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Terrestrial television is a type of television broadcasting in which the television signal is transmitted by radio waves to the TV receiver from a terrestrial (Earth based) transmitter, a television station, and received with an antenna. The term is more common in Europe, while in North America it is referred to as broadcast television or sometimes over-the-air television (OTA). The term "terrestrial" is used to distinguish this type from the newer technologies of satellite television (direct broadcast satellite or DBS television), in which the television signal is transmitted to the receiver from an overhead satellite, and cable television, in which the signal is carried to the receiver through a cable. Terrestrial television was the first technology used for television broadcasting, with the first long-distance public television broadcast from Washington, D.C., on 7 April 1927. The BBC began broadcasting in 1929, and had a regular schedule of television programmes in 1930. However these early experimental systems had insufficient picture quality to attract the public, due to their mechanical scan technology, and television didn't become widespread until after World War 2 with the advent of electronic scan technology. The television broadcasting business followed the model of radio networks, with local television stations in cities and towns affiliated with television networks, either commercial (in USA) or government-controlled (in Europe), which provided content. Television broadcasts were in black and white until the 1960s, when color television broadcasting began. There was virtually no other method of television delivery until the 1950s with the beginnings of cable television and ''community antenna television'' (CATV). CATV was, initially, simply a re-broadcast of over-the-air signals. With the widespread adoption of cable across the United States in the 1970s and 80s, viewing of terrestrial television broadcasts have been in decline; in 2013 it was estimated that about 7% of US households used an antenna.〔("CEA Study Says Seven Percent of TV Households Use Antennas" ), '"TVTechnology'', 30 July 2013〕〔("Nielsen: Broadcast Reliance Grew in 2012" ), ''TVTechnology'', 14 January 2013〕 A slight increase in use began around 2010 due to swichover to digital terrestrial television broadcasts, which offer pristine image quality over very large areas, and offered an alternate to CATV for cord cutters. ==Europe== Following the ST61 conference, UHF frequencies were first used in the UK in 1964 with the introduction of BBC2. In UK, VHF channels were kept on the old 405-line system, while UHF was used solely for 625-line broadcasts (which later used PAL colour). Television broadcasting in the 405-line system continued after the introduction of four analogue programmes in the UHF bands until the last 405-line transmitters were switched off on January 6, 1985. VHF Band III was used in other countries around Europe for PAL broadcasts until planned phase out and switchover to digital television. The success of analogue terrestrial television across Europe varied from country to country. Although each country had rights to a certain number of frequencies by virtue of the ST61 plan, not all of them were brought into service. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Terrestrial television」の詳細全文を読む スポンサード リンク
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