Info

* Trail sceive or split frequency with two built in VFOs CW key er built in * *1F shift - new patented QRM remover* * IF noise blanker* Digital nixie frequency teadout * superb computer grade construction by C.V1I *AFSK keyur *.idjust.ibie output power * broadband tuning +output wattmeter and reflected power meter * 2395

Meter Fm Amplifier With Builtin Ac Power Supply

Operate at home - 110 VAC or car-12 VDC. Supplies regulated DC for transceiver. 1W in 15W out-AC 1W in 1 OW out-DC. AutoT R Send for brochure ONLY 69.95 QUEZAR COMMUNICATIONS PO Box 235 Titusville, N.J. 08560 Operate at home - 110 VAC or car-12 VDC. Supplies regulated DC for transceiver. 1W in 15W out-AC 1W in 1 OW out-DC. AutoT R Send for brochure ONLY 69.95 QUEZAR COMMUNICATIONS PO Box 235 Titusville, N.J. 08560 K T CARRIER DIODES HP260O 5 90,l 'S1D.a0 Matched by HAL ZENERS tfM729l3.5vl, 1N4...

Did

The objective of this article is to provide a ham with enough information to allow him to build a pretty nice minicomputer. An alternative to building your own is at least understanding what makes tile brain machine tick. This means if you don't meet the qualifications of a computer builder, you can buy yourself a good used computer and understand enough of its operation to put it to work for you. (Hint, do not trade the XYL in on a used computer the computer would undoubtedly make a more...

Free Books

Any one of the following books is available (postpaid) as a premium if you buy a subscription to 73 for yourself or a friend (or an enemy or even an ARRL official since few of them get it). One book per subscription. A The Novice Class License Study Guide has not yet been published in 73 or in any other magazine. This book contains all the basic technical information needed to pass the Novice License with flying colors and is invaluable as a basic text for understanding the General Class Study...

Electrolytic Capacitors

4000 MFD at 1BV 75 10 6.00 1000 MFD at 15V 25(f 10 2.00 BO MFD at 15V 20 10 1.50 Miniature reed switch, glass enclosure 3 4 long 25< t ea. 10 2.00 88 MH Toroids, potted 10 3.00 I RC Trimpots RT22C2 1 K-5K-10K-20K Pots, miniature 1 8 shaft 5 K 3 1.00 Knobs for 1 8 shaft, brass inserts . 5 1.00 1000 PIV 1 amp Diodes 10 2.95 R & R ELECTRONICS 311 EAST SOUTH ST. INDIANAPOLIS, IND. 46225 5.00 minimum order Please add sufficient postage.

Flat N Ylon Lacing Tape

One pound twbc of black lacing, about 1,000 yards, should last the average hobbyist several years. Usual price is 10.50. At this pice you can nse it for all kinds of applications berides lacing. Test over 50 lbs. Lacing Cord 11b 2.00 SANKEN HIGH POWER, HIGH PERFORM- ALL EMS WHERE WEIGHT NOT SPECIFIED AJVCE HYBRID VOLTAGE REGULATORS POSTAGE PAID IN THE a s. A. The , hybrid .regulators are easy to p (6l > 53 _5774 or (6l7) 532-2323. nge, requiring no external compon- . . ,, ents. for...

Linear Special

Ten (10) operational amplifiers with a two-page sheet of application notes covering the basic circuits using op amps S.65 each Op-amp package 10-741's, data sheet and application notes 14 DIP, 8 DIP choice only 6.00 LM 100 positive voltage reg 80 747 dual 741 op amp DIP 1,00 LM302 voltage follower op-amp 1.25 709 operational amplifier 36 71 0 voltage comparator 50 LM309K 5V-1A power supply module 2.50

New Hr

1 2 Channel Solid State 6 Meter FM Transceiver Complete dash mount operation . . . does not require black box power hog in your trunk 12 T and R Channels Independently Switched Designed and use tested to perform against TVI. Designed to utilize the most modern components of the solid state art integrated circuits, dual gate MOSFET transistor, silicon BET power trangistor, etc. Designed with the power in the frequency range to work FM Skip. And, designed and built in America in a compact package...

Memorymatic 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 ac, 50 60 Hz, incl. SM-21B and MST-60 features. Sh. wt. S lbs. (Incl. 3-500 and 1 1000 bit memories.) G98.50 Additional Memories 500 bit 21.50

Bpz

JL KD Outfit*. Rr 4oit Limp Tea. Jtf le. 31mkit* ud C mBifrr Kr i hNe. 3L Ply* in M dr. 4 Mo In iacki U iot J IC, d Rr foul. 5. Tw pii J C-I , iwiCopp . G m Epovy 3o d 6. Your ckucf Dil lo 6 se dia oc cor t Boni 7. Gicwpiiu o 2 mm radog-j m tic juk dupUy bwrd. 8. Di Aar taud cvxinu pupcedkular to ir.ln drfitr b jtd. 9 UpfDowr. counting t-id munter BH3CI fo r.w itvUNc I ft 60 MHZ th-pial lasic n t -> s 7*1 . 11. Qjwrele iioc-i i Volt TTL c-aifut 2j< - rqfr msppty Ii....

Professional Digital Counter

Quite a few articles have appeared in the literaure of the past months, describing digital counters as a brilliant. addition to the experimenter's arsenal. Some of these almost stimulated me to action, but there always seemed to be a vital objection to each of them somewhere along the line. A number of these designs required neon bulbs or nixie tubes with the necessary 200V power supply and high-voltage transistors. Some of the logic circuits seemed cumbersome, some of the articles seemed...

Now Has Available

THESE NtCADS ARE AMERICAN MADE AND NEW WITH A FULL YEAR WARRANTY. NICADS ARE AVAILABLE FOR THE FOLLOWING Motorola Page Boy (tone only) Motorola Page Boy (tone & voice) Cook Pager (tone & voice) Please specify model In the near future MANN will have a complete line of NICAD batteries for most portables write us with your needs. Terms Cash or C.O.D. - No C.O D. under 25.00 CALL JIM OR BOB AT OUR NEW NUMBER 213-889 6666

O

Feedback amplifier equivalent circuit. Negative feedback is used in many applications to reduce distortion and, in general, provide stable amplification. If sufficient feedback is used, such factors as transistor (or tube) variations and power supply instabilities have negligible effect on the overall gain of the amplifier. This type of circuitry is more complicated and, therefore, more expensive. In the past, the additional expense has eliminated this technique from the lower priced...

Crossbanding Base Stations

Since there is no prohibition of interconnecting a 146 MHz signal on any other band when an intermediary operator is present, it does not seem reasonable or logical to differentiate against repeaters. If there are adequate safeguards built into the system, an automatic cross connection between two bands should be the same as if it were being done by a third operator. There is nothing illegal if I am in contact with an amateur station on 146 MHz and one on 52.525 MHz simultaneously in a...

Rf Ferrite Core Choke

8 Level punched tape reader with motor drive. Made by TALLY CORP. 115volt 60 cycle AC motor. Appearance like new. 50 postpaid in the U.S. Alpha-numeric keyboards. Excellent to new in condition. Styles may vary slightly from picture. Two models available, one with ASCII encoder in base 55.00 postpaid in the U.S. Keyboard with no encoder in base 35.00 postpaid in U.S. H -permeability, ultra midget style, coated for moisture resistance, color coded. Used In xmtrs, receivers, converters,...

Giant Alphanumeric Readout With Driver Board

This giant size burroughs B7971.16 segment. ube, displays all numbers and letters of the alphabet < n giant 2 numerals. Driver board allows operation from standard TTL levels. With instructions and schcmatics, provided ps two tubes with sockets mounted on single board. Two Giant Nixies with Drivers 5.00 D Mating connector for above l -00 LOUDSPEAKER SYSTEM COMPONENT SPECIAL 1 We have made an excellent purchase of an excess inventory of a local manufacturers speaker systems although we aren't...

Compuiqr Grade Capacitors

, Always one of oar best sellers these high capacitance units need little introduction, Made for long life over wide amhients, molded terminal block with screw terminals. Perfect for power supplies, audio and eiletgy storage applications. Wt.(lb.) Cap(mfd) WVDC Order No. Price 1 1300 50 SP1350 .75 3 3000 250 MA3025 3.50 3 60000 20 GE60020 3.50 HIGH POWER SCR's SCR's - invaluable for high power applications, motor speed controls-circuits, welding controls, etc. Never before at this low price....

S Q

Reset button at top right. that each IC has a panel binding post for each input and output for a total of six per IC. In addition a ground binding post is included in each iC binding post cluster. The only other item on the logic board is a reset button. This normally gives a ground when connected to the Preclear inputs. When pushed, however, it gives a momentary connection to Plus which serves to restore the flip-flop to its normal state. A patch cord system like this...

Saroc Fm Program

As chairman of the FM program at Saroc, I am going to do my best to put on one whale of a show. It will be worth while coming to see, I guarantee. The FM programs will start early on Friday morning and run all day Friday and all day Saturday until the big prize drawing Saturday afternoon. In addition to manufacturers on the spot to answer technical questions, there will be reports on FM activities around the country, an FM Symposium on changes we need in the FCC regulations a report on the...

Location Of Circuit On Board

-vw- OPTIONAL AUDIO INPUT ( FIG5J 02 Oi 3.9 MEG Fig. 16. Phase comparator. Notes 1. See Fig. 4 for diagram. 2. Capacitor marked * is a bypass capacitor not shown on diagram. as shown in Fig. 19. +12V connects near IC13, as shown in Fig. 18, and goes to the VCO through the 68SI resistor (Figs. 17 and 18). A good source of power for the regulator is a 12V car or motorcycle battery. Before applying power, check the resistance between the +5V and +12V lines to ground. If there is a short circuit,...

Tb

FULLY ADAPTABLE EASY INSTALLATION CONTINUOUS TONE POSSIBLE FULL 1 YEAR RP Warranty FULLY ADAPTABLE EASY INSTALLATION CONTINUOUS TONE POSSIBLE FULL 1 YEAR RP Warranty TB-5 5 tone std. encoder (1800. 1950. 2100. 2250. 2400 Hi.) ST-2 Single tone decoder 537.50 (Specify 1800. 1950. 2100. 2250, or 2400 Hz.) Special tones Inquire Adi 1,80 unit for shipping (III. residents add 5 ta )

If You Want Prompt Service

ON AMATEUR PARTS & EQUIPMENT - - WRITE US - - We stock many major lines, including SWAN I EXPERIMENTERS SUPPLIES I DRAKE I TEMPO CORNELL DUBiLIER I G. E. TUBES I MOTOROLA (HEP) HY-GAIN I CALIFORNIA CHASSIS I MSNI PRODUCTS TEN-TEC 1 CALECTRO I B & W i ANTENNA SPEC. CUSH CRAFT I BOOKS & MAGAZINES I NEWTRONICS BOHN-SPAULDING I TFll-EX I ALL SAMS PHOTOFACTS REGENCY 1 OMEGA-T I KENWOOD 1 COLUMBIA PROD'S Please include postage with remittance. 6213 Thirteenth Avenue South Seattle, Washington...

Per

New, Exclusive, Low Cost Miniature Solid State Electronic Buzzer Application* Portable and battar-y-aperatod equipment, j Cim elcqfcs, t& si apfwiralus, intercom sets, seniors. automotive warning signals., tirtiars. ols. Kl h Roll Mity no mowing contacts. A semi-conductor drtv& s a vibrating reed coupled to a plastic diaphragm. Coil is enclosed In a magnetic pot core. Ho arcing, interference Law Pctrar Conrtrmplfort Unit consumes les pawat Vian a signal lamp. ApprbrimalBly 15 mA at votts,...

Very Small

Mounts anywhere - or goes under the arm for walkie-talkie use. One of the sma llest 10 watt rigs avai lable, LOW INTERMOD One of the big miseries in FM is interference from nearby or overly strong adjacent channel repeaters. The ceramic i-f filter in the Ross & White virtually overcomes this problem. This rig will perk perfectly in areas where other rigs are completely bombed out. If you are a newcomer to FM you may not appreciate the importance of this feature - if you are an old timer you...

Last Minute Additions

NE566 Function Generator, DIP (8 pin) . . . 3.50 ea. NE567 Tone decoder, DIP (8 pin) 3.50 ea. 7447 7 segment decoder driver 1.30 74181 Arithmetic Logic Unit, 24 pin, DIP 4,50 8261 fast carry for above 2,00 8223 256 bit bipolar field programmable, read-only memory 10.00 8570 9 bit SI, PO, shift register 2.50 LED Red Emitting Lamp 60 All IC's are new and fully tested - loads are plated with gold or solder. Orders for 5 or more will be shipped prepaid. Add 354...

Competitive Machines

DYNAMIC RANGE 10-99 to 10 DATA STO RAG E 2 Auxiliary Storage Registers plus up to 7 push-up Stack Registers. Roll up and roll down keys for complete control of operational stack Interfacing provisions for printer and programmer Correct X (Allows the operator to correct one digit, without re entering the whole problem) Polar to Rectangular conversion and Retangular to Polar conversion DISPLAY Either full floating or scientific notation, 14 WRITE OR MAIL COUPON FOR ADDITIONAL INFORMATION sm COAL...

Reader Service

Please cither tear out this list of advertisers and send ii in to 73 with as many boxes checked off as you ivoutyi like to see brochures, data sheets or catalogs or else make a copy and send that in. Include your zip' code, please. Am Wholesafe Elec' 91,244 1 Amer. Cancer Society 238 1 Data Eng 23 iJ Datak 131 Elec. Distributors 61 U EL Instruments 80 L' Emporium 119 LJ Environmental Prod. 286, 287 Erickson 70, 71 I Estes 243 Gotham 215 D Gregory 276 Hatry Elec. 203 a Heath 77, 76 Hygain...

Complete Stocks All National Brands We Buyselltrade Used Equipment

Louis, Mo. 63132 Phone (314) 993-6060 You should be participating in the Rig of the Month Contest. Call Keith, W7DXX 1 person to person collect at 603-924-3873 If you want to win the Rig of the Month plus get all your money back for your monthly purchases, you need a nearby participating dealer in the 73 Rig of the Month Contest. If your local dealer is not participating, write him, threaten him, boycott him, but talk him into participating.

Voltmeter

One piece of test equipment found in many hamshacks is the voltmeter, There are many voltmeter variations and each variation has advantages and disadvantages. Many of us have an idea of what we would like for the perfect voltmeter. Over the years, I have thought about my ideal voltmeter but never applied the elbow grease. Recently, the urge became strong and I actually built it. I can best describe my ideal voltmeter by describing the result of this urge. The voltmeter features a zero-center...

With Case

Buy 3 Take 10 < Smaller lijore compact j Houre.seent Ulu -(iwn 0-9 numerals, decimal and letters. ll. x V, Characters Filament V. MINI-7* 1.75 x 1.7 .360 x .570 1.5V AC DC 42 mil Socket - 50c SLIM 7* 1.6 x 0.375 .40 x .20 1.5V AC DC 42 mils Socket - 50c Compatible to 7- eRmeirt driver IC . Comn, ,r Completely w,r d. ready , , Not a kit - hours iav.d, singla chip SX (L ri. T -f t,,< H at and Division. aT well fs tr- Wication 3 LEDS, visible, micro-miniature, axial leads . . , 2 LEDS,...

Wfez

Here is a quick-switch antenna patch box, with built-in transmatch and dummy toad. Douglas S. Byrne G3KP0 Jersey House, Eye, Peterborough, England o you already have half a dozen different transmitters., a like number of antennas, plus a transmatch, dummy-load and rf-am meter OK, OK, but how do you connect up this lot, eh My bet is with odd lengths of coax, alligator clips, or even, like me, by twisting together odd bits of flex, kept in the sockets with matchsticks . . . right the first time...

This Space Contributed By The Publisher

Completed mixer amplifier board mounted in the die-cast housing. transistors used here and on the ramp generator board are unknown surplus silicon units. The pc board for the mixer is 1,5 x 2.9 in. and is mounted in a Bud CU-124 die-cast HI, R2, R3 - WESCOM RV-IK C , C -WESCOM U25-IOOO Al, Z, A3-MOTOROLA MFC S030 ALL RESISTORS-J 4W, 5 Tl-See '.cut Fig. 10. (A) Foil side of power supply pc board. (B) location of parts on component side.

Resister Shifts On Positive Going Edges

RESET Fo_ E O'jrPUTOF 4GATE RESETS COUNTER TO ZERO Fig. 2. TTL Selcal waveform timing diagram. and one half of an XN7476 dual JK flip-flop which is used as a control element to start and stop the clock. When connected as in Fig. 1, Q3 and Q4 act much like a unijunction transistor, but with increased reliability in operation at lower supply voltages. Fig. 5. Expanded decoding TTL SeJcaJ. Fig. 5. Expanded decoding TTL SeJcaJ. As the 0.1 mfd capacitor at the emitter of Q3 charges up, a point is...

Henry Ka

CW, RTTY or SSTV through commercial ratings * 3.5 to 30 MHz * Continous duty * Silver piated Pi-L plate tank * DC relays * ALC * Built in SWR bridge * Output power 2 KW min. in commercial service * THE linear for THE CX-7A * S995 YOU will never know how little it costs to own THE incomparable CX-7A or Alpha 77A until YOU write or phone us and let us know the trade in deal YOU WANT. * We usually say yes NO ONE ANYWHERE BEATS OUR DEAIT*

Commission

APPENDIX Part 97 of the Commission's Rules is amended as follows 1. Section 97.3 is revised to read as follows The following definitions are used in this part (a) Amateur Radio Service. A radio-comm u ni cation service of self-training, intercommunication and technical investigation carried on by amateur radio operators. (b) Amateur radiocommunication. Non-commercial radiocommunication by or among amateur radio stations solely with a personal aim and without pecuniary or business interest. (c)...

Circuits

The Tumstille antenna, two dipoles phased 90 apart, is an omnidirectional horizontal antenna developed originally for mobile use. Dimensions for operation at 145 MHz are elements 19W 1 8 brass rod S0i2 coax Q-section RG59, 13'A long. Support details are shown below. From VHF Antenna Handbook by K5JKX, available from 73 for 3.00.

Immediar

ALL STANDARD REPEATER CHANNELS IN STOCK AT ALL TIMES-NO BACK ORDERS. SHIPPED FROM MASSACHUSETTS. YOU GET FAST MAIL* DELIVERY. *We realize that tJiis is a contradiction of terms, Crystals in HC-25 U holders for the 146 MHz channels listed in the order blank are available for . . .plus per complete order for postage and handling. This low price for Drake Regency Simpson SBE Sonar Standard and Tempo. ONLY Eastern customers may appreciate our fast mail service it can save you days to weeks on your...

Switch

Wire, or even an elastic band and should be mounted on the wood base or panel, adjacent to the on-off switch, SI. For those with variable voltage power supplies SI is probably not required and can be connected to the voltage reversing switch, S2, directly through a plug and jack arrangement. It could even be made an integral part of the board if desired. In using the board any components such as coils, transformers, etc., not provided for on the panel are conveniently placed on the base...

Weey

NULL OUT REPEATER INTERFERENCE ONLY 39.95 Deep back null for co-channel rejection Broadband, low vswr 144 to 148 MHz Quality materials, construction Logan LOG PERIODIC beams and arrays can be used vertically or horizontally and mounted on top or side of tower of mast with negligible tower effect. Stacking kits available. Ideal for rejecting that high-power repeater you've been hearing. Only 39.95 F.O.B. Farmingdale, N.Y.

Taz

The output voltage swing determines the series resistance for the milli-amnieter. Full scale current for the lower ranges was selected at 0.75 A. The feedback resistance, which also will be constant for the lower ranges, is equal to the full scale output voltage divided by the full scale current, or 0.5V divided by 0.7 5 juA. With this resistance (667 Ki2), we now have an input current sensitivity of 0.75 fJ.A full scale. The multiplier resistances are calculated as if we...

Mars

Box 27015 Memphis TN 38127 Several months ago when this column was visualized, it was intended to be a sort of clearinghouse for MARS information - a column designed primarily to inform MARS members in one area of happenings elsewhere. Many telephone calls were made, many letters written and scores of personal friends were contacted, requesting information that would be of general interest to the entire MARS membership. After the first effort appeared in the May, 1972...

METER

I recently wanted to do some work on a 2 meter antenna and since no other instrument was handy, started to use an SWR meter manufactured for use on the high frequency bands. After some erratic results, it was decided to check the SWR meter accuracy on 2 meters with some carbon resistors to simulate different SWRs. The results readily confirmed that the SWR meter was useless at VHP unless one didn't care whether a SWR was really 1 2 or 1 5. Rather than purchase another SWR meter, it was decided...

Apc

One of the most common, least expensive, and useful variable capacitors around is the APC type. They are available new and used in military surplus as well as in the form of replacement parts. These capacitors are well made and have practically endless uses in any builder's shack. The major disadvantage of this capacitor is the single bearing design, but this is a problem only in frequency determining circuits such as a vfo. A second and relatively minor disadvantage is the almost universal...

Note

Full size transformer end plates. rig- 4. Full size transformer end plates. 62 pi dipped mica Urielco 1000 mmf 1 Jf 50 v disc .01 if BOv disc .001 if 50u disc 25 it 35v electrolytic 2.2 JLrh molded inductor 100E1 1 2w carbon 1.012 1 2 iv carbon lOOfi 2w carbon TRWPT5741 Identical To 25 w T2. Tl.Sare not mounted on P.O. end plates. Identical to 25 vu T1 except wire winding is ST No. 13. Identical to 25 wT3 except wire winding is 4T No. 18 Tr-TS and T5-T7 are mounted on the same P.C. end...

Integrated Circuits

WE STOCK THESE transistors & diodes power transformers items & more resistors 8. capacitors pc board drills ENVIRONMENTAL PRODUCTS 48 Page cataio9u e FREE with order PO BOX 1014A or sent' *or copy. Glenwood Springs, CO 81601 303-945 8527 Fig. 2. No roller coasters in the junkbox Then wind a coil of 30 turns on a 2'A in. former, and short out every few turns by means of a 12-way Yaxley switch. Fig. 2. No roller coasters in the junkbox Then wind a coil of 30 turns on a 2'A in. former, and...

Ccwpufr

Into the gate which clocks the register. The TTY CONTROL signal could be generated by a circuit which detects the depression of a key on the TTY. The TTY TIMING signal is one that occurs at TTY bit times and each bit of the TTY signal is clocked into the machine. When ihe STRF (store) signal goes high, the computer's internal timing reads out the signal stored in the byte register. This signal is routed to the control circuits (Fig. 1 1 and the control circuit will decide what to do with it....

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. 7400, 7401, 7402, 7404, 7405, 7410, 7420, 7430,7440, 7450, 745 1,7453 . . 100 fDr 20.00 . . . . ea. .22 7441 BCD decoder driver 1.00 7442 BCD decoder 90 7473 dual J K flip-flop 55 74 74 dual type D FF 40 7475 quad latch 1.15 7476 dual JK FF 55 7480 gated full adder 50 7483 4...

Hpb Time Interval Plugin

TS-413 U SIGNAL GENERATOR 75KHZ TO 40MHZ IN 6 BANDS, PRECISE CALIBRATION FROM LMHZ CRYSTAL OSCILLATOR, HAS MODULATION METER CW, OR AM 400 1OOOCPS VARIABLE 0-50 AND RF LEVEL METER 0-1.0V. IDEAL FOR AMATEUR, MARINE, AIRCRAFT and HOBBYIST FOR IF AND RECEIVER TRANSMITTER ALIGNMENT OR DEVELOPMENT WORK 89.50 SG-66A ARM-5 OMNI SIGNAL GENERATOR, MILITARY VERSION OF ARC H-14. FAA APPROVED FOR Al RCRAFT RADIO SHOPS 550.00 TS-382 U AUDIO OSCILLATOR, 0 200KHZ WITH 60 AND 400 CYCLE REED

Ascf

Nice letter and enclosure from Bill Turner (WA0ABI). It seems Bill works in the Gallium Arsenide facility (that's the Gunn and Impatt diode material GaAs) of Monsanto Chemical in St. Louis, and found a few hundred surplus GaAs diodes in the microwave package. Unfortunately the diodes had been used in a destructive life test, and were 75 shorted and 25 open. Oh, well, Bill had good intentions of supplying all you microwave cats out there with free diodes. Sorry it didn't work out. How about some...

Pms

Fig. 11. (A) Foil side of power supply PC board. (B) Location of parts on component side. Fig. 11. (A) Foil side of power supply PC board. (B) Location of parts on component side. aluminum box. Note that here again some of The Power Supply the components are mounted between the Figure 7 is a schematic for the power board and their external connectors. These supply. Voltage requirements for the sweep include both the 10 pF and 100 pF input generator are +15V, 15V and +5V dc. The capacitors to...

Digital Time

Ever since tne first digital clocks came on the market, probably 30 years or so ago, we've been fascinated by them. And when the nixie readout clock became practical as a result of large scale ICs, we had to go that route, at any cost. We started out with the Logiconcepts clock - a beauty. We use them in every part of the 73 offices. Those numbers lighting up are fun to watch, better than a navel. The only drawback was that the Logiclocks are over S100 and that limits their appeal a bit. So...

Communications Corp

213 775-6284-639 North Marine Avenue. Wilmington, California 90744 another band having higher operator privilege requirements is unfair to those operators who have properly qualified for the higher requirements. For these reasons, we are persuaded to adopt the provisions of the Notice prohibiting multiband,crossband and linked repeater operation even where operator privileges would permit it.' Similarly it is not in the interest of spectrum conservation to utilize cross-band and multiband...

Amateurs In Poland

The Polish Amateur Radio Society (Polski Zwiazek Kro'tkofalowcow PZK) is continuing its training programme in close cooperation with the Polish PTT Administration. This cooperation is based on the well-known fact that the field of amateur radio is one of the best training schools for highly qualified radio and telecommunication specialists. And what is also important - this specialized training is provided by the amateurs themselves, without any expensive buildings, equipment or teachers. The...

Dju

Pictorial demonstration of ramp generation. Fig. 5. Pictorial demonstration of ramp generation. you are planning to use this oscillator for VHF applications, a more suitable diode would be in order. According to rhe data sheet on the MCI648, typical maximum output frequency is 225 MHz. The vernier attenautor is a 1 OOii RV6 style potentiometer mounted inside the enclosure. A coupling and extension shaft are used to bring the control out to the front panel. The value of the resistor at...

Led

Electrically and physically identical to the popular MAN-1. Has higher light output than MAN-1. Includes LH decimal point. W spec sheet & app information. LED700 7 Segment LED Display 6.95 The 1101 Random Access Memory (RAM) will store and readout 256 bits. The chip Is TTL compatible and comes with a complete spec sheet w applications. 1101 256 Bit RAM Build several Instruments with this chip and little else. First really useful LSI chip for th experimenter. Contains Four decade counters +...

Inc

Nont ft 925 Sherwood Drive uepx v Lake Bluff, III. 60044 can get all the energy into one tiny point. When you gather it all together, a little bit will go a long way. In fact, a flash that lasts only 1 1 000th of a second will, if concentrated by a magnifying glass, burn a hole through a piece of steel such as a razor blade. However it would be very impractical to use a laser beam to make a hole in an enemy warship. You would have to have somebody near the ship to hold the magnifying glass, and...

Hygain Electronics Corporation

BOX 5407-WH LINCOLN, NEBRASKA 68505 WRITE FOR DETAILS Fig. 14. Minicomputer block diagram. Mix up all instruction address counter. TnSLrucf on number J ingredients in the manner shown and you have a tells the computer what to do next via the control complete minicomputer All the action begins circuits. The instruction will be whatever you when the timing circuits start the count in the program into the computer. Fig. 14. Minicomputer block diagram. Mix up all instruction address counter....

The New Regulations

The heavy hand of an insensitive government has just dealt a cruel blow to the most exciting and fun aspect of amateur radio in many, many years. FM will never be the same. It is sad to listen to the voices on the bands agreeing that, yes, the new rules do seem rather restrictive, but we can live with them. Sure, we can live with them. Man has shown himself to be eminently adaptable able to live under almost any conditions, from Russian prison camps to the Inquisition. But now, just as amateur...

Complete With Drilled Board

BETTER THAN .3 JUV SENSITIVITY DUAL CONVERSION 10.7 Mhz AND 455 Khz IFs ALL IC EXCEPT FOR FRONT END OPERATES FROM 12 VOLTS NEGATIVE GROUND Order TX-144 or 220- 39.95 PA-144 or 220- 29.95 RX-144 or 220- 59.95. Receiver with 7 Khz ceramic filter 65.95. Include 1.00 postage and handling for each kit ordered. New York state residents add 6 sales tax.

Digital Clock

This product of space age technology computes and displays time of day to the exact second. High visibility Nixie tube readout. Encased in handsome oiled solid walnut case with matching base for desk or shelf mounting in any decor. Silent solid state operation. Fractional second accuracy. Polaroid displays red filter. Three special time settings Full year guarantee (made in USA). 12 or 24 hour time display. Please specify 1 2 or 24 hour model. Send check or M .O. for 1 59, postpaid. COD's...

Amateur Radio And Education

The Union of Radio-Amateurs of Yugoslavia (Savez radioamatera Yugo-slavije SRJ) is one of the youngest national organizations of radio amateurs in Europe. In 1971 it will celebrate the twenty-fifth anniversary of its foundation. Today, SRI has in its ranks about 42,000 members, and among these are some 10,000 licensed radio operators. It is evident that the technical education of such a large number of members and radio operators in a relatively short period of time has required considerable...

Kaw

Author's note When building the synthesizer, remember that the VCO has all the problems of a two-meter VFO. It is just as prone to drift off frequency under shock or mechanical stress. While the phase-locked loop will bring it back on frequency, that takei about second. In our prototype we found that, under mobile operation on bumpy roads in a small, bouncy foreign car, the VCO would wander back and forth. For this reason it is important to build the VCO stage as rigidly as possible, using all...

Binders

CUSTOMIZED DX BEARING 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 all 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...

Hal Communications

Box 365L, Urbana IL 61801 217-359-7373 COMMUNICATIONS HAL ID-1 REPEATER IDENTIFIER Circuit board wired & tested---- 75.00 With rack w cabinet 115.00 TTL logic. Power line frequency counter for 3 minute or less timing and control. Easily reprogrammable diode ROM uses only 27 diodes (depending on call) to send DE any call. Low impedance audio with volume arid tone control. All circuitry including PS on small G10 glass PC board. Write for full details. HAL COMMUNICATIONS, Box 365L, Urbana IL...

Miniature Subaudible Tone

Compatible with aJl sub-audible tone systems such as Private Line, Channel Guard, Quiet Channel, etc. Glass Epoxy PCB, silicon transistors, and tantalum electro-lytlcs used throughout Any miniature dual coil contactless reed may be used (Motorola TLN6824A, TLN6709B - gramco RF -20 Powered by 12vdc < )3rna Use on any tone frequency 6 H to 250H2 Miniature in size 2.5x.75x1.5 high Wired and tested 14.95 Complete less reed Available in 33 freqs. for 17.50 ea> Output 3v RMS s'inewave, low...

Instruction Address Counter Timing

1& CLF INSTRJCTIO address COUNTER LOAD PLSL5E CYCLE I j CYC LE 2 CYCLES i i IACL Fig. 11. Timing circuits. These circuits provide timing to the various computer circuits at the proper sequence. When the command is a con ditioned branch, and the condition is positive FF-A forms a new timing cycle (see text). the timing card only, except where you run a wire out. The circuits shown in Fig. 1 1 are based on operational circuits. Stick closely to the recommended logic and you should have your...

Hd

It also facilitates cleaning the bus wires of excess solder buildup when it is only necessary to tilt the board up, resting on its panel and run a hot iron along each wire when it will run off, leaving everything nice and clear again, ready for the next project. If you use a computer board and have any usable copper underneath each hole where the ends of the bus wires project, you can anchor each wire by soldering and snipping off any excess wire. If not, an...

Hewnadio

Olympic Blvd., Los Angeles, Calif. 90064 931 N. Euclid, Anaheim, Calif. 92801 714 772-9200 Butler, Missouri 64730 816 679-3127 un-tuned crystal oscillator. Any fundamental crystal between 1 and 30 MHz will drive the 50 jA meter to full scale. Inserting an unknown impedance in pins 1 & 3 of the test socket will allow you to read the impedance on the calibrated dial. Should it be convenient to drive the bridge with an alternate rf source such as the transmitter or an rf generator,...

Tea Camera

6741 -GE 1 Vidicon TV camera. 500 line center resolution, 4000 1 ALC, both video 1.4V (p-pl composite and RF output, tuneable channels 2 through 6. Solid state input power t17V 60 cps 12W. Dimensions 5.26W 3.54H 11.75L, wt. 8 lbs. Used, reconditioned, complete with standard 1 lerjs. Only 199.95 Free Flyers 972i 3M - Special flyer containing bargain prices on both new < used television cameras, VTR's < S associated equipment such as lenses, video tape, etc. 972 6 - Loads of bargains in CCTV...

Utc Type

WE START AT 765 & GO TO 2805. HAVING THEM IN 170 CYCLES STEP. LiMITED QUANTITY PRiCE 7.95 ea. 2 15.00 ALL PRICES ARE F.O.B. OUR WAREHOUSE, PHILADELPHIA, PA. ALL MERCHANDISE DESCRIBED ACCURATELY TO THE BEST OF OUR KNOWLEDGE. YOUR PURCHASE MONEY REFUNDED IF NOT SATISFIED. TERMS ARE CASH. MIN. ORDER 5.00. ALL MERCHANDISE SUBJECT TO PRIOR SALE. RFE - REMOVED FROM EQUIPMENT. WINTRONIX MODEL 850 INDUCED WAVE FORM ANALYZER. This unit, in conjunction with your present...

Active Editors

Only one ham magazine of the four has editors that are active and on the air and 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 ham 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 you've...

Features

Single stage solid-state power amplifier using balanced emitter VHF power transistor with VSWR protection. Designed to be used with the TR-22 or any transceiver with up to 1.8 watts output power. At least 10 watts output 13.8 VDC. Has no relays automatic transmit receive switching Small size 5V2 x 2 x

Amateur FM Comes of

Henry Radio proudly announces the new Tempo fine of amateur FM transceivers for the 146 and 220 MHz bands. The Commercial Line transceivers are so fine they can meet the tough FCC requirements for Type Acceptance in commercial two-way service. A broad line of transceivers so modestly priced that any amateur can own one. Transceivers that defy comparison for both performance and value. Transceivers that are not a dream for tomorrow but are available right now . . . today. TEMPO'S COMMERCIAL LINE...

Classes Of License

With the restriction of repeaters in all of the amateur bands to frequencies allocated to all classes of license, from Technician through Extra Class, there cannot be any question of the repeating of a Technician operating on his own authorized frequencies into a band for which he is not licensed. Thus there can be no such excuse given for limiting or prohibiting cross band operation of repeaters. FREQUENCY CONSERVATION The availability of several different 220 MHz transceivers would seem to...

Antennas

Indoors Try reflector and director lengths, spacings, numbers, combining yagis, extended-expanded collineais, V* wave, Vi wave, and two-half waves in phase for 160 and SO meters right inside your shack Complete construction details for an antenna test set of 432 MHz. Easy-to-build units a 432 MHz oscillator and a tuned detector are detailed for you. These rf units may be used later to build a complete hand-carried solid state portable station on 432, with...

Srr Receiver

MODULAR CONSTRUCTION. STEEP SKIRT SELECTIVITY. DOUBLE CONVERSION. CRYSTAL CALIBRATOR. NOISE LIMITER. VERY POPULAR AS A GENERAL COVERAGE R ECEIVER FOR HAM USE. . . 199.00 SG 71 AUDIO OSCILLATOR VARIOUS MANUFACTURERS, TRANSCOM, MEASUREMENTS, HEWLETT PACKARD. COVERS THE FR EQUENCY RANGE OF 50HZ to 500KHZ WITH A METERED OUTPUT THAT'S BALANCED OR UNBALANCED. THIS GENERATOR HAS A HIGH OUTPUT FOR DRIVING FLIP FLOPS ETC. WE HAVE A LIMITED QUANTITY SO HURRY . 34,95 AM...

Special Offer

BCD to 7 - Segment Decoder driver PLESSEY SL4D3D 3.5 W AUDIO AMP IC HI-FI QUALITY 3.95 The Ml NITRON readout is a miniature direct viewed incandescent filament (7-Segment) display in a 16-pin DIP with a hermetically sealed front lens. Size and appearance are very similar to LED readouts. The big different is in the price. Any color filter can be used. MC1550 Motorola R F amp S1.80 CA3020 RCA W audio 3.07 CA3020A RCA 1 audio S3.92 CA3028A RCA RF amp 1.77 CA3001 RCA 6.66 MC1306P Motorola V, W...

Kai

This simple device gives a quick check of diodes. If lamp A lights, the diode is good. If B lights, the diode is good, but connected backwards. If neither lamp Ughts, the diode is open, and if both ligln, it is shorted. From the Diode Circuits Handbook, edited by WA1CCH, available for 1.00 from 73. Xtal checker. When the button is pushed, a good xtal should cause the bulb to light.

External Blanking

SUMMING JUNCTION FROM STOP' a 'START' POTS Fig. 7 (A) Foil side of ramp generator board. (B) location of parts on component side. the oscillator output frequency will be constant during the sweep period. The same is true whenever both ramps are of equal amplitude, except that the output will be a steady voltage other than zero. Alsc note that the resultant ramp could have a negative slope if the stop' input is lower than the 'start' input, and the oscillalor would ob-

Oscillator

Subtract output frequency from input frequency If difference is 3 to 20 MHz use OX LO If difference is 20 to 60 MHz use OX HI If difference is ouer 60 MHZ divide by 3 and mixer will work on third harmonic of oscillator OX HI CRYSTAL Same frequency as difference in input-output above. If difference is over 60 MHz order crystal for 1 3 of frequency difference. can be slide or toggle. The miniature imported switches work very well. Assemble the printed circuit kits with the following changes The...

Modkits

These universal counting modules have heavy duty outputs to drfv all 7 segment displays requiring up to 15V and 40mA per segment. TTL used throughout. Requires 5 volt 120mA per module and any number of modules may be cascaded. Typ. count rate Is 20MHz except the NR-3H which is 70 MHz. Wili drive any display In this ad (not Included). NR-3 Modulo 10 Counter 20 MHz 7.95 NR-3A Modulo 6 Counter 20 MHz 7.95 NR-3H Modulo 10 Counter 70 MHz 8.95 NR-3B Modulo 12 Counter clock 12.95 The most versatile...

Prompt Order

We carefully pack and ship ham gear, accessories and parts to most any part of the world. Address your orders to 18 SMITH STREET FARMING DALE, NY 11735 Or Phone your orders to (516) 293-7990 22 65 ROUTE 110 2 miles South of LIE exit 49S (516) 293-7990 OPEN NITES TILL 9 P.M. 22 65 ROUTE 110 2 miles South of LIE exit 49S (516) 293-7990 OPEN NITES TILL 9 P.M. 8 BARCLAY STREET 10 SUNRISE HWY. Near City Hall (At Rockaway Ave.)

Balun

TYPICAL TELREX MONO-BAND ANTENNAS - Monarch, 10 DBD, 3 El., 4 KWP, 2-1 2 O.D, 17' boom - Monarch, 10 DBD, 3 El., 8 KWP, 3-1 2 O.D, 26' boom - Monarch, 14 DBD, 6 El., 6 KWP, 1 O.D, 9' boom - Monarch, 16 DBD, 8 El., .8 KWP, 1.375 O.D, 14' boom - Monarch, 13 DBD, 5 El., .8 KWP, 1.5 O.D, 16' boom and many, many more send for PL-71 Dept. C

L

If you prefer not to shred your copy of 73 there is no real reason why you should not put the subscription information on a separate piece of paper, on the margin of a hundred dollar bill, or whatever turns you on. Regular subscriptions ordinarily start with the next published issue of 73 the November issue, in this case. Gift subscriptions marked for Christmas will start with the Giant January issue since that is the one that should arrive right around Christmastime. If you want otherwise just...

Mme

SAROC room rate 15.00 per night plus room tax single Dr double occupancy send directly to Flamingo Hotel, Las Vegas NV 89109. SAROC Advance Registration 10,00 per person, includes admission to Swan and Hy-Gain Cocktail parties, Exhibit area, Technical sessions and seminars, Sunday Hunt Breakfast with Champagne, SAROC Advance Registration with Flamingo Hotel Dinner show (brisket of beef) 21.00 per person, includes tax and gratuity, no drinks. SAROC Advance Registration with Flamingo Hotel...

Electronics

LOUIS, MISSOURI 63130 314-427-6116 MEMORY PLANE 4096 CORES 10 x 16 x Vz. Ship. wt. 2 lb. 6.00 HIGH VOLTAGE TRANSFORMER new 115 220 V input 5000 V and 3500 VDC output .35 ma 4 x 3 x 6 Ship, wt 8 lb. 5763 TUBES new Ship. wt. Vi lb. 1.50 MINIATURE LAMPS 327, 328, 330 new 100 25.00 .35 ea. 40-0-40 MICRO-AMP METER 3 Round Ship, wt. Vz ib. 1.50

Learn Radio Code

Album contains three 12 LP's 21 i fir. Instruction Album contains three 12 LP's 21 i fir. Instruction No Visual Gimmicks To Distract You Based on modern psychological techniques This course will take you beyond 13 w,p,m, in LESS THAN HALF THE TIME Available on magnetic tape S9-95 - Cassette, 10.35

Phones

Pot, set it to zero if not, simply note the average no-signal reading. Then set the pre-amp's slug-tuned coils (L2 and L3) to about mid-position and apply power to the pre-amp. Disconnect the antenna from the receiver, place the preamp in line, and connect the preamp's output to the receiver antenna terminal. Slowly adjust the L2 slug for a maximum S-meter indication, then adjust L3. L2 is slightly more critical than L3, and it should be readjusted after each L3 adjustment. The S-meter reading...

IS

45.103333 45.113333 45.123333 45.133333 45.143333 45.153333 45.103333 45.173333 45.183333 45.193333 45.-203333 45. 213333 45. 223333 45.233333 45.243333 45.253333 45.263333 45.273333 45.283333 45.293333 45.303333 45.313333 45.323333 45.333333 45.343333 45.353333 45.363333 45.373333 45.383333 45.393333 45.403333 45.413333 45.423 333 45.433333 45.443333 45.453333 45.463333 45.473333 45.483333 45.493333 45.503338 45.513333 45.523333 45.533333 45.543333 45.553333 45,563333 45.573333 45,583333 45....

Plate

Typical originally causing the high current remains, it will be impossible to reset the overload, or rather it will reset only long enough for the SCR to conduct again. The circuitry is also such that it is impossible to apply high voltage without the filaments heaters having been turned on first. Interlock switches are provided for both the power supply and main chassis. It will be noted that these are required to carry only low dc voltage. As yet nothing has been said about the pilot...

Uhf Transmitter

One of the later designs being released. Superb workmanship by HUGHES. Utilizes 3 pencil triodes worth over 46.00. Looks like a natural for 220 mc transmitter as it's on .264mc now. Simple to lower freq. W tubes & schematic. Built-in power supply 400 cycle would have to be changed. Measures only 3x4x8 inches. Nice piece of scarce gear, easy to work on & first class condition 4 lbs TA-40IC 15.00 Complete miniature 455kc IF. amp assembly. 1.5 inches long, little over H inch square. Ready to...

Wajgp

On the other hand, if you reside in an isolated area with no ham club, you are just as important and welcome. In such a case, if you live in the East write MARS Director First Army, Ft. George Meade, MD in the Southeast write MARS Director Third Army, Ft. McPherson, GA in She Mid- and Southwest write MARS Director Fifth Army, Ft. Sam Houston TX in the West and Northwest write MARS Director Sixth Army, Presidio, San Francisco, CA. They will gladly furnish information concerning your entry into...

Source

The DCC- derives precision gating and clock signals from the 60 Hz line. The input is a combination schmidt trigger and integrator which eliminates false triggering from line noise. The input is over-voltage protected and requires no ad ustmant. TTL compatible output frequencies are 10, 1, 0.1, & 0.01667 (1 pulse mln.) Hz. PC board measures 1.2 x 3.5. DCC-2B Line Frequency Standard 9.95 Power your OP-AMPS with this versatile, low cost, dual-polarity regulator. One control varies both outputs...

Vhf

CHANNEL FREQUENCIES CHANNEL FREQUENCIES 2 55.25-59.75 MHz 8 181.25-185.75 MHz 3 61.25-65.75 MHz 9 187.25-191.75 MHz 4 67.25-71.25 MHz 10 193.25-197.75 MHz 7 175.25-179.75 MHz 13 211.25-215.75 MHz CALCULATOR ON A CHIP 40 pin DIP package -Add, subtract, multiply, and divide 12 digit display and calculate Chain calculations True credit balance sign output Automatic overflow indication Fixed decimal point at 0, 2, 3, or 4 Leading zero suppression Complete data supplied with chip CD-3 Universal...

New Equipment

Several manufacturers have taken note of the growth possibilities of the amateur 220 MHz band and have been working diligently to provide good FM transceivers for this band. TPL has a 220 transceiver in production which will sell for around 250. Henry Radio has a fine 220 FM transceiver which should sell at around 300. The Clegg 21 is in production. And several other companies are rushing transceivers into production for this band. Both TPL 3nd Clegg are also working on repeaters for the band...

Fairchild Voltage Regulator

FairohiM UGH7805 5 Volt 1 amp Jveitage regulator. Perfect for logic nipplies, very compact 1.95 NE560 Phase Locked Loop 4.45 NE561 Phase Locked Loop 465 NE562 Phase Locked Loop 4.65 NE565 Phase Locked Loop 4.65 NE566Fnnction Generator Tone Encoder., 4.65 a NE567 PLL Tone Decoder 4.65 a NE595 Four Quadrant Multiplier 3.75 NE555 Timer. 2u See So 1 hour. Special 1.25 o NE540 Power Driver, for lOOw AB amp. . . J2.25 MEMORIES, SHIFT REGISTERS, ROM'S 1101 254 Bit RAM.MOS 4,00 1103 1024 Bit RAM.MOS...

Crystal Bargains

We supply crystals from 16 KHz to 100 MHz. Over 6 million crystals in stock. SPECIAL Crystals for most amateur 2-Meter F.M. Transceivers 3.75 ea. Inquire about quantity prices. Order direct. Send check or money order. 2 400 Crystal Dr. Fort Myers Florida 33901 (813) 936-2397 catalog with oscillator circuits and lists of thousands of frequencies in stock

Erratus

The Parts Placement Diagrams were not quite complete for A Modern Frequency Counter in the September issue. Here are the corrections. Also, the fifth line from the bottom on page 95 shouid read 220il resistors. Above sketch shows location of circuit on main circuit board

Brand New Lowest Prices

GENERAL 2 95 ELECTRIC 3 FOR 6.00 3-WATT AUDIO AMP Similar to Mostek > 001, Outperforms Texas S-digit TMS1S02, A 40-pin DIP. Adds, multiplies, subtracts, and divides. Use with 7-segment readouts. Nixies, and LRD's. We include sdic-matics. instructions from factory to build calculator. ft 3 for 35

Only Telrex Gives You All These Features

Power rating 4 KW PEP . . . rain or shine Wind rating survival 110 MPH Patented broad-band coaxial Baiun Heavy-duty steel gusset mounting plate Aluminum boom 2 in., 2 in. O.D. x 18 ft. Large diameter, .058 wall taper-swaged dural elements for minimum weight and exceptional strength to weight ratio Stainless steel electrical hardware With a Telrex Tri-band Array you get 49 lbs. of educated aluminum engineered and built to provide many, many years of performance unmatched around the world by any...