[CQ-Contest] Band edges?

Scott Ellington sdelling at facstaff.wisc.edu
Mon Dec 18 09:33:56 EST 2000

Dan Weisenburger wrote:

> The sidetone you
> hear is  to help you monitor your sending, not the transmitters
> performance.  The audio produced is nothing more than an audio
> oscillator like the old CPO. 

This is not true of many transceivers, like the FT-1000, TS-850/930/940.  The
IC-765, as I recall, is a notable exception.  These produce the sidetone by
mixing the carrier with the BFO, so the sidetone pitch represents difference
between the two. If you tune a received signal so the pitch matches the
sidetone, your transmitter will be on exactly the same frequency as the received
signal.  (Of course, you can deliberately tune a little above or below, if you
wish.)  This sidetone pitch allows you to transmit exactly where you want to
with respect to the received signal.  On a crowded band, the station calling CQ
may have a clear window only a couple hundred Hz wide.  If you call outside that
window, you're probably not going to be heard.  Or worse, another station may
respond to you, resulting in an invalid QSO.

In every contest, I find many callers 500 Hz or more from my transmitter
frequency.  No doubt I miss many more.  Even if the QRM isn't bad, it takes a
while to tune the RIT over that 1 kHz range, so often I only get a partial call.
 Every CW contester needs to know exactly where the transmitter is.   If you're
not sure of your technique or the alignment of your transceiver, check it out
with a separate receiver.  


Scott  K9MA

Scott Ellington
Madison, Wisconsin   USA

sdelling at facstaff.wisc.edu

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