On Mar 4, 4:49*am, John Smith wrote:
Am 04.03.11 13:01, schrieb Nigel Cottrell:

This looks a lot like the Trig 21 which I have had fitted in a powered
plane for about 18 months and am very happy with.

http://www.trig-avionics.com/library/TT2xBrochure.pdf

The TT21 is a class 2 transponder and therefore *not* suited for
gliders. If you choose to go with Trig, then do yourself a favour and
buy the TT22.

The TT21 is very suitable for gliders. Its being installed in many
gliders in the USA and I expect elsewhere. The issue between class 1
and 2 transponders comes down to a fairly meaningless difference in
output power when you compare 15,000' vs. the maximum altitude we
typically fly at. If the difference in price between say a TT21 and
TT22 puts anybody off who should otherwise be installing a transponder
please install the TT21

Darryl