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GTR200B Problems

Throwing this out there to see if anyone else has experienced similar issues.

Flying home from Thanksgiving yesterday I started noticing some intermittent comm issues. Another aircraft had to relay a message from center and I could respond to him just fine but could not hear center. This was at 6500 feet over Oklahoma. Should have no problem getting signal at that altitude. A few minutes later I lost the ability to transmit. "TX" was still showing on the radio but it was clear I couldn't be heard. Tried a few other options in the air. Switched headsets, switched to the co-pilot headset, messed with the SQ. Nothing. Landed about an hour from home to troubleshoot as it was getting dark. Could hear the AWOS on the ground just fine, but still couldn't transmit.

This was the first flight with the A20's where I had piped in music through the Bluetooth on the headset. Assuming that wouldn't cause any issues, but its the only thing I've done differently vs. previous flights.

Will be retrieving the airplane today with a handheld radio. Once its home I can start troubleshooting.

Any advice would be appreciated!
 
Check the terminal tight on the radio breaker. Typically what happens is it gets a little loose creating a high resistance contact - good enough for power for reception but not for transmit.

Carl
 
Throwing this out there to see if anyone else has experienced similar issues.

Flying home from Thanksgiving yesterday I started noticing some intermittent comm issues. Another aircraft had to relay a message from center and I could respond to him just fine but could not hear center. This was at 6500 feet over Oklahoma. Should have no problem getting signal at that altitude. A few minutes later I lost the ability to transmit. "TX" was still showing on the radio but it was clear I couldn't be heard. Tried a few other options in the air. Switched headsets, switched to the co-pilot headset, messed with the SQ. Nothing. Landed about an hour from home to troubleshoot as it was getting dark. Could hear the AWOS on the ground just fine, but still couldn't transmit.

This was the first flight with the A20's where I had piped in music through the Bluetooth on the headset. Assuming that wouldn't cause any issues, but its the only thing I've done differently vs. previous flights.

Will be retrieving the airplane today with a handheld radio. Once its home I can start troubleshooting.

Any advice would be appreciated!

Hello Michael,

A few things to consider in your troubleshooting efforts.

I suspect that you are also using the GTR 200B as your intercom. When you talk normally while using the pilot/copilot headsets, does your intercom work well? If it does, then the headset microphone is probably not an issue.

For single COM radio installations, pin 5 (TX Interlock In) should not be connected to anything. I know of at least one installation where this pin was incorrectly grounded all the time, which permanently de-senses the GTR receiver to protect it from being damaged by another COM radio transmitting in the same aircraft. When this installation error is made, the receiver is still operative, but very insensitive, so you will have to get very close to an airport before you can hear the tower and it would be nearly impossible to stay in radio contact with ATC when flying cross country.

The most likely issue is a poor antenna connection. It is surprising how often a BNC connector is installed incorrectly and one that works initially, starts having problems later on. Determining the quality of the connection between the center coax conductor to the BNC connector pin would be high on my list of things to check if I were having your problems. In some cases the center connector pin is not properly snapped into the BNC connector housing, and this allows the pin to back out and cause problems.

At times, the GTR 200/200B rack is installed incorrectly and the radio bezel bottoms out against the instrument panel before the radio is fully engaged in the back connectors. If this is happening with your installation, the antenna coax connection between the radio unit and the backplate connector may be poor. Inspect your installation and verify that 1) your radio is fully engaged in the rack and 2) the bezel does not touch or just barely touches the instrument panel when the installing the radio in the rack.

Hope this helps.

Steve
 
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thought I would throw this out. My gtx200 not the b, would make a weird squeal noise when transmitting with my bose 20's. I switched the antenna cable to the other antenna, same thing. tried all kinds of things to fix this, yes the tower heard it also when I talked to them. than I got into the radio and lowered the mic gain 1 number, 5 is default, went to 4. problem went away, nice and clear now. hope this helps
 
Thanks for all the help. Problem ended up being the BNC connector attached to the antenna. When I opened the inspection panel and gave the coax a little tug it popped right off. Reconnected and locked the BNC connector. Everything is working great now. Glad it was a simple fix.
 
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