Ron ZL1TW and I have been bemoaning the slooooow recovery time of the AGC that we were experiencing with both of our K1's.
Ron's been doing some experimenting as have I using componants from out junkboxes. What we ended up with was changing C31 from a 2.2ufd cap to a 0.22ufd cap. Ron added a 47k resistor between pins 9 and 10 of RP3. I had a 22k here and used that value in my K1. We then changed C67 to a .01. Basically it became an RF bypass cap rather than any kind of AGC timing cap. I would now describe the AGC time constant more along the lines of the "slow" agc setting of the K2 but much quicker than the stock K1. Additionally, in MY K1 I added a 0.47ufd cap in series between the /AGC OFF line and the positive side of C31. When I turn "OFF" my agc the time constant gets greater and sounds closer to a stock K1. A 1ufd or even the original 2.2 from c31 or C67 could be used here. I never use the K1 with the AGC off so this gives me a rudimentary "Fast/Slow" setting on my AGC. Of course...those of you who used the /AGC OFF line to change the brightness of the backlight would not be able to take advantage of this. Unless perhaps "Bright background = Fast AGC, Dim background = Slow AGC" 8-). Neither of us are recommending that anyone else make these changes. We're just letting people know in case there are others who find the slow recovery time of the AGC a bit too long for their liking in the stock K1. 73 de Tom K2TA K2-TA-100 #1117 K1-4 #2146 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
