[Elecraft] Sideband reversal

[Ron D' Eau Claire]

> The Swan-350 (and possibly other swan rigs) reversed sidebands
> between upper
> and lower bands.  It was an analog rig, so there were backward
> scales on the
> dial for the reversed bands. In fact I think this is how the convention of
> using LSB below 20m, and USB for 20m and up got started.


The early "low cost" commercial SSB filters used an i-f of 9 MHz. With
simple, single conversion designs that resulted on the output sideband being
the lower one on bands below that frequency and on the upper side for those
above.

The 'convention' has gotten so ingrained that I was "reading the mail" on 40
SSB one day and heard some ops telling two others who were on USB that they
were transmitting "illegally" since the FCC required lower sideband on 40
and below and upper on 20 and up. Not true at all, of course. The choice of
sidebands is just a long-standing convention based on what was 'convenient'
for the manufacturers.

Ron AC7AC
K2 # 1289