An antenna rotator is a device which is used to change the orientation of a directional antenna. Most antenna rotators have two parts, the rotator unit and the controller. The controller is normally placed near the equipment which the antenna is connected to, while the rotator is mounted on the antenna mast directly below the antenna.
Rotators are commonly used in amateur radio and military communications installations. They are also used with TV and FM antennas, where stations are available from multiple directions, as the cost of a rotator is significantly less than that of installing a second antenna to receive stations from multiple directions.
Rotators are manufactured for different sizes of antennas and installations. For example, a consumer TV antenna rotator has enough power to turn a TV/FM or small Ham antenna. These units typically cost around US$70.
Heavy-duty Ham rotators are designed to turn extremely large, heavy, high frequency (shortwave) beam antennas, but cost hundreds and possibly thousands of dollars.