On Fri, 19 Feb 2010 09:53:50 -0800 (PST), Bruno
wrote:

I have now had my unit fail twice without any indication of failure.
It still seemed to be working fine until I saw a jet whiz by real
close and realized that I hadn't had any alerts for a flight or two.


Flarm and compatible units may develop a very similiar fault.
These devices will show no apparent sign of malfunction, though they
have become almost "deaf".
The cause seems to be in the damage caused by static charges in the
receiver circuit; the antenna probably gets the static from the
plastic canopy. Or maybe from the pilot itself (especially after
touching/cleaning the canopy on a dry day).

send the unit back for repair, if it doesn't spot other gliders in
flight (known to have a flarm on board).

Unfortunately, ground testing isn't conclusive, as the damaged
receiver still gets messages from nearby gliders (less than 50-100
meters).

Aldo Cernezzi