I have an old COM radio I'm trying to use as a base station in my hangar (to listen to RVs flying in = RV related ) which I wired to use with an aviation headset or speaker / microphone. I made up a quarter wave antenna out of copper sheet and heavy copper wire based on this. It receives okay though somewhat staticky. But on transmit it just broadcasts a very loud HMMMM along with maybe a tiny bit of voice signal.
I've gone through the wiring many times and even wired up a couple of different radios independently, and tried a couple of different antenna setups including a handheld rubber-duck, and I get the same thing always.
I'm quite comfortable with avionics wiring having done my RV-6 and work on other planes and non-aviation electronics, and I'm pretty careful with grounding only one end and common ground etc. And I've never had a problem like this in any A/C. It seems likely that it's antenna related though I have tried more than one. The only difference I can think of from what I've done before is using an antenna without an airframe for a ground plane, but the quarter wave ground plane antenna is supposed to be in lieu of that (right?)
Any radio gurus with an "oh that's always X" or diagnostics to try? Something specific to the antenna coax or connectors maybe?
I've gone through the wiring many times and even wired up a couple of different radios independently, and tried a couple of different antenna setups including a handheld rubber-duck, and I get the same thing always.
I'm quite comfortable with avionics wiring having done my RV-6 and work on other planes and non-aviation electronics, and I'm pretty careful with grounding only one end and common ground etc. And I've never had a problem like this in any A/C. It seems likely that it's antenna related though I have tried more than one. The only difference I can think of from what I've done before is using an antenna without an airframe for a ground plane, but the quarter wave ground plane antenna is supposed to be in lieu of that (right?)
Any radio gurus with an "oh that's always X" or diagnostics to try? Something specific to the antenna coax or connectors maybe?
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