A
mast radiator (or 'radiating tower') is a
radio mast or tower in which the entire structure functions as an
antenna. This design, developed around 1930, is commonly used for
transmitting antennas operating at low
frequencies, in the
VLF,
LF and
MF ranges, in particular those used for AM
broadcasting. The metal mast is electrically connected to the
transmitter. Its base is usually mounted on a nonconductive support to insulate it from the ground. A mast radiator is a form of
monopole antenna.