Wernher's distress signal

Wernher's distress signal is a radio signal $$

Background
Receiveable with the Pip-Boy 3000, it is a call for help received by a runaway slave named Wernher who has just escaped from the Pitt. Tracking down the origins of this broadcast leads to Wernher at the north end of the map in a fight with three Pitt raiders. This also triggers the quest Into The Pitt.