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 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 (short ...
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 (radio), antenna. The transmitter itself generates a radio frequency alternating current, which i ...
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 ant ...
transmission can occur via
analog television
Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...
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 advanc ...
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 broa ...
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 by ...
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 ...
from a
government agency
A government or state agency, sometimes an appointed commission, is a permanent or semi-permanent organization in the machinery of government that is responsible for the oversight and administration of specific functions, such as an administrati ...
which sets the requirements and limitations on the station. In the United States, for example, a
television license
A television licence or broadcast receiving licence is a payment required in many countries for the reception of television broadcasts, or the possession of a television set where some broadcasts are funded in full or in part by the licence f ...
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 ...
, 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, e ...
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
A non-commercial educational station (NCE station) is a radio station or television station that does not accept on-air advertisements (TV ads or radio ads), as defined in the United States by the Federal Communications Commission (FCC) and was or ...
(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
Concentration of media ownership (also known as media consolidation or media convergence) is a process whereby progressively fewer individuals or organizations control increasing shares of the mass media. Contemporary research demonstrates in ...
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. Some ...
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 broadcast network, networks identifying themselves on-air, typically by means of a call sign or brand name (sometimes known, ...
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
![Cerro de Punta as seen from Museo de Arte de Ponce, Ponce, Puerto Rico (DSC03460)](https://upload.wikimedia.org/wikipedia/commons/3/39/Cerro_de_Punta_as_seen_from_Museo_de_Arte_de_Ponce%2C_Ponce%2C_Puerto_Rico_%28DSC03460%29.jpg)
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
In radio engineering, an antenna or aerial is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver. In transmission, a radio transmitter supplies an ...
, which is often located at the highest point available in the transmission area, such as on a
summit
A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topography, topographic terms acme, apex, peak (mountain peak), and zenith are synonymous.
The term (mountain top) is generally used ...
, the top of a high
skyscraper
A skyscraper is a tall continuously habitable building having multiple floors. Modern sources currently define skyscrapers as being at least or in height, though there is no universally accepted definition. Skyscrapers are very tall high-ris ...
, 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 switc ...
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 data collection, collection of measurements or other data at remote points and their automatic data transmission, transmission to receiving equipment (telecommunication) for monitoring. The word is derived from the Gr ...
back to the station, but this may be
embed
Embedded or embedding (alternatively imbedded or imbedding) may refer to:
Science
* Embedding, in mathematics, one instance of some mathematical object contained within another instance
** Graph embedding
* Embedded generation, a distributed ge ...
ded in
subcarrier
A subcarrier is a sideband of a radio frequency carrier wave, which is modulated to send additional information. Examples include the provision of colour in a black and white television system or the provision of stereo in a monophonic radio broa ...
s 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, tro ...
, 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 hav ...
(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 i ...
, 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 described ...
bill
Bill(s) may refer to:
Common meanings
* Banknote, paper cash (especially in the United States)
* Bill (law), a proposed law put before a legislature
* Invoice, commercial document issued by a seller to a buyer
* Bill, a bird or animal's beak
Plac ...
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
North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...
, full-power stations on
band I
Band I is a range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum. The first time there was defined "for simplicity" in Annex 1 of "Final acts of the European Broadcasting Conference in the VHF and U ...
(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 standards, ATSC digital television standard. ATSC and 8VSB modulation is used primarily in North America; in contrast, the COFDM#DVB-T, DVB-T standard uses COFDM.
A modulation method ...
) ERP. Stations on
band III
Band III is the name of the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 174 to 240 megahertz (MHz). It is primarily used for radio and television broadcasting. It is also called high-b ...
(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
Electromagnetic interference (EMI), also called radio-frequency interference (RFI) when in the radio frequency spectrum, is a disturbance generated by an external source that affects an electrical circuit by electromagnetic induction, electros ...
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 jurisdiction ...
(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
The digital television transition, also called the digital switchover (DSO), the analogue switch/sign-off (ASO), the digital migration, or the analogue shutdown, is the process in which older analogue television broadcasting technology is conv ...
. 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
Commercial broadcasting (also called private broadcasting) is the broadcasting of television programs and radio programming by privately owned corporate media, as opposed to state sponsorship. It was the United States′ first model of radio (an ...
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
An independent station is an independent radio or terrestrial television station which is independent in some way from broadcast networks. The definition of "independence" varies from country to country, reflecting governmental regulations, market ...
or part of a
broadcasting network
A terrestrial network (or broadcast network in the United States) is a group of radio stations, television stations, or other electronic media outlets, that form an agreement to air, or broadcast, content from a centralized source. For example, ...
, or some other structure. They can produce some or all of their programs or buy some
broadcast syndication
Broadcast syndication is the practice of leasing the right to broadcasting television shows and radio programs to multiple television stations and radio stations, without going through a broadcast network. It is common in the United States where ...
programming for or all of it from other stations or independent production companies.
Many stations have some sort of
television studio
A television studio, also called a television production studio, is an installation room in which video productions take place, either for the production of live television and its recording onto video tape or other media such as SSDs, or for ...
, 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
The terms local programme, local programming, local content or local television refers to a television program made by a television station or independent television producer for broadcast only within the station's transmission area or televisio ...
. There is usually a
news
News is information about current events. This may be provided through many different Media (communication), media: word of mouth, printing, Mail, postal systems, broadcasting, Telecommunications, electronic communication, or through the tes ...
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 journalism ...
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 technol ...
(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 productio ...
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 truck
A television production truck or OB van is a small mobile production control room to allow filming of events and video production at locations outside a regular television studio. They are used for remote broadcasts, outside broadcasting (OB), ...
s, 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
Electronic field production (EFP) is a television industry term referring to a video production which takes place in the field, outside of a formal television studio, in a practical location or special venue. ZettlHerbert Zettl, ''Television Pro ...
(EFP) equipment are sent out with
reporter
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 journalism ...
s, 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
Live may refer to:
Arts, entertainment, and media Films
* ''Live!'' (2007 film), 2007 American film
* ''Live'' (2014 film), a 2014 Japanese film
*'' ''Live'' (Apocalyptica DVD)
Music
*Live (band), American alternative rock band
* List of albums ...
.
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
Broadcast automation incorporates the use of broadcast programming technology to automate broadcasting operations. Used either at a broadcast network, radio station or a television station, it can run a facility in the absence of a human opera ...
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. Some ...
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 ''transla ...
) 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, simultane ...
another, usually the programmes seen on its owner's
flagship
A flagship is a vessel used by the commanding officer of a group of naval ships, characteristically a flag officer entitled by custom to fly a distinguishing flag. Used more loosely, it is the lead ship in a fleet of vessels, typically the fi ...
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, simultane ...
produce their own
station identification
Station identification (ident, network ID or channel ID or bumper) is the practice of radio and television stations and broadcast network, networks identifying themselves on-air, typically by means of a call sign or brand name (sometimes known, ...
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 radio ...
s, particularly co-owned
sister station
In broadcasting, sister stations or sister channels are radio or television stations operated by the same company, either by direct ownership or through a management agreement.
Radio sister stations will often have different formats, and somet ...
s. 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 distingu ...
in some cases.
See also
*
Class A television service
The class A television service is a system for regulating some low-power television (LPTV) stations in the United States. Class A stations are denoted by the broadcast callsign suffix "-CA" (analog) or "-CD" (digital), although very many analog -C ...
*
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
Low-power broadcasting is broadcasting by a broadcast station at a low transmitter power output to a smaller service area than "full power" stations within the same region. It is often distinguished from "micropower broadcasting" (more commonly " ...
*
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 business model, subscription-based television services, usually provided by multichan ...
*
*
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 ant ...
*
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
This is a list of broadcast station classes applicable in much of North America under international agreements between the United States, Canada and Mexico. Effective radiated power (ERP) and height above average terrain (HAAT) are listed unless ot ...
References
External links
*
{{Authority control
Broadcast engineering