Last Monday Mike and Andy had the exchange below. Andy has the right idea about keeping the AGC slope setting so that it reduces the AGC compression. That would be Slope=0. The threshold also has an effect and determines the signal level that the AGC compression cuts in. At present, the highest threshold setting is THR=8, for which AGC starts to operate at signals at about S3 level. In my experience from C6 (and others), that is too low. I think the AGC works great when you have a spectrum of differing signal levels, some loud and some weak. The problem that I see is when you have a pileup of signals where they are all about the same signal level. That often happens on European pileups. I wish there were a way to set the THR at a higher signal level, say S7-S8, and then to crank in a slope greater than 0. This would give us a greater range of signals in the linear response region before AGC compression sets in, and allow better discrimination of those almost alike signals. That would, if using Slope>0, make for some non-linearities when strong signals are there but I would think it would be better than the audio clipping that exists when you run with AGC off.
I wish we could try a firmware test version during CQWW that would let me test my theory, but I don't know how big of a software change that would be or if there are other ramifications of letting THR be higher. Good luck and have fun at J6. The Team Vertical guys will be on from C6, operating C6AAW M/M (lite) with at least 5 K3s. I'll be C6AKX before the contest. 73 and cheers, Fred, KE7X "The Elecraft K3: Design, Configuration, and Operation" www.ke7x.com [quote] Jim, At P49Y, I have found it useful on CW to use an AGC slope setting that reduces agc compression. That way you can use the RF gain control to help manage the pileup. But I recommend keeping the AGC on so that you don't get blasted by a very strong signal after you have been straining to pull out a weak one with the af gain turned up. 73, andy ae6y -----Original Message----- From: W0MU Mike Fatchett Sent: Monday, November 07, 2011 9:51 AM To: Elecraft Reflector Subject: [Elecraft] Best setup for DX pedition K3 I am looking for suggestion on the best receiver setup for our trip to J6. I know we are going to have some pretty big pileups. I recall reading about the VP6DX guys probably using no AGC and riding the RF gain if my memory is correct. Are there any other tweaks that might come in handy? [/quote] Fred fcady at ieee dot org "The Elecraft K3: Design, Configuration, and Operation" www.ke7x.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
