At 10:06 PM 11/29/2010, you wrote: >Noted your comment on noise reduction by phase nulling. Have you >looked on info on pages by pa0sim, see www.pa0sim.nl, he has done >more or less what I think you are considering. Ie connecting the >output from 2 phase locked receivers fed with separate antennas and >do the amplitude/phase nulling at AF level. > >Some of the sound samples on his website are impressive in terms of >noise reduction. > >I would love to see an application which could do this, would be >nice to check out if phase nulling works at a site before trying an >MFJ unit or similar. I really would like to see this done in the K3 >as all the hardware is there to do such phasenulling in software, >could eg use the VFO B knob for phase control and the volume knobs >for amplitude control. Only requirement is to feed the 2 RXs with >separate antennas, ie an alternative use of diversity capability. > >I was not able to respond on the reflector. Would be nice if you >could keep the group updated if you get more info on this. > >73 de Olaf LA3RK
Olaf, Thanks for writing. I somehow lost your e-mail and wanted to look at the pa0sim webpage. I merely suggested the idea. I really have no prospect for doing this. I thought maybe Elecraft might be interested in the idea; provide firmware to do it. A modification on doing diversity reception was what I had in mind. Use a small "sniffer" antenna on the aux Rx input to sample noise and null it from the main receiver in sw. I think it would be easiest to accomplish in digital before conversion to audio. All the DSP routines are done there: NB, NR, AGC, APF, DSP bandwidth. Phase shift and amplitude adjustments would be possible in digital, so assigning VFO-B would be relatively simple for phase and use the sub-Rx volume for amplitude adjustment. I guess it's now up to Elecraft if they want to explore this. 73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-800*w, 432-100w, 1296-testing*, 3400-winter? DUBUS Magazine USA Rep dubus...@hotmail.com ====================================== *temp not in service ______________________________________________________________ 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
