Eric, I wasn't too impressed with the antenna extenders that Zaon
offers. They use RG-174 cable, and while it's OK for short runs it
would markedly decrease the signal strength running from my tail cone
to my instrument panel. I've found several places on line that offer 6
meter male to female RP SMA cables made from LMR 200 for less than
$15. The attenuation with LMR 200 at 1 GHz is 10 dB per 100 feet,
rather than the 22 dB per 100 feet with RG-174.

I guess there's a possibility that high interrogation rates could mess
up the Zaon range estimate, but even here in the PHL NY area the
transponder's transmitting triangle only flashes about once a second.
Could be that there are many, many transmissions per flash, but I've
noticed that generally if the Zaon says the range is within 3 miles of
me it is pretty accurate (to my "calibrated" eye, that is).

-John

On Jul 7, 2:39 pm, Eric Greenwell wrote:
Shadowing is certainly a possibility. I've also wondered if the amount
of radar interrogations can cause the same thing; e.g., where I fly in
SE Washington state, my transponder is triggered only 5-10 times a minute.

Rather than just relocating the antenna, you can get Zaon's dual antenna
option. That puts antennas top and bottom on the aircraft, essentially
eliminating all shadowing. It might be easier than moving one antenna to
the tail, but it's pricey at $280 for the option, plus two blade antennas.

--
Eric Greenwell - Washington State, USA