FLARM is an affordable collision-warning system for general aviation and recreational flying. It is the only prevalent alternative to the commercial airliners’ expensive ACAS/TCAS system.
The FLARM is ideal for gliding situations. One of the highest risks we have is traveling in a group. No matter how good our look out (see and avoid) is, we have double blind situations and distractions which are hard to avoid. FLARM helps.
TODO - Aerial discussion and how to check your signal strength (upload file etc)
Get one !
I recommend also looking at: http://www.flarmnet.org/