A tower array is an arrangement of multiple radio towers which are mast radiators in a phased array. They were originally developed as ground-based tracking radars. Tower arrays can consist of free-standing or guyed towers or a mix of them. Tower arrays are used to constitute a directional antenna of a mediumwave or longwave radio station.
The number of towers in a tower array can vary. In many arrays all towers have the same height, but there are also arrays of towers of different height. The arrangement can vary. 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.