television station
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A television station is a set of equipment managed by a business, organisation or other entity, such as an
amateur television Amateur television (ATV) is the transmission of broadcast quality video and sound reproduction, audio over the wide range of frequencies of radio waves allocated for radio amateur (Ham) use. ATV is used for non-commercial experimentation, pleasure, ...
(ATV) operator, that transmits video content and audio content via
radio waves Radio waves are a type of electromagnetic radiation In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space a ...

radio waves
directly from a
transmitter In electronics Electronics comprises the physics, engineering, technology and applications that deal with the emission, flow and control of electrons in vacuum and matter. It uses active devices to control electron flow by amplifier, amplifi ...
on the earth's surface to any number of tuned
receivers Receiver or receive may refer to: Arts, entertainment, and media Music Albums * Receiver (album), ''Receiver'' (album), the second and final album of the band Farmer Not So John, released in 1998 * Receivers (album), ''Receivers'' (album), the fo ...
simultaneously.


Overview

Most often the term "television station" refers to a station which broadcasts structured content to an audience or it refers to the organization that operates the station. A
terrestrial television Terrestrial television is a type of television broadcasting Broadcasting is the distribution of sound, audio or video content to a dispersed audience via any electronic medium (communication), mass communications medium, but typically one u ...
transmission can occur via
analog television Analog television is the original television Television (TV), sometimes shortened to tele or telly, is a telecommunication medium used for transmitting moving images in monochrome (black and white), or in color, and in two or three ...
signals or, more recently, via
digital television Digital television (DTV) is the transmission of television audiovisual Audiovisual (AV) is electronic media possessing both a sound and a visual component, such as slide-tape presentations, films, television programs, corporate conferencing, c ...
signals. Television stations are differentiated from
cable television Cable television is a system of delivering television Television (TV), sometimes shortened to tele or telly, is a telecommunication medium used for transmitting moving images in monochrome (black and white), or in color, and in two o ...
or other video providers in that their content is broadcast via terrestrial radio waves. A group of television stations with common ownership or affiliation are known as a
TV network A television network or broadcaster is a telecommunications network A telecommunications network is a group of nodes interconnected by links that are used to exchange messages between the nodes. The links may use a variety of technologies bas ...
and an individual station within the network is referred to as O&O or Network affiliate, affiliate, respectively. Because television station signals use the electromagnetic spectrum, which in the past has been a common, scarce resource, governments often claim authority to regulate them. Broadcast television systems standards vary around the world. Television stations broadcasting over an analog system were typically limited to one television channel, but digital television enables broadcasting via subchannels as well. Television stations usually require a broadcast license from a government agency which sets the requirements and limitations on the station. In the United States, for example, a Television licence#United States, television license defines the broadcast range, or geographic area, that the station is limited to, Frequency allocation, allocates the broadcast frequency of the radio spectrum for that station's transmissions, sets limits on what types of television programs can be broadcast programming, programmed for broadcast and requires a station to broadcast a minimum amount of certain programs types, such as public affairs (broadcasting), public affairs messages. Another form a television station may take is non-commercial educational (NCE) and considered public broadcasting. To avoid concentration of media ownership of television stations, government regulations in most countries generally limit the ownership of television stations by television networks or other media operators, but these regulations vary considerably. Some countries have set up nationwide television networks, in which individual television stations act as mere repeaters of nationwide television program, programs. In those countries, the local television station has no station identification and, from a consumer's point of view, there is no practical distinction between a network and a station, with only small regional changes in programming, such as local television news.


Transmission

To broadcast its programs, a television station requires Operator (profession), operators to operate equipment, a transmitter or Antenna (radio), radio antenna, which is often located at the highest point available in the transmission area, such as on a summit (topography), summit, the top of a high skyscraper, or on a tall Radio masts and towers, radio tower. To get a signal from the master control room to the transmitter, a studio/transmitter link (STL) is used. The link can be either by radio or Digital Signal 1, T1/E-carrier#E1, E1. A transmitter/studio link (TSL) may also send telemetry back to the station, but this may be Distributed generation, embedded in subcarriers of the main broadcast. Stations which retransmit or simulcast another may simply pick-up that station terrestrial television, over-the-air, or via STL or satellite. The license usually specifies which other station it is allowed to carry. VHF stations often have very tall antennas due to their long wavelength, but require much less effective radiated power (ERP), and therefore use much less transmitter power output, also saving on the electricity Invoice, bill and emergency backup generators. In North America, full-power stations on band I (channels 2 to 6) are generally limited to 100 kW analog video (Vestigial sideband, VSB) and 10 kW analog audio (FM broadcasting, FM), or 45 kW digital (8VSB) ERP. Stations on band III (channels 7 to 13) can go up by 5decibel, dB to 316 kW video, 31.6 kW audio, or 160 kW digital. Low-VHF stations are often subject to TV and FM DX, long-distance reception just as with FM. There are no stations on Channel 1 (NTSC-M), Channel 1. UHF, by comparison, has a much shorter wavelength, and thus requires a shorter antenna, but also higher power. North American stations can go up to 5000 kW ERP for video and 500 kW audio, or 1000 kW digital. Low channels travel further than high ones at the same power, but UHF does not suffer from as much electromagnetic interference and background "noise" as VHF, making it much more desirable for TV. Despite this, in the U.S., the Federal Communications Commission (FCC) is taking another large portion of this band (channels 52 to 69) away, in contrast to the rest of the world, which has been taking VHF instead. This means that some stations left on VHF are harder to receive after the Digital television transition, analog shutdown. Since at least 1974, there are no stations on channel 37 in North America for radio astronomy purposes.


Program production

Most television stations are commercial broadcasting enterprises which are structured in a variety of ways to generate revenue from television commercials. They may be an independent station or part of a broadcasting network, or some other structure. They can produce some or all of their programs or buy some broadcast syndication programming for or all of it from other stations or independent production companies. Many stations have some sort of television studio, which on major-network stations is often used for newscasts or other local programming. There is usually a Television news#Television news, news Departmentalization, department, where journalists gather information. There is also a section where electronic news-gathering (ENG) operations are based, receiving remote broadcasts via remote pickup unit or satellite TV. Outside broadcasting vans, production trucks, or SUVs with electronic field production (EFP) equipment are sent out with reporters, who may also bring back news stories on video tape rather than sending them back Live television, live. To keep pace with technology United States television stations have been replacing Operator (profession), operators with broadcast automation systems to increase profits in recent years. Some stations (known as repeaters or Broadcast relay station, translators) only simulcast another, usually the programmes seen on its owner's Flagship (broadcasting), flagship station, and have no television studio or production facilities of their own. This is common in Developing country, developing countries. Low-power stations typically also fall into this category worldwide. Most stations which are not simulcast produce their own station identifications. TV stations may also radio advertisement, advertise on or provide weather (or news) services to local radio stations, particularly co-owned sister stations. This may be a barter in some cases.


See also

*Class A television service *Digital television transition *Fernsehsender Paul Nipkow: the world's first regular television service *Low-power broadcasting *Must carry *Pay television *Significantly viewed out of market TV stations in the United States *Terrestrial television *List of European television stations *List of North American broadcast station classes


References


External links

* {{Authority control Television stations, Broadcast engineering