"Michael Black" wrote in message
news:alpine.LNX.2.02.1308241914010.27526@darkstar. example.org...
On Sat, 24 Aug 2013, gareth wrote:
I wonder if some more experienced and senior (in the literal sense)
amateur
could explain to me one difficulty that I have in understanding single
signal
reception with the crystal phasing control?
AIUI, the phasing control is adjusted so that the frequency that would
give
the audio image is phased out by being in the notch.
When I had an SP-600, I don't remember using the phasing control much. I'd
leave it somewhere, I'd set the BFO and all was generally fine.
When that type of filter came along, it didn't replace anything, it added
something (so there was a wave of commercial receivers where you could get
two models, one without the filter, the other with the filter). The
single signal was because it suddenly did get rid of the audio image.

I think that it can only do that if the CIO / BFO is half way between the
peak
and the notch?

Tghe phasing control doesn't really change that, it allows some level of
control and you also get a notch at the same time.

If the notch is variable, then it will be some other audio frequency which
would be
notched out (clearly you'd go for the most troublesome interference, but
that
would not necessarily be the audio image)


TNX FER contribution OM