It would be interesting to see if that feature could be added.
-------- Original message -------- From: Don Wilhelm <[email protected]> Date: 05/26/2015 8:26 PM (GMT-05:00) To: Tony McRae <[email protected]>, [email protected] Subject: Re: [Elecraft] K3, diversity and noise reduction 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] ______________________________________________________________ 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]
