A memo to Bell Labs employees explained that radar could be defined as a powerful electronic “eye” that used high-frequency radio echoes to determine the presence and location of unseen objects in space: “Specifically, a radar system does the following: (1) it generates high-power electrical waves; (2) it projects these waves from an antenna, usually in a narrow beam; (3) it picks up the waves which reflect back from objects in its range; and (4) converts these into a pattern on a fluorescent screen.”
