On Monday, July 22, 2019 at 6:54:33 PM UTC-4, wrote:
On Monday, July 22, 2019 at 5:30:12 PM UTC-4, George Haeh wrote:
"Apparently I was not clear enough above.
Do NOT put both transponder antenna and a FLARM antenna in the vertical fin."

Could you share the reasons and data supporting this statement?

I'll give you 3 reasons not to put the PowerFLARM antenna in the vertical fin.
1- It is a very low power device and antenna losses matter.
2- The elevator push rod will do no good things for performance.
3- There is no reason to do so. There are many well functioning systems with the A antenna up front as suggested. The higher the better.
Reason for not putting the transponder antenna in the fin? The suppliers of the devices say best performance is on the bottom of the aircraft.

FWIW
UH

All good points. But I think Dave emphasized the word "both". As in: you can put either one of those antennas in the fin, but not both. As he wrote in his first posting in this thread: "If you put the transponder antenna near the FLARM antenna (as in both in the fin), you will fry the FLARM receiver." The transponder transmits at about 200 watts!

FLARM A antenna in front is good, but where to put the B antenna, that's what I'm pondering. If the A antenna is in front of the pilot, I suspect there will be a gap in reception from the direction behind (and somewhat below) the pilot. It's not too hard in my case, given no carbon (and no transponder) in the glider, so even if the B antenna is mounted high (under the turtledeck) it should have a "view" of that direction. Aluminum control rods nearby won't help, but perhaps won't hurt too much.

Anybody know where I can get adhesive pads with small non-metallic rings attached? That would help with experimenting with antenna locations. There is one such in my glider holding some electrical cables tidy, but when searching for such on Amazon I got the strangest irrelevant search results.