Also, the glider
above would almost certainly have it's transponder antenna on the
bottom, while the glider below would have it's PCAS antenna "on top"
(glare shield mounted) and have no trouble receiving it.

Eric, only if they both have both transponder and PCAS. Re the
stronger signal, you may well be right – I don’t know.

But PCAS of course does not distinguish between proximity but going to
miss, and proximity and going to hit. My unit also only knows in
1/10ths of a mile the approximate distance. Still, better than
nothing, of course.

Chris N