In article ,
"gareth" wrote:

snip

Wanted signal in the peak of series resonance.

Bfo adjusted on the HF side to give a pleasant tone.

Notch moved using the phasing control to be at the IF frequency that would
produce
the audio image from the current BFO setting.

What I was after was the procedure to set the notch frequency, because
unless you have a narrow
CW filter in the AF strip, how would you judge that you'd created the same
AF heterodyne whistle?

TKS FER heads-up on Lamb, I'll follow that.


You judge it by listening. If there isn't an interfering signal at that
frequency you don't have to do anything and you don't care where the
notch is (unless you use it to suppress a signal at a different
frequency which is probably less of a nuisance as the beat note is
different). You only have to adjust the notch if there is an
interfering signal, and you adjust it to make the desired signal easier
to read. If the phasing control makes no audible difference, or there
isn't any QRM, don't bother with it.

--

Percy Picacity