Wernher's distress signal is the distress signal picked up on your Pip-Boy shortly after you download The Pitt add-on. It is a call for help received by a runaway slave named Wernher who has just escaped from the treacherous industrial slaving town The Pitt. Tracking down the origins of this broadcast leads you to Wernher at the north end of the map in a fight with 3 Pitt raiders. This also triggers the quest Into The Pitt.