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Update on the comms issue

In earlier posts, I've written about an issue I had with the communication system. To recap, there have been times where I could not hear incoming transmissions in my headset, though they've always been audible over the cabin speaker. Things I've tried include turning off the intercom (which connects the pilot headset directly to the audio panel) and turning up the volume on the radio.

One suggestion I was given by the mechanic at Harvey Field, when I was talking with him about this problem, was to turn off the cabin speaker. This is done on the audio panel. I did that and, well, it looks like that had an effect because I haven't had that behavior occur since. I did have that one issue where it appeared Whidbey Approach wasn't hearing my transmissions, but that's a different issue and I don't think it's actually a problem with my system. As far as I know, my transmissions have otherwise always been heard by the intended recipients.

Assuming this really did solve the problem, or at least work around it, I'm guessing that the issue is with the audio panel. It's an old Bendix/King KMA-24, and may very well be the original panel installed at the factory. One possibility that comes to mind is that the amplifier that's built into the panel can only provide so much power, and that having the speaker and headphone both enabled was drawing too much from the amplifier. The result was that it didn't have enough to drive both the headset and the cabin speaker so the headset was cutting out.

When my plane goes in for annual in July, I'm still going to have the mechanic give the audio system the once-over, but it looks like it's working well enough for now. At some point, I may replace the panel with a newer model. Ideally, I'd like to get one that has the intercom built-in, and also supports Bluetooth. Until then, it appears I'll be able to get by well enough on what I have.

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