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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 audio over the wide range of frequencies of radio waves allocated for radio amateur (Ham) use. ATV is used for non-commercial experimentation, pleasure, and public servic ...
(ATV) operator, that transmits video content and audio content via
radio waves Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz ( GHz) and below. At 300 GHz, the corresponding wavelength is 1 mm (s ...
directly from a
transmitter In electronics and telecommunications, a radio transmitter or just transmitter is an electronic device which produces radio waves with an antenna. The transmitter itself generates a radio frequency alternating current, which is applied to the ...
on the earth's surface to any number of tuned receivers 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 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 ante ...
transmission can occur via analog television signals or, more recently, via
digital television Digital television (DTV) is the transmission of television signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an innovative adva ...
signals. Television stations are differentiated from
cable television 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 bro ...
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 television broadcaster is a telecommunications network for distribution of television program content, where a central operation provides programming to many television stations or pay television providers. Until the mi ...
and an individual station within the network is referred to as O&O or 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 Broadcast television systems (or terrestrial television systems outside the US and Canada) are the encoding or formatting systems for the transmission and reception of terrestrial television signals. Analog television systems were standardized b ...
standards vary around the world. Television stations broadcasting over an analog system were typically limited to one
television channel A television channel is a terrestrial frequency or virtual number over which a television station or television network is distributed. For example, in North America, "channel 2" refers to the terrestrial or cable band of 54 to 60 MHz, with ...
, but digital television enables broadcasting via
subchannel In broadcasting, digital subchannels are a method of transmitting more than one independent program stream simultaneously from the same digital radio or television station on the same radio frequency channel. This is done by using data compressi ...
s as well. Television stations usually require a
broadcast license A broadcast license is a type of spectrum license granting the licensee permission to use a portion of the radio frequency spectrum in a given geographical area for broadcasting purposes. The licenses generally include restrictions, which vary f ...
from a government agency which sets the requirements and limitations on the station. In the United States, for example, a television license defines the
broadcast range A broadcast range (also listening range or listening area for radio, or viewing range or viewing area for television) is the service area that a broadcast station or other transmission covers via radio waves (or possibly infrared light, which is ...
, or geographic area, that the station is limited to, allocates the broadcast frequency of the
radio spectrum The radio spectrum is the part of the electromagnetic spectrum with frequencies from 0  Hz to 3,000 GHz (3  THz). Electromagnetic waves in this frequency range, called radio waves, are widely used in modern technology, particula ...
for that station's transmissions, sets limits on what types of
television program Television, sometimes shortened to TV, is a telecommunication medium for transmitting moving images and sound. The term can refer to a television set, or the medium of television transmission. Television is a mass medium for advertising, ...
s can be programmed for broadcast and requires a station to broadcast a minimum amount of certain programs types, such as public affairs messages. Another form a television station may take is non-commercial educational (NCE) and considered
public broadcasting Public broadcasting involves radio, television and other electronic media outlets whose primary mission is public service. Public broadcasters receive funding from diverse sources including license fees, individual contributions, public financing ...
. 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
repeater In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Som ...
s of nationwide programs. In those countries, the local television station has no
station identification Station identification (ident, network ID or channel ID or bumper) is the practice of radio and television stations and networks identifying themselves on-air, typically by means of a call sign or brand name (sometimes known, particularly in th ...
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 News broadcasting is the medium of broadcasting various news events and other information via television, radio, or the internet in the field of broadcast journalism. The content is usually either produced locally in a radio studio or telev ...
.


Transmission

To broadcast its programs, a television station requires
operators Operator may refer to: Mathematics * A symbol indicating a mathematical operation * Logical operator or logical connective in mathematical logic * Operator (mathematics), mapping that acts on elements of a space to produce elements of another sp ...
to operate equipment, a transmitter or radio antenna, which is often located at the highest point available in the transmission area, such as on a summit, the top of a high skyscraper, or on a tall
radio tower Radio masts and towers are typically tall structures designed to support antennas for telecommunications and broadcasting, including television. There are two main types: guyed and self-supporting structures. They are among the tallest human-made ...
. To get a signal from the
master control Master control is the technical hub of a broadcast operation common among most over-the-air television stations and television networks. It is distinct from a production control room (PCR) in television studios where the activities such as sw ...
room to the transmitter, a studio/transmitter link (STL) is used. The link can be either by radio or T1/ E1. A transmitter/studio link (TSL) may also send
telemetry Telemetry is the in situ collection of measurements or other data at remote points and their automatic transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Greek roots ''tele'', "remote", an ...
back to the station, but this may be embedded in subcarriers of the main broadcast. Stations which retransmit or simulcast another may simply pick-up that station 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 In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, t ...
, but require much less
effective radiated power Effective radiated power (ERP), synonymous with equivalent radiated power, is an IEEE standardized definition of directional radio frequency (RF) power, such as that emitted by a radio transmitter. It is the total power in watts that would h ...
(ERP), and therefore use much less
transmitter power output In radio transmission, transmitter power output (TPO) is the actual amount of power (in watts) of radio frequency (RF) energy that a transmitter produces at its output. This is not the amount of power that a radio station reports as its power, as ...
, also saving on the
electricity Electricity is the set of physical phenomena associated with the presence and motion of matter that has a property of electric charge. Electricity is related to magnetism, both being part of the phenomenon of electromagnetism, as describ ...
bill and emergency
backup generator An emergency power system is an independent source of electrical power that supports important electrical systems on loss of normal power supply. A standby power system may include a standby generator, batteries and other apparatus. Emergency p ...
s. In North America, full-power stations on band I (channels 2 to 6) are generally limited to 100 kW analog video (
VSB VSB may refer to: * Vancouver School Board, common name for School District 39 Vancouver, British Columbia * Finno-Soviet Treaty of 1948 ( sv, links=no, Vänskaps-, samarbets- och biståndsavtalet), the basis for Finno–Soviet relations from 1948 ...
) and 10 kW analog audio ( FM), or 45 kW digital (
8VSB 8VSB is the modulation method used for broadcast in the ATSC digital television standard. ATSC and 8VSB modulation is used primarily in North America; in contrast, the DVB-T standard uses COFDM. A modulation method specifies how the radio sig ...
) ERP. Stations on band III (channels 7 to 13) can go up by 5 dB to 316 kW video, 31.6 kW audio, or 160 kW digital. Low-VHF stations are often subject to long-distance reception just as with FM. There are no stations on 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 The Federal Communications Commission (FCC) is an independent agency of the United States federal government that regulates communications by radio, television, wire, satellite, and cable across the United States. The FCC maintains jurisdicti ...
(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 analog shutdown. Since at least 1974, there are no stations on
channel 37 Channel 37 is an intentionally unused ultra-high frequency (UHF) television broadcasting channel by countries in most of ITU region 2 such as the United States, Canada, Mexico and Brazil. The frequency range allocated to this channel is important f ...
in North America for
radio astronomy Radio astronomy is a subfield of astronomy that studies celestial objects at radio frequencies. The first detection of radio waves from an astronomical object was in 1933, when Karl Jansky at Bell Telephone Laboratories reported radiation comin ...
purposes.


Program production

Most television stations are commercial broadcasting enterprises which are structured in a variety of ways to generate
revenue In accounting, revenue is the total amount of income generated by the sale of goods and services related to the primary operations of the business. Commercial revenue may also be referred to as sales or as turnover. Some companies receive reven ...
from
television commercials A television advertisement (also called a television commercial, TV commercial, commercial, spot, television spot, TV spot, advert, television advert, TV advert, television ad, TV ad or simply an ad) is a span of television programming produce ...
. 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
newscast News broadcasting is the medium of broadcasting various news events and other information via television, radio, or the internet in the field of broadcast journalism. The content is usually either produced locally in a radio studio or telev ...
s or other local programming. There is usually a
news News is information about current events. This may be provided through many different media: word of mouth, printing, postal systems, broadcasting, electronic communication, or through the testimony of observers and witnesses to events. N ...
department, where
journalist A journalist is an individual that collects/gathers information in form of text, audio, or pictures, processes them into a news-worthy form, and disseminates it to the public. The act or process mainly done by the journalist is called journalis ...
s gather information. There is also a section where
electronic news-gathering Electronic news-gathering (ENG) or electronic journalism (EJ) is usage of electronic video and audio technologies by reporters to gather and present news instead of using film cameras. The term was coined during the rise of videotape techn ...
(ENG) operations are based, receiving
remote broadcast In broadcast engineering, a remote broadcast (usually just called a remote or a live remote, or in news parlance, a live shot) is broadcasting done from a location away from a formal television studio and is considered an electronic field producti ...
s via
remote pickup unit A remote pickup unit or RPU is a radio system using special radio frequencies set aside for electronic news-gathering (ENG) and remote broadcasting. It can also be used for other types of point-to-point radio links. An RPU is used to send program ...
or
satellite TV Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commo ...
.
Outside broadcasting Outside broadcasting (OB) is the electronic field production (EFP) of television or radio programmes (typically to cover television news and sports television events) from a mobile remote broadcast television studio. Professional video camera ...
vans, production trucks, or
SUV A sport utility vehicle (SUV) is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive. There is no commonly agreed-upon definiti ...
s with electronic field production (EFP) equipment are sent out with reporters, who may also bring back news stories on
video tape Videotape is magnetic tape used for storing video and usually sound in addition. Information stored can be in the form of either an analog or digital signal. Videotape is used in both video tape recorders (VTRs) and, more commonly, videocassett ...
rather than sending them back live. To keep pace with technology United States television stations have been replacing
operators Operator may refer to: Mathematics * A symbol indicating a mathematical operation * Logical operator or logical connective in mathematical logic * Operator (mathematics), mapping that acts on elements of a space to produce elements of another sp ...
with broadcast automation systems to increase profits in recent years. Some stations (known as
repeater In telecommunications, a repeater is an electronic device that receives a signal and retransmits it. Repeaters are used to extend transmissions so that the signal can cover longer distances or be received on the other side of an obstruction. Som ...
s or
translators Translation is the communication of the meaning of a source-language text by means of an equivalent target-language text. The English language draws a terminological distinction (which does not exist in every language) between ''transl ...
) only
simulcast Simulcast (a portmanteau of simultaneous broadcast) is the broadcasting of programmes/programs or events across more than one resolution, bitrate or medium, or more than one service on the same medium, at exactly the same time (that is, simulta ...
another, usually the programmes seen on its owner's flagship station, and have no television studio or production facilities of their own. This is common in
developing countries A developing country is a sovereign state with a lesser developed industrial base and a lower Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreem ...
. Low-power stations typically also fall into this category worldwide. Most stations which are not
simulcast Simulcast (a portmanteau of simultaneous broadcast) is the broadcasting of programmes/programs or events across more than one resolution, bitrate or medium, or more than one service on the same medium, at exactly the same time (that is, simulta ...
produce their own
station identification Station identification (ident, network ID or channel ID or bumper) is the practice of radio and television stations and networks identifying themselves on-air, typically by means of a call sign or brand name (sometimes known, particularly in th ...
s. TV stations may also
advertise Advertising is the practice and techniques employed to bring attention to a product or service. Advertising aims to put a product or service in the spotlight in hopes of drawing it attention from consumers. It is typically used to promote a ...
on or provide weather (or news) services to local
radio station Radio broadcasting is transmission of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radi ...
s, particularly co-owned sister stations. This may be a
barter In trade, barter (derived from ''baretor'') is a system of exchange in which participants in a transaction directly exchange goods or services for other goods or services without using a medium of exchange, such as money. Economists disti ...
in some cases.


See also

* Class A television service * Digital television transition *
Fernsehsender Paul Nipkow The Fernsehsender "Paul Nipkow" (''TV Station Paul Nipkow'') in Berlin, Germany, was the first public television station in the world. Carrying programming from Deutscher Fernseh-Rundfunk, it was on the air from 22 March 1935, until it was shut ...
: the world's first regular television service * Low-power broadcasting *
Must carry In cable television, governments apply a must-carry regulation stating that locally licensed television stations must be carried on a cable provider's system. North America Canada Under current CRTC regulations, the lowest tier of service on ...
*
Pay television Pay television, also known as subscription television, premium television or, when referring to an individual service, a premium channel, refers to subscription-based television services, usually provided by multichannel television providers, b ...
*
Significantly viewed out of market TV stations in the United States Significantly viewed signals permitted to be carried or Significantly Viewed list (SV) is a federal law permitting terrestrial television, television stations as determined by the Federal Communications Commission (FCC), to be carried by cable te ...
*
Terrestrial 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 ante ...
*
List of European television stations List of European television stations is a list of television stations which are notable in Europe. Notability refers to them being the dominant stations within their countries in terms of viewers. ...
* List of North American broadcast station classes


References


External links

* {{Authority control Broadcast engineering