Antenna farm
Encyclopedia
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
or radio
Radio
Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
telecommunications transmitting or receiving antenna equipment, such as C
C band
The C band is a name given to certain portions of the electromagnetic spectrum, including wavelengths of microwaves that are used for long-distance radio telecommunications. The IEEE C-band - and its slight variations - contains frequency ranges that are used for many satellite communications...
, Ku
Ku band
The Kμ band is a portion of the electromagnetic spectrum in the microwave range of frequencies. This symbol refers to —in other words, the band directly below the K-band...
or Ka
Ka band
The Ka band covers the frequencies of 26.5–40 GHz. The Ka band is part of the K band of the microwave band of the electromagnetic spectrum. This symbol refers to "K-above" — in other words, the band directly above the K-band...
band satellite dish antennas, UHF/VHF/AM
AM broadcasting
AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is carried out in the medium wave band world wide, and on long wave and short wave...
/FM
FM broadcasting
FM broadcasting is a broadcasting technology pioneered by Edwin Howard Armstrong which uses frequency modulation to provide high-fidelity sound over broadcast radio. The term "FM band" describes the "frequency band in which FM is used for broadcasting"...
transmitter
Transmitter
In electronics and telecommunications a transmitter or radio transmitter is an electronic device which, with the aid of an antenna, produces radio waves. The transmitter itself generates a radio frequency alternating current, which is applied to the antenna. When excited by this alternating...
towers or mobile cell towers.
In telecom circles, any area with more than three antennas could be referred to as an antenna farm. In the case of an AM broadcasting
AM broadcasting
AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is carried out in the medium wave band world wide, and on long wave and short wave...
station (mediumwave
Mediumwave
Medium wave is the part of the medium frequency radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz...
and longwave
Longwave
In radio, longwave refers to parts of radio spectrum with relatively long wavelengths. The term is a historic one dating from the early 20th century, when the radio spectrum was considered to consist of long, medium and short wavelengths...
, occasionally shortwave
Shortwave
Shortwave radio refers to the upper MF and all of the HF portion of the radio spectrum, between 1,800–30,000 kHz. Shortwave radio received its name because the wavelengths in this band are shorter than 200 m which marked the original upper limit of the medium frequency band first used...
), the multiple mast radiator
Mast radiator
A mast radiator is a radio mast or tower in which the whole structure itself functions as an antenna. This design is commonly used for transmitting antennas operating at low frequencies, in the VLF, LF and MF ranges, in particular those used for AM broadcasting. The metal mast is electrically...
s may all be part of an antenna system for a single station, while for VHF and UHF the site may be under joint management
Joint venture
A joint venture is a business agreement in which parties agree to develop, for a finite time, a new entity and new assets by contributing equity. They exercise control over the enterprise and consequently share revenues, expenses and assets...
. Alternatively, a single tower with many separate antennas is often called a "candelabra
Candelabra
"Candelabra" is the traditional term for a set of multiple decorative candlesticks, each of which often holds a candle on each of multiple arms or branches connected to a column or pedestal...
tower".
Safety & security
Commercial antenna farms are managed by radio stationRadio station
Radio broadcasting is a one-way wireless transmission over radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both...
s, television station
Television station
A television station is a business, organisation or other such as an amateur television operator that transmits content over terrestrial television. A television transmission can be by analog television signals or, more recently, by digital television. Broadcast television systems standards are...
s, satellite teleports or military organizations and are mostly very secure
Security
Security is the degree of protection against danger, damage, loss, and crime. Security as a form of protection are structures and processes that provide or improve security as a condition. The Institute for Security and Open Methodologies in the OSSTMM 3 defines security as "a form of protection...
facilities with access limited to broadcast engineers, RF engineer
RF engineering
Radio frequency engineering is a subset of electrical engineering that deals with devices that are designed to operate in the Radio Frequency spectrum...
s or maintenance
Maintenance, Repair and Operations
Maintenance, repair, and operations or maintenance, repair, and overhaul involves fixing any sort of mechanical or electrical device should it become out of order or broken...
technician
Engineering technician
An engineering technician is a specialist who is trained in the skills and techniques related to a specific branch of engineering, with relatively practical understanding of the general engineering concepts...
s. This is not only for the physical security of the location (including preventing equipment
Electrical equipment
Electrical equipment includes any machine powered by electricity. They usually consists of an enclosure, a variety of electrical components, and often a power switch...
/metal theft
Metal theft
Metal theft is the theft of metal items on a very large scale. These thefts usually increase when worldwide prices for scrap metal rise. In recent years, prices for metals have risen dramatically due to rapid industrialization in India and China...
), but also for safety, as there may be a radiation
Radiation
In physics, radiation is a process in which energetic particles or energetic waves travel through a medium or space. There are two distinct types of radiation; ionizing and non-ionizing...
hazard unless stations are powered-down.
Locations
Terrain
Terrain, or land relief, is the vertical and horizontal dimension of land surface. When relief is described underwater, the term bathymetry is used...
allows, mountaintop sites are very attractive for non-AM broadcast stations and others, because it increases the stations' height above average terrain
Height above average terrain
Height above average terrain is used extensively in FM radio and television, as it is actually much more important than effective radiated power in determining the range of broadcasts...
, allowing them to reach further by avoiding obstructions on the ground, and by increasing the radio horizon. With a clearer line of sight
Line-of-sight propagation
Line-of-sight propagation refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line...
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
Structural failure
Structural failure refers to loss of the load-carrying capacity of a component or member within a structure or of the structure itself. Structural failure is initiated when the material is stressed to its strength limit, thus causing fracture or excessive deformations...
in a severe ice storm and/or high winds. Multiple small towers also allow stations to have backup facilities co-located on each others' towers for redundancy
Redundancy (engineering)
In engineering, redundancy is the duplication of critical components or functions of a system with the intention of increasing reliability of the system, usually in the case of a backup or fail-safe....
.
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 area
Metropolitan area
The term metropolitan area refers to a region consisting of a densely populated urban core and its less-populated surrounding territories, sharing industry, infrastructure, and housing. A metropolitan area usually encompasses multiple jurisdictions and municipalities: neighborhoods, townships,...
s have at least one antenna farm, such as Mount Wilson
Mount Wilson (California)
Mount Wilson is one of the better known peaks in the San Gabriel Mountains, part of the Angeles National Forest in Los Angeles County, California. It is the location of the Mount Wilson Observatory and has become the astronomical center of Southern California with and telescopes, and and tall...
in greater Los Angeles
Greater Los Angeles Area
The Greater Los Angeles Area, or the Southland, is a term used for the Combined Statistical Area sprawled over five counties in the southern part of California, namely Los Angeles County, Orange County, San Bernardino County, Riverside County and Ventura County...
(seen at right), Sweat Mountain
Sweat Mountain
Sweat Mountain is a low mountain located in far northeastern Cobb County, Georgia, in the suburbs north of Atlanta. The exact GNIS location of its summit is , and it has an official elevation of above mean sea level...
in metro Atlanta
Metro Atlanta
The Atlanta metropolitan area or metro Atlanta, officially designated by the US Census Bureau as the Atlanta-Sandy Springs-Marietta Metropolitan Statistical Area, is the most populous metro area in the U.S. state of Georgia and the ninth-largest metropolitan statistical area in the United States...
, Farnsworth Peak
Farnsworth Peak
Farnsworth Peak is a peak located on the northern end of the Oquirrh Mountain range, approximately south west of Salt Lake City, Utah. The mountain is named for Philo Farnsworth, the inventor of the first completely electronic television. It is used mainly for radio and television transmission,...
for the Salt Lake Valley
Salt Lake Valley
Salt Lake Valley is a valley in Salt Lake County in the north-central portion of the U.S. state of Utah. It contains Salt Lake City and many of its suburbs, notably West Valley City, Murray, Sandy, and West Jordan; its total population is 1,029,655 as of 2010...
, Riverview
Riverview, Hillsborough County, Florida
Riverview is an unincorporated census-designated place in Hillsborough County, Florida, United States. It is located near Brandon. The population was 71,050 at the 2010 census....
in Tampa
Tâmpa
Tâmpa may refer to several villages in Romania:* Tâmpa, a village in Băcia Commune, Hunedoara County* Tâmpa, a village in Miercurea Nirajului, Mureş County* Tâmpa, a mountain in Braşov city...
, Florida, Baltimore's Television Hill and Slide Mountain
Slide Mountain (Nevada)
Slide Mountain is a peak in the Carson Range near Reno, in Washoe County, Nevada. The Mount Rose Ski Tahoe resort is located on this mountain...
(Mount Rose ski area) in the Reno
Reno
Reno is the fourth most populous city in Nevada, US.Reno may also refer to:-Places:Italy*The Reno River, in Northern ItalyCanada*Reno No...
/Tahoe
Lake Tahoe
Lake Tahoe is a large freshwater lake in the Sierra Nevada of the United States. At a surface elevation of , it is located along the border between California and Nevada, west of Carson City. Lake Tahoe is the largest alpine lake in North America. Its depth is , making it the USA's second-deepest...
area. Some cities instead have combined many stations onto one tower, often through diplexer
Diplexer
A diplexer is a passive device that implements frequency domain multiplexing. Two ports are multiplexed onto a third port . The signals on ports L and H occupy disjoint frequency bands...
s into just one or two antennas, such as atop the Empire State Building
Empire State Building
The Empire State Building is a 102-story landmark skyscraper and American cultural icon in New York City at the intersection of Fifth Avenue and West 34th Street. It has a roof height of 1,250 feet , and with its antenna spire included, it stands a total of 1,454 ft high. Its name is derived...
in New York
New York metropolitan area
The New York metropolitan area, also known as Greater New York, or the Tri-State area, is the region that composes of New York City and the surrounding region...
, the landmark Sutro Tower
Sutro Tower
Sutro Tower is a three-pronged antenna tower near Clarendon Heights in San Francisco, California. Rising from a hill between Twin Peaks and Mount Sutro, it is a prominent part of the city skyline and a landmark for city residents and visitors...
of San Francisco, or the huge Miami Gardens tower serving the Miami and Fort Lauderdale region
South Florida metropolitan area
The South Florida metropolitan area, also known as the Miami metropolitan area, and designated the Miami–Fort Lauderdale–Pompano Beach, FL Metropolitan Statistical Area by the U.S...
. Cleveland, Ohio
Cleveland, Ohio
Cleveland is a city in the U.S. state of Ohio and is the county seat of Cuyahoga County, the most populous county in the state. The city is located in northeastern Ohio on the southern shore of Lake Erie, approximately west of the Pennsylvania border...
has its antenna farm in the suburb of Parma, Ohio
Parma, Ohio
Parma is a city in Cuyahoga County, Ohio, United States. It is the largest suburb of Cleveland and the seventh largest city in the state of Ohio...
due to Parma's high elevation.
Objections
Antenna farms have often been the source of complaints from local neighborhoods, particularly when a new tower is added. This has been increasingly so for TV stations, which have been pursuing with alacrity the construction of new digital televisionDigital television
Digital television is the transmission of audio and video by digital signals, in contrast to the analog signals used by analog TV...
antennas. Because many of these towers are already full, or were built well before there was the expectation of DTV, many stations have been forced to go through the even greater expense of constructing a new tower.
One such situation was in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, in the late 1990s and early to mid-2000s. Many of the Denver metropolitan area TV stations already transmitted analog TV from Lookout Mountain
Lookout Mountain (Colorado)
Lookout Mountain is one of the larger foothills which overlooks Golden, Colorado. The Denver metropolitan area can be seen clearly from the mountain. It is known for its natural scenery and has played a major role in area recreation, transportation, water supply and telecommunications...
, but needed the extra space for more antennas. Additionally, since many people live on Lookout Mountain, there was also the concern about safety, not only from falling ice or even the slight risk of a tower collapse, but also ongoing from the additional RF that it would create. Residents and the city of Golden
Golden, Colorado
The City of Golden is a home rule municipality that is the county seat of Jefferson County, Colorado, United States. Golden lies along Clear Creek at the edge of the foothills of the Front Range of the Rocky Mountains. Founded during the Pike's Peak Gold Rush on 16 June 1859, the mining camp was...
filed legal objections, including challenging the authority of the Federal Communications Commission
Federal Communications Commission
The Federal Communications Commission is an independent agency of the United States government, created, Congressional statute , and with the majority of its commissioners appointed by the current President. The FCC works towards six goals in the areas of broadband, competition, the spectrum, the...
(FCC) to override denial of zoning
Zoning
Zoning is a device of land use planning used by local governments in most developed countries. The word is derived from the practice of designating permitted uses of land based on mapped zones which separate one set of land uses from another...
permits by local government (in this case, the Jefferson
Jefferson County, Colorado
Jefferson County , whose slogan is the "Gateway to the Rocky Mountains", is the fourth most populous of the 64 counties of the State of Colorado of the United States. Located along the Front Range of the Rocky Mountains, Jefferson County is adjacent to the west side of the state capital, Denver....
county commission
County commission
A county commission is a group of elected officials charged with administering the county government in local government in some states of the United States. County commissions are usually made up of three or more individuals...
). The city of Golden also sought to condemn
Eminent domain
Eminent domain , compulsory purchase , resumption/compulsory acquisition , or expropriation is an action of the state to seize a citizen's private property, expropriate property, or seize a citizen's rights in property with due monetary compensation, but without the owner's consent...
the site, even though it was outside city limits. It was decided that scenic Eldorado Mountain
Eldorado Mountain
Eldorado Mountain is located on the eastern edge of the Colorado Front Range. It is largely in Boulder County. But it straddles the border, and its southern flanks are located in Jefferson County...
near Boulder
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
might be a better site, but there were also objections that it would ruin the view of that mountain from the valley. Despite other alternatives, the new "supertower" was forced on Lookout Mountain by the U.S. Congress, allowing the existing towers to be removed in 2009 after analog shutdown. The site began operating in spring 2008.
Antenna farm requirements
- Clear line of sight, especially for microwave dishes
- Free of radio interference, such as marine radarRadarRadar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...
- Higher ground elevation, to maximize coverage
- Away from high-rise structures and other obstructions
- Must be at least 20 miles away from airportAirportAn airport is a location where aircraft such as fixed-wing aircraft, helicopters, and blimps take off and land. Aircraft may be stored or maintained at an airport...
s.
Antenna farm staff
- RF engineerRF engineeringRadio frequency engineering is a subset of electrical engineering that deals with devices that are designed to operate in the Radio Frequency spectrum...
s - Broadcast engineerBroadcast engineeringBroadcast engineering is the field of electrical engineering, and now to some extent computer engineering and information technology, which deals with radio and television broadcasting...
s - Air conditioningAir conditioningAn air conditioner is a home appliance, system, or mechanism designed to dehumidify and extract heat from an area. The cooling is done using a simple refrigeration cycle...
engineers - Electrical engineerElectrical engineeringElectrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics and electromagnetism. The field first became an identifiable occupation in the late nineteenth century after commercialization of the electric telegraph and electrical...
s (for power systems) - Maintenance, repair and operationsMaintenance, Repair and OperationsMaintenance, repair, and operations or maintenance, repair, and overhaul involves fixing any sort of mechanical or electrical device should it become out of order or broken...
technicianEngineering technicianAn engineering technician is a specialist who is trained in the skills and techniques related to a specific branch of engineering, with relatively practical understanding of the general engineering concepts...
s - Telecommunications facilityTelecommunications facilityIn telecommunications, a facility is defined by Federal Standard 1037C as:# A fixed, mobile, or transportable structure, including all installed electrical and electronic wiring, cabling, and equipment and all supporting structures, such as utility, ground network, and electrical supporting...
managerManagementManagement in all business and organizational activities is the act of getting people together to accomplish desired goals and objectives using available resources efficiently and effectively... - Security guardSecurity guardA security guard is a person who is paid to protect property, assets, or people. Security guards are usually privately and formally employed personnel...
s