I monitored Atlantic City approach on LiveATC a few minutes ago (the archive file for 1700-1730UTC and 1730-1800UTC)1210- 2 FAA jets flying crazy patterns all over northern NJ, currently over central NJ. very low altitudes. Shadowing each other.
FLTCK2U is a larger jet, no info showing except the HEX- FAAFC1
N47 smaller jet BOMBARDIER BD-700, HEX- A5BEC0
The radar controller was confused as well. When N47 came up on frequency for landing back at KACY, the controller asked them if they had two transponders on. N47 replied that they are doing a WHAM project and it requires the use of two active transponders. So you have N47 flying but showing as two aircraft (two separate active transponders).
Hope that helps. Could not find any information related to WHAM and FAA - although I found a bunch of unrelated stuff.