On Sunday, January 18, 2015 at 12:15:22 PM UTC-7, pete purdie wrote:
But most 'modern' composite gliders have carbon in the fuselage, so act
like metal for RF purposes.

As far as sailplane antennas go, the AV-22 'lollipop stick' is far too
fragile; blade antenna looks prettier but the flex is probably optimal; I
back up the conductive fuselage with a mesh screen inside the skin as 'belt
and braces'.

At 18:25 18 January 2015, Cookie wrote:
Well, yes on a METAL aircraft...and maybe carbon fiber...but
fiberglass...no...the L2 antenna usually goes on the inside wall of the
tail boom....radio waves go through fiberglass...


Cookie


On Sunday, January 18, 2015 at 9:40:48 AM UTC-5, Bob Pasker wrote:
I'm sure everyone knows this already, but its worthwhile saying again:
transponder antennas need to go on the bottom of the aircraft so they can
have line-of-sight to the radar facility, without being in the shadow of
the fuselage or the wings.



I installed a blade antenna with groundplane (yes, you need one!) in the lower fuselage (where the factory said) on my Discus 2b and it has worked well for ten years and never been knocked off by ground handling.

If you decide to put it in the tail, make sure you have low-loss coaxial cable.

Mike