Traditionally, the April issue of QST magazine carries one groundbreaking technical article. The first one I recall came out the first year I was licensed, in the April 1974 issue. This article espoused the virtues of a new form of modulation, namely, Suppressed Sideband A-M Telephony. The author, a Canadian genius named N.G. Attaway, VO1DER, proposed an alternative to single sideband. Instead of suppressing the carrier, he suppressed the sidebands and kept the carrier.
Attaway wrote:
One remarkable fact struck us: the amplitude of the modulated carrier was never modulated in amplitude modulation! To verify this, one needs only to listen to any a-m signal with the BFO on in the receiver. The carrier just sits there and carries. Only it doesn’t really even “carry” anything either. It just sits there.
Attaway presented a simple method to suppress the sidebands, but keep the carrier. Because the carrier has no bandwidth, he points out that SSA-M (suppressed sideband A.M.) doesn’t cause QRM. He points out: “In fact, in all of our transmissions to date, we have received no reports of having caused interference to anyone!”
The June issue contained a number of laudatory letters from readers. One, for example, from a confirmed CW man, was very encouraged by the way in which Attaway’s system eliminated phone QRM. A letter in the August issue took these letter writers to task, as the August letter writer was under the impression that the April article was actually an April Fools’ joke.
My favorite ever letter to the editor of QST appeared in the October 1974 issue, from a writer who was also apparently of the opinion that the April article was a joke. He called the article a “potential time bomb.”
The writer, Dr. Chas. R. Fisher, K0TYB/K4KGN of Oak Ridge, Tennessee (I’m guessing a nuclear scientist) had always been bothered by such articles. He noted that QST is “kept in all technical and scientific libraries as one of the foremost reference journals and is used more by non-hams than hams in this instance.” He noted that these scientists might be skimming through magazines, without “reading details which might clue them in on a gag and the articles are not plainly marked.”
Fisher notes that this could lead to death! “What about a deliberate, well designed deception resulting in damage or potentially death? I think every April issue you have put out is a potential time-bomb for the League in this sense. An [anonymous, of course] attorney agrees that if the articles appear as I say and intent is shown, the ARRL would porentially be found liable!”
Now that we have this Google thingie, it is my hope that researchers investigating SSA-M will find this post, in addition to the 1974 article. It is my fervent hope that they heed the warning: Suppressed Sideband AM can cause (by some mechanism which is unclear) death!
I hope I have defused that particular time-bomb.
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