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.

Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo\ Sonoran Radio Research
(__)\ _ P.O. Box 25240
\ \ .' `. Tempe, Arizona 85285-5240
\ \ / \
\ '" \ IEEE Member #40274515
. ( ) \
'-| )__| :. \ Email:
| | | | \ '. http://www.home.earthlink.net/~christrask
c__; c__; '-..'.__

Graphics by Loek Frederiks

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, ttbomk.

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.

Tom

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, ttbomk.

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.

Tom

On Thu, 26 Feb 2004 18:23:23 GMT, "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.

Chris

can't give you the proper reply, but if you are interested in
different types of mixers and detectors, you might like to see the
sub-harmonic RA3AAE anti-paralell diode mixer or detector which I've
tested in applications on 3.5, 7, 10, 14, 144MHz using 2x 1N4148 with
7dB NF
http://home.online.no/~la8ak/c21.htm - the important rule to succeed
is that it must be terminated with low impedance on all other
frequencies than which should pass. It has been mentioned several
times by G3VA in his column "technical topics" in Radcom

73
JM
----
Jan-Martin, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/

On Thu, 26 Feb 2004 18:23:23 GMT, "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.

Chris

can't give you the proper reply, but if you are interested in
different types of mixers and detectors, you might like to see the
sub-harmonic RA3AAE anti-paralell diode mixer or detector which I've
tested in applications on 3.5, 7, 10, 14, 144MHz using 2x 1N4148 with
7dB NF
http://home.online.no/~la8ak/c21.htm - the important rule to succeed
is that it must be terminated with low impedance on all other
frequencies than which should pass. It has been mentioned several
times by G3VA in his column "technical topics" in Radcom

73
JM
----
Jan-Martin, LA8AK, N-4623 Kristiansand
http://home.online.no/~la8ak/

"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.

Chris

"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.

Chris

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

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

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.

Chris

,----------------------. High Performance Mixers and
/ What's all this \ Amplifiers for RF Communications
/ extinct stuff, anyhow? /
\ _______,--------------' Chris Trask / N7ZWY
_ |/ Principal Engineer
oo\ Sonoran Radio Research
(__)\ _ P.O. Box 25240
\ \ .' `. Tempe, Arizona 85285-5240
\ \ / \
\ '" \ IEEE Member #40274515
. ( ) \
'-| )__| :. \ Email:
| | | | \ '. http://www.home.earthlink.net/~christrask
c__; c__; '-..'.__

Graphics by Loek Frederiks

I have a reciprocating detector (RD) kit that I purchased from Stirling Olberg,
W1SNN, in the early 70's. I have built it into a broadcast band AM receiver to
eliminate selective fading distortion. This receiver has switch selection of
diode, quasi-synchronous and RD detectors. I could probably run some tests for
you using this receiver.

I can also provide a bibliography of articles on the RD if you do not presently
have one.

Bob, K4QQK