My message for a long time has been: If you fly near areas of dense airliners, fast jets and military traffic, just get a transponder, Mode S or used Mode C does not matter... get what you can afford.


This seems logical, but I heard another corner case where might not be so.

I sat in a presentation from our local Approach Control folks. They noted that with the new ADSB ground stations they had better visibility than from their existing radar plus ModeC. Specifically, low and far out. This like it might permit them to route controlled traffic in new places where gliders are, but where a Mode C transponder on the glider might not help.