I see tons of US Coast Guard helicopters in my area in West Michigan. I notice that they are not visible on my nearby ADSB feeder (1080 & 978 capable) or on any aircraft tracking sites. Why is that? I am aware that many Military and Law Enforcement aircraft are capable of controlling their transponder in a way that the general public cant see. Is this a case of them using ADSB Mode 5? Which is an encrypted mode of ADSB. Or are they just not transponding at all? I just find it weird that I can see Navy and Army helicopters on the ADSB exchange map, but why not a coast guard helicopter going to a water rescue?
if it's ModeS and low altitude, maybe no MLAT coverage. otherwise could just be a really old ModeC transponder, not hex code with those, no MLAT either. well it might not care to switch around the transponder all the time, so it's disabled as a general rule? idk.
