In the absence of antenna diversity, I'm pretty sure all general
aviation factory built aircraft have the transponder antenna on the
bottom of the aircraft.Â* I would think the manufacturers must know
something.

On 12/30/2019 12:13 AM, Darryl Ramm wrote:
On Sunday, December 29, 2019 at 10:43:44 PM UTC-8, wrote:
Well, Here is a picture of Schlicher's recommended location for the Antenna-same as Schempp Hirth-Above landing gear doors.
Interesting.

https://www.alexander-schleicher.de/...reinbau-27.pdf
Dan
Dang. Well I don't like that either :-)

My ASH-26E has a more central transponder antenna location behind the gear (and offset to avoid the fuselage join seam and a fuel pump on one side) as can an ASH25 and some others, so I guess I've mostly noticed those. And ASH-30/31 etc. owners all seem to be ordering the tail mounted antenna (which is what I'd do on a new glider).

Again, if I was looking at your glider, based on gut feel (and some background in microwave engineering), I personally would install the upper antenna, I wonder if SH came out with that to improve on the lower location, or to make the install easier or both....

And since you asked about different style 1/4 wave dipoles. The rods, blades etc. should all behave the same from a RF viewpoint. They are effectively the same internally. Rods/single attach point style antennas may be easier to attach/mount on curved surfaces, but have higher drag than a blade if that small drag worries you. I've also seen A&Ps recommend the rod style so that if you do manage to crunch it will bend and hopefully do less damage to the fuselage/finish.





--
Dan, 5J