Power inverter

[DrDave]

Greetings:

If I am understanding you correctly you have static in two separate radios during flight but not on the ground. You didn't say if the engines were running on the ground or what equipment was on at the same time. The best place to start is to determine what kind of noise you are hearing and where it is coming from. It sounds like you have ruled out audio panel. However, there is another quick test to conduct. Is the noise coming through the cabin speaker as well as the headsets?

A scope meter or simple o-scope would give an idea of what the noise looks like. This would also help locate the noise.

I think the simple thing to do at this point is to test tx and receive on the ground with the engine off. It's more that we want the mags off. If the radios are clean in this configuration I would start the rear motor. The rear mags being further from the radios is the purpose of the rear engine start. Try single mag operation and see if you can hear a difference in the headsets. An open shield on a mag p-lead can give you fits until it is corrected.

The other question being is the noise a recent occurrence or always been present?

An independent data point could also be established if there is any beacon or strobe noise in the headsets with everything else off. This would give an indication of ground loops in the airframe.

Everything can be fixed. There's no such thing as "they are just that way."

IF you will follow a logical troubleshooting path and IF you will report your findings I'd be glad to help.

Dave