Television station
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 5dB(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 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 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.
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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.
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See also
- Class A television service
- Low-power broadcasting
- List of broadcast station classes
- Fernsehsender Paul Nipkow: the first[citation needed] television station in Germany
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