Chris Trask wrote:
"Tom Holden" wrote in message
. ..
Chris Trask wrote:
I learned by way of Google that there was a thread
on this newsgroup last Summer regarding reciprocal
detectors. I'm interested in learning what sort of
success any of have you have had with regard to noise
immunity and adjacent signal suppression.

This was probably the discussion I triggered on the
Reciprocating Detector. I had intended to migrate my
proto-board version to a more rf friendly board this
Winter but still have not done so. I have done little
home brewing and even less experimentation with
detectors so can't really provide much perspective. I
thought it worked well on SSB with carrier, such as CHU,
but it seemed to null the audio at centre lock on DSB
signals - as though the sidebands were demodulated with
opposite phase. Thought it might have been a consequence
of the strays on the proto-board because I am the only
one to have observed this phenomenon with the RD.

Additionally its self-oscillation frequency pulled on
strong bass modulation towards the sideband of SSB
suppressed carrier - a kind of FM distortion. It
likewise was pulled by strong ICW signals.


I happened to discover a copy of the original IEEE
conference paper in my files here, and I see that the
circuit requires that the input signal be reduced to a
half-wave rectified signal. The Ham Radio articles state
that it was difficult to achieve a faithful half wave
signal. I know that I can overcome this problem with my
patented method of augmentation, which I have used to
make very linear 1W HF/VHF/UHF amplifiers. Another
problem is that the circuit needs to be balanced, and in
the Ham Radio articles this need is not faithfully
implemented. Looks like there's lots of room for
improvement.
I would certainly agree that there is need for improvement and hope that
your insight will deliver some!

73, Tom