On Dec 14, 6:43�am, Bill Horne wrote
:

ISTR that early Swan transceivers offered only USB
for 20, 15, and 10,
and only LSB for 80 and 40.

You are correct, sir! But they were not the only ones to do
that - National and some others did too. The early Heath
monobanders had no sideband switch, for example.

Swans used IFs in the 5 MHz range.

They say the memory is the second thing to
go, but perhaps that was where this convention got started.

The problem is that by the time Swan showed up in the early 1960s,
the standard was already in place. And later Swans let you use
either sideband.

The 9 MHz IF/ 5 MHz VFO system was popular in the 1950s. The
Central Electronics 10A, 10B and 20A exciters all used it, as did
the popular W2EWL SSB rig featured in the article
"Cheap and Easy SSB". You'd think those popular rigs would have
caused the standard to be that the same sideband would be used
on both 20 and 75, because they don't invert the sideband. Swan
would then have been bucking an established trend. Yet the opposite
is true. I suspect that Swan chose their heterodyne scheme to
save a little money by not needing a second BFO xtal nor a switch.

BTW, given a choice between LSB and USB, the
military's preference is
for Upper sideband, since using USB makes it easy to talk another
station on to a net frequency: if his voice sounds high, then so is his
frequency.

IMHO, there's also the simplicity. If everyone is on USB, regardless
of band, you don't have to think about which one to use, or even
provide a choice.

73 de Jim, N2EY