Just had a GTN650 installed in our club PA28 with GMA 340 audio panel. Works well except that when transmitting, the sidetone volume is deafening – really loud for P1 and P2 – while when just monitoring/listening it’s OK. I can only think this is a 650 issue rather than a 340 one.
Is there a hidden option in some settings page somewhere that can adjust that, or do we need to get an avionics engineer to sort the problem?
There is an option in the system menu (press and hold the home button while turning the unit on), but strictly speaking you need an engineer to change things and sign them off in a logbook.
Thanks – another quick result via EuroGA. There’s lot of expertise on here
You need to go into setup, COM, and set sidetone volume to about 45dB. Default is 65.
You can probably also change the configuration to enable the sidetone setting to be changed in the normal (not configuration) menu on the GTN – you can do that at least with the GTR225A and I’d imagine the GTN has a similar option.
I’ve found that settings in the range of +53 to +58db generally work well. The default setting is the maximum possible value I believe or 62.5db … an impossibly high value in many installations. I’ve always found that the sidetone needs to reduced, sometimes dramatically reduced, on all GTN installations.
Basically the way you set the sidetone is:
1-Set your headset volume control to whatever you normally use (make sure you are using the correct Mono/Stereo headset setting).
2-Turn on ANR if you have it, it generally dramatically affects volume level.
3-Adjust your intercom volume to whatever level you normally use.
4-Talk to yourself on the Intercom, note the volume in your ears.
5-Transmit on 123.45, note the volume in your ears.
If step 5 is louder than step 4, REDUCE the Sidetone level.
If step 4 is louder than step 5, INCREASE the Sidetone level.
A 3db increase is roughly a doubling of the volume.
Repeat steps 4 and 5 and adjust the sidetone level in the GTN’s COM setup until you have a perfect setup. Quote
