Tom, Check that your MKII has the capacitor modification that decouples the USB cable shield. If not, RF on the cable can cause audio problems. Details are on the MicroHam site.
73 Stewart G3RXQ On Tue, 11 Mar 2014 17:58:00 -0400, tom...@videotron.ca wrote: > Ok, thanks, that's what I thought. A little more complicated since I have a MicroHam microkeyer II in the circuit but probably fixable. > > 73's Tom > > On 3/11/14, "donehrl...@q.com" <donehrl...@q.com> wrote: >> Almost certainly RF getting into the mic circuit. Try a different mic .. or use the rear panel mic connector as a check. You probably have high SWR into the antenna feedline (or coax) after the tuner on 20 meters and that is why you only see problem on 20M. High SWR on the feedline (Note: your rig can be seeing low swr .. it is AFTER the tuner where you have high SWR) results in high current or high voltage that then couples into other shack wiring. Of course, the higher power from the KPA500 pushes those voltages/currents to levels that are more likely to cause problems. Been there, done that .. many times. >> >> Don K7FJ >> >> >> >Ok, >> > >> >So my audio is quite distorted as I can hear in my headphones with the monitor. But this only happens on 20m and only with the KPA500 in operate. >> >Sound like RF? or is something else going on? >> > >> > >> >Thanks >> >______________________________________________________________ >> >Elecraft mailing list >> >Home: http://mailman.qth.net/mailman/listinfo/elecraft >> >Help: http://mailman.qth.net/mmfaq.htm >> >Post: mailto:Elecraft@mailman.qth.net <Elecraft@mailman.qth.net> >> > >> >This list hosted by: http://www.qsl.net >> >Please help support this email list: http://www.qsl.net/donate.html >> > >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:Elecraft@mailman.qth.net <Elecraft@mailman.qth.net> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> >> > ______________________________________________________________ > 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 ______________________________________________________________ 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
