Setting up Mic Gain and Side Tone - should I be transmitting as I do the test?

[MJKTuck]

I'm having problems with my transmissions being inaudible/garbled - maybe even non-existent as all my 'can anyone hear me' radio calls go unanswered. Other than that everything else works just fine, receive, intercom, etc. I do plan to move the transponder antenna as I can hear popping - unless I turn the transponder to STBY, then it stops. I'm following the instructions to adjust the Mic Gain but even up to 100, still shows LOW even when I speak loudly. Having read other threads, am I supposed to be transmitting when I do the test or doesn't it matter? Same with the side tone adjustment which doesn't seem to have any effect either. I've triple checked all my wiring and it's all as it should be. Any ideas what I might try? I'm beginning to think I have a dodgy unit.

 

[RV8JD]

I'm following the instructions to adjust the Mic Gain but even up to 100, still shows LOW even when I speak loudly.

I'm interested in responses to this part of your post, since I see the same thing with my setup. But folks can hear my radio transmissions fine.

 

[Steveden]

If you haven't already you need to check all your grounds to make sure they are clean. Then test your RG400 coax connectors at your radio and transponder to the antennas to make sure you have ground and signal continuity thru the connectors to make sure you don't have any signal bleed thru to the ground. When testing the coax make sure both ends of the coax are disconnected from the hardware and antennas.
If that all checks out and you are still not transmitting or the person on the other end can only hear you if you are within 100 yards it may be your COM unit. I had the same issue where I could only be faintly heard within 100 yds of my airplane when transmitting on the ground with the engine off. I could hear everyone else just fine, however, they couldn't hear me. I had to get my COM replaced.

 

[swatson999]

All good suggestions. Don't forget to test the coax to make sure there isn't a short between the center conductor and the outer shield, as well.

 

[MJKTuck]

Thanks for the suggestions. Well, I finally got it figured out! With the help of the guy in the next hangar listening in, in his aircraft confirmed he could hear the mic click and got TX, but no voice. We eventually switched the mic jacks between pilot and co-pilot positions on the panel and he could hear me. One of my checks when I had the panel pulled was to make sure they were not switched - plus all the wiring went to the correct intercom pins - so what was causing the apparent switch? Well, it turns out I had mislabeled the wires coming from PTT the switch on the control stick. So intercom would work fine as would the TX function but the other (passenger side) headset was the one being keyed by the PTT switch. Locally no one could hear me but I suspect ATC was picking up the sound of my engine from the headset resting on the passenger seat when I transmitted. Initially I got a howling sound when I transmitted but that is because my mic gain was set too high. Turning it down to 35 seems to give the best reception even though I'm using old school Dave Clarke headsets.

 

[MJKTuck]

Dynon Tech Support confirmed that you should be transmitting as you do the Mic Gain diagnostic. Just pick an empty frequency and test. I suspect the sidetone adjustment is similar.

 

[RV8JD]

Dynon Tech Support confirmed that you should be transmitting as you do the Mic Gain diagnostic. Just pick an empty frequency and test. I suspect the sidetone adjustment is similar.

Thanks for posting that. I'll try it while transmitting.