On Tuesday, January 20, 2015 at 7:19:04 AM UTC-5, wrote:
Anyone thinking of installing a transponder in a plane that currently doesn't
have one in an area (esp US or EU) that supports ADS-B should seriously
consider getting one with Mode-S, and that can participate in ADS-B
http://en.m.wikipedia.org/wiki/ADS-B

--bob

For more info, see: http://www.gliderpilot.org/FLARM-Transponders
Enjoy, Best Regards, Dave