KB6NU's Ham Radio Blog

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Technical advances in QST 25 and 50 years ago in QST

Posted: 22 Sep 2016 12:36 PM PDT
http://feedproxy.google.com/~r/kb6nu...m_medium=email


My last postÂ*talked about how QST covered one the technical advances 100
years ago—the move to undampedÂ*wave transmitters. The October 1966 and
October 1991 issues of QSTÂ*alsoÂ*had interesting articles on new
technologies of the day. The October 1966 issue featured the article, Field
Effect Transistors: What They Are, How They Work.

Field-effect transistorsÂ*(FETs) are, of course, now an important part of
nearly every amateur radio set. In 1966, however, they were cutting edge
technology. Im not sure when they first became available, but the article
notes, A recently introduced semiconductor device called the field-effect
transistor, or FET

The nice thing about articles from this era of amateur radio is that they
were very descriptive. This article starts out by describing how junction
diodes work, which leads to a discussion of how junction FETs work (see the
diagram below), and finally how insulated-gate FETs work.



Also included are some typical characteristic curves and some circuit
examples. Great stuff if youre just learning about FETs or want to review
what you know about them.
The next breakthroughÂ*in 1991: DSP

Dave, K1ZZ, hit the nail on the head in his October 1991 editorial when he
wrote, Its pretty clear that the next major development to hit our ham
shacks will be digital signal processing (DSP). He couldnt have gotten it
any more right.Â*After more than 25 years of development in DSP, nearly all
of our radios use some form of DSP, and some of them are just one big
digital signal processor.

Some hamsÂ*wax nostalgic about the good, old days of tubes and analog
circuits, but not me. DSP makes amateur radio a lot more fun.

Also worth noting in this issue is the Audio Filter Roundup. In this
article, Jim, KR1S reviews the J-Com Magic Notch Filter, the Modular
Systems Smart Filter, and the JPS Communications NIR-10. The first two are
analog filters, the third a DSP filter. None of these products are still
available, nor are the companies Â*still in business. Perhaps that was an
omen of things to come.

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