Radios becoming unusable - interference from engine.

[JackinMichigan]

I've been flying my RV-10 for 6 years now. I use noise cancelling Bose headsets, and over the past couple of years it seems as if the noise cancelling is working less and less well.

I finally tracked it down to some sort of interference coming from the engine. When the engine isn't running the com is clear as a bell, but as soon as the engine starts there's an electronic hiss that gets louder the more I rev the engine. Since my last annual inspection (last month) the hiss has become so loud that I can't hear anything over the radio. I must have done something during the annual to make this problem much worse, but I can't think of what it could have been.

Does anybody have any tips or ideas on what I can look for or do to remedy this? I have two radios and the problem is identical on both.

 

[Dad's RV-10]

This thread has a lot of good info.

Other links here.

 

[painless]

As I said in another forum, I would check your alternator.

 

[JackinMichigan]

As I said in another forum, I would check your alternator.

What specifically should I be checking for?

 

[Ironflight]

What specifically should I be checking for?

Turn off the alternator (pull the field breaker if you have no switch) with the engine running and the whine in your headset, and see if the noise goes away.

 

[JackinMichigan]

Thank you. These are all some very good suggestions. I now move forward armed with a plan.

It didn't occur to me that my radios could be actually picking this up thru the air - I thought it was some sort of EMF interference from a poorly shielded cable somewhere.

For the longest time I had no idea where this noise was coming from - I just knew it became harder and harder to understand the ATC. I thought my noise cancelling headset was crapping out.

 

[BobTurner]

Another place to look is your engine grounding cables/braid. Connections should be snug and corrosion free, and, obviously, cables not broken.
Besides turning off alternator, try turning off one ignition at a time, see if anything improves.

 

[Carl Froehlich]

Try turning off your landing, nav and strobe lights. Disconnect your USB charger connection.

Carll

 

[mturnerb]

One more suggestion - if you have standard mags check grounding of the P-lead shields.

Good thread on the topic: https://vansairforce.net/threads/p-lead-shield-grounding.142891/

 

[cgarts1]

I recently went through this and it turned out to be bad spark plugs (I'm running auto plugs). Engine ran just fine just an annoying clicking noise in the headset.

 

[painless]

What specifically should I be checking for?

Paul answered your question.