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  #1  
Old 02-24-2016, 10:33 PM
Tom Delaney Tom Delaney is offline
 
Join Date: Dec 2007
Location: St. Louis, MO
Posts: 170
Default Help with feedback while transmitting

I would appreciate some thoughts after listening to the audio of two transmissions from my last flight.

https://www.dropbox.com/s/3fkb9raqka...oblem.mp4?dl=0

I posted the following comment with the video:

Hello,
I have had the GTR200 installed in my RV12 for several months. Recently I have experienced what seems like feedback or echo while transmitting. The video link first transmission shows what I am hearing intermittently while my second transmission sounds good. Usually only occurs while in the pattern at low rpm. I have gone through all the GTR200 settings and I believe they are set properly. In the RV12 low rpms drops voltage to 13.1 but the GTR200 still transmits transmits at the normal 3.5 volts regardless of the bus voltage.
I would appreciate any hints..
Thanks,

Tom
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RV-10 - Purchased & flying
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  #2  
Old 02-25-2016, 07:56 AM
AZLeeJay AZLeeJay is offline
 
Join Date: Dec 2013
Location: Phoenix
Posts: 139
Default

I had the same thing and resolved it by adjusting the mike gain.
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  #3  
Old 02-25-2016, 08:11 AM
Tom Delaney Tom Delaney is offline
 
Join Date: Dec 2007
Location: St. Louis, MO
Posts: 170
Default

Quote:
Originally Posted by AZLeeJay View Post
I had the same thing and resolved it by adjusting the mike gain.
Thanks for the suggestion. That is one setting I had not experimented with but will do so this weekend and report back.
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RV-10 - Purchased & flying
Magni M24 Gyroplane - Built - Sold
Magni M16 - Built - Sold
Magni M24 (Rotax 915) - Built & Flying - For Sale
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  #4  
Old 02-26-2016, 09:14 AM
MK77 MK77 is offline
 
Join Date: Apr 2013
Location: Evanston, IL
Posts: 140
Default

Could have to do with a strange interaction between the mic gain, headset level (sidetone), and noise cancelling of the headset. That's the only way I can think that it would only happen at low RPM (when there's probably lower noise levels in the cabin). In addition to tweaking the mic gain, a couple other things you could try to isolate the issue:

1.) If you turn the headset volume down, does it still happen? Don't remember if you can adjust the sidetone level in the GTR200 or if you have messed with that, but you can also try turning that down. Sidetone is the amount of audio level that is fedback into the headset when you transmit over the mic.

2.)If you use another non-active noise cancelling headset does it still do it?

Best of luck,
Matt
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  #5  
Old 02-26-2016, 01:55 PM
vasrv7a vasrv7a is offline
 
Join Date: Jul 2006
Posts: 190
Default

Quote:
Originally Posted by MK77 View Post
Could have to do with a strange interaction between the mic gain, headset level (sidetone), and noise cancelling of the headset. That's the only way I can think that it would only happen at low RPM (when there's probably lower noise levels in the cabin). In addition to tweaking the mic gain, a couple other things you could try to isolate the issue:

1.) If you turn the headset volume down, does it still happen? Don't remember if you can adjust the sidetone level in the GTR200 or if you have messed with that, but you can also try turning that down. Sidetone is the amount of audio level that is fedback into the headset when you transmit over the mic.

2.)If you use another non-active noise cancelling headset does it still do it?

Best of luck,
Matt


Tom,

Matt's comments above are on the right track. I had the same problem with a louder than desired feedback when transmitting. I adjusted the "sidetone" way down low so that it was not tied to the radio's volume level. The radio's default sidetone level is usually tied to the radio's volume...

Victor
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  #6  
Old 02-28-2016, 09:07 AM
Tom Delaney Tom Delaney is offline
 
Join Date: Dec 2007
Location: St. Louis, MO
Posts: 170
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Problem appears resolved!

I decreased the microphone gain in the Garmin GTR200. 5 is the default setting (1-10) and I dropped to 4.

Additionally I found the Bose headset volume near the max setting so I decreased that.

Two flights, four landings and idle flight with voltage at low end produced crystal clear audio

Thanks gentlemen for pointing me in the right direction.
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RV-10 - Purchased & flying
Magni M24 Gyroplane - Built - Sold
Magni M16 - Built - Sold
Magni M24 (Rotax 915) - Built & Flying - For Sale
RV-12 - Built - Sold
Rotorway 162F Built - Sold
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