Originally Posted by
almost professional
Been playing off the NE coast today as well, along with a pair of Voyagers and KC135s, hawks and things that were noisy but didn't have Mode S on.....ADSB exchange gives access to Callsigns and airframe info.
They likely had Mode S (but not ADS-B).
In the absence of Mode S, the only way to ID an aircraft (other than Mk.1 eyeball) is to correlate the Mode A squawk that ATC have allocated.