page_title: Television
section_title: Terrestrial television
hierarchical_section_title: Television / Broadcast systems / Terrestrial television
caption_attribution_description: English: Yagi antenna for UHF HDTV reception. The antenna's main lobe is off the right end of the antenna; it is most sensitive to stations in that direction. Each of the metal crossbars along the antenna support boom is called an element, which acts as a half-wave dipole resonator for the radio waves. The antenna has one driven element which is attached to the TV; it is behind the black box (left). The black box is a preamplifier which increases the power of the TV signal before it is sent to the TV set. The 17 elements to the right of the driven element are called directors; they reinforce the signal. The 4 elements on the V shaped boom (left) are called a "corner reflector"; they serve to reflect the signal back toward the driven element. Yagi HDTV antennas use a corner reflector to increase the bandwidth of the antenna. The rest of the antenna increases the gain at higher channels, while the corner reflector increases the gain at lower channels.
context_page_description: Television, sometimes shortened to tele or telly, is a telecommunication medium used for transmitting moving images in monochrome, or in color, and in two or three dimensions and sound. The term can refer to a television set, a television show, or the medium of television transmission. Television is a mass medium for advertising, entertainment, news, and sports.
  Television became available in crude experimental forms in the late 1920s, but it would still be several years before the new technology would be marketed to consumers. After World War II, an improved form of black-and-white TV broadcasting became popular in the United States and Britain, and television sets became commonplace in homes, businesses, and institutions. During the 1950s, television was the primary medium for influencing public opinion. In the mid-1960s, color broadcasting was introduced in the US and most other developed countries.
context_section_description: Programming is broadcast by television stations, sometimes called "channels", as stations are licensed by their governments to broadcast only over assigned channels in the television band. At first, terrestrial broadcasting was the only way television could be widely distributed, and because bandwidth was limited, i.e., there were only a small number of channels available, government regulation was the norm. In the U.S., the Federal Communications Commission (FCC) allowed stations to broadcast advertisements beginning in July 1941, but required public service programming commitments as a requirement for a license. By contrast, the United Kingdom chose a different route, imposing a television license fee on owners of television reception equipment to fund the British Broadcasting Corporation (BBC), which had public service as part of its Royal Charter.
  WRGB claims to be the world's oldest television station, tracing its roots to an experimental station founded on 13 January 1928, broadcasting from the General Electric factory in Schenectady, NY, under the call letters W2XB. It was popularly known as "WGY Television" after its sister radio station. Later in 1928, General Electric started a second facility, this one in New York City, which had the call letters W2XBS and which today is known as WNBC. The two stations were experimental in nature and had no regular programming, as receivers were operated by engineers within the company. The image of a Felix the Cat doll rotating on a turntable was broadcast for 2 hours every day for several years as new technology was being tested by the engineers. On 2 November 1936, the BBC began transmitting the world's first public regular high-definition service from the Victorian Alexandra Palace in north London. It therefore claims to be the birthplace of TV broadcasting as we know it today.
  With the widespread adoption of cable across the United States in the 1970s and 80s, terrestrial television broadcasts have been in decline; in 2013 it was estimated that about 7% of US households used an antenna. A slight increase in use began around 2010 due to switchover to digital terrestrial television broadcasts, which offered pristine image quality over very large areas, and offered an alternate to cable television (CATV) for cord cutters. All other countries around the world are also in the process of either shutting down analog terrestrial television or switching over to digital terrestrial television.
caption: A modern high gain UHF Yagi television antenna. It has 17 directors, and one reflector (made of 4 rods) shaped as a corner reflector.
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