Antenna farm
From Wikipedia, the free encyclopedia
Antenna farm or satellite dish farm or just dish farm are terms used to describe an area dedicated to television or radio telecommunications transmitting or receiving antenna equipment, such as satellite dish antennas, UHF / VHF / AM / FM transmitter towers or mobile cell towers [1] [2] .
In telecom circles, any area with more than three antennas could be referred to as an antenna farm. Commercial antenna farms are managed by radio stations, television stations, satellite teleports or military organizations and are mostly very secure facilities with access limited to broadcast engineers, RF engineers or maintenance personnel. This is not only for the physical security of the location (including preventing metal theft), but also for safety, as there may be a radiation hazard unless stations are powered-down. In the case of an AM broadcasting station (mediumwave and longwave, occasionally shortwave), the multiple mast radiators may all be part of an antenna system for a single station, while for VHF and UHF the site may be under joint management. Alternatively, a single tower with many separate antennas is often called a "candelabra tower".
Where terrain allows, mountaintop sites are very attractive for non-AM broadcast stations and others, because it increases the stations' height above average terrain, allowing them to reach further by avoiding obstructions on the ground, and by increasing the radio horizon. With a clearer line of sight in both cases, more signal can be received. While the same is true of a very tall tower, such towers are expensive, dangerous, and difficult to access the top of, and may collect and drop large amounts of ice in winter, or even collapse in a severe ice storm and high winds. Multiple small towers also allow stations to have backup facilities co-located on each others' towers.
Satellite antenna farms are usually located at remote locations, far away from urban development, especially high rise buildings or airplane flight paths, to avoid and minimize disruption to transmission and reception, and so as to not be an eyesore.
Most metropolitan areas have at least one antenna farm, such as Mount Wilson in greater Los Angeles, Sweat Mountain in metro Atlanta, Farnsworth Peak for the Salt Lake Valley, and Mount Rose in the Reno/Tahoe area. Some cities instead have combined many stations onto one tower, or through diplexers into one or two antennas, such as atop the Empire State Building in New York, or the huge Miami Gardens tower serving the Miami and Fort Lauderdale region.
[edit] Antenna farm requirements
- Clear line of sight, especially for microwave dishes
- Free of radio interference, such as marine radar
- Higher ground elevation, to maximize coverage
- Away from high-rise structures and other obstructions
