Hi Guy, The problem reported has the classic characteristics of in-passband IMD caused by a small dynamic range (IMDDR3) IF system, rather than being something caused by the AGC sub-system. Yes changing the AGC's loop characteristics will alter the effect, but the root cause is still non-linearity in the signal path. I suspect the second mixer.
Trouble is that large IMDDR3 IF systems can consume a lot of power, and low power drain by the K3's receiver was a design goal I believe. 73, Geoff GM4ESD On Saturday, February 06, 2010 at 5:17 AM, Guy Olinger K2AV wrote: > Hi Dave, > > Using slope 000 is likely most of your problem. With that setting all > signals regardless of strength are set to the same level regardless of > how loud they are coming in. If they are zero beat or close, it will > mush the dickens out of the copy by making them all the same level in > your ear. I set AGC SLP to 15 for contests. I also use slow AGC the > entire time. If there are key clicks, I use NB with IF off and dsp to > t3-7 or t2-7. It rounds off CW bauds some but does not make them > uncopyable. > > Make sure your ATT/PRE/RFGAIN use conforms to something like: > > 160m ATT plus RF gain at 2 oclock > 80m ATT plus RF gain at 3 oclock > 40m ATT plus RF gain fully clockwise. > 20m " " > 15m off plus RF gain fully clockwise. > 10m PRE plus RF gain fully clockwise. > 6m " " > > ...if you are listening on your transmit antenna. At least to start. > Make sure the ambient noise on the band is moderately low audio > listening on a clear frequency. > > Using the NB with those settings, including the ATT/PRE/RFGAIN > settings. Just today I was listening to an S4 Cuban underneath what > were S9/5 key clicks with the NB off. Offending station up 500 Hz at > 30 over 9 (really), and was using 250 filter running at WIDTH 350. > > Good luck in Sprint this weekend! > > 73, Guy. ______________________________________________________________ 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
