Okay, so it's not the radio..... ??? I took off with the TKM,
yesterday morning, and it failed within 20 minutes! Same symptoms!
Reception started to get scratchy, then no transmission with a loss of
side-tone...

I'm not sure if it makes sense to isolate the audio panel from the
radio, since we have confirmed that the radio works in another plane
and a working radio does not work in my plane???

Is the audio panel the logical culprit? I failed to mention earlier
that the audio panel had been replaced last year with a used one,
because I was encountering a "stuck-mike"... However, the radio worked
fine for several months as I finished up my IFR work and took my
check-ride in the plane.

I haven't spoken with my mechanic yet this morning, but I'm thinking
that he is leaning towards the audio panel as well... Any next step
suggestions? See if I can swap out the audio panel with a working one
too, I guess???

Thanks for the feedback!

Clyde - I have seen a lot of unhappy Narco owners in the newsgroups,
and probably wouldn't make it one of my top choices if I were to go
down the road of buying a new radio. At this point, I'm trying not to
throw good money after bad and am just trying to get up in the air
again without having to rely on my hand-held! ;-) If the day comes,
where I am faced with the purchase of a new radio, I will probably bite
the bullet and see how I can tweak the finances to put in something
like a Garmin GNS with built in com. As for a second radio, I'll have
to start hitting the research! Best Regards!