Fm

Last month we started describing our requency synthesizer and gave the parts list. This month we will show all the diagrams and describe how it works, and next month we will have the printed circuil board layout, parts layout drawings, and construction and operation information. Figures 2 thru 12 show the diagrams of the various parts of the synthesizer. To see how these parts lit together refer back to Fig. , the block diagram, in last month's article.

Division Qf

2400 Crystal Di Fort Myers Florida 33901 (813) 936 2397 catalog with oscillator circuits and lists of thousands of frequencies in stock. Almost AD CB Sets. Trans, or Rec, 2.50 Any Amateur Band in FT-243 1,50 < E*cepi 80 meters) J for 5.00 Color TV 3579 545 KH fwtre leads) 1.60

Hz Selectivity

DRAMATIC IMPROVEMENT FOR TRANSCEIVERS ON CW Ready to use, Add 1,00 for shipping in USA. (Calif, residents add 5 sales tax,) Don't confuse our new Q-Box with old fashioned audio filters It has no coiis, insertion loss, or oscillation. Instead, it's a transistorized ACTIVE FELTER variable, to match conditions, from 30 HZ (3dB bandwidth) to a flat response, 800 Hz center. 40 dB skirts. Plugs into rcvr phone jack. Output for phones (1000 ohms or more) or external amp. 4Mx8 xlVi . Order today and...

Electronic Feather Touch Key

Delects mere fOuf h of finger. Use as single or twin Jever key- Operates with all positive or negative ground digital keyers. (RemoteS S Swk, for MM-500B) and MM 8000 27.95 DATA ENGINEERING. INC 5554 Port Royal Road, Ravensworth Industrial Park, Springfield VA 22 I 5 1 The time drift calibration method may seem a little tedious, requiring several weeks to months to achieve good calibration. There is actually very little to it, however. In my case, I spend about five...

Communications

Operates on 12 Volts DC.3 - 10 W in Gives 100 Watts Out. Units are new in original factory cartons, but sold as is, no factory warranty. All Solid State, 10 Watts Out, 12 Volt.Made in England. Units are new less crystals and antenna, no factory warranty. MARRY THESE UP FOR 100 Watt 10 Channel 2 Meter Rig Money refunded without question if equipment is returned within seven days from shipment, undamaged, freight prepaid 28710 Canwood Road Drawer M Agoura CA 91301 (213) 342-8297 Unless otherwise...

Noise Actuated Switch S

Solid state noise actuated switch fully wired, includes mike pick-up, amplifier, SCR switch. Actuates by noise or whistle. Useful for burglar alarms, lamp lighter, etc. 15 ft range. Ruby red, gold plated feads. With mercury cei for instant testing. Fully wired, transistorized, uses 6 volts 64 bit ASC IICharacter Generator C sets. Vertical scan set includes SK0002 kit, two MM502 and one NH0013C. Honzontai scan sets includes S K0G01 kit, two MM502, and one NH0013C. Make your own CRT readout or...

G H

The Rolls-Royce of currently available surplus VHF receivers. AM, FM and CW over the range of 30-60 and 60 to 260 mHz. Separate front ends provide optimum performance on each band.Three separate I.F. strips provide 20, 40 and 300 kHz selectivity. The 40 kHz I F utilizes nuvistors yielding a remarkable system noise-figure, LF, and video outputs allow spectrum display and analysis. After all this, the engineers found a few extra square inches on the chassis and added a car rier operated relay to...

Kpur

Schultz, Active liandpiiss 1 liter With Adjustable Center i requency and Constant Bandwidth, Leslie FET's in RC Network Tune Aclivc liter, Arthur D. Delagrange Electronics,December 7, 1970. Variable Frequency and Q in a Notch Miter, Signetics Corporation Application Note AN 107, FET varies Q of Tuned Circuit by Several Thousand. Gary A, Vander Haagen Electronics. September 1969. Receiver Cirlicits, PopuJar Electronics Including Electronics World February 1972....

Pocket Calculator

Thi* is the kit you bwn ertit irnj tor. So compoct it actuaJIy fits in a thin podkut < 3 13 16 * 4-5 6 * 1 1 ML it perform*, ev*ry iunction you would expect in a dfik calculti tOfF inciudirtq consianr *nd dn*n operation, end lull floating decirrul Th unit +j poby vff tfin tamed bittw and usn 3 dkjii .E 0 diip ayi The c*icuLatiom *re rf or mttf try ungie 40 pm intif-flrtited occult, which can truly be falfecf largo intt grMiOft I LSI). As a sludunt, cngineor, uletnian, accountant, or myone who...

Active Editors

Only one ham magazine of the four has editors that are active and on the air andl have been for years, 73 has its own repeater going the only ham magazine staff that has done this. 73 has its own mountain top laboratory for VHF the only bam magazine with one. 73 is active on slow scan television - the only magazine to do this, 73 goes on DXpeditions the only ham magazine to do this. 73 runs DX tours - the only ham mag to do this. And so it goes. And what difference does all this make Perhaps...

Linear If Amplifiers

A new 4-page product bulletin (IFA-203) describes the expanded line of linear i-f amplifiers available from RHG Blectronics Laboratory, Inc., manufacturers of microwave components, receivers and transmitters. The bulletin contains information on the new line of Hybrid IC i-f amplifiers, in addition to the new products, the bulletin lists new fea tures, improved specifications and reduced prices on many models Scope photos, performance charts, and outline configuration drawings are shown along...

Two Frequency Tone Squelch

Alpha Electronic Services announces the smallest and most reliable two-frequency sub-audible tone encoder decoder available lior the F Mer. The Alpha SS-8QJ du< il rone, measuring 2-2 3 x 1 x 5 8 can now provide for many of the smaller mobile units and certain hand-held units two distinct tone frequencies for the purpose of controlling or selecting repeaters, base stations or mobile units. Two frequency sub-audible tone operation makes possible the employment of multiple repeater systems,...

Communications Specialists

Board with holes that match I he pins on the ICs. Small wire, solder soldering iron and long patience are required. The wire ends can be inserted in the holes alongside the K pin (in the same hole) and soldered. A desoldering tool of some type is helpful since molten solder often sticks in a blob between 1C pins and is difficult to remove because of surface tension. The entire thing can be wired in one day, but it may seem like forever. An LM 335 IC regulator makes an excellent component for a...

Contests

New York, will be the site of the 1972 ARR1. Hudson Division Convention on October 21 and 22, There will be exhibits, lectures and a banquet. Technical experts will be on hand to explain the latest gear. Registration is S3,00 and is required tor forum attendance and special events. Banquet tickets are Si0.00 in advance, or SI 2,00 at the door. There are free gifts to early registrants. To register or for more information contact Dave Popkin, WA2CCF, 303 Tenafly...

Pot W W

You don't already have them lying around. The filament source can porbably be found or borrowed from existing power supplies in the transmitter or receiver, as can the B plus needed. Figure I illustrates the basic circuit. Figure 2 illustrates how I used this idea in one power supply that 1 built, T2 is a 6.3V filament transformer, back-connected to a 6,3 V winding of transformer I 1. i his circuit supplies negative bias voltage for the buffer and final stages, through a resistor network and...

Info

14 Progress Line Case, consisting of front basket and front plate with lock 10. Low band dual front endf 2 freq. RX strip Hi-Band TPL RX with TX exciter strips less speaker, as is, missing parts 25. 15,000 2-way FM mobile units in stock Send for new 1972 catalog. The FM Used Equipment People 243 Route 46, Saddle Brook. N. J. 07662 Instant access to 144 frequency pairings with 20 watts out on the new HR-212 twelve channel 2 Meter FM Transceiver by Regency Pou er Output 20 watts nom. at 13.8 V DC...

Digital Special

Ten brand new (on carriers* dual-in-line JK flip* flops-LU321 with data sheet and two pages of application notes describing hookups for-divide by three through ten, and twelve. Also self correcting ring counter hookups, etc. 10 LU321 l V data S4.00 TTL dual-in-line 7400, 7401, 7402,7404, 7405, 7410, 7420,7430, 7440, 7450,745 1,7453 J00 for 22.00 ____ea. . .25 744 I BCD decoder driver 1 IS 7442 BCD decoder 115 7473 dual JK flip-flop 65 74 74 dual type D FF 50 74 75 quad latch U5 7476 dual JK FF...

Ksth

There's a lot of old commercial gear around just waiting for you to buy and convert to amateur use. This book, written by Glen E. Zookf K9STH, is a complete guide to converting all of that gear and getting you on FM , . . cheap. ORDER RADIO FROM PETERBOROUGH, NEW HAMPSHIRE, 03458 Since Yaesu makes and sells more factory-assembled amateur rigs than any other company in the world, it follows that we'll only place dependable, fully-perfected products on the market. So now, after more than two...

Frequency

Part in 106 (.0001 ) with only a WWV receiver and a little patience. There is no need to elaborate on the usefulness of a frequency counter, as it is fairly well recognized, 1 his counter is different from most others in that it works to 220 MHz and has a different approach to the time base. The counter is intended to be used with the companion time base to get the specified accuracy, but has provision to use the power line for a reference with reduced accuracy (.0 i ) for use away from the...

Fma

Never a crystal To purchase Complete with Noise Cancelling Microphone and Antitheft Mobile Mount Only the FM-27A offers the 2 Meter FM'er the complete freedom of frequency receive and transmit with accuracy and stability comparable with conventional crystal control. In addition the FM-27A provides the hottest performing receiver and most conservatively rated 25 watt transmitter on the market. See your Clegg Dealer today or write or phone our factory for detailed data...

Waller Electronics

Box 9913, Chevy Chase MD 20015 Telephone 301 652-0996 The ' TESCO PAD has no tuned coils to go off frequency, no tuning necessary or even there It's all In one Black Box I.C. ready to go. The TESCO PAD has a 1 second hold-up for your transmitter, complete P.T.T- operation, available with dual audio output levels, 12 or 16 tone combinations. (Add 1.00 for 16 tone version) ( 2,00 for dual output version)

Electronics Company

Bo* 1050 Garland, Tx. 75040 The Tucker Model 5509 Frequency Counter has a full 9 digit readout from 10 Hz to 550 MHz. The Tucker Mode 5509 provides the finest resolution, highest accuracy, and highest sensitivity of any counter in this price range. Many features found on the Model 5509 can only be found on a counter costing much more. Like the Model 60. the Model 5509 is simple to operate just apply the signal (10 MV or less) and select the frequency resolution required (from 1 KHz to 1...

Sp

Still the all-time great general coverage receiver, 540 kHz to 54 mHz. Selectivity down to 200 Hz. Completely overhauled and guaranteed. Write for complete specifications and photograph. An Com maintains an extensive inventory of military and commercial equipment and publications. We continuously research methods of utilizing surplus military equipment. Write or call stating your requirements. NEW and SURPLUS ELECTRONICS FOR THE HAM BA-.tr t. D. Ti ' vr BA-.tr t. D. Ti ' vr

Is

Positive logic Where the logical more positive than logical Negative logic - Where the logical *T' is more negative than logical 0* Modulo (Mod) - A counter circuit. The number indicates how many pulses arc counted, i.e. a Mod 10 counts 10 input pulses. 1 he output occurs on the 10th pulse. A Mod 5 wilt count 5 pulses, etc. Permuting A means of providing a feedback path to stages into counter to force it into desired state. References 1 Lancaster, Don - Digital Volt-Ohmmeter, Fopu ar...

Contents

15 Frequency Synthesizer for 2 Meter FM Part II K20AW 25 A Big New Voice in Chicago W9NLT 29 Solid State 6 Meter Crystal HET VFO K1CLL 37 The FET Voltmeter As A Nano-Amperemeter ZL2AMJ 39 Time Frequency Measuring System Part I K50US 43 Active Filter Design and Use Part IV K3PUR Movie rights for thrs thriller available 49 Transmission-Limit Timer for Repeaters K6MVH 53 Extra Class License Study Guide Staff 64 A Simple and Inexpensive Auto ID WB6BIH Just what you need for the mobile rig 71...

Close

3 Pair Walkie-Talkie TR 3 Eis co per pair 10.00 8 Travel Clock Radio Model 8NC-11 5 10.00 3 Imperial Edition 5.00 18. 10 Transistor AM-FM-AFC -AC Model 10FD-212 Digital Timer Clock Radio 19.00 4 North American Solid State AM Clock Radio Lamp Model No. LC9898 15.00 1 3 K-l 2 Prep Slide Rules 3.00 Please enclose separate sheet listing books ordered. Once the parts have all been soldered to the board an easy hour's effort yotfre ready for testing, i think it best to try the splitter on a...

Coax

Then they sold millions of feet of this stuff by calling it coax We won't argue why electromagnetic waves propagate down this .stuff, hut we will note that the electric lines of force extend from the shield to the center conductor. Later (in the 430s) sonic machinist with time on his hands made some big and small rectangular tubes and rectangular insulators, and. by fitting them together, made rectangular coax. By careful measurement, they found that almost a I the electric force lines were...

Silicon Tubes

Elurrqughs > 7 1N 0-tO- , A-U> Z. 2Vz high characters, l t)V Type il. 1 2 dt 1 Inch. Mount- 1 I hnle. With ljn*- ir. LL 75 G 5.OK 25.Kfc 3 1 lOO 7.K 75Jhtg I 500 10,K 100,K Ttrff 2.OK 20. K 5 Mefi ity We stock Lock nut Bushing & I Screwdriver types tf same low prices, Uses single Texas Instrument Ctiip'r Features found In more expensive units for Home, Office. Shop, Student, School The lowest price digil l clock kit iwith cabinet) far a* we can see in U.S.A. Scientific Devices' cn...

Scarpt Solid State Repeater

The Standard SR-ARPT-l is the latest in totally solid state repeaters for the land, mobile and amateur radio communications industry. Constructed to the most critical specifications for years of mountain fop. trouble-free service, this unit willi pro vide that extra edge of range needec for even difficult locations. Ready fo_ immediate standard 19 inch rack mounting, the Standard repeater will fit in immediately to your existing communications network. Simply add 12 volts and Connect your input...

Rf Amplifier

Test results, rf on batteries and leads. final destined for use in the 432'er solid state assembly. Niote the one volt of rf at test point D without the filter. At the same point, also without the filter, about a tenth ol a volt was found with only the exciter fired up. See Fig. 9. You can see what that kind of rf path will do for feedback from a Quarter watt or j one-half watt final. So a piece of copper-clad was put down under the two units as shown in Fig. 4 and the two filters...

New Counter And Display Modules Available

A new series of counter and display modules is available from Display Electronics. The CM Series modules include a decade counter, tafch, decoder-driver. and readout for each digit. Standard modules are available with from 2 to 6 digits. The price of a typical four digit module is 79.00 in single quantity. Delivery is from slock to 30 days. Custom designed modules are available on special order. Further information is available from Display Electronics, P.O. Box 044, Littleton CO 80120.

Engineers

Properly terminated, even if the actual termination is an open or short circuit. In this case, the effect will be nil. If, however, the line is relatively short, the effects then depend upon the exact type of termination as well as the length of the line. If the line is any exact multiple of 1 2 wavelength long (electrical length as distinguished from physical length), the load seen by the transmitter will be the same as that existing at the load end of the line. If this load is highly...

Am

Jim White W5LET 100 Dianne Street West Monroe LA 71291 For several years most of my hamming has been done with a three-band transceiver. Now, that's fine most of the time, but then there are times when 1 gel to wondering what's going on on tile other bands. So 1 began to look around for a good, simple, economical solution. It was during this search that I ran across the hot carrier diode. One of the claims made by the manufacturer - The hot carrier diode's performance . . . can be described as...

Si

TG34A CODE KEYER self contained, automatic, reproduces code practice siqnaJs from paper taoe. 5 to 12 WPM built-in speaker. Brand new with tech manual Code practice tapes. Price upon request. Receiver 200 to 400 Kc. Operates from 24V DC 1.5A. Continuous tuninq_*vol. control, on oft switch and phone jack. Very sensitive-Compact. Complete with tubes, NEW

Dix

A Next higher frequency may be useful also. B Difficult circuit this period. In a previous article, two dual regulated power supplies were described for use with the new linear I s, which require 6V or i5V.J While the dual supply approach is not a bad one. the method herein described has several advantages. By plugging this splitter into any existing regulated power supply, a center ap is electronically created which will stay midway, voltage wise, between the plus and minus terminals. This...

All Transistors Hepm

Breadboard Jayour, 6 meter-HET-vfo. as needed, testing transistors, and selecting another set of components for packaging in a minihox. I he ground plane works as it should, with no ground-loop currents noticed so far. You can see the four separate stages on the breadboard and check out the individual operation of each stage by itself if you need to, heir packaging in a small box should not be difficult providing a little shielding is used correctly. Of course, nothing slops you from...

Amateurwholesale Electronics

8817 S.W. 129 Terrace-Miami, FL 33156 Telephone-days (305) ' 33-3631 - nights and weekends call (305) 666-1347 Use yout Master Charge earri final righl past a bypass 7 capacitor and into (he exciter and knock it right out, subject to the phase involved. Or worse, throw the stages into self oscillation, because I he input of these devices is also low and so operates on very small voltages of just the kind we're talking about. This is further aggravated if low cost levices ire used in tiie first...

Bc Fm Receiver

Converted for 35*50 mHz. 10 preset push button channels or manual tuning. Complete with10 tubes, checked out, like new AC PowK Supply, N& w 14 T rchmcat Manual S 50 dm 34 24V Pow ( Supply 4 4S Sel o 10 iub*i for BC 603 5 96 DM 35 24 V P*t Supply E*c (J d S2 25 BC-604 FM TRANSMITTER < 20 to 27.9 MC.I 12,50

Big Deals

CUSTOMIZED DX HEARING CHART 4.00 This is not available on the subscription bonus because it is provided purely as a service of 73. An amateur who works for a big computer company has a program which permits him to plug in your location and have it print out the bearings of ail of the countries of the world from your shack. Once you have this list you will use it for every DX contact. The chart gives the bearing and distance to all major cities and countries. Be patient when you order for these...

Binders

These are not available as a subscription bonus. But you still need them to make your issues of 73 stand up on the shelf. It also helps keep back issues from getting lost or spilt on. Or into the hands of the Jr Op The binders are a gorgeous red and come with the nicest set of year stickers you've ever seen. Dress up your shack with these binders. Name and call identifies you at club meetings, hamfests, busted pot parties. Hand engraved by skilled New Hampshire craftsman with loving care. Only...

Broadband Power Amplifier

Kit MP- 00 is an all solid state broadband power amplifier covering the range of 0.5 100 MHz Rated at 2.5W CW. it accepts inputs of AM, SSB, Pulse, and other complex modulation. It delivers full power output when driven by any signal or sweep source of 0.15V over the entire frequency range without tuning adjustments. The unit will not oscillate for any condiiion of load or source impedance and will withstand a 15 dB overdrive including short and open circuit loads. Of printed circuit board...

C

The basic reference for the synthesizer is an AT-cut series resonant 10 MHz crystal in a simple circuit using the four gates from an SN7400N IC. This is a fairly simple circuit which is stable enough for the prupose. if you want the utmost stability, though, you may want to put the entire circuit into an oven. The crystal oscillator circuit is mounted at the very edge of the px. board, and so is easily removed later, if you want. But we haven't found this necessary so far. Reference Frequency...

Mzk

Brand rte* plete with consumer appliratkmj manual. 2N1844 C20A t 2N1& 46 C2 B o2N5169 SCR's - invaluable for high power application*, motor -.peed controls, lighting circuits, welding control*, elc. Never before at thi& low price, Plastic I00Y 1 amp Plastic 200V I amp I00Y 8 amp stud 200VfQ amp stud 400V 8 amp stud 400V 3 amp pre*a fit 100V 8 amp stud 2Q0V 8 amp stud 400V 8 amp stud 100V 12 amp stud 200V 12 amp stud 200V 20 imp stud 500V 20 amp stud 700V 20 amp stud 100V 25 amp stud 200V...

Nyi

Fig, 1, Notes AJJ flip-flops Vi MC791P, all inverters 1 6 MC789P, Vcc is 3.6 V to aiJ IC's, F.F, & Inv. - Vcc Pin 11 - pnd pin aJi diodes 1J T9M. So we have to change the binary numbering system to the decimal system. This can be done with discrete components (diodes, resistors and transistors), but this costs as much as using a single integrated circuit. The single IC route was chosen for simplicity the one used is made by Fairchild. and is completely compatible with RTL ICs. This I- i 11 s...

Uzw

Swj ic ed buffer amplifier. number by which we divide, is a constant between 29,000 and 29,599 during transmitting , and is 2 140 less during receiving. Te mporarily forget about what happens during receiving, and look al the numbers 29,000 and 29,599. Since the digits 29 at the beginning are the same all the time, ICI2 is permanently wired to count lo 2, while 1(7 is permanently wired to count to 9. The last three digits of N are entered into C6, IC5, and IC4t in that order, by the 1 I...

Calculator Chip Special

We are ool alk wed D and I lias integr JLlkjri to mention Ute spees should make (hem Set X - Four 24 pin I.C btD output, 16 digit, fix I'd automatic decimal point, po stable memory expansion instant 29.00 Set Y - Single 40 pilL 7 nrftivienl output, 2 digit, filed autojw ntjf dierunal, no ronstanl . r 15.00 Set X Sii te 40 pin LC, 7 meni output. A digit, floating point, constant 19.50 7400 SERIES TTL SUMMER CLEARANCE MOST POPULAR LC SERIES MADE itttit 6 and F...

CI

Professionally Engineered Antenna Systems transmission line TRI-BAND ARRAY By the only test that means anything . . on the air comparison . , this array continues to outperform all competition . and has for two decades. Here's why . . . Telrex uses a unique trap design employing 20 HiQ 7500V ceramic condensers per antenna, Tetrex uses 3 optimum-spaced, optimum-tuned reflectors to provide maximum gain and true F B Tri-band performance,

Circuit

ny ham who has shopped around for a time delay relay knows they are hard to come by, particularly the adjustable type. Not only are they large but they are also relatively expensive. I have recently seen the vacuum type sealed relays advertised on the surplus market, but have never tried them, even though they were offered at ridiculously low prices, because the delay time was always some figure that didn't tie in with wl at I had in mind, such as 5 seconds or 5 minutes- Several years ago I...

Deskfax Transceiver

Conversion in May '7 2 QST Complete Unit S15.00. 2 825.00 TOROIDS 88 or 44 mhy Never pott ed center-tapped Ppd in USA only. 5 for 2,50 30 for 10.00 Ribbons for alt teletype (nylon) 12 for 3,50 ppd 11 16 paper tape 40 rolls-FRESH. 8.00 Single sheet roM paper (S 'O-FRESH, case of 1 2 for 12.50 SPECIAL 60 speed mod 15-19 gears (74912 74913)t 3.50 set ppd Manual (TM 1 1-2258) for TXC 1t A, B( Cf D Facsimile Transceivers. 7,50 ppd Fax paper. 12 x 19 for TXC-1, Cut up for Deskfax, 250 sheets. 3,00...

Digital Clock Kit With Nixie Display

30.000 surplul nmiet in itock, jnd bflCHUH Ql thij ii d r q a in purchate mm can sail a EDFiplei dnguji (io< k kn for 4iu than ihc usual cos oi the display lutoa only We piovide compleiF fiihfiJ tnri thru-pfatad t< rcui hoard ill 'nt grated Qjrcuiu, comply En porter lupply. dupifly lutoatr t.C tocketi and d nicr honi piinnl witii poiwOkJ u wr Wa tuiva rtevpr 411 anyone flfiar this kir Int lass tfun S100 00 twfor* Includes BCW Outputs uip at tth timer oohon Mev be *ir*td for fi n* 4 houi...

Digital Clock

SPACE AGE TECHNOLOGY PRODUCES SOLID STATE DIGITAL CLOCK WHICH COMPUTES AND DISPLAYS TIME TO THE EXACT SECOND THE HANDSOME WALNUT CASE AND NIX rE TM TUBE DISPLAY WJLL COMPLEMENT ANY DECOR INCLUDED IS A WALNUT BASE F Of* USE ON TABLE OR DES . Polaroid Red Display Filter Fraction oi Second Accuracy 3 Available in 1 2 or 24 Hour Versions Send Check or Mo ney Ordet for Si5-9 q Postpaid < COD's Accepted uiith 30 Deposit 5 California Residents Add Sales Tan MELREX PRODUCTS 8142 Ridgefield Dr., Box 5...

Dipped Mica

This unit is the heart of my future 6 meter transmitters, and probably will he for the two meter design as well, along with the Miller MD-4 dial, an automatic two-speed dial and very handy. Using the inductor, padding capacitors, and the 100 pF variable shown, the range tuned is from 50 to 51 MHz. That is, the actual vfo 3G303 AURORA RO.-CLEVELAND (SOLONI OHIO 4413 3 Phone 216-248-1200 Cable BIRDELEC RPC-3,3U Internal Unit RPC-3C Cabinet Mode ( 24.95) ( 34,95) Internal units & modules work...

Disastrous Disasters

J lie Hoods this summer exposed the weakness of our emergency communications. In Pennsylvania all existing communication systems fell apart. Civil Defense was set up in cellars in preparation for bombs and they immediately flooded out. Police and other short haul systems were useless. CB operators tried to help, but lacked any organization or experience and more often than not were a waste of time. The fact was that, as in most other serious emergencies, (he responsibility fell on amateur radio...

Dresmdie Books

G The BEST of FM is a compilation of the best articles thai appeared in the FM Journal from March 1968 through June 1969. the last of the magazine. Read the extremely controversial Chronicles of 76. PJus dozens of technical and circuit articles available nowhere else. 4.95 value. S0 D-STAT PROJECTS far tfrt Erpemncr-t J Solid State Projects for the Experimenter contains over 60 projects taken from the pages of 73 Magazine. Build a Six-Mpter Fet Converter. Or, maybe a ham TV receiver. It's all...

Dx Engineering Clipper

Quite a few schemes have been developed to increase the average power of the voice for sideband transmission, with the system used in the DX Engineering clipper being one of the more successful and popular. The problem is that when you set the sideband transmitter to operate properly without splattering, the aver age power is quite low. Only the voice peaks fully modulate the transmitter. A clipper increases the average voice power, effectively increasing the transmitter output power, indeed,...

Easily Converted For Mc Operation

This equipment oriamally cost over SI000. You get all in original factory carton. Dependable Two Way Communication more than 15 miles. Frequency Range About 435 to 500MC Transmitter has 4 tubes WE 316A, 2-GF6, 7F7 Re ceiver has 11 tubes 2-955, 4 7H7, 2-7E6 3-7F7 Size x 13-V x 4-Y, Makes wonderful mobite or fixed rig for 420 to 500 Mc. Easily converted for phone or CW operation. BC-645 Transceiver, Dynamotor and all BRAND NEW, accessories below, including conversion m while stocks structions for...

Editorial By Wayne Gpeen

How many of (he old experimenters have been able to convert to solid state Our technology has been escalating rapidly. Twelve years ago when we started 73 we had a few transistor circuits mostly audio amplifiers and code oscillators. The nuvistor was the big news in if you remember. By 1965 tubes were in the minority and virtually all articles were on transistorized construction. Now transistors are about gone by and we are dealing with integrated circuits most of the time. Counters which...

Electronic Clock

MACHINE utilises the J *st electr nie tec ni iucs and .n. vinces K provide lime information 11 kf iu clock be I ore. A Large Sl iU. LritograUcm LSil circuit prcTidq Joai< _- L-. nu rt iht. bLI hertz line frequency into fj di pi ayoble time, Enternn ntj -iu includfl a pr* suitable a I a mi elf gull, five tnintiLu snoi e, seconds di. play, and 24 hout time. Because of the new technology involved, this ,-iii is not ncommendftd tor the beginner. The circuit board connections Are small...

Electronic Preset Counter

This counter m from a copying machine, It ude- (wo tiurant electro-imechanical decade counters, and includes a nior power *upplyt etc. Two Hilary Kwitchca allow the unit to be ptTset with any number from 1 to 50* when the number of pill, in reaches tfiL- rount a relay opens, FLAT NYLON LACING TAPE jfcuHinp off the controlled unit, should be naeful for eoil winders, asd other applications pcqTiirm fflul-off One (w> und tube of black lacing, abo l 1,000 yards, lt a mUttt J e parts alone a t our...

Electronics

When reaching out for long range contacts, Swan's VHF-150 Linear Amplifier is a perfect companion to the FM-1210A or the FM-2X. Operates class C1' at 150 watts DC input on CW or FM with a frequency range of 143 to 149 mHz. A flip of a switch gives you 180 watts of P.E.P, when working SSB class Its self-contained AC power supply is designed for continuous operation, and a DC converter is available for mobile installations.

Entry Blank On Page And At Participating Dealers

The first Rig Of The Month drawing was for a Gladding-25 transceiver (drawing October 15th). The November drawing will be for the SBE-144 rig. Future rigs are being arranged for with some being transceivers and some being interesting units such as the Data Engineering super memory 8000 keyer - and like that. The purpose of the contest is to encourage you to visit your local ham dealer and get your entry blanks, The fact is that there is a rumor going around that several amateurs have been...

Fair Child Voltage Regulator

Fairrhild UGH7805 5 Voit I imp voltage regulator. Perfect for lo*ic fUppli , very compart f 1.95 E560 Pha.se Locked Uop 4.65 NE56I Phase l,ocked Loop 4,65 NE562 Pha*- Locked Loop . . , , i65 NE565 Plias*1 Lock l Loop -1.65 N 565 Function Generator Tone Encoder. * 4.65 NE567 PLU Tone Decoder 4,65 E595 Four Quadrant Multiplier 3.75 NE555 Timer. 2u Ser o I hqur. Sperul . . , St .25 NE540 Power Driver. for 100* B amp. . . 2.25

Fat November Issue

There are a few more ads in this issue of 73 than we expected, so if is a little more packed than we like. Fills is one of the problems with last minute ads - by the time they come hi. unannounced, we have already laid out the articles and have them in negative form ready to print and it is too late to change them. If the ads keep coming in for November the way they have started, this could be the biggest issue we've ever published* Well see. We have some corking good articles being readied for...

Fm Books

FM Repeater Handbook 6*95 This hardbound book from Howard Sams is not available on the subscription bonus deal. Sorry, because it is one you will want it you intend to set up a repeater. A huge selection of the best technical and construction articles from the FM Journal including data on the formation (if a repeater group* licensing a repeater, transistor switching for receivers, 450 MHz gain an-t ennas, adjusting deviation without test equipment, narrowband vs wideband, Crystal production...

Fm Developments

Old timers are coming on the FM repeaters in droves all over the country. No wonder, of course, since the word has been spreading that here, for the first time in years, Ls a way to get on the air and have contacts without interference. Mobile on the lower bands was fun - kind of - if you didn't mind always being the low man, getting stepped on by higher powered stations, losing contacts, and extremely fragmented conversations. About the only gripe on FM is that a few of the repeaters are so...

Fm Frequency Standard

This is a precision frequency standard that has been designed specifically for the 1'Mer. For the first time you can be exact with your channel spacing and deviation, This deluxe standard provides precise markers for both receive and transmit channel spacing for all FM channels in the 10, 6, 2, and 1 MHz meter FM bands. An extremely fast rise-and-fall time square wave produces rich harmonics that are usable beyond 220 MHz. Calibration of the Standard's precision 12 MHz crystal to the National...

For

There is a particularly nasty form of trouble which can afflict solid staie transmitters, and multi-rf stage receivers too. much more Than the old fashioned tube jobs, and considerable attention must be paid in order to avoid it+ This is interstage coupling through the low-impedance power lead connections and wires which ordinarily with tubes would not allow sufficient rf voltage to he sent from stage lo stage to cause much trouble. Even with tubes, precautions against this type of trouble had...

Free Alarm Cata

4 PAGES FILLED WITH DURCLAH INSTALLERS AND ELECTRONIC TECHNICIANS, INCLUDES RADAR, IhFfiAHfD, CONTROLS, HAH D*TO FIND FA fiTS, AND & FADES OF APPLICATION NOTES. mountain west alarm 4215 n. 16th sl.t phoenix, az. 85016 Compatible with all sub-atfditofe tone systems such as Pnvate Line. Channel Guard, Quiet Channel, etc. Glass epoxy PCB s & Silicon xstrs throughout. Anv reeds, except special rlual cotl types may be used Motorofa, G.E , RCA, t D.L., Bramco, etc. All are powered by 1 2 vdc....

Free Iandmok

Where else can you get an amateur radio handbook for free That's right, you get about 1200 pages of articles in 73 every year and the magazine is designed so that each and every article is on separate pages - and 73 s the only magazine that does this-with no flipping to the back of the magazine for a parts list or anything. Every page of the magazine is numbered with the regular numbers plus special yearly handbook page numbers all so you can, if you like, take apart your issues of 73 and put...

Full Refund

Just in case the SBE-144 enough to get you to enter the Rig Of The Month contest, we are also offering you the opportunity to buy as much ham gear as you like and possibly get a ful 100 refund on every penny you spend. When you get your local dealer to initial your entry blank you should have him mark down at the same time the amount that you have spent with him during your visit. If your entry wins you wilt get a check from 73 Magazine for the amount of your purchases. We thought we'd give...

Genave

FM tr nscaivor 30 WATTS OUTPUT ALL SOLID STATE Mo lubes * l O chanrwTs 9 Witti mic and mobile mounting bf3c.ktif PfQ'i tevfl const, by ontinju if had avionics rnfg. * (Amd ur n < 249.95t Our price S2 1 2.50.< v> th AC supply IRftg. 239.95) S242.4S. AMATEUR - WHOLESALE ELECTRONICS BB17S.W 129 Terras Miami FL 33156 Phone < 305)233 36311 N> flhti- Weekend) (3051 666 1 347

Giant Alphanumeric Readout With Driver Board

This giant tiza burroughs H7971.16 segment uheh displays all numbers end SGttef of th* Jphatffi in gi*ni T' numefali. Dhvef board allows operation from standard TTL Jevell. VViFh mstftictionj and schemffUcs, provided n two rubei with socket) mourned on single board. Two Giant NjKfets with Of iveri 5,00 El Mating connector for abovt l.00 LOUDSPEAKER SYSTEM COMPONENT __SPECIAL We have mrndt an excef-lent pofcha of an exmj Inventory of local man ufneturers speaker tyilnrm although we aren't...

Guide

46L What is the vacuum tube counterpart of a (1) grounded base circuit (2) grounded emitter circuit (3) grounded collector circuit A. (1) the grounded-grid circuit (2) the conventional grounded-cathode circuit (3) the cathode follower. 47 What useful functions does a balanced modulator perform in a radio transmitter A. None, except in a SSB or DSB transmitter. The function of the balanced modulator is to simultaneously provide amplitude modulation and carrier suppression. In a DSB or SSB...

Hf Frequency Standard

Markers at 5, 10, 25. 50, 100, 20C and 400 kHz. 400 kHz crystal No unwanted markers. Latest low-power ICs. Osc, and output buffered. Sh. wt. 2 lbs. (Less Batteries) 32.95 Precision timer for meteoric scatter communications. 60 Hz time base provides 15, 20, 30 and 60 second out put. Synchronized to WWV. Automatic and manual outputs. Sh. wt. 2 lbs. . 49.50

Highquality Coated Copy Lenses

Excellent uxd t -i i IcM ittmrn & V*m J nfd) fw titt L i cop> njc. rnljrsiflt. praiectiaR Gutrd opfit , hliik meial birreli Hioit -click ri u f 4 T f 6. f 6 3. f fi . 195.00 _ 25.00 50.00 37,50 95.00 150.00 75.00 _ 35.00 95,00 ALL MERCHANDISE IN EXCELLENT CONDITION SEND CHECK OR MONEY ORD fl WiTH ORDER Sartie as Itm above bur wifh click srups f 4 V t 5.6, f'B. I ft, f i6. t 22. f 2 MERCHANDW& SHIPPED FREIGHT COLLECT , CALtFORStA RESIDENTS ADD 5* SALES TAX 2176 E. Colorado Blvd.,...

Highsensitivity Wide Band Receiver

COMMUNICATIONS BUG DETECTION SPECTRUM STUDIES 38-1000 MHZ AN ALR 5 Consist of brand new tuner converter t -' bS W.H tn original factory paek and an cxr, used, checked OK & grid main receiv er R-444 modified Cor 120 v 50 60 h Yhv tuner covers the r< int e in i bands each band has its ou n Type N Ant. input. Packed with each tuner i- the factory ijrisnector's checkout sheet. The one we opened showed SENSITIVITY 1.1 at 38.-1 mh . (lt9 al 133 mh ( 5 at 538 mh . i al 778 mhz, 7 at 1 gh + Thr...

Inc

Output conditions for a series of input pulses, and the 7490 counter has ten. The drawing of Fig. , as with other drawings is an actual wiring diagram rather than a schematic. This will aid in construction and will simplify the description of what it does rather than how it does it. When the simple circuit of the counters and decoders is wired together and activated it can be seen that applying a pulse to the input of the 7493 will cause the output of the 74154 to change by one position. A...

Pxm

Output circuit is correctly lined up on 50 MHz. I also listen on an untuned diode to note any spurious, squegging, discontinuous jumps in power or frequency, etc, This is a little diode plank, made up as in Fig. 7, Note the variety of inputs to suit the various frequencies you may be monitoring, For UHF up into microwaves use the 1.5 pF On VHF and UHF the 3 to 30 trimmer is good For lower frequencies the .001 capacitor delivers more rf to the diode for test purposes. The diode output also has...

Jamaica Ave Hollisny

Hysteresis refers to discontinuous mode jumps in output power when the input power or frequency is increased or decreased ' So don't be downhearted if you iind troubles in your solid-state building projects. You're not alone There will be more of this cautionary material, so keep reading, and try to understand what I mean by smooth tuning, You really need it with solid state devices. When everything is working right, the mixer collector or circuit does tune...

Kacj

Wilii the Memphis Hamfest on September 7. 1 will see yon there and gladly discuss any MARS matter. For a MARS brochure or other information contact me at Harry Simpson A4SCF 73 Magazine MARS Editor Peterborough NH 03458 WA600J What is micros rip and stripling* The answer to that question is reasonably simple. One day in the I920N some enterprising amateurs took two different sizes of copper water pipe, cut some rubber supports, slid all three pieces together and, presto, the world's first...

Kcll

Stortz K3QK0 5122 Alberta Avenue Baltimore MD 21236 Complete power system in operationt Unit B to the left - Unit A to the right Adding a 12V dc to 1 10V ac 60 Hz static inverter to the equipment list of the amateur experimenter will increase the versatility of his station to a degree that makes any reasonable labor in this direction worth while. The two units, presented here, are intended to be used together and, with a 2V auto battery as primary power, have the necessary output...

Keying Line

Sent up to 144 units, or a 7493 and 74154 could be used in place of the 7490 and 7442 to increase the length of the message, at higher cost. Figure 5 is a phase shift oscillator that was used with the ID'er. It is keyed by biasing the transistor on from the high output of the last 7430, The 1 meg pot is used to set bias on the transistor so that the collector voltage is about half of the B+ voltage. There will be beta variations between different transistors so the pot is needed to set bias...

L

Notes 1. Uses components and board of International Crystal PAX-1 rf power amplifier 2. .Add a 33 K resistor inio hoies marked R on PAX-1 board 3, Select L and C as shown in PAX-1 instructions for range covered, Adjust for max output with synthesizer set for 146.5 MHz 4, Use 10-turn link with yel ow coil and 5-turn Jink with red coil for coupling to next multiplier, Experiment with correct number of turns on final Unk to transceiver. Fig. 12. Frequency...

Last Minute Additions

NE565 Phase lock loop, TO-5 S3.5 ea, NE566 Function Generator, DIP (8 pin) . . . 3.50 ea, NE567 Tone decoder, DIP (8 pin) . S3.50 ea. 7447 7 segment decoder driver . . . . SI .60 74181 Arithmetic Logic Unit, 24 pin, DfP , . - . 4,50 8261 fast carry for above 2.00 8223 256 bit bipolar field programmable, read-only memory 10.00 8570 9 bit SI, PC, shift register 2.50 LED Red Emitting Lamp .60 AH IC's are new and fully tested - leads are plated with gold or solder. Orders for 5 or more will be...

LC

Deep notch filter w variable Q, frequency. gain while R3 fine tunes Q. Ganged variable resistors R4 and R5 control the frequency of the notch while resistor R2 limits feedback. Carrying the design of Fig. 3 further yields the configuration shown in Fig. 4. This deep notch filter may be varied in both 0 and frequency. Using an operational amplifier as the active element allows differential operation of the amplifier to assure high attenuation of the notch frequency. The input signal is...

Linear Special

Ten (10) Teiedyne TO-5 741 operational amplifiers with a two-page sheet of application notes covering the basic circuits using op-amps . S.65 each Op-amp package 10-74Ts, data sheet and application notes only 6.00 LM i 00 positive voltage reg 80 747 dual 741 op amp DIP UO LM302 voltage follower op-amp .25 709 operational amplifier -40 710 voltage comparator ,75 LM309K 5V-1A power supply module 2.50

Memory Matic Deluxe

Capacity for 8000 bits in 8 Read Write Pluggable Memories. Each memory can store either a single message or a number of sequential (messages. Near full and Overload alarms. ''Message Stop for char, insertion. ''Full Control weight ratio, message interrupt switch, var. trans, delay, 115 220V acp 50 60 Hz, ncf, SM-21B and MST-60 features. Sh, wt. 8 lbs. OncL 3-500 and 1 -1000 bit memories.) 393.50 Additional Memories 500 bit 21.50

Meters Panel Type Weston Model

0-500 microamps full scale calibrated .005 to 500 roentgens hours. 270 degree scale, approx. 3 dia. excellent for wavemeter etc. New and in original boxes. bandwidth DC to 500 KC. Sensitivity .05 DIV. 50V DJV. waveforms required for hot. deflection. Size 4 x 12 x 14 160A regulated power supply for above indicator. Size 4 x 12 x 14 ff162 wave form generator for above indicator. Size 4 J x 12' x 6 SPECIAL PRICE FOR ALL 3 UNITS SHIP. WT. 35- PRICE 99.95

Mohx

1(1 fiF. t li 11W - * -i f -. r p VOLTAJE HMil l.ATUKS. Jnlrmallv -l, r rrliud od thur < nHI pruof rntul4tun hrrd no CTfrfiui 1 - UUfa Jjl j ni jinl .,f.i li, .ifn .n he Ica T(l1 P fk.i t. I M-W, ,'S fjlHhltA r. W.B5 IA1 -IHhll * . . . h H H ( . l I -ly 14 I SV, ti mi ii h. J . . . flu iUWntt Iti.imJ I h r III' i SINK M.JH '.f lfi VI I UAifip rtilhhl oritu r. lidp'al fpif u-i n-illi I J-Ht-Ji I .nil UpT- np r> p JC i BRAMJ Ntw ith * Jil jiltLfiJ pnw V

Motorola Tuning Diodes

Silicon voltage variable capacitance diodes in TO-92 plastic case like plastic transistors. Both standard Motorola and HEP numbers are listed devices are same. Capacitance value is typical at 4Vdc. Tuning ratto is approx. 3 1 - MV2101 R2500 6.8 pF 31.10 MV2103 R2501 10 pF 31.10 MV2105 R2502 15 pF 31.10 MV2109 R2503 33 pF 1.10 MV2112 R2504 56 pF 31.10 MV2115 R2505 100 pF 31.10 UL900 Buffer 80 UL914 Dual 2-input Gate 80 UL923 JK flip-flop 31.50

New Item

RT 176 PRC-10 TRANS. & RECEIVER FM 38.0 to 54,9 MHz. Approx. 1 Walt Portable Pack Set, 16 tubes, amimuous tuning, i MC calibration cluck poiriLs Hattery power required 7,5 67.5,6 intl 1.5 VDC. Sizei 9.5 x 3rx 10,5 Actual Wl< 9 lbs. less Bait. Price - Used AM 59ft U POWER SUPPLY & AMPLIFIER Operates from 24 VDC and PRC-10 plugs into top of unit. Size 11 x 11 x 10 Wt 34 lbs. Price-Used 18.96 H 33IPT Handset and Plug for PRC Sets - Used . . . 5,96 MANUAL for PRC-JO Radio Set 7.50 AN 130...

Nepb

Goes io +5V, and the output of ICL3c ground pin 12 of KT3d, Either of these two conditions brings pin l I lo +5, turning off the optional LED LOC K indicator, and bringing the LOC k signal, which goes lo the switched buffer amp, to about OV. This LOCK signal is about +5V (a binary I when the loop is in lock, and goes to ground (binary 0) when the loop is unlocked. The optional LHP diode makes a very handy way of checking whether the loop is locked or not. Ihere is room for the diode right on...

News

Michael Frye WB8LBP 640 Deauviilc Dr. Dayton OH 45429 have been recently informed that A-O-C will again be delayed until November and possibly into early December, his is again tine to NASA sched uling. Tins column will be just a short rundown of recent happenings since all activities are progressing normally. 1 strongly suggest that you at least monitor the AMSAT Nets as quite a lot of current information can be gathered there. If you have specific questions, check in and ask it. someone in...

NI

J-all resistors i 4w, 5 carbon. 2-all capacitors in pf i0 , 20v produces an output without external drive. It will maintain this frequency very well when providing power for resistive appliances, such as soldering irons and lamps, thai require inputs within the range of 50 to 100W. Both units make excellent projects for amateurs with an urge to use their oscilloscope and to gain experience with transistor power switches. The fundamental problem in making our high power square wave is to switch...

Order

ALL STANDARD REPEATER CHANNELS IN STOCK AT ALL TIMES-NO BACK ORDERS. SHIPPED FROM MASSACHUSETTS. YOU GET FAST MAIL* DELIVERY. Crystals are available for the following two meter FM transceivers at this special price offer Drake, Regency, Simpson, SBE, Sonar, Standard, and Tempo. Please specify the make and mode transceiver when you place your order so we can be sure to send you the correct compensated Crystals. Crystals are available for other FM transceivers and other channels . . . please...

Pavne Radio

Days (615) 384 5573 Sundays < 615) 384 5643 trie can tell nie what they are, and for how much to amateurs interested in good UHF feed through bypasses. Ihey do seem to work as well as the final form shown in Fig, 5, so if you can find them, pay the price, and have a wall 0 put them in, such as in an enclosed rf stage, you can use them. The test setup of Fig, being in operation, a smaller version was tried, (o he ready for the size reduction being looked forward to with all kinds of new and...

Output No

Figure 2 is an astable multivibrator that generates a square wave train of pulses to drive the counters This is also a wiring diagram, but a bottom view. The multivibrator is made from an RTL dual gate RTL seems to work better in this application than T I L and a few 914's were available for this use. The 7400 is a quad two input gate used to square up the output of the 914. and to turn the output of the clock circuit Example for Encoding Character Sequence

Payne Radio

Days (615) 384-5573 Sundays (615) 384-5643 connector, which had some inductance In ground, was absolutely no good. I then cut out a small brass frame as in Fig. 4. Hurray The first time to hit a real zero volts. It makes you haul out the ohm meter and check for a short oi an open Same, but without choke, also zero. I noticed that every time I checked with another 1 000 pF on a little coffee stick from A or B to ground, in effect paralleling the one already there, I he meter plunged to near...

Ptt

This timer circuit is ideal for repeater applications because its period can be adjusted to any duration from 2 seconds to 4 minutes. The top set of COR contracts starts the timed sequence and the lower set, on ciosing, resets the circuit. The relay is a Potter-Brum field RS5D with a 6V coil having a resistance of 335Other re ays can be used but the coil resistance must be no lower than that of the RS5D< the other. It can be set for a period as short as 2 seconds, or as long as 4Vz...

R

The R-599 can be operated directly off your 12V battery with very low drain, it is also an ideal novice receiver . . . having standard provisions for crystal control ling the T 599. The T 599 Tiansmitter Cfear, stable, selectable sideband, AM and CW 4-way VFO flea rbility plus Receiver incremental Tuning (R T) when used with the R-599 * Amplified ALC Burlt in VOX - Full meter ing. including cathode current, plate volt age, ALC and relative Power Output Built-in CW Sidetone monitor and semi...