Re: [Elecraft] K3 RF Feedback Problem
Jim, I've been on travel so apologize for the delayed reply. All I can say is WOW...I thought I was the only one who had this symptom with the K3! I have a similar setup with a Heil boom-mic going through a DX Doubler SO2R switch box, and had horrible SSB distortion on bands above 14 MHz and power levels above about 12 watts (the point where the PA kicks in). I unplugged and replugged cables and changed orientation; somehow eliminating the distortion, but never really found a smoking gun or understood the distortion mechanism. The thing that was killing me was that the K3 simply replaced an IC756ProII in the same spot and I had not previously experienced such transmit distortion. Several calls and emails to K3 support had me check the power supply. However the only conclusion we could come to over time was some kind of a weird ground loop. Other posts seem to be right on target. RF on the mic shield line isn't being taken to true ground...and it's finding it's way into the microphone amplifier. Thanks to you smart guys out there, and for Elecraft, how about a design review? 73 Rick N6CY -- View this message in context: http://n2.nabble.com/K3-RF-Feedback-Problem-tp1442033p1452766.html Sent from the Elecraft mailing list archive at Nabble.com. ___ 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
Re: [Elecraft] K3 - bad CW note
I recently completed building my K3 and listening on a different transceiver in the shack, I also noticed a light hum/buzz superimposed on my 18-24 MHz CW signal at levels above 12, up to 100 watts, into a dummy load. Also using a switching power supply, Astron SS-30. I don't own a linear power supply to substitute. However when I switch to battery-only, the buzz is still present. So over time I'll try to verify with stations if this is just a local, in-station phenomenon, or truly going out on the air. Propagation hasn't actually been good for these upper frequencies... 73 Rick N6CY John W2XS wrote: Is there a difference in the power supplies at the two stations? I had a very similar bad CW report when I first got my K3 which was due to a switching power supply that I was using. The note was bad at all power levels on several bands. I bought an Astron RS-35A and the reports were good. I still wonder why the switcher didn't work well since it was a 12V, 24A supply. Good luck. John W2XS -- View this message in context: http://n2.nabble.com/K3---bad-CW-note-tp1334054p1339315.html Sent from the Elecraft mailing list archive at Nabble.com. ___ 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
