On Mon, 12 Jul 2004 11:50:46 EDT, [EMAIL PROTECTED] wrote: > Hello Stewart, > I have experienced "fuzzy" transmitted audio with my K2/100,KAT100-1 on 75 > meters also. My KSB2 has all the KI6WX mods and has a bandwidth of 2.5 Khz. > It looks great on Spectrogram, and the received audio is excellent. I have > two K2s (both with KI6WX mods) and they both sound fuzzy so I suspect it is > an RF feedback. I removed the Elecraft MH2 (electret) mike and removed the > 5.6K resistor across pins 1 and 6 of the mike connector and connected the > Kenwood dynamic mike that came with my TS-850. This mike seems to clear up > the problem and I am getting good clean audio reports. This seems to mean > that the RF is getting into the mike input. I also did the mod to ground the > mike connector, but I don't think much of that mod, and don't think it helped > much if at all. Now I will have to tackle the same problem in my older K2. > BTW, my hamshack is on the second floor of my garage. This can present some > challanging grounding "opportunities". Anyway, I thank you for sharing your > remedy with us by using the RF choke in series with C32 on the KSB2 board. > Roy Morris W4WFB
Roy, Thanks for your mail. Although I am using a balanced antenna system, on some bands particularly 40m there is still a significant amount of RF in my shack. Your grounding situation will be a lot worse (been there, done that, got the Tee shirt !) It only needs a small trace of RF getting into the audio side to make your transmission sound "fuzzy". The RFC mod I did got rid of all the RF feedback problems I was getting, without affecting the TX audio frequency response one jot. Anyway, putting it in can do no harm. 73 Stewart G3RXQ _______________________________________________ Elecraft mailing list Post to: [email protected] 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
