A tower array is an arrangement of multiple radio towers which are mast radiators in a phased array.
[1] They were originally developed as ground-based tracking radars.
Tower arrays are used to constitute a directional antenna of a mediumwave or longwave radio station.
For directional antennas with fixed radiation pattern, linear arrangements are preferred, while for switchable directional patterns (usually for daytime groundwave versus nighttime skywave), square arrangements are chosen.
This mast or transmitter tower article is a stub.