Re: cw sidebands

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From: John F. Woods (jfw@ksr.com)
Date: Tue May 03 1994 - 10:35:04 EDT


> I Guess that I'm not sure what the big deal is over the which sideband
> you guys want to use.
> let's think about this for a minute...
> First of all to make it clear, we are on ONE frequency when we send cw.
> One frequency, not the upper sideband or the lower.. just one frequency.

Well, actually, no.

If you send an actual continuous wave (no keying), starting at the dawn of
time, then you will, in fact be sending a pure frequency. But you cannot
modulate a carrier *in any fashion whatsoever* without generating sidebands.
The sidebands generated by a CW transmitter look suspiciously like very thin
AM sidebands, and if you think about it, that's exactly what CW modulation is.

But that's not actually what's being discussed.

> Second with D.C. receivers, you can listen on whichever side of zero beat
> (that one frequency, 7.040) you want.

Bingo. But if you listen on the wrong side of zero beat with a DC transceiver,
that expensive commercial transceiver you're talking to will have your carrier
outside of *its* sideband filter, because it looks to him like you're sending
on "the wrong sideband" (think of sending MCW using an SSB rig). Two DC
rigs talking to each other don't care about sidebands (exotic single-signal
schemes excepted, of course).

73, John, WB7EEL/1


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