Digital I Control

Digital Control of Repeaters, by Tom Yocom, WA0ZHT. Here's a book for the FM'er who wants to design and build a digital repeater control system. Contains sections on repeaters, basic logic functions, logic circuit design, control systems, support circuits, mobile i ns tal I a t i ons, touch-tone, plus special section on a mini repeater control system. 224 pages, softbound 5 hardbound 7. 'iXir I rE I*L I -*3 1J iii-iii iriiiifn.l '( iiKirnsnEui .rjj.t.H.TCTiipmmm The transistor replaced the...

Is Volt

Schema tic of the sine wave output power inverter, TTie inverter is nothing more than a vfo controlledt push-puli output transmiiter operating at 60 Hz. Frequency can be varied hy the 10K potentiometer in the oscillator section. The transformers in the output stage can be any filament transformers with adequate power ratings. reasonably near the desired range of 115-120 volts. In the circuit of Fig. 2, the output voltage is determined by the setting of the 4K potentiometer between the...

T

Pj watts transmitted d meters from transmitter But, the power available to the receiver is dependent on frequency because the effective area for capture of rf energy by the receiving antenna is dependent on wavelength. The power available to a receiver is Pft watts square meter X the area (effective) Without going through the calculations, let me jot down from my notes several approximate values for effective areas For the 500 kHz case we have (600)2x ,119 43,200 square meters and for 50 MHz it...

Heathkit Electronic Centers

Indian School CALIF. Anaheim. 330 E. BaN Rd.f El Gerrite, 6 OQ Potrero Ave. Los Angeles, 2309 S. Flower SL Pomona, 1555 Orange Grove Ave. U . Redwood City, ZQ01 Middieheid Bd. San Diego La Mesa), 8363 Center Drr Woodland Hills, 22504 Ventura Slvd, COLO, Denver, 5540 W. 38th Ave, CONN. Hartford (Avon)t 395 W. Main St. (Rte. 44) FLA, Miami IHialeah), 4705 W. 16th Ave, GA. Atlanta, 5285 Roswell Rd. (LL Chicago, 3462-66 W. Devon Ave. Downers Grqve, 224 O den Ave IND....

Fpy Hondpm

Those of you who have worked your 73 countries in the first 73 days of 1973 should send in your list of the 73 countries so I can issue you the 73-73-73 award (remember the year 1973 is 73 magazmeyear). Maybe we should try to get President Nixon to make some sort of a declaration I bet if Goldwater was in this would maybe be done, because he understands such things. The WTW is coming right long again and the appircations are coming )n very good, i still think this is the best DX award there is,...

IfiiiliEter Fm Transmitter

An inexpensive rig offering compact construction without sacrificing circuit quality. his article describes a simple narrow band two meter FM transmitter that uses inexpensive transistors and provides a little more than one watt output. It features double-tuned circuits Tor selectivity, a mosfet buffer for frequency stability, and voice-shaped audio f requency response. For the amateur who has had some experience in solid state VHF circuitry, this transmitter can provide a convenient and...

OUTPUT

SimpJe phone patch for experimentation purposes. -Adjust the mike gain on the transmitter as you would normally and set the 5OOft potentiometer (Continued on page 143) for proper modulation by the telephone audio. Thanks to WA7CYY. Price 52 per 25 wtirds for non-commercial ads 10 per 2b words for busmess ventures. No dtsplay ads or agency discount Jncfude your check with order Deadline for ads is the 1st of the monlh iwo months pritir to publication For example January l i is the deadline lor...

Parts List

Dual NAND Schmitt Trigger SN7413 Divide-By-Twelve Counter SN7492 Decade Counter SN7490 ESCD-ToSeven Segment Decoder Driver SN7446 Hex Inverter SN7404 Triple 3-lnput Positive NAND Gate SN7410 Quadruple 2-lnput Positive NAND Gate SN 7400 Up-Down Counters SN74193 Seven-Segment LIGHT Emitting Diode Displays Litronix Data-Lit 10 or Monsanto MAN 1 + 1 5000 jUF 10V electrolytic 3 .01 fJif 50V ceramic 2 220 pF 300V, silver mica 1 .001 fXF 500V ceramic 6 100 JF 10V electroyltic 1 3 amp fuse 1 Thermalloy...

Scholarships

The Foundation for Amateur Radio, Inc a non-profit organization with its headquarters in Washington, DX., announces its intent to award year 1973-74. Alt amateurs, wherever resident in the U.S. and holding an FCC license of at least General class, can compete for one or more of the awards. The John W. Gore Scholarship pays S500. Applicants must intend to pursue a career in electronics or a related science and have completed at least one year in an accredited college or university. The Richard...

Printed Circuit Negatives

SASE AND QUARTER FOR INFORMATION PRICES. P-C NEGA SYSTEMS, 186 - 80th STREET, NIAGARA FALLS, NEW YORK 14304. DGTX-200 with built-in DC PS 259.95 2 AC POWER SUPPLY 49.95 3 2 Extra xtals stock list 12.00 30 WATTS OUTPUT, ALL SOLID STATE no tubes , TRUE FM not Phase modulation for superb audio quality. 100 channels with 146.94 146.94 included. Three pole low pass filter on both transmit and receive. 1 watt low power position Provision for tone encoder, Multichannel use of any crystal....

Rcmp Centennial

The Royal Canadian Mounted Police wilt be operating an Amateur Radio Station at Ottawa, Ontario, to commemorate their 100th anniversary. This station wilt operate during the period commencing 23 May 1973 to 30 August 1973 from 1200 hours GMT to 0400 hours GMT daily. Operation will be on 80 through 2 meters, using CW, SSB and FM, A special call sign, VE3RCMP, has been approved by the Department of Communications for this purpose, A commemorative QSL card will be sent to all stations worked. No...

Northern Canada To Add Twenty Amateur Stations

Government employees being posted to isolated stations will soon be able to keep in touch with things back home via amateur radio stations now being supplied at some twenty locations in various provinces and the Territories. DOC will issue amateur calls, with an official of the Ministry of Transport in Ottawa, Frank Lay, VE3ZN, as licensee. A series of 3-letter suffixes will be available in order to readily identify these stations to other amateurs. The suffix block MTA to MTL will be assigned,...

Info

19 Mobile Burglar Alarm 25 The Burst Box 29 Power inverter w Sine Wave Output , . . W70XD For people with short extension cords. 33 450 MHz 1 0 dB gain on the receiver is a Jot easier than on the transmitter. 39 Roof Mounted VHF 47 LED Readout Crystal 53 Voltage Limit Sensor 55 Build a Digital Clock with 19 inexpensive fCs WA6QVQ 61 Portable Use for the 63 Fixed and Mobile 2m How to make your car look ridiculous. 65 Two Meter FM Transmitter 71 Mini-Repeater Control System, Part II WA0ZHT 81...

Hewlettpackard Spectrum Analyzer

The famous Model 8551B with Display H.P, 851ES, Excel. cond, CERTIFIED with new TWT. Now reduced to less than half of original price Special. Only 5500.00 schematic and hookup info. Like new. Smashing low price . 19-95 24 VDC POWER SUP PLY for above , 4.95 70-100 Mc. Single channel. 50 W. output. 110 V, 60 cycle. New and like new, R-19 TRC-1 Receiver 49.50 T-14 TRC-1 Transmitter 49,50 FREE schematics. Convertible to 6 or 2 meters. 190 550KC Q-S r Good Condition Recvr 14.95 or like New Receiver...

Continuous

F gr, 2t The area inside the dotted lines show the extra components needed for connecting the Burst Box to a transceiver. Power is drawn through the 33resistor. frequency range of 100 Hz to 1 kHz or 1 kHz to 10 kHz f l RC . In the burst mode, a 1 M i resistor charges up a L0 F capacitor in roughly .6 second which gates off the square wave. High frequency components of the square wave are filtered by the 10 KH and a ,01 uF capacitor. The emitter follower drives the volume control, which couples...

Equipment From

The following list of gear, unless otherwise noted, consists of brand f new equipment purchased for testing purposes only. Some have been tested, some remain unopened in original cartons, We are offering this gear at a considerable discount on a first-come-first-served basis, Hallicrafters FPM 300 SSB xcvr 480 Miida Digipet 60 counter with Digipet 160 converter 400 HR2MS 8 ch scanning 2m xcvr 7 5W 255 T1VIE-H-LMU 16 ch scanning rcvr 6 2 m 255 FOR SALE TO THE HIGHEST BIDDER - Collins KWM2-A, AC...

Laboratories

TV And Communications Antennas Since 1921 Asbury Park, New Jersey 07712 201-775-7252 Marvin Jack Moss W4 UXJ P.O. Box 28601 Atlanta GA 30328 1 senior that continuously monitors vour mobile s electrical svstem and indicates voltage variance outside a pre described range, Tlhe voltage limit sensor VLS is a compact, self-contained go, no-go indicator which Letts at a glance if the voltage in an automobile or boat electrical system is satisfactory. Many of the latest state-of-the-art electronics...

Lancaster Hamfest

Hundreds attended the first winter hamfest in Lancaster County PA on Feb. 11th. It was sponsored by SERCOM of Lancaster County who operates the 01 61 repeater for the community and the local CD RACES unit. Highlights were an amateur TV demonstration and a two meter FM information session also attracted interest. Amateurs from as far away as New York State and Washington, D.C. made their way to the Naval Reserve Center in Lancaster, Imaieur TV demonstration by Rojj Cohen K3ZKO of Philadelphia PA...

New Semiconductor Replacement Manual

A comprehensive 52-page Semiconductor Replacement Manual has just been released by Sprague. Containing over 30,000 OEM part numbers listed alpha numerically which are cross referenced with Sprague's new line of 82 popular semiconductor devices, the manual afso includes performance characteristics, outline drawings and pertinent parameters for the entire Sprague line. Copies of Semiconductor Replacement Manual K 500 may be obtained without charge from Sprague distribu tors or by wruing to...

Watt Op

A new multi-purpose 7-ampere, lowdistortion, operational amplifier has been announced by the RCA SoMd State Division. Designated RCA TA8651 A, this developmental power hybrid circuit is a low-distortion, 100-watt linear amplifier. The output section can be externally biased class AB for low intermodulation 0.05 at 50 mil and low total harmonic distortion. Terminals are available for external frequency compensation, external short-circuit protection, and inverting and non-inverting inputs. The...

Georgia Qso Party

Starts 2000 GMT, Sat., May 5, 1973, Ends 0200 GMT, Monday, May 7, 1973. The twelfth annual Georgia QSO Party is sponsored by the Columbus Amateur Radio Club, Inc. There are no time nor power restrictions and contacts may be made once on phone and once on CW on each band with the same station. Each complete contact counts 2 points. Georgia stations multiply their total QSO points by number of different states and Canadian provinces worked, DX stations may be worked for QSO points but do not...

Mjha

CN-1M 2 m cam 17 11 1 18 I.F.I w PS t AC ITIH rand. 43 i alTrrnini nflwi lirfiHed quantity COLUNS KWM-1 xcvf W 516F-1 AC ikndJl2 3 same 3176 1. patch, SWF J em 1 Lafol. npw eortd. 62S-1 VHP com, . Like nrw 30L-1 linut, nbwund. HK 6 gt C f C rnod. CWDt L cSP 1 1 RF ehecitftd bi Drake. ttrw Ciind R4 A w 7 ax n r.ilt inctud. 160 mitttn. rawcond, T4X umiittt liVfi now 5W4A gen. tov revr. new epnd.

Vlf Metal Detector Circuit

C1972 Transistor Transmitter Schematic

For ha 11 e ry p or ta hie. m o hi I e a n d e m e rge n cy tigs, FM a n d A M. is a description of design methods, L circuits, and components for homebrew generation of up to 5W input on 6 meters, for use with FM or AM, using reasonable cost transistors. A Vi to W output is obtained from a crystal oscillator, followed by a parallel connected pair of Motorola HEP 75 transistors. These list for 2.95 amateur net, so you can see the truth of the low-cost mention. The output can be pushed to equal...