The US Navy also maintained a picket on both east and west coasts about 500 miles offshore with overlapping radars. https://en.m.wikipedia.org/wiki/Guardian-cl

The US Navy also maintained a picket on both east and west coasts about 500 miles offshore with overlapping radars. https://en.m.wikipedia.org/wiki/Guardian-class_radar_picket_ship https://en.m.wikipedia.org/wiki/Guardian-class_radar_picket_... My father as a newly minted ensign in 1958 served aboard the USS Interpreter and would recall fondly one of his first conversations with the captain. My father asked about how the analysts they reported contacts to would know “when it was the real one”. To which the captain laughed “You damn fool. They’ll know it’s the real one when we don’t report in.”