antenna Antenna ( antennas or antennae) may refer to: Science and engineering * Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves * Antennae Galaxies, the name of two collid ...

rotator (or antenna rotor) is a device used to change the orientation, within the horizontal plane, of a

directional antenna A directional antenna or beam antenna is an antenna which radiates or receives greater power in specific directions allowing increased performance and reduced interference from unwanted sources. Directional antennas provide increased performanc ...

. 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 Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency commu ...

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 often 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

torque In physics and mechanics, torque is the rotational equivalent of linear force. It is also referred to as the moment of force (also abbreviated to moment). It represents the capability of a force to produce change in the rotational motion of th ...

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 High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz). It is also known as the decameter band or decameter wave as its wavelengths range from one to ten ...

(

shortwave Shortwave radio is radio transmission using shortwave (SW) radio frequencies. There is no official definition of the band, but the range always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (100 to 10 me ...

) beam antennas, and cost hundreds or possibly thousands of dollars. In the center of the reference picture, the accompanying image includes an AzEl installation rotator, so named for its controlling of both the

azimuth An azimuth (; from ar, اَلسُّمُوت, as-sumūt, the directions) is an angular measurement in a spherical coordinate system. More specifically, it is the horizontal angle from a cardinal direction, most commonly north. Mathematical ...

and the

elevation The elevation of a geographic location is its height above or below a fixed reference point, most commonly a reference geoid, a mathematical model of the Earth's sea level as an equipotential gravitational surface (see Geodetic datum § ...

components of the direction of an antenna system or array. Such antenna configurations are used in, for example, amateur-radio satellite or EME (communications), moon-bounce communications. SatNOGS_v2_in_FOSDEM_2015

An open hardware AzEl rotator system is provided by the

SatNOGS SatNOGS (Satellite Networked Open Ground Station) project is a free software and open source hardware platform aimed to create a satellite ground station network. The scope of the project is to create a full stack of open technologies based on open ...

Groundstation project.

Manufacturers of consumer TV antenna rotators

Past

Before the era of

cable TV Cable television is a system of delivering television programming to consumers via radio frequency (RF) signals transmitted through coaxial cables, or in more recent systems, light pulses through fibre-optic cables. This contrasts with broa ...

and the rise of satellite TV, many homes had outdoor antennas designed to capture

over-the-air television Terrestrial television or over-the-air television (OTA) is a type of television broadcasting in which the signal transmission occurs via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having an ant ...

signals. The rotator market was served by a number of manufacturers including * The Alliance Manufacturing Co., Inc.,

Alliance, Ohio Alliance is a city in eastern Stark County, Ohio, United States. With a small district lying in adjacent Mahoning County, the city is approximately northeast of Canton, southwest of Youngstown and southeast of Cleveland. The population was 2 ...

Radio Shack RadioShack, formerly RadioShack Corporation, is an American retailer founded in 1921. At its peak in 1999, RadioShack operated over 8,000 worldwide stores named RadioShack or Tandy Electronics in the United States, Mexico, United Kingdom, Austra ...

Channel Master Channel Master is a manufacturer of TV Antennas and Accessories. History The original company, now defunct, was founded in Ellenville, New York, in 1949 by 23 year-old former Merchant Marine radio operator and DuMont TV antenna installer ...

* The Radiart Corp.,

Cleveland, Ohio Cleveland ( ), officially the City of Cleveland, is a city in the U.S. state of Ohio and the county seat of Cuyahoga County. Located in the northeastern part of the state, it is situated along the southern shore of Lake Erie, across the U.S ...

* Cornell-Dubilier Corporation,

South Plainfield, New Jersey South Plainfield is a borough in Middlesex County, New Jersey, United States. It is located in the heart of the Raritan Valley region. As of the 2010 United States Census, the borough's population was 23,385,RCA The RCA Corporation was a major American electronics company, which was founded as the Radio Corporation of America in 1919. It was initially a patent trust owned by General Electric (GE), Westinghouse, AT&T Corporation and United Fruit Comp ...

Sears, Roebuck and Co. Sears, Roebuck and Co. ( ), commonly known as Sears, is an American chain of department stores founded in 1892 by Richard Warren Sears and Alvah Curtis Roebuck and reincorporated in 1906 by Richard Sears and Julius Rosenwald, with what began ...

* American Phenolic Corporation * Leader Electronics, Inc.,

* Gemini Industries, Inc.,

Passaic, New Jersey Passaic ( or ) is a city in Passaic County, in the U.S. state of New Jersey. As of the 2020 U.S. census, the city had a total population of 70,537, ranking as the 16th largest municipality in New Jersey and an increase of 656 from the 69,7 ...

Philco Philco (an acronym for Philadelphia Battery Company) is an American electronics industry, electronics manufacturer headquartered in Philadelphia. Philco was a pioneer in battery, radio, and television production. In 1961, the company was purchased ...

* Lance Industries,

Sylmar, California Sylmar is a suburban neighborhood in the San Fernando Valley and is the northernmost neighborhood within the City of Los Angeles. Historically known for its profusion of sylvan olive orchards, Sylmar can trace its past to the 18th century and th ...

Philips Koninklijke Philips N.V. (), commonly shortened to Philips, is a Dutch multinational conglomerate corporation that was founded in Eindhoven in 1891. Since 1997, it has been mostly headquartered in Amsterdam, though the Benelux headquarters is ...

* Pro Brand International, Inc. (Eagle Aspen brand) *

Zenith The zenith (, ) is an imaginary point directly "above" a particular location, on the celestial sphere. "Above" means in the vertical direction ( plumb line) opposite to the gravity direction at that location ( nadir). The zenith is the "high ...

* Alinco Electronics, Inc. * Radio Merchandise Sales, Inc. * Kenpro * Nippon Antenna *Stolle * Hy-Gain

Current

Although the cord-cutting movement has increased interest in receiving free over-the-air television signals, as of December 2021 consumer options are limited. * VOXX Accessories Corporation of

Carmel, Indiana Carmel is a suburban city in Indiana immediately north of Indianapolis. With a population of 100,777, the city spans across Clay Township in Hamilton County, Indiana, and is bordered by the White River to the east; the Hamilton-Boone county l ...

, a wholly-owned subsidiary of VOXX International, using the RCA trademark, offers a remote-controlled antenna rotator, the model VH226E.
Channel Master's stock of model CM-9521HD is depleted
and it is unclear whether more units will be manufactured. Antennas {{Mast-stub