All of our (Navy) ejection seats have a "seat beeper", URT-33 if I remember correctly) in them that is activated when the seat starts up the rails. I imagine the Air Force seats have the same or one similar. The automatic transmissions on the frequencies of 243.0 and 121.5 of the beeper can be disabled in a combat situation so the bad guys can't zero in on the location.
We were always briefed to find the beeper in the seat pack and turn it off because it essentially jams those frequencies which are used by SAR along with 282.8.
