Re the Archer dipole, there is nothing theoretical to suggest it should work any
better. Like any dipole, it should be more sensitive to nearby metal elements
to degrade performance (including its own feedline, if not aligned properly).
The fanciful shape of the PC board antenna elements I imagine are quite
intentional,
but no generic text I'm aware of says that's the best way to do it.
Only Mr. Archer knows for sure, and it may indeed optimize radiation pattern
for xponder use.
However, the case with any antenna is that pure line-of-sight always works,
360-deg
around the aircraft (looking through only fiberglass is OK). Also, how much
actual xmit power your transponder has is important, because we can't compare
user reports w/o knowing that. In the U.S., where a periodic xponder test
is required, the box will pass with considerably less power than the spec of any
box currently sold (the King KT78/KT78A the only one on the weak side when
new or working to spec).
Fred F.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=124271#124271
|