In response to John Kleber's question re ground planes, I should probably
toss in my .02$ worth.
After flying my LIV for 5 years, the transponder antenna and the second comm
antenna I have on the bottom of the airplane have proven to function very
well. In neither case did I install any secondary ground plane. They both
rely on a good contact with the carbon fiber skin of the fuselage.
IMHO, it would be worth it to try that and check VSWR before installing
welding rods or copper screening.

Fred Egli LIV N1228E