On Tue, 6 Apr 2010, Edward Knobloch wrote:

Hi, Gang

Pete Millett has recently moved to a new hosting site, and expanded
his collection of old electronics textbooks available for download.
The new site is he
http://www.tubebooks.org/technical_books_online.htm

One very good book is the GE Sideband Handbook,
a compilation of all the SSB info appearing
in the GE "Ham News". Included is the GE "SSB, Jr."
the forerunner of the Central Electronics 10A.

I'll grab it, but does it have much on DSB? GE seemed to be
the proponent for DSBsc (versus Collins and SSB), and Webb who
wrote an article about DSBsc and then a construction article about
making a synchronous detector (about 1957 in "CQ"), I thought he
worked for GE. They were talking about full blown DSB with proper
detectors, to do away with the carrier but make use of the benefits
of two sidebands. DSB is covered in the other SSB books, but there it's
an intermediate step, simpler to build than an SSB transmitter but simpler
and better than an AM transmitter, but one was expected to receive it
with an SSB receiver which turned the DSB signal into an SSB signal before
the product detector.

Michael VE2BVW

Pete's site can be rather slow, so I moved a copy of the GE SSB Manual
to Rapidshare, since it is a large file (151MB):
http://rapidshare.com/files/37282345...dbook_1961.pdf

73,
Ed Knobloch

On 4/6/2010 9:55 PM, Michael Black VE2BVW wrote:
One very good book is the GE Sideband Handbook,
a compilation of all the SSB info appearing
in the GE "Ham News". Included is the GE "SSB, Jr."
the forerunner of the Central Electronics 10A.

I'll grab it, but does it have much on DSB? GE seemed to be
the proponent for DSBsc (versus Collins and SSB), and Webb who
wrote an article about DSBsc and then a construction article about
making a synchronous detector (about 1957 in "CQ"), I thought he
worked for GE. They were talking about full blown DSB with proper
detectors, to do away with the carrier but make use of the benefits
of two sidebands. DSB is covered in the other SSB books, but there it's
an intermediate step, simpler to build than an SSB transmitter but simpler
and better than an AM transmitter, but one was expected to receive it
with an SSB receiver which turned the DSB signal into an SSB signal before
the product detector.

Hi,

Yes, the book has two DSB transmitters featured, the "DSB, Jr."
an 80m QRP rig with a pair of 6AQ5's in the balanced mixer final,
and a 200W input bandswitching DSB rig using a pair of 6146's.

For SSB receiving, they have a 12 tube phasing IF adapter
(quite advanced for 1948), or the simpler "slicer" adapters
later commercialized by Central Electronics.
The book doesn't include the synchronous DSB adapter
printed in a late 1950's CQ magazine.

73,
Ed Knobloch

On 2010-04-07, Michael Black wrote:

I'll grab it, but does it have much on DSB? GE seemed to be
the proponent for DSBsc (versus Collins and SSB), and Webb who
wrote an article about DSBsc and then a construction article about
making a synchronous detector (about 1957 in "CQ"), I thought he
worked for GE. They were talking about full blown DSB with proper
detectors, to do away with the carrier but make use of the benefits
of two sidebands. DSB is covered in the other SSB books, but there it's
an intermediate step, simpler to build than an SSB transmitter but simpler
and better than an AM transmitter, but one was expected to receive it
with an SSB receiver which turned the DSB signal into an SSB signal before
the product detector.

That's an interesting comment. I was reading a biography of Art Collins
recently and it mentions his efforts to get SSB into the Air Force, and
that it was in competition with G.E. wanting to push DSB.

One of the famous papers on this topic is "Poisson, Shannon and
the Radio Amateur" by John Costas in Proceedings of the I.R.E., December
1959, p. 2058. Costas covers a lot of ground in this paper, but a couple
of the points in favor of DSB are that you can recover the carrier
precisely from the signal, rather than having a local oscillator that
is approximately the correct frequency of the carrier. And that you
add the energy from the two sidebands coherently, so that just as
Shannon proposes you gain SNR by occupying more bandwidth. I guess the
attraction of SSB was that you get twice as many channels in the same
piece of spectrum as you do with DSB. And having an approximately correct
carrier frequency is good enough for most purposes, and is not hard to
achieve. Also Art Collins may have had better connections with his
friendship with Curtis LeMay and Butch Griswold. He participated in the
famous flying demonstrations of the capabilities of SSB. So far as I
know G.E. didn't get to do the same thing with DSB.

At any rate, Costas was one of G.E.s wise men.