NEW DIRECTIONS RADIO

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The author of this column, who has been writing for MOTHER since 1973, is the inventor of slow-scan television . . . a method of amateur radio transmission that allows ham operators to both hear and see each other during shortwave broadcasts.

PUT THAT HOME COMPUTER ON THE AIR

Radio amateurs, like many other people these days, are buying home computers. And regardless of how many additional uses he or she might plan for the machine, a ham purchaser almost always wants it to be part of a system of communication.

In theory at least, personal computers and ham rigs can be interconnected, and the combination can then be used to transmit and receive text by radio. Three types of codes are commonly employed for these transmissions: ASCII (standard computer code), Baudot (normal teleprinter code), and Morse (dots and dashes).

However, in this case, what seems to be simple in principle turns out to be not so easy in practice. For one thing, obtaining all the necessary bits and pieces of equipment—and integrating them into a smoothly functioning system—requires knowledge and patience. In fact, during the past few months, I've received a number of inquiries from hams who've tried to accomplish such a "marriage", but who've been frustrated by the lack of information on how to go about it.

Well, if you already have a ham radio transceiver and a home computer, you have two of the four elements needed to create a working system. The third component is a piece of interface hardware called a modem (short for modulator/demodulator). This unit functions as a kind of translator, converting the 1's and 0's of computer language into the changing audio tones of radio language . . . and vice versa. Finally, you'll require the appropriate software. Just as a home computer needs game software to play games and accounting software to do bookkeeping, it will also need communication software in order to communicate. The overall problem is further complicated by the fact that there are many different makes and models of home computers . . . each with its own peculiarities!

If you want to build your own hardware and write your own software, I'd suggest that you take a look at back issues of ham magazines such as CQ, QST, 73, and Ham Radio. You might find an article that addresses your particular situation. Otherwise, you'll have to go out and buy the parts you'll need.

Again, before you purchase a modem and software, check out the ads in those same magazines. I recently did this and was drawn to a particularly interesting and reasonably priced hardware/software combination offered by Kantronics (Dept. TMEN, 1202 East 23rd Street, Lawrence, Kansas 66044). The firm calls its modem The Interface, and its software Hamsoft. The Interface has a suggested retail price of $189.95 (though you can get it for less at some dealers). Hamsoft is priced at $30 to $75, depending on the make of computer it serves. Clearly, the folks at Kantronics have done their homework. They offer plug-in software modules (or diskettes) for most of the popular home computers: Apple II, Apple II Plus, TRS-80 Color Computer, Atari 400, Atari 800, Commodore 64, VIC-20, and Texas Instruments 9914A. Write to Kantronics for a catalog, dealer list, and full technical details.