A SHORT HISTORY OF SINGLE
by James W. Nash, K4HMS/V31AW
On the night of September 21, 1947, bizarre sounding voices appeared on the 75 meter phone band. These strange signals were audible in California and adjacent states. In fact, they came, not from outer space as some might have thought, but from W6YX , the club station of Stanford University, operated by O. G. Villard, Jr., W6QYT. (Villard, 1948.)
No doubt there were listeners out there who could not believe their ears. But what they were hearing was actually single sideband modulation. This event represented the beginning of the postwar SSB revolution in amateur radio. It was the most important technical development to hit the hobby since spark gave way to CW. As we have seen, its implications have gone far beyond the technical.
We all owe Villard and
his co-experimenters a debt of thanks for bringing us SSB when they did.
However, itís worth knowing that single sideband had already been around
for over thirty years. And, not only that, hams had been on the air with
the squawky stuff as early as 1933.
During 1954, I bought my first shortwave radio, a used Hallicrafters S-53 (cost $40), and launched my short career as a pure SWLóI would receive an amateur license the next year. One night, tuning around between Radio Moscow and the BBC, or whatever, I was astonished to hear ducks talking. Yes, a twelve year-old SWL in Georgia had discovered that ducks were indeed on the radio. For there was, sure enough, Donald talking to his goofy nephews. It never occurred to me that, in theory, I could tune this stuff into English by flipping the toggle switch which said "BFO" and making some very careful adjustments.
I had, of course, discovered single sideband transmission. In the next few years, I received a Novice and then a General license. At the ramp-up to the peak of Cycle 19, I tried "phone," meaning AM, and liked it a lot. For me, the big fun was on 15 meter phone, especially since I had a 3-element Yagi for the band. After all, the Globe Scout put out only 50 watts on AM.
SSB was still in the experimental stages as far as I knew. So while I worked AM, as well as CW, I would hear the duck-talkers up there in their own part of the band. Quacking away.
Then my career on phone hit a major snag. Because then came those phone calls to my parents from the neighbors. The problem was that many of the TVís still used 21 mc. IFís. Well, despite the helpful efforts of the Kennehooche ARC TVI Committee, I went back to CW. Except for my long absence from the air in the later 70ís and much of the 80ís, Iíve been there for the most part since.
As for sideband, I
forgot it was even there for a long time. In 1988, however, inspired by
news stories of the newly approaching peak of Cycle 22, I acquired a
TS-680S. With the help of my two youngest children I erected a G5RV
antenna. After a long absence I got back on the air. I soon discovered
this newfangled transceiver had SSB on itósoon I tried it out and was
overwhelmed with its superiority to AM. How could I have missed this for
so long? And how long had it really been around? I remembered hearing
sideband 30 years before, but I had thought it was something brand new. I
Bell Labs and Others
Well, itís like this. The story starts in 1915, when mankind discovered sidebands. Now possessing this superior understanding of the AM signal, radio scientists began to understand the implications of their discovery. Soon afterwards, our old friends at Bell Labs, who have discovered practically everything, developed a method for removing one of the sidebands of an AM signal but retaining all the essential modulation components. As an expert of that day supposedly said, "both sidebands are saying the same thing" (Goodman, 1948).
Or, as the Messenger said in one of his mysterious transmissions many years ago, "some day you will gain many dB, for both sidebands say same thing."
Bell soon discovered
that it was possible to increase the capacity of overseas telephone
circuits using SSB modulation, and such circuits were in telephonic use by
1918. The first single sideband radio transmissions occurred by 1923. From
the beginning equipment stability problems slowed development of SSB. In
1927, a trans-Atlantic SSB commercial radio circuit was in place, but at
low frequencies. In fact, it was in the mid-1930ís before commercial
shortwave SSB was practicalóthe frequency stablity problems were solved by
using new generation AFC equipped receivers and a pilot carrier from the
Hams at Work
By the time the 1930ís came along, licensed amateurs were hard at work on the problem. Apparently the all-time ham radio SSB pioneer was Robert M. Moore, W6DEI. He published three articles on the subject in R9 magazine in 1933 and 1934. At that point, this experimental mode was referred to as "single sideband suppressed carrier" transmission, or SSSC. The articles reveal that what Moore was talking about was real single sideband. In his articles he acknowledges the prior work of Bell Telephone Laboratories in developing the techniques he was using. (Moore, 1933, 1934.)
Another pioneer in this endeavor was J. Evans Williams, W2BFD, who in 1948 wrote a letter to QST pointing out that Moore was indeed the original 1930ís ham radio SSB pioneer. Williams himself build a 500 watt SSSC transmitter based on Mooreís designs, and reported in his letter that a half-dozen or so sideband stations had been on 20 meters during the 1930ís.
As Williams also pointed out, the idea simply did not yet catch fire. One reason was that the bands were not yet so crowded. Another was that many hams had only recently become involved in AM in the first placeóthose were the days when one started in CWóand had recently built or purchased new AM equipment. Finally, FM was coming on the scene and many of its advocates claimed that it alone was the mode of the future. So SSSC had to wait a while.
SSB Takes Over
What finally made SSB feasible for amateurs was a workable solution to the problem of transmitter stability. This came after World War II, with the work of Villard and others. The techniques which were ultimately most workable involved a balanced modulator which generated the sidebands, but no carrier, followed by a sideband filter which eliminated one of them.
The phone bands were really jammed in the 1950ís, much worse so than today. This was largely because of the width of AM signals. The ham community soon grasped the fact that SSB was more than a way to get 8 dB. It was a long term solution to the problem of bands jammed every night with heterodynes howling like banshees. Iím not sure how many of us today realize how vital SSB has been to the history of the avocation. After sideband became well-established the process of working DX on phone with moderate power and antennas became vastly easier. By the early 1970ís, there was more DX on sideband than on CW, and the gap has probably continued to grow ever since.
Of course, in the 1950ís we non-SSB heathens still referred to it as "duck talk." Yet it was soon established that any receiver with adequate frequency stability and a variable BFO could receive this squawky stuff so that it sounded more or less human. Also, a clever ham without an expensive receiver could get some help from a frequency meter or VFO (most of us had separate ones in those days), for use in carrier reinsertion.
It was the early sixties before commercial rigs with sideband were widely available. Iím not sure which manufacturer put out the first commercial ham SSB rig. (If you know, let me know.) But by the late 1960ís SSB had come to dominate the phone bands. Today the terms "phone" and "sideband" are synonymous.
As for me, a ham who had worked AM in the 1950ís, my first QSO on SSB came in 1988. I was amazed at the ease with which one could work phone DX with 100 watts and modest antennas. The clarity and capability of reading signals in QRM was remarkably improved over the AM of my boyhood. And although today my preference still remains strongly for CW, that is a personal preference.
KWM-1: One of the first SSB rigs. >>
Without single sideband, Iím not sure amateur radio would be nearly as strong an institution as it is today. Who knows what will come next?
Goodman, Byron, W1DX. "What is Single-Sideband Telephony?" QST, January 1948, pp. 13-15, 126 ff. If you donít know, Goodman was the first editor of "Howís DX" back in the 1930ís.
Moore, Robert, W6DEI. "Single Sideband Transmission," R9, September, December, and January, 1933-1934 (three installments).
Villard, O.G., W6QYT. "Single-Sideband Operating Tests, " QST, January 1948, pp. 16-18, 128, 130.
Williams, J. Evans, W2BFD. "SSSC," letter to the editor, QST, February 1948, p. 64.
About the writer: