Jim, if I install a transponder pin with a carbon fiber ground plane,
inside a fiberglass fuselage, what equipment is needed to see how well
it's working? Or do I just fly around and ask ATC "Can you see me
now? Can you see me now?"

(actually, I've already installed it, but I'm not flying yet.)


On Wed, 31 Dec 2003 15:57:13 -0800, Jim Weir wrote:

:Yes, I got results on the carbon fiber and I would have SWORN that I posted them
:to this site.
:
:Putting a GPS antenna UNDER a small bowl-shaped carbon fiber radome immediately
:killed any GPS signal into a 27 dB gain active antenna INCLUDING satellites that
:were directly overhead.
:
:Figuring that the carbon was so lousy a transmissive path, I drilled a hole on
:the top of the bowl and used the bowl as the groundplane. VIOLA. The GPS
:antenna worked every bit as well on TOP of the carbon fiber as it did on a metal
:ground plane of approximately the same size.
:
:I can't say this is true for any other service than GPS (transponder, vhf nav &
:com, etc.) but it did test well for GPS.
:
:Jim
:
:
:
:Richard Riley
:shared these priceless pearls of wisdom:
:
:-
:-Did you ever get results on the carbon?
:
:Jim Weir (A&P/IA, CFI, & other good alphabet soup)
:VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
:http://www.rst-engr.com