Even with monitor running into headphones? I was running the contest with monitor off at first, but I turned monitor on only in response to my contact telling me my audio was garbled. That said, I initially wondered if the garble was due to frequency drift not feedback. Though if it was a monitor problem it would also manifest on HF and through the vocal mic?
I can try though. I know the headphones leak, closed as they are, as I've picked up notification beeps when using the field recorder and monitoring on headphones while recording my voice. - Richard On Wed, 5 Feb 2020 at 15:29, Nr4c <n...@widomaker.com> wrote: > Turn down TX Monitor volume. > > Sent from my iPhone > ...nr4c. bill > > > > On Feb 5, 2020, at 5:23 AM, Richard Corfield <richard.corfi...@gmail.com> > wrote: > > > > I had issues with RF feedback on the MH3 during the UKAC SSB 2m contest > > last night. It seemed intermittent. Result was terrible noise in Monitor > > output (my headphones) and to the other station, so it affects the audio > > input. With experiments at the time and this morning: > > > > > > - Occurs when RF power is increased above 0 and when Mic Gain is > > increased. I could operate with Mic Gain set low, obviously at reduced > > power out. (Indicative of a feedback loop) > > - Occurs with a dummy load. (Also when I moved the antenna away last > > night). So is the loop internal or is it so sensitive the small leak > from a > > dummy load is enough? > > - Does not occur if I feed a stage Mic In through a field mixer (kit I > > have to hand). The field mixer claims an output impedance of 150R and > is > > running at mic level to match the MH3 allowing same gain setup in the > KX3. > > Mic Bias is turned off in this case. > > - Does not occur on HF into the dummy load. > > - Manifests as buzzing on 2m FM > > - May result in phantom button presses on the KX3 Mic (I didn't think I > > knocked the dial) > > > > As an aside - one station last night was loud enough to activate the "RX" > > indicator which I take to be input overload. S meter was well over S9 but > > not at the top. I didn't see anyone else at the site, unless they were > > hiding the the woodland carpark but I saw no light there or on the summit > > behind me. I hit ATT, should have swung the beam to try to null them. > But I > > guess the ATT and even maybe the input protection is after the 2m > module's > > input? > > > > My thought is I need to inspect the wiring in the mic. Or could there be > > anything else I need to check? > > > > Thanks > > - Richard > > ______________________________________________________________ > > 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 > > Message delivered to n...@widomaker.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 Message delivered to arch...@mail-archive.com
