Re: cw sidebands


From: Mont Pierce (
Date: Tue May 03 1994 - 11:07:45 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...
> I've heard comments maybe he was listening on the wrong sideband..
> and D.C. receivers and wrong sideband..
> Well, I think that either I'm really confused, or there seems to be a general
> missunderstanding about what we are doing with cw here.
> 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.
> ...
> Second with D.C. receivers, you can listen on whichever side of zero beat
> (that one frequency, 7.040) you
> want. So you will hear the nice 700 Hz tone when your d.c. receiver oscillator
> is set at 7.0407 or 7.0393 mHz.
> Remember the transmitted signal still looks like the above! You hear a tone
> only when your receiver oscillator signal is +- 700 Hz from the cw signal.

I think you're missing the point. There is a problem if you are listening
to the wrong sideband if the wrong sideband is described as follows:

    As you tune, the tone of the receiving station rises while the tone
    of your key sidetone oscillator falls, or vice versa. I.e. your
    listening some 1.4 khz off the frequency your transmitte is tuned to.

Your right about signle image superhet receiption though, if your using
a tranceiver where both the receiver and the transmitter are using the
same offset direction from the beat frequency. But if you're using
separate transmitter and receiver, you still have the same problem. You
need to make sure that your using the same offset on both rigs.

The easiest thing to do is to just tune your receiver slightly and make
sure that the tone of the station your receiving is changing in the same
direction as your transmitter's signal.


Mont Pierce

+-------------------------------------------------------------------------+ | Ham Call: KM6WT Internet: | | bands: 80/40/20/15/10/2 | | modes: cw,ssb,fm | +-------------------------------------------------------------------------+

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