I've just gotten my K3 built and integrated into the shack about a week ago. Operated WPX CW this weekend with GREAT success. Was very happy.
Tonight in setting up FSK, I was getting a lot of "AGN?" after my cq's. Listening to my signal on a 2nd receiver, I realized that my signal had a hum on it - basically sounded terrible. Tested in CW mode as well, and the hum was also there (haven't dug out the mic yet for the dreaded SSB mode to know if the hum was there as well, but I would suspect it would have been). Tried changing a bunch of menu settings to no avail. Then I disconnected everything from the back of the K3 except for the antenna, power and FSK input. Beautiful clean signal. The hum reappeared when I connected the amp keying line. I've been using the Ameritron ARB-704 Amp Keying buffer, and even though the K3 can handle the relay voltage on my AL-80 (the key voltage is not in the AL-80 manual, but I believe it's 125v), I've kept in in line. However this seems to be the item causing the hum. When I take it out of the line, and connect the rig directly to the amp, no hum. My shack is NOT well RF grounded, and things are not bonded together at this point (that's a needed project - but the ARB-704 doesn't have a ground post to connect to - I'd have to go directly under one of the case screws to ground it). Anybody else experience this? Am I correct in my deduction that the K3 key out relay will handle the relay voltage on the AL-80? If so, I'll just ditch the ARB-704 for now. Thanks. 73 de Al, KE1FO ----- Visit my amateur radio contesting blog at ke1fo.wordpress.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
