[Elecraft] USB on all bands ??

[Sandy]

One of the original theories for the LSB/USB differences was brought about 
by the use of a 9Mhz. "IF" frequency in some of the early SSB gear.

Originally, there was no voice modes at all on the 40 meter band.  Also 15 
meters hadn't been opened yet and there was little SSB activity on 10 
meters.  Hence, the "primary" SSB activity was mainly on 75 and 20 meters. 
Generating SSB on 9 Mhz. was chosen for ease of operation and also to 
minimize "spurious mixing byproduct signals."  This was heterodyned to 4 and 
14 Mhz bands by use of a 5 Mhz VFO (hence 14-14.3 and 3.8-4.0 Mhz bands used 
the same VFO range.)  If Upper sideband was selected on the 9 Mhz. SSB 
generator, this would result in USB on 20 meters and LSB on 75 meters for 
basically the same VFO range.
The first widely popular SSB transmitter was the "SSB Jr." exciter which 
came out in GE Ham News as I recall.  The circuit was adapted and refined by 
Central Electronics when they manufactured their then famous model 10A and 
later, 10B exciter/transmitter.  A paltry 10 watts SSB!  SSB advocates were 
quick to point out how well SSB "got out" compared to AM voice using much 
less power and band space.  The practice of using LSB on 75 and USB on 20 
continued, as changing over would necessitate turning another switch, and 
the practice of not switching sidebands in the 9 MHZ. SSB generator had been 
the "norm" for several years so the practice persisted.  For those who don't 
know it, the "phasing" method of generating SSB was the "most used" method 
in the beginning and lent itself to homebrew construction from junkbox parts 
of SSB gear in the early days.  HF filters were then very expensive, and few 
amateurs who "built" gear could afford the Collins mechanical filters!  The 
complex crystal filter much used these days, hadn't come into widespread use 
yet.

When 40 meters was eventually assigned a "voice" sub-band and 15 meters was 
opened, the practice of USB from 20 meters to 10 meters and USB on 160-40 
meters was established.  I have no idea just "who" established it!  ARRL? 
General use?  The "little band of SSB advocates" in a world of AM diehards? 
Ideas any of you old timers?

When use of SSB became popular in commercial marine radio circuits and 
eventually the military and aeronautical long haul communications, Upper 
Sideband was "standardized" for these services.  (By the FCC?)  The amateur 
services did not follow suit.

Should we do that today?  Some people say yes, some say leave it as it is. 
It WOULD simplify manufacturing the radios by elimination of un-needed 
parts/switching devices.  I would imagine very little vacuum tube homebrew 
gear is still in use that worked only USB on 20 and LSB on 75 meters!

Anyway, that's the "WHY" of sideband use on the ham bands today digging back 
to when SSB was for all practical purposes, "non-existent" practiced by a 
few radical amateurs during the days of what turned out to be mostly 
unstable receivers in the "old days".  Am was "too easy" to keep using on 
the hundreds of watering holes on 75 meter AM for "local" operation before 
the widespread popularity of 2 meters!

73,

Sandy W5TVW
----- Original Message ----- 
From: "Jim Miller" <JimMiller at STL-OnLine.Net>
To: <elecraft at mailman.qth.net>
Sent: Friday, May 23, 2008 10:37 PM
Subject: [Elecraft] USB on all bands ??


>
> ----- Original Message ----- 
> From: "Ron D'Eau Claire" <ron at cobi.biz>
> To: <elecraft at mailman.qth.net>
> Sent: Friday, May 23, 2008 5:38 PM
> Subject: RE: [Elecraft] Dayton Discovery [OT]
>
> .....snip......
>
> Indeed, one of the first things I expect to see is pressure on Hams to 
> adopt
> USB as the "standard" sideband on all Amateur bands so the manufacturers
> don't have to consider sideband switching in their product offering.
>
> Ron AC7AC
>
> Anybody been around long enough to explain the theory behind the use of 
> LSB
> on the lower bands vs. USB higher up?  What is the advantage to doing so?
>
> 73, de Jim KG0KP
>
>
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