> Mark Quinn (mquinns@aol.com) writes:
>
> I have been reading through the archives and have been unable to answer the
> question whether a transponder antenna ground plane should be mounted
> externally on the skin or internally on a carbon fiber aircraft.
> Does it make a difference either way and if so, which is best?

Pretty much all antennas have to be outside the carbon fiber skins.
Carbon fiber is opaque to radio waves, especially at the higher frequencies
used by the transponder and GPS. Some have reported good results
using the carbon skins themselves as ground planes, but most recommend
using a metallic screen or paint to form a highly conductive ground plane.
BTW, we are using the term "ground plane" rather loosely. It's more of a
counterelectrode in this case.

Use the search function at http://lancaironline.net/lists/lml/
to search for "ground plane", "conductive paint", "transponder antenna",
and similar phrases. There is plenty of information there.
With the carbon 320, you probably want to mount your antennas just
like the Legacy builders.

-bob mackey