Seventy-five years ago this month, the cover of Popular Mechanics, June 1942, pictured this aircraft spotter with the latest in portable listening equipment. This plane detector featured a parabolic microphone worn as a headpiece. The spotter would listen for the low-pitched hum of an approaching aircraft, and turn his body until the sound was the loudest. He would then be facing the source and could use his binoculars to swiftly and accurately focus in on the plane.

The amplifier, featuring miniature tubes, was worn in a carrying case slung over the shoulder, which also included batteries and accessories. The magazine noted that the set could be used in places where more elaborate units were not available.

For another aircraft detector, see our earlier post.