big.al
4th Jul 2005, 10:51
Not sure if this belongs on a tech. forum or Private Flying (BRL - feel free to move if you see fit).
I fly a 172 and use three Avcomm headsets (more or less the same models, but purchased at different times). The headsets all work perfectly as they are nearly new. I've had no problems with compatibility with other headsets I've occasionally borrowed for a 3rd passenger when all the seats have been full.
Recently, I've had problems with one of the radios in the 172. The problem is major distortion and interference, but only seems to be an issue with the engine running. If I make a call to the tower before startup, I get "readability 5". With the engine running this can be as low as "3" when right next to the tower, and the last time I flew it was "unreadable" as I entered the runway to backtrack.
I've tried just using one headset at a time - same result with each one. This suggests that the problem lies with the radio and not the headsets - perhaps some kind of suppressor failure? I'm not a techie and don't know the particular model of radio (Bendix King I think - that's about all I know).
The odd thing is that everyone else who flies the 'plane never has a problem. Always "readability 5" so they tell me.
And when I switch over to the second radio everything is perfect - it's just COM1 that gives me the trouble (COM2 is the original Cessna radio and whilst it's fine, it doesn't have the frequency toggle etc of COM1). Clearly I can fly with one radio working ok (I'm only a VFR daytime pilot) but I'd like to understand what the issue is (or might be) so I can point the owner in the right direction. He has had the radio tested (including a bench test) and no-one can replicate the problems I have every time I fly!
Any wise owls out there with any ideas?
Thanks!
I fly a 172 and use three Avcomm headsets (more or less the same models, but purchased at different times). The headsets all work perfectly as they are nearly new. I've had no problems with compatibility with other headsets I've occasionally borrowed for a 3rd passenger when all the seats have been full.
Recently, I've had problems with one of the radios in the 172. The problem is major distortion and interference, but only seems to be an issue with the engine running. If I make a call to the tower before startup, I get "readability 5". With the engine running this can be as low as "3" when right next to the tower, and the last time I flew it was "unreadable" as I entered the runway to backtrack.
I've tried just using one headset at a time - same result with each one. This suggests that the problem lies with the radio and not the headsets - perhaps some kind of suppressor failure? I'm not a techie and don't know the particular model of radio (Bendix King I think - that's about all I know).
The odd thing is that everyone else who flies the 'plane never has a problem. Always "readability 5" so they tell me.
And when I switch over to the second radio everything is perfect - it's just COM1 that gives me the trouble (COM2 is the original Cessna radio and whilst it's fine, it doesn't have the frequency toggle etc of COM1). Clearly I can fly with one radio working ok (I'm only a VFR daytime pilot) but I'd like to understand what the issue is (or might be) so I can point the owner in the right direction. He has had the radio tested (including a bench test) and no-one can replicate the problems I have every time I fly!
Any wise owls out there with any ideas?
Thanks!