Burble when Transmitting

[AuntPeggy]

Sometimes lately when transmitting on Comm 1 (the Garmin 530) we hear our voice burbling in our headsets. It happens when transmitting from either the left or right seat and it is heard in both headsets. When we query ATC how we sound, they say everything is OK at their end. This only happens like once in 10 or so transmissions, but it is likely to happen two or three times in a row before the problem goes away again.

Any ideas what is happening?

 

[Let'sgoflying!]

I have an intercom that does that sometimes. If we lower our voices slightly, it disappears.

 

[mikea]

Check your audio panel. I get a noisy sidetone whenever I transmit while monitoring another source. The panel is supposed to cut the 2nd source out when you transmit but I guess it doesn't work so well.

 

[SkyHog]

Sheri and I actually had this happen when leaving Bentonville after flying some formation with Chip. He reported that he heard us ok though.

I have no clue what causes it.

 

[AuntPeggy]

During our recent upgrade of the G-530, our Comm-1 antenna was moved from the top of the plane to the belly. Any ideas whether this would have an effect?

If it is the intercom, wouldn't both Comm-1 and Comm-2 be affected?

It isn't a sidetone. It makes a voices sound that TV shows attribute to talking underwater.

 

[gismo]

During our recent upgrade of the G-530, our Comm-1 antenna was moved from the top of the plane to the belly. Any ideas whether this would have an effect?

If it is the intercom, wouldn't both Comm-1 and Comm-2 be affected?

It isn't a sidetone. It makes a voices sound that TV shows attribute to talking underwater.

Could be the transmitter output is leaking into the audio of the intercom. There's plenty of ways this could happen but they pretty much all involve a poor ground connection in the comm antenna cable/antenna.

 

[AdamZ]

Sounds like a reverse wave retro modulation problem. Check the Audio capacitor frequency adjustment and see where the needle on the sine wave scale rests. If there is no reflux in the sine wave the problem lies elsewhere. If there is reflux then check the cat III cable for ohm creep on the low to mid frequency range. Depending upon the range you might want to Degauss the entire system.

can you tell I have NO CLUE what I'm talking about, cause I don't.

This actually once happend to me on a rental. Then on the flight home it just went away

 

[EdFred]

I talked to an avionics shop, because I have the same thing happen on my 430. Tech said that the squelch might be set too high on the non transmitting radio. I haven't messed with it yet though.

 

[AuntPeggy]

Tonight:
Talking to tower (118.575) on the ground and on takeoff, Comm1 was fine.
Five miles later, the burble appeared when transmitting to tower at handoff.
Ten miles later, contacted tower for a radio check and the burble was gone.

Talked with another pilot on 123.45 after the five-mile burble, and there was no problem in transmission or in our headset.

Ten or twenty minutes later, when talking to the same pilot on the same frequency, the problem occurred on 123.45. We tested with comm 2 completely turned off. Burble occurred with comm 1. Tried turning off comm1 and transmitting on comm 2. No burble. Went back to comm 1 and the burble.

Arriving at our destination 30 minutes later, the problem did not occur on comm 1 frequency 123.45 or the destination CTAF 121.8. Except once when turning onto downwind.