The Outcast distress signal is acquired automatically upon entering the Capital Wasteland after loading the Operation: Anchorageadd-on. This may take several minutes (as described below) but exiting a building may speed up the process.
"This is Defender Morrill, any Outcasts listening on this frequency report to sector 7-B, Bailey's Crossroads. This is a high-priority message, backup is needed at our location. Any personnel listening on this frequency please report at once."