No kidding, I was thinking of suggesting this as well... -- Thanks and 73's, For equipment, and software setups and reviews see: www.nk7z.net
For MixW support see; http://groups.yahoo.com/neo/groups/mixw/info For Dopplergram information see: http://groups.yahoo.com/neo/groups/dopplergram/info For MM-SSTV see: http://groups.yahoo.com/neo/groups/MM-SSTV/info On Tue, 2015-05-26 at 21:01 -0700, David Gilbert wrote: > I have on three different occasions requested of Elecraft that such a > feature be added to the K3. Two of those requests never received a > response, while the third got a "we'll see if anyone in engineering is > interested" reply (apparently nobody was). > > Personally, I think this is a significantly missed opportunity to expand > the usefulness of diversity reception in the K3, especially now that the > new synths retain phase lock when changing frequency. If even only one > receiver in the K3 had the ability to time shift the audio signal, it > would work. The K3 already has separate volume controls and already has > the ability to mix the two channels. With two antennas separated > horizontally (i.e., two verticals a suitable distance apart), the phase > could be adjusted to boost a desired signal by roughly 3db or null an > undesired signal (noise or QRM) by 20 to 30 db or more (depending upon > how stable the signals were). Directional antennas are not needed at all. > > I also think it would be interesting, and maybe useful, to use two > antennas separated vertically, such as a couple of dipoles or yagis on a > tower. Adjusting the phase could potentially drop a severe notch on an > interfering signal IN THE SAME DIRECTION as a desired signal. > > Phase is preserved in the down conversion to audio so all this could be > accomplished at the audio level. I'm not saying that's the best place > to do it, but worst case I'm going to learn enough software code to do > it myself using the sound card of my computer since nobody else seems > interested. > > 73, > Dave AB7E > > > On 5/26/2015 5:45 PM, Harry Yingst via Elecraft wrote: > > It would be interesting to see if that feature could be added. > > > > > > > > -------- Original message -------- > > From: Don Wilhelm <w3...@embarqmail.com> > > Date: 05/26/2015 8:26 PM (GMT-05:00) > > To: Tony McRae <a...@ttecs.com.au>, elecraft@mailman.qth.net > > 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:Elecraft@mailman.qth.net > >> > >> This list hosted by: http://www.qsl.net > >> Please help support this email list: http://www.qsl.net/donate.html > >> Message delivered to w3...@embarqmail.com > >> > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Elecraft@mailman.qth.net > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to hlyin...@yahoo.com > > ______________________________________________________________ > > Elecraft mailing list > > Home: http://mailman.qth.net/mailman/listinfo/elecraft > > Help: http://mailman.qth.net/mmfaq.htm > > Post: mailto:Elecraft@mailman.qth.net > > > > This list hosted by: http://www.qsl.net > > Please help support this email list: http://www.qsl.net/donate.html > > Message delivered to xda...@cis-broadband.com > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to d...@nk7z.net ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
