Which body must license RADAR units' radio transmitters?

The Federal Communications Commission (FCC) is the governing body responsible for licensing radio transmitters, including those used in RADAR units. This regulation falls under the FCC's jurisdiction to manage and allocate the radio frequency spectrum to prevent interference between different radio services. The FCC ensures that all transmitted signals, including those from RADAR systems, comply with technical standards and are operated within designated frequency bands.

Other agencies mentioned, such as the Federal Aviation Administration, primarily oversee aviation safety and air traffic control but do not handle radio frequency licensing. The Environmental Protection Agency focuses on environmental protection rather than communications regulation, and the Nuclear Regulatory Commission regulates nuclear energy and safety, not radio communications. Thus, the role of the FCC is crucial in maintaining orderly communication and compliance in systems relying on radio waves, such as RADAR.