Radio Amateur 06-1976

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...

Microcomputers At Microcost

Microcomputer system ESKS E HHSKV No expensive terminal is required. Everything is built-in to a single PC board including a hexi-dectmal keyboard and display Easy-to-undersfand Hard- Hft ware and Programming Manuals guide you e ery step of the way You will gain a practical knowledge of microprocessing plus invaluable hands-on experience. All at micro cost. The heart of ihe EBKA FAMILIAR-IZOR is a MOS TECHNOLOGY 6502 Microprocessor an eight bit processor that can address up to 65K byies of...

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...

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...

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...

Paying For Repeaters

As more and mora repeaters are put on the airr the question of who is going to pay for them gets stickier and stickier. Ii isn'i all that diificutt where there is a bona fide repeater club which is handling the situation , ., having regular meetings, classes for newcomers, charging dues, putting out a newsletter, etc. T,. but where an individual has set up a repeater and then tries to force the users to reim* burse him for the expenses involved that's going to take some discussion. Not a few...

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...

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...

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...

Editorial

Of course it is always possible that pressure on Congress will get so great that the postal monopoly will be broken. Right now it is a federal crime i o compen-j with the posi office, Thv mail couM bij carried at a good profit by private industry, if it were per rutted. Industry could et the postal system back on its feet if permitted fav the bureaucracy and the postal unions, something that doesn't seem ven remotely* likely. Last year the post office rang up art 825 million d& fint and 1...

Is just what you need

Double your pleasure with the first truly linear solid state power amplifier available. The 100ALT0 guarantees increased range and clarity in your VHF communications under all operating conditions. It operates in the frequency range of 144-148 MHz withpoweroutputof 100W (norn) with 10W nom)in, Modern solid-state technofogy is used throughout, along with conservatively rated components to assure the highest possible reliability, Microstrip design on glass epoxy circuit boards give added...