Satellite television

The satellites used for broadcasting television are usually in a geostationary orbit above the earth's equator. The advantage of this orbit is that the satellite's orbital period equals the rotation rate of the Earth, so the satellite appears at a fixed position in the sky. Thus the satellite dish antenna which receives the signal can be aimed permanently at the location of the satellite and does not have to track a moving satellite. A few systems instead use a highly elliptical orbit with inclination of +/−63.4 degrees and an orbital period of about twelve hours, known as a Molniya orbit. Satellite television, like other communications relayed by satellite, starts with a transmitting antenna located at an uplink facility. Uplink satellite dishes are very large, as much as in diameter. The increased diameter results in more accurate aiming and increased signal strength at the satellite. The uplink dish is pointed toward a specific satellite and the uplinked signals are transmitted within a specific frequency range, so as to be received by one of the transponders tuned to that frequency range aboard that satellite. The transponder re-transmits the signals back to Earth at a different frequency (a process known as translation, used to avoid interference with the uplink signal), typically in the 10.7–12.7 GHz band, but some still transmit in the C-band (4–8 GHz), Ku-band (12–18 GHz), or both. The leg of the signal path from the satellite to the receiving Earth station is called the downlink. A typical satellite has up to 32 Ku-band or 24 C-band transponders, or more for Ku/C hybrid satellites. Typical transponders each have a bandwidth between 27 and 50 MHz. Each geostationary C-band satellite needs to be spaced 2° longitude from the next satellite to avoid interference; for Ku the spacing can be 1°. This means that there is an upper limit of 360/2 = 180 geostationary C-band satellites or 360/1 = 360 geostationary Ku-band satellites. C-band transmission is susceptible to terrestrial interference while Ku-band transmission is affected by rain (as water is an excellent absorber of microwaves at this particular frequency). The latter is even more adversely affected by ice crystals in thunder clouds. On occasion, sun outage will occur when the sun lines up directly behind the geostationary satellite to which the receiving antenna is pointed. The downlink satellite signal, quite weak after traveling the great distance (see path loss), is collected with a parabolic receiving dish, which reflects the weak signal to the dish's focal point. Mounted on brackets at the dish's focal point is a device called a feedhorn or collector. The feedhorn is a section of waveguide with a flared front-end that gathers the signals at or near the focal point and conducts them to a probe or pickup connected to a low-noise block downconverter (LNB). The LNB amplifies the signals and downconverts them to a lower block of intermediate frequencies (IF), usually in the L-band. The original C-band satellite television systems used a low-noise amplifier (LNA) connected to the feedhorn at the focal point of the dish. The amplified signal, still at the higher microwave frequencies, had to be fed via very expensive low-loss 50-ohm impedance gas filled hardline coaxial cable with relatively complex N-connectors to an indoor receiver or, in other designs, a downconverter (a mixer and a voltage-controlled oscillator with some filter circuitry) for downconversion to an intermediate frequency. Central to these designs was concept of block downconversion of a range of frequencies to a lower, more easily handled IF. The shift to cheaper technology from the hardline and N-connectors of the early C-band systems to the cheaper and simpler 75-ohm cable and F-connectors allowed the early satellite television receivers to use, what were in reality, modified UHF television tuners which selected the satellite television channel for down conversion to a lower intermediate frequency centered on 70 MHz, where it was demodulated. This is because the LNB is translating two different circular polarizations (right-hand and left-hand) and, in the case of K-band, two different frequency bands (lower and upper) to the same frequency range on the cable. The reason for using this orbit is that the satellite circles the Earth at the same rate as the Earth rotates, so the satellite appears at a fixed point in the sky. Thus satellite dishes can be aimed permanently at that point, and do not need a tracking system to turn to follow a moving satellite. A few satellite TV systems use satellites in a Molniya orbit, a highly elliptical orbit with inclination of +/-63.4 degrees and an orbital period of about twelve hours. Satellite television, like other communications relayed by satellite, starts with a transmitting antenna located at an uplink facility. Mounted on brackets at the dish's focal point is a feedhorn RG-59 is not recommended for this application as it is not technically designed to carry frequencies above 950 MHz, but will work in many circumstances, depending on the quality of the coaxial wire. This happens for about a 10-minute period daily around midday, twice every year for a two-week period in the spring and fall around the equinox. During this period, the sun is within the main lobe of the dish's reception pattern, so the strong microwave noise emitted by the sun on the same frequencies used by the satellite's transponders drowns out reception. ==Uses==

Direct-to-home and direct broadcast satellite (2006). Direct-to-home (DTH) can either refer to the communications satellites themselves that deliver service or the actual television service. Most satellite television customers in developed television markets get their programming through a direct broadcast satellite (DBS) provider. Programming for satellite television channels comes from multiple sources and may include live studio feeds. The broadcast center assembles and packages programming into channels for transmission and, where necessary, encrypts the channels. The signal is then sent to the uplink where it is transmitted to the satellite. With some broadcast centers, the studios, administration and up-link are all part of the same campus. The satellite then translates and broadcasts the channels. Most systems use the DVB-S standard for transmission. With pay television services, the data stream is encrypted and requires proprietary reception equipment. While the underlying reception technology is similar, the pay television technology is proprietary, often consisting of a conditional-access module and smart card. This measure assures satellite television providers that only authorized, paying subscribers have access to pay television content but at the same time can allow free-to-air channels to be viewed even by the people with standard equipment available in the market. Some countries operate satellite television services which can be received for free, without paying a subscription fee. This is called free-to-air satellite television. Germany is likely the leader in free-to-air with approximately 250 digital channels (including 83 HDTV channels and various regional channels) broadcast from the Astra 19.2°E satellite constellation. These are not marketed as a DBS service, but are received in approximately 18 million homes, as well as in any home using the Sky Deutschland commercial DBS system. All German analogue satellite broadcasts ceased on 30 April 2012. The United Kingdom has approximately 160 digital channels (including the regional variations of BBC channels, ITV channels, Channel 4 and Channel 5) that are broadcast without encryption from the Astra 28.2°E satellite constellation, and receivable on any DVB-S receiver (a DVB-S2 receiver is required for certain high definition television services). Most of these channels are included within the Sky EPG, and an increasing number within the Freesat EPG. India's national broadcaster, Doordarshan, promotes a free-to-air DBS package as "DD Free Dish", which is provided as in-fill for the country's terrestrial transmission network. It is broadcast from GSAT-15 at 93.5°E and contains about 80 FTA channels. While originally launched as backhaul for their digital terrestrial television service, a large number of French channels are free-to-air on satellites at 5°W, and have recently been announced as being official in-fill for the DTT network. In North America (United States, Canada and Mexico) there are over 80 FTA digital channels available on Galaxy 19 (with the majority being ethnic or religious in nature). Other FTA satellites include AMC-4, AMC-6, Galaxy 18, and Satmex 5. A company called GloryStar promotes FTA religious broadcasters on Galaxy 19. Satellite TV has seen a decline in consumers since the 2010s due to the cord-cutting trend where people are shifting towards internet-based streaming television and free over-the-air television. Television receive-only satellite dish used by TVRO systems. The term television receive-only, or TVRO, arose during the early days of satellite television reception to differentiate it from commercial satellite television uplink and downlink operations (transmit and receive). This was the primary method of satellite television transmissions before the satellite television industry shifted, with the launch of higher powered DBS satellites in the early 1990s which transmitted their signals on the Ku band frequencies. Satellite television channels at that time were intended to be used by cable television networks rather than received by home viewers. Early satellite television receiver systems were largely constructed by hobbyists and engineers. These early TVRO systems operated mainly on the C-band frequencies and the dishes required were large; typically over in diameter. Consequently, TVRO is often referred to as "big dish" or "Big Ugly Dish" (BUD) satellite television. TVRO systems were designed to receive analog and digital satellite feeds of both television or audio from both C-band and Ku-band transponders on FSS-type satellites. The higher frequency Ku-band systems tend to resemble DBS systems and can use a smaller dish antenna because of the higher power transmissions and greater antenna gain. TVRO systems tend to use larger rather than smaller satellite dish antennas, since it is more likely that the owner of a TVRO system would have a C-band-only setup rather than a Ku band-only setup. Additional receiver boxes allow for different types of digital satellite signal reception, such as DVB/MPEG-2 and 4DTV. The narrow beam width of a normal parabolic satellite antenna means it can only receive signals from a single satellite at a time. Simulsat or the Vertex-RSI TORUS, is a quasi-parabolic satellite earthstation antenna that is capable of receiving satellite transmissions from 35 or more C- and Ku-band satellites simultaneously. ==History==

Early history In 1945 British science fiction writer Arthur C. Clarke proposed a worldwide communications system which would function by means of three satellites equally spaced apart in Earth orbit. This was published in the October 1945 issue of the Wireless World magazine and won him the Franklin Institute's Stuart Ballantine Medal in 1963. The first satellite relayed communication was achieved early on in the space age, after the first relay test was conducted by Pioneer 1 and the first radio broadcast by SCORE at the end of 1958, after at the beginning of the year Sputnik I became the first satellite in history. sent back the first televised image of Earth from space, becoming the first weather satellite. First satellite relayed broadcasts Telstar 1 test (first satellite TV broadcast, July 11, 1962) The first public satellite television signals from Europe to North America were relayed via the Telstar satellite over the Atlantic ocean on 23 July 1962, although a test broadcast had taken place almost two weeks earlier on 11 July. The signals were received and broadcast in North American and European countries and watched by over 100 million. The first geosynchronous communication satellite, Syncom 2, was launched on 26 July 1963. The subsequent first geostationary Syncom 3, orbiting near the International Date Line, was used to telecast the 1964 Olympic Games from Tokyo to the United States. (1965), the world's first commercial communications satellite, was used among others to relay the Our World multi-national broadcast (1967), the first multi-satellite relayed television broadcast The world's first commercial communications satellite, called Intelsat I and nicknamed "Early Bird", was launched into geosynchronous orbit on April 6, 1965. The first national network of television satellites, called Orbita, was created by the Soviet Union in October 1967, and was based on the principle of using the highly elliptical Molniya satellite for rebroadcasting and delivering of television signals to ground downlink stations. , Neil Armstrong making humanity's first step onto an extraterrestrial body, transmitted from Honeysuckle Creek Tracking Station and distributed globally via the Intelsat III F-4 satellite. Development of the direct satellite TV industry The first domestic satellite to carry television transmissions was Canada's geostationary Anik 1, which was launched on 9 November 1972. (OTC) for the Aloha from Hawaii via Satellite, broadcast via the Intelsat IV F-4 satellite, an early international broadcast event featuring Elvis Presley live in concert. ATS-6, the world's first experimental educational and direct broadcast satellite (DBS), was launched on 30 May 1974. It transmitted at 860 MHz using wideband FM modulation and had two sound channels. The transmissions were focused on the Indian subcontinent but experimenters were able to receive the signal in Western Europe using home constructed equipment that drew on UHF television design techniques already in use. The first in a series of Soviet geostationary satellites to carry direct-to-home television, Ekran 1, was launched on 26 October 1976. It used a 714 MHz UHF downlink frequency so that the transmissions could be received with existing UHF television technology rather than microwave technology. The satellite television industry developed in the US from the cable television industry as communication satellites were being used to distribute television programming to remote cable television headends. Home Box Office (HBO), Turner Broadcasting System (TBS), and Christian Broadcasting Network (CBN, later The Family Channel) were among the first to use satellite television to deliver programming. Taylor Howard of San Andreas, California, became the first person to receive C-band satellite signals with his home-built system in 1976. In the US, PBS, a non-profit public broadcasting service, began to distribute its television programming by satellite in 1978. In 1979, Soviet engineers developed the Moskva (or Moscow) system of broadcasting and delivering of TV signals via satellites. They launched the Gorizont communication satellites later that same year. These satellites used geostationary orbits. They were equipped with powerful on-board transponders, so the size of receiving parabolic antennas of downlink stations was reduced to 4 and 2.5 metres. The front cover of the 1979 Neiman-Marcus Christmas catalogue featured the first home satellite TV stations on sale for $36,500. The dishes were nearly in diameter and were remote controlled. The price went down by half soon after that, but there were only eight more channels. The Society for Private and Commercial Earth Stations (SPACE), an organisation which represented consumers and satellite TV system owners, was established in 1980. Early satellite television systems were not very popular due to their expense and large dish size. and in the United States cost more than $5,000, sometimes as much as $10,000. TVRO/C-band satellite era, 1980–1986 By 1980, satellite television was well established in the US and Europe. On 26 April 1982, the first satellite channel in the UK, Satellite Television Ltd. (later Sky One), was launched. Its signals were transmitted from the ESA's Orbital Test Satellites. People in areas without local broadcast stations or cable television service could obtain good-quality reception with no monthly fees. A municipality could require a property owner to relocate the dish if it violated other zoning restrictions, such as a setback requirement, but could not outlaw their use. Since cable channels could prevent reception by big dishes, other companies had an incentive to offer competition. In January 1986, HBO began using the now-obsolete VideoCipher II system to encrypt their channels. Other channels used less secure television encryption systems. The scrambling of HBO was met with much protest from owners of big-dish systems, most of which had no other option at the time for receiving such channels, claiming that clear signals from cable channels would be difficult to receive. One by one, all commercial channels followed HBO's lead and began scrambling their channels. Videocipher II used analog scrambling on its video signal and Data Encryption Standard–based encryption on its audio signal. VideoCipher II was defeated, and there was a black market for descrambler devices which were initially sold as "test" devices. 1987 to present By 1987, nine channels were scrambled, but 99 others were available free-to-air. The piracy on satellite television networks in the US led to the introduction of the Cable Television Consumer Protection and Competition Act of 1992. This legislation enabled anyone caught engaging in signal theft to be fined up to $50,000 and to be sentenced to a maximum of two years in prison. A repeat offender can be fined up to $100,000 and be imprisoned for up to five years. This was one of the first medium-powered satellites, transmitting signals in Ku band and allowing reception with small dishes (90 cm). In the US in the early 1990s, four large cable companies launched PrimeStar, a direct broadcasting company using medium power satellites. The relatively strong transmissions allowed the use of smaller (90 cm) dishes. Its popularity declined with the 1994 launch of the Hughes DirecTV and Dish Network satellite television systems. Digital satellite broadcasts began in 1994 in the United States through DirecTV using the DSS format. They were launched (with the DVB-S standard) in South Africa, Middle East, North Africa and Asia-Pacific in 1994 and 1995, and in 1996 and 1997 in European countries including France, Germany, Spain, Portugal, Italy and the Netherlands, as well as Japan, North America and Latin America. Digital DVB-S broadcasts in the United Kingdom and Ireland started in 1998. Japan started broadcasting with the ISDB-S standard in 2000. On March 4, 1996, EchoStar introduced Digital Sky Highway (Dish Network) using the EchoStar 1 satellite. EchoStar launched a second satellite in September 1996 to increase the number of channels available on Dish Network to 170. In addition to encryption, the widespread availability, in the US, of DBS services such as PrimeStar and DirecTV had been reducing the popularity of TVRO systems since the early 1990s. Signals from DBS satellites (operating in the more recent Ku band) are higher in both frequency and power (due to improvements in the solar panels and energy efficiency of modern satellites) and therefore require much smaller dishes than C-band, and the digital modulation methods now used require less signal strength at the receiver than analog modulation methods. Each satellite also can carry up to 32 transponders in the Ku band, but only 24 in the C band, and several digital subchannels can be multiplexed (MCPC) or carried separately (SCPC) on a single transponder. Advances in noise reduction due to improved microwave technology and semiconductor materials have also had an effect. In a return to older (but proven) technologies of satellite communication, the current DBS-based satellite providers in the US (Dish Network and DirecTV) now utilize additional capacity on the Ku-band transponders of existing FSS-class satellites, in addition to the capacity on their own existing fleets of DBS satellites. This was done to provide more channel capacity for their systems, as required by the increasing number of High-Definition and simulcast local station channels. The reception of the channels carried on the Ku-band FSS satellite's respective transponders was achieved by DirecTV & Dish Network issuing to subscribers dishes twice the diameter (36") than the previous 18" (& 20" for the Dish Network "Dish500") dishes used initially, equipped with 2 circular-polarized LNBFs (for reception of 2 native DBS satellites of the provider, 1 per LNBF), and 1 standard linear-polarized LNB for reception of channels from an FSS-type satellite. These newer DBS/FSS-hybrid dishes, marketed by DirecTV and Dish Network as the "SlimLine" and "SuperDish" models respectively, are the current standard for both providers, with their original 18"/20" single or dual LNBF dishes either now obsolete, or only used for program packages, separate channels, or services only broadcast over the providers' DBS satellites. On 29 November 1999 US President Bill Clinton signed the Satellite Home Viewer Improvement Act (SHVIA). The act allowed Americans to receive local broadcast signals via direct broadcast satellite systems for the first time. ==Legal==

The 1963 Radio Regulations of the International Telecommunication Union (ITU) defined a "broadcasting satellite service" as a "space service in which signals transmitted or retransmitted by space stations, or transmitted by reflection from objects in orbit around the Earth, are intended for direct reception by the general public." In the 1970s some states grew concerned that external broadcasting could alter the cultural or political identity of a state leading to the New World Information and Communication Order (NWICO) proposal. However, satellite broadcasts can not be restricted on a per-state basis due to the limitations of the technology. Around the time the MacBride report was released, satellite broadcasting was being discussed at the UN Committee on the Peaceful Uses of Outer Space (COPUOS) where most of the members supported prior consent restrictions for broadcasting in their territories, but some argued this would violate freedom of information. The parties were unable to reach a consensus on this and in 1982 submitted UNGA Res 37/92 ("DBS Principles") to the UN General Assembly which was adopted by a majority vote, however, most States capable of DBS voted against it. The "DBS Principles" resolution is generally regarded as ineffective. ==See also==