Bird slicer or AN/APX-109 is an advanced IFF compared with older AN/APX-101 we have. The advance IFF differs with conventional IFF is its capabillity to interrogate other aircraft, without interrogate capabillity, F-16 will need supporting systems such as ground based radars, awacs to conduct IFF interrogation.
Basically IFF has 5 modes, mode 1, 2, 3a, 3c, 4 and lately most advanced mode 5 for BVR
Mode 1 is assigned by the wing and identified by tail number
Mode 2 is pilot settable called as pilot identifier
Mode 3a is simillar to civilian transport aircrafts with ATC, ATC will direct the aircraft. In F-16 A/B it has panel in the cockpit while F-16 C/D through up front control
Mode 3c encoding altitude, IFF signals receive data from CADC & reports pressure altitude
Mode 4 is where IFF gets fame
Basically an aircraft will respond to interrogation it hears, if there's 10 aircrafts flying f.e can hear mode C, all 10 will all respond. IFF interrogating sorts out the confusion by tying IFF to radar.
Somewhere on your base, there's a big, red Air Traffic Control radar antenna turning in a circle. You'll notice that bolted to the top of this antenna is a much smaller antenna. That one's for IFF. So even though more than one aircraft may hear (and respond) to IFF interrogations, the ground (or AIFF) system keeps track of them all by displaying IFF information next to radar skin paints on the scope.
Australian embassy reports on AURI Tu-16 Badger in 1960s
View attachment 571343 View attachment 571344
Credit to Fb page Lembaga Keris