On Oct 17, 9:43*am, Mark Dickson wrote:
Sorry, but thermalling gliders will almost always show on radar. *


I fly at Lasham (UK) which is relatively close to the ATC Radar
station at Farnborough. It is set to filter out anything moving at low
speeds such as clouds, flocks of birds and gliders thermalling. They
can usually get weak returns from gliders flying straight, but this is
not guaranteed.

Derek C