: Based on the TKM's failing in my plane, and my radio working in another
: plane, it seems unlikely that it is in the radio, but not impossible.
: I could easily be experiencing one set of coincidences after another!

Sounds like you've pretty much removed the radio from the equation.

: "The side tone is a product of the radio not the audio panel",
: perplexes me though... Reception loss and sidetone loss at the same
: time is the current prevolent symptom. At the occurence of failure, I
: have reception loss and sidetone loss, I do have sidetone going
: through the intercom though, as I can communicate with the passengers
: fine.
"Sidetone" generally refers to hearing what you are transmitting on the radio,
not what you are saying on the intercom. One could argue it's a pedantic difference,
but for what you are troublshooting, the difference is important.

It is only on xmit where I lose sidetone...

Correction: It's only when you transmit that you should *HAVE* sidetone.
Any other time your "sidetone" is simply the intercom intercom'ing.

Plugging into the
: aircraft jacks directly doesn't help because if I understand correctly,
: you wouldn't get sidetone there anyways. Sidetone in that respect is a
: product of the intercom, is it not?
It could be on the intercom, on the radio, or *both*, depending on how
whomever installed it decided to wire it up.

So... there are three components
: (radio, intercom, audio panel) that are all interconnected somehow, and
: that's where my eye's glaze over and I start to drool... I just don't
: get it???

: Are there any recommended readings out there, that anyone could
: recommend to at least bring my up to a third grade level on this stuff?
: A search for "avionics for dummies", came up goose eggs!

Trouble is that there is no "one true way" to install the stuff. There are
generally enough connections included in all of the devices that there are different
ways to accomplish the same thing.

Judging by your statement he
:Reception loss and sidetone loss at the same
: time is the current prevolent symptom. At the occurence of failure, I
: have reception loss and sidetone loss, I do have sidetone going
: through the intercom though, as I can communicate with the passengers
: fine.

I'd say you've got a bad connection between the "audio out" of the radio and
the COM[12] on the audio panel, or between the audio panel and the intercom. I would
also speculate that the intercom is not producing sidetone, but the radio is... thus
the loss of sidetone upon transmit, but the intercom remains functional.

I don't specifically remember other details that may contradict this idea, but
I'm sure they'll be pointed out to me by someone...

-Cory

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************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
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