N

1 k Ohm Va W 5 SPST N.O. relay 1N400 diode 0.1 uF disc SPDT power switch T keyboard Digi-key, James, Poly P > ks, etc Digi key, James, Poly Psks, ere. Digi key, James. Poiy Paks, etc Data Signal Co JBT JMT 123 Digman KL 0025 or Chromeric ER 21623 AD1 Complete Kix - Ail parts, PC board Idrilled) and AD4B switch. Less case and battery For AD4A swttch, add AD2 Chip Kit MC14410, 7493, 74154. 555, LM309K 1-2N3904, 1 MHz crystal AD4A Switch 1 7 pole 9 position rotary switch AD4B Switch 1 7 pole 5...

Good News

Mr. fieiley said that the station he was manning was in touch with about half dozen English-speaking hams in Guatemala, including a young Call fornian known as Joanne K6GFW+ who operated with a portable radio transmitter and emergency generator from her home just outside Guatemala Among the good news received irom Joanne. Mr. Reiley reported, w s a message for a family in Elmhurst, Queens, whose daughter, a registered nurse married to a Dutch United Nations official* had not been heard from....

Z Z Q D D D

MCSG502 MQS Technology) MC6810L 1 (Motorola) D-3624-4 liniel SN 74LS74 N SN 74LS20N SN 74LS02 N NE 555 2N5682 Motorola,any 100 I SOvoJi NPN silicon) 2N3904 1N414S 1N4004 470 Ohm 5 Wan composition resistor 3 2,7k Ohm I Ok Ohm 4.7k Ohm 27k Ohm 47k Ohm 10 pF ceramic NPQ 4l mF 10 voit tantalum 10 mf 10 voir tantalum Mfsc. sockets, terminals, circuii hoard The following items aft available from Levy Associates Kit of alt ICs, etectron< c parts, pre-programmed ROM, sockets, double sided plated...

Don T Let Us Down

Where are the MARCH PROPAGA TION CHARTS I received my April issue oi 73 Magazine, and no chart for March, Oi course ihert- was the April Propagation Chart. but this doesn't help for March t started taking 73 Mapatwe when Jound they had Propaudt on Charts Thanks, for Idling me bring this to youi attention. Please don't lei us down again, Ivan S. Miller W5HFU Oklahoma City OK Sorry it won't happen agartt Onr to a change (acceleration) of our oroduc-tfon schedu we wert_> forced to miss a nujnth...

Ii

Clemens, Michigan 48043 The RRRI Southenstern Diuision Convention and Htlanta HamFestiual 197G WHEN Saturday and Sunday, June 12th and 13th WHERE Dunfey's Royal Coach Motor Hotel I-75 at Howell Mill Road Atlanta, Georgia 30318 Contact the Hotel directly for room reservations at special HamFestival rates 16 single, 21 double Airconditioned Exhibit Hall with nearly 100 manufacturers, distributors, and other exhibitors Saturday Night Awards Banquet and Dance Forums and...

S

Howard W, Sams& Co,, inc,, 1974. pp, 262-265. 3, ' Usmg a Bargain Surplus Keyboard ' Cole Ellsworth, 73 Magazine, January. 1975, p 21 . 4, ASCI I to Baudot Converter, Cole Ellsworth, 73 Magazine, February, 1976, p. 52. 5, RTTY Autocali - the Digital Way, L, W, Sanders. 73 Magazine, February, 1976, p, 76, 6, The Mainline UT-4, Irvin M. Hof f, RTTY Journal, March, 1975, p, 4. 7, Hand Wire Wrap Too*. Cambion 601*2506. Less than S3 from disirrbutors. 3. The...

OUT

Simultaneous square and friangk wave generatort (qu7 - are some applications where it is necessary Lo use an uncompensated amplifier and do the compensation yourself. First we must determine what compensation is and why it is necessary. Unlike the periect amplifier, our op amp has a limited bandwidth. At some hi h irequency point the response (gain) tends to tall off. Without compensation the rate of tall off is usually quite last. When the op amp is used as a feedback amplifier, there...

Processing Oscar

Here's j picture of Franklin WB4BWK who,, together with VE28YG 3 . now VE3SAT, made the first computer to-computer QSO via Oscar 7 mode 6 on October 9th last. This came about on orbit 4101 using ASCII RTTY a ham radio first Franklin has now Interfaced his Oscar station with Ersklne College's PDP-11 minicomputer and he is looking for RTTYASCtl contacts via Oscar 5 or 7. modi A or B. A note from a reader out in Michigan grumbles that he has been warned that his newly installed pace maker should...

IN

Clary, Birmingham, 205 322-2486 Ack Radio, Birmingham 205 3220588 ALXSKA - Service Electric, Ketchikan ARIZONA - Masters Communications, Glendale ARKANSAS - M. J. Communications, North Little Rock, 501 945-9307 CALIFORNIA - Buddy Sales, Reseda C & A Electronics, Long Beach Gary Radio, San Diego Metro Audio, Bakersfield Henry Radio, Anaheim Henry Radio, Los Angeles Hallcom, Riverside H.E.M.E.C., Santa Barbara Ham Radio Outlet, Burlingame M-Tron, Oakland Quement Electronics,...

Info

Tile HAL 87-6000 demoduiator keyer and the DS-3000 and DS-4000 KSR RO series of communications terminals are designed to give you superlative TTY performance today and in the future, DS series terminal for example, are re-programmable, assuring you freedom from obsolescence, Sophisticated systems all, these HAL products are attractively priced for industry, government and serious amateur radio operators. The HAL ST-6000 operates at standard shifts of 850, 425, and 170 Hz. The tone keyer Is...

Two Meter Portables Rca Tactecs

Tne TACTEC is the latest model portable made by RCA and features extensive use oi ICs and separate transmitter and receiver boards for easier servicing. Conversion to ihe two meter amateur band requires ordinary alignment procedures. COMPONENTS NEED NOT BE CHANGED FOR AMATEUR USE. An external speaker mike can be added without modifying the radio, TACTECs are made in iwo basic, iriodels Standard housing winch accommodates up to two frequencies plus dual squelch, and Options housing which can...

Fm Squelch Schema

Fig, 72 Coi wcf ofi of npi f of rto digital COR to the squelch circuit of the repeater receiver. lt circuit shown is a portion from a Motorola G-strip receiver 77 f co wecWo j point wilt be similar in othet types of tube receivers. I Simple 5 uo regulated power supply. commcrcial FM receivers the grid of the first stage following the noise rectifier has this characteristic. A simplified sketch of the squelch circuit of a typical tube-type receiver and 1 he correct point of connection to the COR...

More On The Two Timer

Nexus Trading Company will pro vide a free information package with board layouts for the Two-Timer clock, upon receipt of an SASE. An etched and drilled board set is avail able for S3.95. Specify .3 or .6 readouis. The WC calls you may begin to hear soon on the ham bands aren't Novices in the Caroline stands or newfy licensed hams they are RACES calls In the Report and Order on Docket 19723, the FCC rewrote the RACES rules to affirm that all such stations must be controlled by licensed...

Vouae Bounce

Al the beginning of a read cycle, both the read and write data lines are preset to some voltage. When the address decoder produces a read select signal, Q3 is ready to begin conducting. If the charge on Cg is sufficient logic t t Q2 turns on and currcni flows through Q2and Q3, reducing the voltage on the read data line. With no charge on the capacitance, Q2 and Q3 remain off and the read data line slays at its preset level. Because of the gale isolation, Cg is in the same condition charged or...

Ts

KLM 420-4 70- 14, 5 feet. 4 lbs, 13.7 dB iso gam KLM 420-450-27. 10 feet, 7,5 lbs, 16,7 dB iso gain With either antenna, use balun KLM 1 1 Balun Notes 1. Use corfect antenna polarization for your area, 2. Mount antenna high enough to clear nearby obstructions including trees, 3. 2 antennas may be stacked together for additional 3 dB ain S2 .95 postage 39 95 postage 13,95 H postage

Vhf Engineering Announces Two New Power Supplies

VHF Engineering, of Binghamton, N.Y., has announced two new high current, regulated 12 voll power supplies lor use in amateui ,md com merciaf applications The two supplies have ratings of 15 Amps and 25 Amps, over voltage ranges 0 lt approximately 10 14 V dc and 10 14 V dc respectively, Load regulation is from no toad to maximum rated current. These new supples feature both over-voltage protection and foldback current limiting,, The over-voltage pro tection is provided by a crowbai circuit...

Digital Data Recorder

Computer or Teletype Use Up to 4800 Baud Uses the industry standard tape saturation method to beat a 11 FSK systems ten to one. No modems or FSK decoders required. Loads 8K of memory in 17 seconds. This recorder enables you to back up your computer by loading and dumping programs and data fast as you go, thus enabling you to get by with less memory. Great for small business bookkeeping. Imagine A year's books on one cassette. Can be software controlled. Comes complete with a software program...

Klm

Morgan Hill CA 95037 FX 12-50H, 50 Ohm, V inch outei conductor. insulated, mm. hendjng radius 5, appro . K9 dB loss per 100 feet at 440 MHz. b. N male, 22-654 q. UHF female, FXCC12 50H sim as abovt but corrugated outer conductor considerably more flexible and easier to v ork with. Marlboi o l JJ 07746 201 462 1 830 Note RG B cable can be used fOT runs up to BOft i Measured lots 3 dE 50 feet 12 dB worse than hardline . down into the 420-450 MHz amateur band. Considering...

H C

Co ecf brt from RTTYloop to BA C-Z puis could be treated the same way Two ot the circuits are described further in the references. The current loop interface can be used with any terminal unit and may be of interest to non-RTTY microprocessor users who want tu use Baudot teletype equipment. The current loop interface is tot,illy isolated from the loop. Tig, 3A details the heart of the unit the Baudot to ASCII convener dubbed the BAC-2 someone has pi oba bly designated a BAC-1 . The...