FW: [Elecraft] Sideband reversal

Mon Jan 28 17:25:09 2002

EVERYONE wants the telephone turned back upside right. Lots of people =
know how to extract a square root with pencil and paper. Does anyone =
know how (if it's even possible) to extract a cube root with pencil and =
paper (iteration doesn't count - Thanks Issac).

Dan / WG4S / K2 #2456

-----Original Message-----
From: [email protected]
[mailto:[email protected]]On Behalf Of Steve Lawrence
Sent: Monday, January 28, 2002 11:43 AM
To: [email protected]
Cc: [email protected]
Subject: RE: [Elecraft] Sideband reversal

Wow!  You've answered one of lifes mysterious questions I've always=20
wondered about:  why LSB below 20, USB above?  Somehow, I'm not =
surprised=20
at the outcome.  It's sort of like the question:  Why are calculator=20
keypads (specifically the numbers) arranged bottom to top and telephones =

arranged top to bottom?  (I'm still looking for the answer to this =
one....=20
but like the USB/LSB convention its probably some stupid early technical =

problem that's no longer an issue either.)

Steve

"Ron D' Eau Claire" <[email protected]>
Sent by: [email protected]
01/28/2002 11:29 AM
Please respond to rondec

=20
        To:     <[email protected]>
        cc:=20
        Subject:        RE: [Elecraft] Sideband reversal

> 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=20
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=20
being
the lower one on bands below that frequency and on the upper side for=20
those
above.

The 'convention' has gotten so ingrained that I was "reading the mail" =
on=20
40
SSB one day and heard some ops telling two others who were on USB that=20
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=20
'convenient'
for the manufacturers.

Ron AC7AC
K2 # 1289

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