Everything about Television Station totally explained
A
television station is a type of broadcast station that
broadcasts both
audio and
video to
television receivers in a particular area. Traditionally, TV stations made their broadcasts by sending specially-encoded
radio signals over the air, called
terrestrial television. Individual television stations are usually granted
licenses by a
government agency to use a particular section of the
radio spectrum (a
channel) through which they send their signals. Some stations use
LPTV broadcast translators to
retransmit or
rebroadcast to further areas. Television stations are a form of
television channel, but not all television channels are necessarily stations.
Many
television stations are now in the process of
converting from
analogue (
NTSC,
PAL, or
SECAM) to
digital (
ATSC,
DVB, or
ISDB). In some countries, this is being forced on
consumers and stations, while in others it's entirely voluntary.
In countries such as the
United States, television stations usually just have one
transmitter (or, more recently, two transmitters if the station broadcasts a
digital signal in addition to its standard analog signal); most of these stations should be independent or affiliated to a
television network such as
ABC,
CBS,
Fox, or
NBC.
Outside the US, television stations are generally associated with a nationwide television network, through which they get all of, or at least significant amounts of, their
programming. In those countries, the signals broadcast in different areas have no well-known
callsigns or other individual traits known to the general public (although a network might have
regional variations, possibly broadcast from several different transmitters) and therefore from a consumer's point of view, there's no practical distinction between a network and a station.
In the
United States, each nationwide terrestrial broadcast network can have a few "
O&Os" — stations that it owns and operates, usually in the larger
broadcast markets, like
New York or
Chicago. They can only own a limited number of stations because of
FCC regulations.
Facilities
Production
Large television
stations usually have some sort of
television studio, which on major-network stations is often used for
newscasts or other
local programming. There is usually a
news department, where
journalists gather information. There is also a section where
electronic news gathering operations are based, receiving
remote broadcasts via
remote pickup unit or
satellite TV.
Vans,
trucks, or
SUVs with this equipment are sent out with
reporters, who may also bring back news stories on
videotape rather than sending them back live.
Weather is also a significant part of the station. Stations with
newscasts also have their own
meteorologists and
Doppler weather radar, and produce their own
forecasts, which often vary from station to station. In the U.S., most
NBC stations now carry
Weather Plus on a second digital channel, which mixes national and local segments.
Stations not
affiliated with major networks generally don't produce news or weather, or much other programming. Some stations (known as
repeaters or
translators) only
simulcast another, usually the programmes seen on its owner's flagship station, and have no production facilities of their own. This is common in most countries outside of the U.S., Canada, U.K. and Australia. Low-power stations typically also fall into this category worldwide.
Most stations which are not
simulcast produce their own
station identifications, using digital TV graphics. TV stations may also
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.
Transmission
As with other stations, the
radio antenna is often located on a
summit, the top of a high
skyscraper, or on a tall
radio tower. A
studio/transmitter link (STL), via either radio or
T1/
E1, is used to get the signal there. A
transmitter/studio link (TSL) may also send
telemetry 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 is it 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 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 (
VSB) and 10 kW analog audio (
FM), or 20 kW digital (
8VSB) ERP. Stations on
band III (channels 7 to 13) can go up by 5
dB(
W) to 316 kW video, 31.6 kW audio, or 63.2 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 doesn't 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
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 will be harder to receive after the
analog shutdown. Since at least
1974, there are no stations on
channel 37 in North America for
radioastronomy purposes.
In numismatics
Television has had such an impact in today's life, that it has been the main motif for numerous collectors' coins and medals. One of the most recent ones is the
The 50 Years of Television commemorative coin minted in
March 9 2005. The obverse of the coin shows a "test pattern", while the reverse shows several milestones in the history of television.
Further Information
Get more info on 'Television Station'.
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