If Rousseau's message had been hijacking that signal for 16 years, the man from Hurley's hospital would have 'heard' the broadcast either before Rousseau arrived on the island, or after the Losties turned it off. * The radio tower may be a Numbers Station:http://en.wikipedia.org/wiki/Numbers_station used in espionage. * The tower may be located near the Black Rock, but rather than risking everyone's lives where the monster is known to be active, Danielle took the castaways via a different route around the Dark Territory, hence why the journey took a while.