Tony,
You are looking at information about how to compensate two unequal
receivers for true diversity reception - two orthogonally opposed
antennas receiving the same signal.
The K3 makes that easy with a sub-receiver that is identical with the
main receiver and they are phase locked together in diversity. When
placed in diversity mode (using two antennas hopefully having different
polarity or directional characteristics), you will hear enhancement of
the reception from whichever antenna is receiving the best signal - you
have each receiver in each of your ears, and the human brain will
respond to the best signal. No phase adjustment is necessary.
OTOH, if you are looking to reduce the noise of your plasma TV and
routers, that is another form of reception that could (but not
necessarily) be related to diversity. You would want to use a
directional antenna aimed at the noise source to feed one receiver while
being able to adjust the amplitude and phase of that noise signal to
cancel out the noise source.
It is possible that you could use the K3 with subRX to do that, the AF
and RF gain controls will do the amplitude part of the process and if
you provide an external mechanism for changing the phase of the two
antennas, you may be successful. The easiest phase change is simply to
flip the noise receive antenna terminals which should achieve a 180
degree phase shift, but the actual phase shift will depend on several
other factors such as the length of the antenna feedlines and the
physical placement of the antennas (which control the arrival time of
the noise signal at the antennas).
So, yes, it is possible that with suitable antennas placed properly, the
K3 with subRX *could* serve as a noise cancelling system, but it was not
designed for that purpose, it was designed to counter propagation
effects such as fading due to polarization.
73,
Don W3FPR
On 5/25/2015 9:00 PM, Tony McRae wrote:
I have been watching some youtube clips showing how by adjusting the phase and
amplitude of two received signals on a diversity receiver local noise can be
reduced by more than 20db.
This would be particularly useful to me as I have the dirtiest plasma TV on one
side of me and a gaggle of cheap ADSL routers on the other. When pointed at
them with my yagi the noise floor on 20-15m is over S7.
The equipment used in the clip was the ANAN 100D SDR.
Is anyone aware if this technique is possible using the K3 dual receivers?
I have not found any place in the manual where it is possible to alter the
phase of the secondary or primary signals.
Thanks for reading this
Tony VK4CH
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[email protected]
This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [email protected]
