Re: Recommended AGC settings for separation of signals in CW pile-ups

Posted by Chris GM3WOJ on Dec 06, 2010; 3:19pm
URL: http://elecraft.85.s1.nabble.com/Recommended-AGC-settings-for-separation-of-signals-in-CW-pile-ups-tp5804756p5808179.html

Hello Bob et al

I guessed you might raise this subject, Bob!  I used my 10-week old K3 in CQ WW SSB with the default AGC settings and was a bit surprised by the trouble I had copying any signal less than about S3 when multiple stations around that signal strength were calling. I have local power-line QRN (smooth - similar to white noise) which is about S1-2 and I felt that this might be a factor in the DSP behaviour ?  Just a guess which may be completely wrong.

For my CQ WW CW DXpedition, I set AGC-SLP = 0 and AGC-THR = 8 (as per Dave K6LL's posting) and this made things seem slightly better. Although I was now in a low noise location, I still felt that when a bunch of stations were of similar (but not the same) signal strength and almost on the same frequency, they did become an unreadable mush.

The front-end performance of the K3 is excellent - I had no problem finding a space on any band in either big contest, but the AGC does seem to have some problems, which I hope can be addressed.

Off-topic, I also wonder if the K3 RX has too much gain (I've tried the default RX calibration and also borrowed an XG1 and done the calibration using that) - maybe e.g. IF gain could be made an adjustable parameter ? Or maybe it is the distribution of RX gain ?

73
Chris
GM3WOJ / ZL1CT

Sent from my ancient PIII shack PC