where exactly to put the noise filter

On Sat, 21 Feb 2004 02:24:12 GMT, "Jay Honeck"
wrote:

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).

I don't think I've got enough information here. What position would I have
the audio panel in for this test? Com 1, Com 2, or Both?

And, assuming Both, what do you mean when you say "Can I hear the AWOS over
the audio panel?" Do you mean on the speaker? Or in my headphones?

Ahhh, not exactly clear given your audio panel. I was debugging this
thinking of the KMA24 in my plane. I meant headphones only.

Going back a few steps (to make sure we're debugging the correct
problem) - the initial problem was with ONLY COM1 selected, you hear
the station that COM2 is tuned (to) through the headset?

For step 1 above, listen ONLY to COM1, but leave COM2 on and tuned to
the AWOS. You should still hear the AWOS on the bleedthrough on COM1.

Once you get far enough away that you no longer hear the bleedthrough,
deselect COM1 and select COM2 to be played through the headset. See
if you can hear the AWOS.

If you can hear the AWOS, I suspect the problem is due to IF coupling
between the radios. The reasoning being that if COM2 is still
receving the AWOS and producing audio - but the bleedthrough is gone,
than it is not a wiring/audio panel problem.

Anyway, Mike's idea is a bit easier to check. Vary the volume on COM2
and see if the volume on the bleedthrough changes. If it does, you
probably have some combination of a wiring/audio panel problem.

If it doesn't try my test.

Aren't avionics in 30 year old planes fun?

-Nathan