
^^Zip,
73 Reader Service Coupon \
Now w« dort't say that every single reader must buy every last product advertised m 73. W© believe that, but we don't say it. The very feast every reader can do is to put on a show of interest in the products herem advertised. To make this a simple task, even for ttie faziest reader (now there Is a contest for you!), we have cF overly arranged the advertising index to double &% a readers service coupon. AH you have to do is tear it out ^or photocopy it) and send it in with the appropriate boxes marked. (We have a prize for the most boxes marked , . , a silent prayer of thanks from the pub- lisherK WeMl accept postcards, slips of paper, or I almost anything else that lists the companies * you want to hear from and your address.
I
I
I I
I
I
I
I
I I
I MAIL TO 73 Inc., Peterborough NH 03458 |
J
PROPAGATION CHART
J. H. Nelson Good O Fair (open) PoorU
December 1970
SUN MON 1UES WED TNUA FRI SAt
© © ® ^ ^^ ^^ ^2
13 14 © @ 17 @ ©
20 21 22
21 28 29 30 31
EASTERN UNITED STATES TO:
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30 |
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■J |
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■i1 |
31 |
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ABQC^TIlSA |
;4 |
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7* |
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7 |
14A |
31A |
SIA |
2IA |
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11 |
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AirftTtlALIA |
11 |
14 |
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31 |
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JAPAN |
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7B |
7t« |
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MEXICO |
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11 |
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A = Next higher frequency may be useful also. B = Difficult circuit tliis period.
128
73 MAGAZINE
Here's a transceiver designed for the amateur who would rather spend his hard-earned radio dotlar on performance than frills. The NCX-1000 is built to meet the demands of the operator who needs and desires a high perfor- mance SSB-AM-CW-FSK rig with solid-state dependability and plenty of power. Add to this the convenience of having your transmitter {including linear amplifier), receiver, power supply, and monitor speaker in a single, com- pact, smartty styled 59 pound package.
So let's look at the NCX-1000, starting with the double-conversion, solid state receiver. After the received signal is processed by a doubie-tuned preselector, a stage of RF amplifi- cation, and another preselector, it is applied to the first mixer for conversion to the first IF frequency. The first IF contains passband filters and a stage of amplification. A second mixer then converts the signat to the second IF frequency for additional processing by a 6- pole crystaMattice filter and four IF stages. Finally, the signal is detected and amplified by four audio stages. The unparalleled high dynamic range lets you tune in weak stations surrounded
by strong interfering signals. The result? High performance for SSB, AM, CW, and FSK. Sensitivity of 0,5 EMF microvolt {for a 10 db S + N/N ratio).
In the transmitter you'll find three stages of speech amplification followed by a balanced modulator, a crystal-lattice fitter, a filter ampli- fier, and an IF speech processor {clipper). A mixer converts the signal to a first IF frequency for processing by two crystal passband filters, and two IF amplifiers, A second mixer converts the signal to the transmitting frequency where It is amplified in five RF stages before it gets to the grid of the 6BM6 driver. Final power amplification takes place in a forced^air-cooled 8122 ceramic tetrode which feeds the antenna through a pi network- Other features? You bet! Grid block keying for CW. Complete metering. Amplified automatic level control (AALC).
So here's a package that can give you 1000 watts PEP input on 80 through 10 meters, 1000 watts on CW, and 500 watts for AM and FSK„ The speech processor lets you double your SSB average power output with minimum distor- tion. No frills with the NCX-1000. Just top
performance.
For complete (and impressive) specifications and details, writei
NATIONAL RADIO COMPANY, INC.
MwF€%^M 111 Washington Street, Melrose, Mass. 02176 (617-662-7700)
At last— Drake quality in a
*
VHF FM Transceiver
Marker Luxury
f/
The best of the Japanese, the Marker Luxury VHF FM Transceiver is built for and distributed and backed by the R. L. Drake Co.
mclLdes transceiver, two channels supplied, I hH^ ^fm mobile mount, microphone,
• Exceptional receiver
• Backed by R. L. Drake
• Complete package for .*. .
e ^
329
95
coax cable and antenna.
General
Frequency Coverage 144-148 MHz
SPECIFICATIONS
Transmitter
Humher of Channels
Modulation Transmitter Control Power Drain
Power Source
Dimensions Weight
12 Channels, 2 supplied
Channel 1 Receive 146,94 MHz Transmit 146.34 MHz
Channel 2 Simplex 146J4 MHz
Frequency Modulation
Push-to-Talk
AC: Receive 6 Watts Transmit 50 Watts
DC: Receive 0.5 Amps Transmit 4 Amps
AC: 117 Volts Factory Wired 220/240 Volts 50-60 Hz
DC: 13.5 Volts ±10%. 7%" W X 2W H X 10y4" D. m lbs.
RF Output Power Frequency Deviation Frequency Stability Spurious Radiation
10 Watts
15 KHz maximum
±.001% or less
Greater than —80 dB below Carrier
Frequency Multiplication 12
Input Impedance Sensitivity
Standard Accessories Dynamic Microphone,
Antenna, Connector Plug, AC/ DC Cord
Receiver , i.
Receiver Circuit Crystal-controHed Double
Conversion Superheterodyne
Intermediate Frequencies 1st 107 MHz, Znd 455 kHz
50 to 75 Ohms
0,5 >iV or less for 20dBS+N/N ratio
1 >uV or less (30 dB S+N/N ratio at 10 kHz deviation with 1 kHz modulation)
Greater than 80 dB
At 40 kHz separation
, Greater than -80 dB 0.5 Watt with 10% or less distortion.
Intermodutation Spurious Sensitivity Audio Output
See at your distributor, or write for details.. Jl
R. L. ORAKE COMPANY
540 RICHARD ST., MIAMtSBURG, OHIO 45342