Atelevision station is a set of equipment managed by a business, organisation or other entity such as anamateur television (ATV) operator, that transmits video content and audio content viaradio waves directly from atransmitter on the earth's surface to any number of tunedreceivers simultaneously.
TheFernsehsender Paul Nipkow (TV Station Paul Nipkow) inBerlin, Germany, was the first regular television service in the world.[1][2] It was on the air from 22 March 1935, until it was shut down in 1944. The station was named afterPaul Gottlieb Nipkow, the inventor of theNipkow disk.[3]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. Aterrestrial television transmission can occur viaanalog television signals or, more recently, viadigital television signals. Television stations are differentiated fromcable television or other video providers as their content is broadcast via terrestrial radio waves. A group of television stations with common ownership or affiliation are known as aTV network and an individual station within the network is referred to asowned-and-operated oraffiliate, 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 onetelevision channel, but digital television enables broadcasting viasubchannels as well. Television stations usually require abroadcast license from agovernment agency which sets the requirements and limitations on the station. In the United States, for example, atelevision license defines thebroadcast range, or geographic area, that the station is limited to,allocates the broadcast frequency of theradio spectrum for that station's transmissions, sets limits on what types oftelevision programs can beprogrammed for broadcast and requires a station to broadcast a minimum amount of certain programs types, such aspublic affairs messages.
Another form of television station isnon-commercial educational (NCE) and consideredpublic broadcasting.
To avoidconcentration 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 mererepeaters of nationwideprograms. In those countries, the local television station has nostation 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 localtelevision news.
.jpg)
To broadcast its programs, a television station requiresoperators to operate equipment, a transmitter orradio antenna, which is often located at the highest point available in the transmission area, such as on asummit, the top of a highskyscraper, or on a tallradio tower. To get a signal from themaster control room to the transmitter, astudio/transmitter link (STL) is used. The link can be either by radio orT1/E1. Atransmitter/studio link (TSL) may also sendtelemetry back to the station, but this may beembedded insubcarriers of the main broadcast. Stations which retransmit or simulcast another may simply pick-up that stationover-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 longwavelength, but require much lesseffective radiated power (ERP), and therefore use much lesstransmitter power output, also saving on theelectricitybill and emergencybackup generators. InNorth America, full-power stations onband I (channels 2 to 6) are generally limited to 100 kW analog video (VSB) and 10 kW analog audio (FM), or 45 kW digital (8VSB) ERP. Stations onband III (channels 7 to 13) can go up by 5dB to 316 kW video, 31.6 kW audio, or 160 kW digital. Low-VHF stations are often subject tolong-distance reception just as with FM. There are no stations onChannel 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 muchelectromagnetic interference and background "noise" as VHF, making it much more desirable for TV. Despite this, in the U.S., theFederal 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 onVHF are harder to receive after theanalog shutdown. Since at least 1974, there are no stations onchannel 37 in North America forradio astronomy purposes.[citation needed]
Most television stations arecommercial broadcasting enterprises which are structured in a variety of ways to generaterevenue fromtelevision commercials. They may be anindependent station or part of abroadcasting network, or some other structure. They can produce some or all of their programs or buy somebroadcast syndication programming for or all of it from other stations or independent production companies.
Many stations have some sort oftelevision studio, which on major-network stations is often used fornewscasts or otherlocal programming. There is usually anewsdepartment, wherejournalists gather information. There is also a section whereelectronic news-gathering (ENG) operations are based, receivingremote broadcasts viaremote pickup unit orsatellite TV.Outside broadcasting vans,production trucks, orSUVs withelectronic field production (EFP) equipment are sent out withreporters, who may also bring back news stories onvideo tape rather than sending them backlive.
To keep pace with technology United States television stations have been replacingoperators withbroadcast automation systems to increase profits in recent years.
Some stations (known asrepeaters ortranslators) onlysimulcast another, usually the programmes seen on its owner'sflagship station, and have no television studio or production facilities of their own. This is common indeveloping countries. Low-power stations typically also fall into this category worldwide.
Most stations which are notsimulcast produce their ownstation identifications. TV stations may alsoadvertise on or provide weather (or news) services to localradio stations, particularly co-ownedsister stations. This may be abarter in some cases.
Media related toTelevision channels at Wikimedia Commons| International | |
|---|---|
| National | |
| Other | |
