On Fri, 20 Feb 2004 23:11:27 GMT, "Jay Honeck"
wrote:

Jay - what make/model are the COM radios in your plane?

Com 1 is a brand new Narco 810-R, digital. (It's the slide-in replacement
for the Com 120)

Com 2 is an old-but-perfect Narco 120.

Hi Jay,

Take this with a caveat as I am a digital engineer who likes to learn
about RF stuff. I could be in left field here...

I asked because I was trying to determine if the radios utilized the
same IF frequency (which they would if it is the same radio). I don't
know enough about the Narco 810 or 120 to determine if they share the
same IF.

Where I was going with this...

The bleedthrough might be leakage from the IF section of one radio
coupling into the IF of the other radio. That would explain why the
audio is only noticeable as you are near the AWOS transmitter, where
the energy entering the IF stage on COM2 would be strongest.

An interesting test would be:

1. Shut off COM2 on the audio panel
2. Fly to a distant location where you can't hear the bleedthrough.
3. Turn on the audio for COM2
4. Can you hear the AWOS over the audio panel?

If you can hear the audio, then I suspect the audio problem is related
to the radio and not the audio panel (or audio wiring).

-Nathan