FCC number
The U.S. Federal Communications Commission identification number for a transmission point.
The FCC number is an identifier assigned by the United States Federal Communications Commission to points of signal transmission. Objects with FCC numbers include masts, telecommunication towers, and antennae mounted on other types of structures.
The Commission registers the structure rather than the broadcaster, so the number stays with the mast when a licence changes hands. It is issued through the Antenna Structure Registration system, which covers structures that need marking or lighting for air safety.
Registration is required by height and by proximity to an airfield, not by use, so a tall structure that carries no transmitter at all can hold a number while a short rooftop antenna holds none.
An antenna mounted on a building is registered against the antenna structure, so a tower and the building beneath it are two different things in this register and only one of them has a number.