"transponding" . "ground beacon" . "transponder or responder" . "transponder device" . "tracker" . . . . "transponders" . . . "OBE" . . . . "Transponder" . . "transponds" . "transponding radar beacons" . . "radar transponder" . "transponding radar beacon" . . "Transponder" . "transponder" . . . . "transponding radar" .