The radiating pattern on a 1/4-wave monopole (the common xponder stubbie thing,
or whip-type comm antenna) is a half-donut. Sliced laterally, so each half has
a hole.
See
Above is theoretical in one section, and a practical matter there will be
backlobes,
as implied by one of their later diagrams as tested on an actual antenna.
Since I'm sure this radiation is harmless, a 1/4-wave antenna on the fuselage
bottom
at lowest point should be most effective. On my tri-gear, I have it underneath
the central tunnel, which has the advantage of keeping the coax short
enough it makes little difference what type of coax it is.
Fred F.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=124221#124221
|