[SCCC] AM to SSB transition

[w6ph at aol.com]

Wayne said it all.  I am 1955 vintage and this is exactly as I remember it.
Collins was the forefront for SSB.  The Strategic Air Command needed reliable communication in the polar regions for control of its bombers.  SSB solved the problems with AM distortion in the auroral regions. 

SSB was developed in the late 40's for use by hams.  There are many articles in QST showing how to mathematically eliminate the carrier and eliminate one sideband.  It was called the phasing method and several manufacturers came out with these transmitters.  Collins took a different approach and used a balanced modulator and mechanical filter to produce the single sideband suppressed carrier signal.  It was produced on a single frequency and a heterodyne scheme was used to vary the frequency.  Using the heterodyne principle led to the transceiver which used the same VFO to vary both the transmit and receive frequency.  The KWM-1 was the first widely available transceiver and could be used either as a home station or a mobile station.
Heath Company and EF Johnson came out with what they called sideband adapters which were made to convert a normal AM-CW transmitter to SSB using the phasing method.  I converted my DX-100 for implementation of the SB-10 but never bought the SB-10.  Instead the SB-400 came out and was a better choice to get on SSB.  The Heathkit SB series was the poor man's Collins S-Line clone.
There was also a short period of interest in double sideband suppressed carrier or DSB.  Instead of producing the signal at a low level and amplifying, it was produced using balanced modulator techniques in the final tubes.  The control grids of the final tubes were directly driven and the output was operated push-pull.  The screen grids were driven with an audio signal in a push=pull arrangement.  However, the interest was very limited as it was one sideband too many!
Due to the availability of SSB gear at reasonable prices and the advantages of SSB, it became very popular very quickly.  Wayne is absolutely correct in his time lines. 

73, Kurt W6PH
In a message dated 12/16/2018 7:59:05 PM Pacific Standard Time, sccc at contesting.com writes:

Dennis, I'd really like to see some discussion of the AM-to-SSB transition here on the SCCC list.  It would be fun to read what others remember from those days.  Here are some of my recollections.
As a young ham in the 1950s I operated several contests on AM before SSB became the mainstream voice mode on the HF bands.  The high point for me was 1959 Phone Sweepstakes.  I finished second in the L.A. section, running a Heathkit DX-100 transmitter and Hallicrafters SX-101 receiver to a 2-element cubical quad for 10 and 15 meters (up 25 feet at the center--not very high even by 1959 standards).  The guy who beat me (W6LNW) was #2 nationally and he had much bigger antennas than I did.  Size mattered, as it still does.
QST published a list of the equipment used by all of the section leaders in those days.  In 1959 almost all of the winners were running AM transmitters like Viking Valiants, DX-100s or the earlier Viking I and Viking II rigs.  I don't think there was much SSB activity in Phone Sweepstakes until a few years later.  I went off to college and didn't operate SS for several years after 1959.
By 1965, however, everything had changed.  Almost all of the section leaders were running SSB rigs and operating the contest mainly on SSB.  At the same time, overall voice activity dramatically increased.  In 1959 Sweepstakes, CW logs outnumbered phone logs by a 3:1 ratio.  By 1965, the ratio of CW logs to phone logs was only 5:4.  There were more phone logs than CW logs in SS for the first time in 1970, according to the tallies of Ellen White, W1YYM (now W1YL), who wrote most of the SS articles for QST in that era.
Clearly, the transition to SSB led to a major increase in overall voice activity in Sweepstakes.  However, it didn't lead to the kind of increase in overall scores that you might expect.  In 1959, the top phone scores were over 200K (on AM), not that much lower that the top phone scores now, 60 years later.  However, that's really comparing apples to oranges because there was a power multiplier then.  Also, the maximum operating period on each mode was longer than it is today.  And to be honest, I don't think anyone worried much about "rubber clocking" until the 1970s.  Most of us didn't operate anywhere near the maximum time allowed.
I don't remember the best receivers of the 1950s being that bad.  They had good sensitivity and selectivity on the HF bands, even 10 meters.  What was different was the HETERODYNES on the bands.  With all those AM carriers, during SS the phone bands were a sea of squeals and whistles.  Receivers had notch filters, but you couldn't eliminate all of the squeals.  (Null one out and another one would pop up.)
Voice operating didn't seem all that different back then--except for the awful QRM.
 With my DX-100 (about 100 watts of high-level plate modulated AM), I could hold a frequency and run all day on 10 or 15.  S&P was a pain, though.  Without a transceive mode you had to zero-beat every station that you called.  I very much preferred running--and I hated it when 15 dropped out to the east.  I couldn't ever hold a frequency and run on 40 meters.  W6LNW, the guy who beat me in '59 phone SS, could hold a frequency and run all night on 40.  I spent some envious times listening to him.  Size mattered.  Um, did I say that before?
Just some random memories of phone contesting in 1959...
73, Wayne, N6NB (K6YNB back then)



--------------------------------------------On Sun, 12/16/18, Dennis Younker NE6I <NE6I at cox.net> wrote:
Subject: Re: [SCCC] Looking For Write Ups, Comments, Observations AM to SSBTo: sccc at contesting.comDate: Sunday, December 16, 2018, 4:02 PM
Some really good stuff has beensent along to me for the upcoming article.Does anyone have any old photos of that timeperiod? Station photos from the1950s and60s would be a great add to the article! As well, yourcontestexperience during that time framewould be interesting. What was it like tooperate a contest where both AM and SSBco-existed on the bands? Receiverswere soless capable back then that I can only imagine howchallenging itwas for a few years there.
As before, please reply onlyto me so that I can capture your comments andphotos for the article. Thanks!
--Dennis NE6I
_______________________________________________SCCC mailing listSCCC at contesting.comhttp://lists.contesting.com/mailman/listinfo/sccc