While on a reflection jag on diversity out on Core Banks... There is one thing that would help diversity on a noisy band. We already know about needing to lock all the conversion frequencies. The other would be an option to run a composite AGC that controls BOTH receivers that takes the most restricting AGC result from both and uses that to control both. That would remove the roar in one ear when the signal is well down in one RX and up in the other. As it stands now, sufficient separation allows the off-signal RX to bring up the noise level in that ear. It would allow a more proportional separation from signals differing in volume only.
When in the diversity mode, that could be a mode that is cycled through when doing a HOLD on the AGC button, e.g. ON, OFF, LOCKED, ON, OFF, .... There are times when that would help and times it would hinder, so it would need to be on a front panel button. 73, Guy On Thu, Nov 11, 2010 at 10:13 PM, Guy Olinger K2AV <olin...@bellsouth.net> wrote: ...... > > We used orthogonal antennas and dual RX K3's in diversity mode at N4A > in the IOTA on Core Banks NC this summer. It worked very well, and > we had the high North America island expedition score for LP, beating > all but one of the North America HP scores. A pair of three band > inverted vees running NW/SE and NE/SW fed with 450 line feed and tuned > via a 4:1 balun and the K3 antenna tuners. > > What happens is that with both RX on that you do not get the nature of > signal separation you are expecting. You get phasing separation > because the antennas will decode any polarization off pure vertical > and pure horizontal into the same kind of separation you have > listening to a conversation in a crowded room. Signals not low angle > frequently came in on a rotating polarization, moving back and forth > from one ear to the other. What was quickly clear was that if we > turned off the SubRX, the moving back and forth is converted into > rapid deep QSB that defeats copy. The LOUD stations tended more to be > in one ear or the other, but those are easy to work. The WEAK signals > on 40m particularly, would be affected by this rotating polarity. The > same rotation was heard on the band noise, some of the guys having a > hard time listening to this rotating background. I was constantly > cleanly copying signals that sounded like they were starting on a > fadeout but just rotated through my head to the other side instead. > One has to hear it to understand it. ...... ______________________________________________________________ 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
