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Encyclopedia > Communications satellite
U.S. military MILSTAR communications satellite
U.S. military MILSTAR communications satellite

A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications. Modern communications satellites use a variety of orbits including geostationary orbits, Molniya orbits, other elliptical orbits and low (polar and non-polar) Earth orbits. File links The following pages link to this file: Communications satellite Military Strategic and Tactical Relay satellite Categories: United States government images ... File links The following pages link to this file: Communications satellite Military Strategic and Tactical Relay satellite Categories: United States government images ... MILSTAR satellite. ... This article is about artificial satellites. ... Telecommunication involves the transmission of signals over a distance for the purpose of communication. ... Geostationary orbit A geostationary orbit (GEO) is a geosynchronous orbit directly above the Earths equator (0° latitude), with orbital eccentricity of zero. ... Molniya orbit is a class of a highly elliptic orbit with inclination of +/-63. ... In astrodynamics or celestial mechanics a elliptic orbit is an orbit with the eccentricity greater than 0 and less than 1. ... A polar orbit is an orbit in which a satellite passes above or nearly above both poles of the planet orbiting on each revolution. ...


For fixed (point-to-point) services, communications satellites provide a microwave radio relay technology complementary to that of fiber optic submarine communication cables. They are also used for mobile applications such as communications to ships, vehicles, planes and hand-held terminals, and for TV and radio broadcasting, for which application of other technologies, such as cable, is impractical or impossible. This article does not cite any references or sources. ... This article or section does not cite its references or sources. ... Fiber Optic strands An optical fiber in American English or fibre in British English is a transparent thin fiber for transmitting light. ... A submarine communications cable is a cable laid beneath the sea to carry telecommunications between countries. ...

Contents

History

Early missions

The first satellite equipped with on-board radio-transmitter that worked on two frequences, 20.005 and 40.002 MHz was the Soviet Sputnik 1, launched in 1957. The first American satellite to relay communications was Project SCORE in 1958, which used a tape recorder to store and forward voice messages. It was used to send a Christmas greeting to the world from U.S. President Dwight D. Eisenhower. NASA launched an Echo satellite in 1960; the 100-foot aluminized PET film balloon served as a passive reflector for radio communications. Courier 1B, (built by Philco) also launched in 1960, was the world’s first active repeater satellite. Antenna tower of Crystal Palace transmitter, London A transmitter is an electronic device which, usually with the aid of an antenna, propagates an electromagnetic signal such as radio, television, or other telecommunications. ... Sputnik 1 (Russian: , Satellite-1, or literally Co-traveler-1 byname ПС-1 (PS-1, i. ... This article or section is in need of attention from an expert on the subject. ... Jan. ... Store and forward is a communications technique in which messages are sent to a intermediate station where they are kept and sent at a later time to the final destination or to another intermediate station. ... Dwight David Eisenhower, born David Dwight Eisenhower (October 14, 1890 – March 28, 1969), nicknamed Ike, was a five-star General in the United States Army and U.S. politician, who served as the thirty-fourth President of the United States (1953–1961). ... For other uses, see NASA (disambiguation). ... Echo 1 sits fully inflated at a Navy hangar in Weeksville, North Carolina. ... Year 1960 (MCMLX) was a leap year starting on Friday (link will display full calendar) of the Gregorian calendar. ... Biaxially-oriented polyethylene terephthalate (boPET) polyester film is used for its high tensile strength, chemical and dimensional stability, transparency, gas and aroma barrier properties and electrical insulation. ... Launched October 4, 1960, Courier 1B was the worlds first active repeater satellite. ... A Philco 90 cathedral style radio from 1931. ...


Telstar was the first active, direct relay communications satellite. Belonging to AT&T as part of a multi-national agreement between AT&T, Bell Telephone Laboratories, NASA, the British General Post Office, and the French National PTT (Post Office) to develop satellite communication, it was launched by NASA from Cape Canaveral on July 10, 1962, the first privately sponsored space launch. Telstar was placed in an elliptical orbit (completed once every 2 hours and 37 minutes), rotating at a 45° angle above the equator. The original Telstar had a roughly spherical shape. ... This article describes the former AT&T Corp. ... Bell Laboratories (also known as Bell Labs and formerly known as AT&T Bell Laboratories and Bell Telephone Laboratories) was the main research and development arm of the United States Bell System. ... The British General Post Office (GPO) was officially established in 1660 by Charles II and it eventually grew to combine the functions of both the state postal system and telecommunications carrier. ... France Télécom (Euronext: FTE, NYSE: FTE) (often spelled France Telecom, without the accents, in non-French text) is the main telecommunication company in France. ... This article is about the area of Florida. ... is the 191st day of the year (192nd in leap years) in the Gregorian calendar. ... Year 1962 (MCMLXII) was a common year starting on Monday (the link is to a full 1962 calendar) of the Gregorian calendar. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... World map showing the equator in red For other uses, see Equator (disambiguation). ...


An immediate antecedent of the geostationary satellites was HughesSyncom 2, launched on July 26, 1963. Syncom 2 revolved around the earth once per day at constant speed, but because it still had north-south motion, special equipment was needed to track it. Hughes logo adopted after his death Hughes developed the AIM-120 AMRAAM, one of the worlds most advanced air-to-air missiles Hughes Aircraft Company was a major defense/aerospace company founded by Howard Hughes. ... Syncom-type satellite Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. ... is the 207th day of the year (208th in leap years) in the Gregorian calendar. ... For other uses, see 1963 (disambiguation). ...


Geostationary orbits

Main article: Geostationary orbit

A satellite in a geostationary orbit appears to be in a fixed position to an earth-based observer. A geostationary satellite revolves around the earth at a constant speed once per day over the equator. Geostationary orbit A geostationary orbit (GEO) is a geosynchronous orbit directly above the Earths equator (0° latitude), with orbital eccentricity of zero. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Geostationary orbit A geostationary orbit (GEO) is a geosynchronous orbit directly above the Earths equator (0° latitude), with orbital eccentricity of zero. ... Geostationary orbit A geostationary orbit (GEO) is a geosynchronous orbit directly above the Earths equator (0° latitude), with orbital eccentricity of zero. ...


The geostationary orbit is useful for communications applications because ground based antennas, which must be directed toward the satellite, can operate effectively without the need for expensive equipment to track the satellite’s motion. Especially for applications that require a large number of ground antennas (such as direct TV distribution), the savings in ground equipment can more than justify the extra cost and onboard complexity of lifting a satellite into the relatively high geostationary orbit.


The concept of the geostationary communications satellite was first proposed by Arthur C. Clarke, building on work by Konstantin Tsiolkovsky and on the 1929 work by Herman Potočnik (writing as Herman Noordung) Das Problem der Befahrung des Weltraums - der Raketen-motor. In October 1945 Clarke published an article titled “Extra-terrestrial Relays” in the British magazine Wireless World. The article described the fundamentals behind the deployment of artificial satellites in geostationary orbits for the purpose of relaying radio signals. Thus Arthur C. Clarke is often quoted as being the inventor of the communications satellite. Sri Lankabhimanya Sir Arthur Charles Clarke, CBE (16 December 1917–19 March 2008), was a British science fiction author, inventor, and futurist, most famous for the novel 2001: A Space Odyssey, written in collaboration with director Stanley Kubrick, a collaboration which led also to the film of the same name... Konstantin Eduardovich Tsiolkovsky Konstantin Eduardovich Tsiolkovsky (Константин Эдуардович Циолковский, Konstanty CioÅ‚kowski) (September 5, 1857 new style – September 19, 1935) was a Russian and Soviet rocket scientist and pioneer of cosmonautics who spent most of his life in a log house on the outskirts of the Russian town of Kaluga. ... Herman Potočnik (pseudonym Hermann Noordung) (December 22, 1892 - August 27, 1929) was a Slovene rocket engineer and pioneer of cosmonautics (astronautics). ... Herman Potočnik (pseudonym Hermann Noordung) (December 12, 1892 - August 27, 1929) was a Slovene rocket engineer and pioneer of cosmonautics (astronautics). ... Year 1945 (MCMXLV) was a common year starting on Monday (link will display the full calendar). ... Wireless World was the preeminent British magazine for radio and electronics enthusiasts. ... For other uses, please see Satellite (disambiguation) A satellite is an object that orbits another object (known as its primary). ... For other uses, see Inventor (disambiguation). ...


The first truly geostationary satellite launched in orbit was the Syncom 3, launched on August 19, 1964. It was placed in orbit at 180° east longitude, over the International Date Line. It was used that same year to relay television coverage on the 1964 Summer Olympics in Tokyo to the United States, the first television transmission sent over the Pacific Ocean. Syncom-type satellite Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. ... is the 231st day of the year (232nd in leap years) in the Gregorian calendar. ... Longitude is the east-west geographic coordinate measurement most commonly utilized in cartography and global navigation. ... “Date line” redirects here. ... The 1964 Summer Olympics, officially known as the Games of the XVIII Olympiad, were held in 1964 in Tokyo, Japan. ... Tokyo (東京; Tōkyō, lit. ...


Shortly after Syncom 3, Intelsat I, aka Early Bird, was launched on April 6, 1965 and placed in orbit at 28° west longitude. It was the first geostationary satellite for telecommunications over the Atlantic Ocean. Syncom-type satellite Syncom was a program of three experimental, active geosynchronous communication satellites which was started by NASA in 1961. ... INTELSAT I Early Bird Intelsat I (nicknamed Early Bird for the proverb The early bird catches the worm) was the first commercial communications satellite to be placed in geosynchronous orbit, on April 6, 1965. ... is the 96th day of the year (97th in leap years) in the Gregorian calendar. ... Year 1965 (MCMLXV) was a common year starting on Friday (link will display full calendar) of the 1965 Gregorian calendar. ...


On November 9, 1972, North America's first geostationary satellite serving the continent, Anik A1, was launched by Telesat Canada, with the United States following suit with the launch of Westar 1 by Western Union on April 13, 1974. is the 313th day of the year (314th in leap years) in the Gregorian calendar. ... Year 1972 (MCMLXXII) was a leap year starting on Saturday (link will display full calendar) of the Gregorian calendar. ... North American redirects here. ... Anik 1 was a Canadian geosynchronous communications satellite that was launched in 1972 by a Delta rocket. ... Telesat Canada is a Canadian satellite communications company owned by BCE Inc. ... Westar 1 was the first commercially-launched American geosynchronous communications satellite, launched by Western Union and NASA on April 13, 1974. ... Western Union (NYSE: WU) is a financial services and communications company based in the United States. ... is the 103rd day of the year (104th in leap years) in the Gregorian calendar. ...


On December 19, 1974, the first geostationary communications satellite in the world to be three-axis stabilized was launched : the franco-German Symphonie. is the 353rd day of the year (354th in leap years) in the Gregorian calendar. ... Year 1974 (MCMLXXIV) was a common year starting on Tuesday (link will display full calendar) of the 1974 Gregorian calendar. ... Momentum wheels are a type of flywheel, mainly used for gyroscopic stabilization of spacecraft: momentum wheels have high rotation speeds (around 5000 rpms) and mass. ... The Symphonie satellites[1] are the first communications satellites built by France and Germany and the first in the world which were three-axis stabilized on geostationary orbit. ...


After the launchings of Telstar, Syncom 3, Early Bird, Anik A1, and Westar 1, RCA Americom (later GE Americom, now SES Americom) launched Satcom 1 in 1975. It was Satcom 1 that was instrumental in helping early cable TV channels such as WTBS (now TBS Superstation), HBO, CBN (now ABC Family), and The Weather Channel become successful, because these channels distributed their programming to all of the local cable TV headends using the satellite. Additionally, it was the first satellite used by broadcast TV networks in the United States, like ABC, NBC, and CBS, to distribute their programming to all of their local affiliate stations. Satcom 1 was so widely used because it had twice the communications capacity of the competing Westar 1 in America (24 transponders as opposed to Westar 1’s 12), resulting in lower transponder usage costs. Satellites in later decades tended to even higher transponder counts. SES Americom is a major commercial satellite operator based in the United States. ... Satcom 1 was an American communications satellite operated by RCA Americom and launched on December 13, 1975. ... Cable television or Community Antenna Television (CATV) (and often shortened to cable) is a system of providing television, FM radio programming and other services to consumers via radio waves transmitted directly to people’s televisions through fixed coaxial cables as opposed to the over-the-air method used in traditional... TBS Superstation is a popular American cable TV network that shows sports and variety programming. ... For other uses, see HBO (disambiguation). ... The Christian Broadcasting Network, or CBN, is, as its name implies, a Christian television broadcasting network in the United States. ... ABC Family is an American cable television network currently owned by Disney-ABC Television Group, a division of The Walt Disney Company. ... The Weather Channel (TWC) is a cable and satellite television network that broadcasts weather and weather-related news 24 hours a day. ... Cable television or Community Antenna Television (CATV) (and often shortened to cable) is a system of providing television, FM radio programming and other services to consumers via radio waves transmitted directly to people’s televisions through fixed coaxial cables as opposed to the over-the-air method used in traditional... Cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. ... The American Broadcasting Company (ABC) is an American television network. ... This article is about the television network. ... This article is about the broadcast network. ... Satcom 1 was an American communications satellite operated by RCA Americom and launched on December 13, 1975. ...


By 2000 Hughes Space and Communications (now Boeing Satellite Development Center) had built nearly 40 percent of the satellites in service worldwide. Other major satellite manufacturers include Space Systems/Loral, Lockheed Martin (owns former RCA Astro Electronics/GE Astro Space business), Northrop Grumman, Alcatel Space, now Thales Alenia Space, with the Spacebus series, and EADS Astrium. Hughes logo adopted after his death Hughes developed the AIM-120 AMRAAM, one of the worlds most advanced air-to-air missiles Hughes Aircraft Company was a major defense/aerospace company founded by Howard Hughes. ... The Boeing 601, the best-selling large spacecraft model in the world. ... Space Systems/Loral (SS/L), of Palo Alto, California, is the wholly owned manufacturing subsidiary of Loral Space & Communications. ... Lockheed Martin Space Systems is one of the 4 major business divisions of Lockheed Martin. ... The Northrop Grumman Corporation (NYSE: NOC) is an aerospace and defense conglomerate that is the result of a 1994 merger between Northrop and Grumman. ... This article or section does not adequately cite its references or sources. ... Spacebus™ [1] is the name given to a family of geostationary telecommunications satellites developed starting in the 1980’s by Aerospatiale now Thales Alenia Space, in its Space Centre in Cannes Mandelieu. ... EADS Astrium, one of the three business units of EADS Space, this company being a subsidiary of EADS, is an European space manufacturer involved in the manufacture of spacecraft used for science, Earth observation and telecommunication, as well as the equipment and subsystems used therein and related ground systems. ...


Low-Earth-orbiting satellites

Main article: Low Earth orbit
Low Earth orbit in Cyan

A Low Earth Orbit (LEO) typically is a circular orbit about 400 kilometres above the earth’s surface and, correspondingly, a period (time to revolve around the earth) of about 90 minutes. Because of their low altitude, these satellites are only visible from within a radius of roughly 1000 kilometres from the sub-satellite point. In addition, satellites in low earth orbit change their position relative to the ground position quickly. So even for local applications, a large number of satellites are needed if the mission requires uninterrupted connectivity. A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ... A low Earth orbit (LEO) is an orbit in which objects such as satellites are below intermediate circular orbit (ICO) and far below geostationary orbit, but typically around 350 - 1400 km above the Earths surface. ...


Low earth orbiting satellites are less expensive to position in space than geostationary satellites and, because of their closer proximity to the ground, require lower signal strength (Recall that signal strength falls off as the square of the distance from the source, so the effect is dramatic). So there is a trade off between the number of satellites and their cost. In addition, there are important differences in the onboard and ground equipment needed to support the two types of missions.


A group of satellites working in concert thus is known as a satellite constellation. Two such constellations which were intended for provision for satellite phone services, primarily to remote areas, were the Iridium and Globalstar. The Iridium system has 66 satellites. Another LEO satellite constellation known as Teledesic, with backing from Microsoft entrepreneur Paul Allen, was to have over 840 satellites. This was later scaled back to 288 and ultimately ended up only launching one test satellite. A group of electronic satellites working in concert is known as a satellite constellation. ... A satellite telephone, satellite phone, or satphone is a mobile phone that communicates directly with orbiting communications satellites. ... An Iridium phone (without the aerial) The Iridium satellite constellation is a system of 66 active communication satellites and spares around the Earth. ... Globalstar is a low Earth orbit (LEO) satellite constellation for telephone and low-speed data communications, similar to (and competing with) the Iridium satellite system. ... Teledesic was a 1990s proposal to build a commercial broadband satellite constellation for Internet services. ... Microsoft Corporation, (NASDAQ: MSFT, HKSE: 4338) is a multinational computer technology corporation with global annual revenue of US$44. ... For other persons named Paul Allen, see Paul Allen (disambiguation). ...


It is also possible to offer discontinuous coverage using a low Earth orbit satellite capable of storing data received while passing over one part of Earth and transmitting it later while passing over another part. This will be the case with the CASCADE system of Canada’s CASSIOPE communications satellite. Another system using this store and forward method is Orbcomm CASSIOPE is a hybrid satellite project of the Canadian Space Agency. ... Store and forward is a communications technique in which messages are sent to a intermediate station where they are kept and sent at a later time to the final destination or to another intermediate station. ... Orbcomm ORBCOMM is a mobile satellite service provider offering high value, two-way data and message communications globally through international service licensees and in the U.S. through value-added resellers, as well as through direct sales. ...


Molniya satellites

Main article: Molniya orbit

As mentioned, geostationary satellites are constrained to operate above the equator. As a consequence, they are not always suitable for providing services at high latitudes: for at high latitudes a geostationary satellite may appear low on the horizon, affecting connectivity and causing multipathing (interference caused by signals reflecting off the ground into the ground antenna). The first satellite of Molniya series was launched on April 23, 1965 and was used for experimental transmission of TV signal from Moscow uplink station to downlink stations, located in Siberia and Russian Far East, in Norilsk, Khabarovsk, Magadan and Vladivostok. In November of 1967 Soviet engineers created a unique system of national TV network of satellite television, called Orbita, that was based on Molniya satellites. Molniya orbit is a class of a highly elliptic orbit with inclination of +/-63. ... Molniya orbit is a class of a highly elliptic orbit with inclination of +/-63. ... PRIMERGY MultiPath PRIMERGY MultiPath supports redundant Fiber Channel paths, the configured connections between server and subsystem that are such an important component of disaster-tolerant servers and clusters. ... Molniya (lightning) was a military communications satellite system used by the Soviet Union. ... Year 1965 (MCMLXV) was a common year starting on Friday (link will display full calendar) of the 1965 Gregorian calendar. ... In telecommunications, transmission is the act of transmitting electrical messages (and the associated phenomena of radiant energy that passes through media). ... In telecommunication, signalling (or signaling) has the following meanings: The use of signals for controlling communications. ... Look up uplink in Wiktionary, the free dictionary. ... In radio communications, a downlink is the link from a satellite to a ground station. ... This article is about Siberia as a whole. ... Norilsk downtown was designed in a typical Stalinist style. ... Government Country District Krai Russia Far Eastern Federal District Khabarovsk Krai Established 1858 Mayor Alexandr Sokolov Geographical characteristics Area  - City 372 km² Population  - City (2005) 579,000 Coordinates Other Information Postal Code 680xxx Dialing Code +7 4212 Website: www. ... Magadan (Russian: ), a port city on the Sea of Okhotsk and gateway to the Kolyma region, is the administrative center of Magadan Oblast (since 1953), in the Russian Far East. ... Vladivostok (Russian: ) is the administrative center of Primorsky Krai, Russia, situated close to the Russo-Sino border and North Korea. ... Year 1967 (MCMLXVII) was a common year starting on Sunday (link will display full calendar) of the 1967 Gregorian calendar. ... For other uses, see System (disambiguation). ... A television network is a distribution network for television content whereby a central operation provides programming for many television stations. ... Satellite television is television delivered by way of communications satellites, as compared to conventional terrestrial television and cable television. ... Orbita is a Soviet-Russian system of broadcasting and delivering TV-signal via satellites. ...


Molniya orbits can be an appealing alternative in such cases. The Molniya orbit is highly inclined, guaranteeing good elevation over selected positions during the northern portion of the orbit. (Elevation is the extent of the satellite’s position above the horizon. Thus a satellite at the horizon has zero elevation and a satellite directly overhead has elevation of 90 degrees).


Furthermore, the Molniya orbit is so designed that the satellite spends the great majority of its time over the far northern latitudes, during which its ground footprint moves only slightly. Its period is one half day, so that the satellite is available for operation over the targeted region for eight hours every second revolution. In this way a constellation of three Molniya satellites (plus in-orbit spares) can provide uninterrupted coverage.


Molniya satellites are typically used for telephony and TV services over Russia. Another application is to use them for mobile radio systems (even at lower latitudes) since cars travelling through urban areas need access to satellites at high elevation in order to secure good connectivity, e.g. in the presence of tall buildings.


Applications

Telephony

An Iridium satellite
An Iridium satellite

The first and historically most important application for communication satellites was in intercontinental long distance telephony. The fixed Public Switched Telephone Network relays telephone calls from land line telephones to an earth station, where they are then transmitted to a geostationary satellite. The downlink follows an analogous path. Improvements in Submarine communications cables caused a decline in the use of satellites for fixed telephony in the late 20th century but they still serve remote islands such as Ascension Island and Saint Helena where no submarine cable is in service. An Iridium phone (without the aerial) The Iridium satellite constellation is a system of 66 active communication satellites and spares around the Earth. ... Long distance in telecommunications, refers to telephone calls made outside a certain area, usually characterized by an area code outside of a local call area. ... The public switched telephone network (PSTN) is the network of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the network of the worlds public IP-based packet-switched networks. ... This article does not adequately cite its references or sources. ... A landline or main line is a telephone line which travels through a physical, land-based medium. ... A cross-section of a submarine communications cable. ... Anthem: God Save the Queen Capital Georgetown Largest city Georgetown Official languages English Government Dependency of St. ...


Satellite phones connect directly to a constellation of geostationary or low earth orbit satellites. Calls are then forwarded to a teleport connected to the PSTN network or another satellite phone. A satellite telephone, satellite phone, or satphone is a mobile phone that communicates directly with orbiting communications satellites. ... This article is about the satellite communications facility. ... The public switched telephone network (PSTN) is the concatenation of the worlds public circuit-switched telephone networks, in much the same way that the Internet is the concatenation of the worlds public IP-based packet-switched networks. ...


Satellite television and radio

Television became the main market, its demand for simultaneous delivery of relatively few signals of large bandwidth to many receivers being a more precise match for the capabilities of geosynchronous comsats. Two satellite types are used for North American television and radio:

A direct broadcast satellite is a communications satellite that transmits to small DBS satellite dishes (usually 18 to 24 inches in diameter). Direct broadcast satellites generally operate in the upper portion of the microwave Ku band. DBS technology is used for DTH-oriented (Direct-To-Home) satellite TV services, such as DirecTV and DISH Network in the United States, Bell ExpressVu in Canada, and Sky Digital in the UK, Republic of Ireland and New Zealand. Direct broadcast satellite (DBS) is a term used to refer to satellite television broadcasts intended for home reception, also referred to as direct-to-home signals. ... Fixed Service Satellite (or FSS), is the official classification for geostationary communications satellites used chiefly for broadcast feeds for television and radio stations and networks, as well as for telephony, data communications, and also for direct-to-home (DTH) cable and satellite TV channels (although this role has been somewhat... Direct broadcast satellite (DBS) is a term used to refer to satellite television broadcasts intended for home reception, also referred to as direct-to-home signals. ... The Ku band (kay-yoo kurz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 11 to 18 GHz. ... A Satellite dish antenna A satellite dish is a type of parabolic reflector antenna designed with the specific purpose of transmitting signals to and/or receiving from satellites. ... A standard DirecTV satellite dish with 1 LNB on a roof DirecTV (trademarked as DIRECTV) is a direct broadcast satellite (DBS) service based in El Segundo, California, USA, that was founded in 1994. ... DISH Network is a direct broadcast satellite (DBS) service that provides satellite television, audio programming, and interactive television services to households and businesses in the United States, owned by parent company DISH Network Corporation. ... Bell ExpressVu is the division of Bell Canada Enterprises that provides satellite television service across Canada. ... For a wider corporate history and profile, see British Sky Broadcasting. ...


Fixed Service Satellites use the C band, and the lower portions of the Ku bands. They are normally used for broadcast feeds to and from television networks and local affiliate stations (such as program feeds for network and syndicated programming, live shots, and backhauls), as well as being used for distance learning by schools and universities, business television (BTV), Videoconferencing, and general commercial telecommunications. FSS satellites are also used to distribute national cable channels to cable television headends. Fixed Service Satellite (or FSS), is the official classification for geostationary communications satellites used chiefly for broadcast feeds for television and radio stations and networks, as well as for telephony, data communications, and also for direct-to-home (DTH) cable and satellite TV channels (although this role has been somewhat... C band (compromise band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz. ... In broadcast engineering, a remote broadcast (usually just called a remote or a live remote) is broadcasting done from a location away from the regular studio. ... In the context of broadcasting, backhaul refers to uncut program content that is transmitted point-to-point to an individual television or radio station, broadcast network or other receiving entity where it will be integrated into a finished TV show or radio show. ... Distance Learning is learning carried out apart from the usual classroom setting; in an asynchronous setting. ... George W. Bush conducting a video tele-conference at Offutt Air Force Base A videoconference (also known as a videoteleconference) is a set of interactive telecommunication technologies which allow two or more locations to interact via two-way video and audio transmissions simultaneously. ... Cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. ...


Operating at lower frequency and power than DBS, FSS satellites require a much larger dish for reception (3 to 8 feet (1 to 2.5m) in diameter for Ku band, and 12 feet (3.6m) or larger for C band). They use linear polarization for each of the transponders' RF input and output (as opposed to circular polarization used by DBS satellites). FSS satellite technology was also originally used for DTH satellite TV from the late 1970s to the early 1990s in the United States in the form of TVRO (TeleVision Receive Only) receivers and dishes (also known as big-dish, or more pejoratively known as "BUD" or "Big ugly dish" systems). It was also used in its Ku band form for the now-defunct Primestar satellite TV service. In electrodynamics, linear polarization or plane polarization of electromagnetic radiation is a confinement of the electric field vector or magnetic field vector to a given plane along the direction of propagation. ... In electrodynamics, circular polarization of electromagnetic radiation is a polarization such that the tip of the electric field vector, at a fixed point in space, describes a circle as time progresses. ... Television receive-only, or TVRO, refers to satellite television reception equipment that is based primarily on open standards equipment. ... A big ugly dish (often abbreviated to BUD) is a colloquial name for a satellite dish used to receive satellite television signals on the C band. ... PrimeStar is a now-defunct U.S. direct broadcast satellite organization formed in 1991. ...


This all changed when the first American DBS provider, DirecTV, was established in 1994, stealing the limelight from FSS satellite technology for DTH programming (due to DirecTV's smaller 18-inch diameter dishes and lower equipment cost). However, FSS satellites on the C and Ku bands still are used by cable and satellite channels such as CNN, The Weather Channel, HBO, Starz, and others, for distribution to cable TV headends (as mentioned earlier), and to the DBS providers themselves such as DirecTV and DISH Network who then re-distribute these channels over their own DBS systems. The Cable News Network, commonly known as CNN, is a major cable television network founded in 1980 by Ted Turner. ... The Weather Channel (TWC) is a cable and satellite television network that broadcasts weather and weather-related news 24 hours a day. ... For other uses, see HBO (disambiguation). ... Starz can refer to: Starz!, a cable TV network, or Starz the online downloadable movie service from RealNetworks. ... Cable television or Community Antenna Television (CATV) (and often shortened to cable) is a system of providing television, FM radio programming and other services to consumers via radio waves transmitted directly to people’s televisions through fixed coaxial cables as opposed to the over-the-air method used in traditional... Cable television headend is a master facility for receiving television signals for processing and distribution over a cable television system. ...


The fact that these channels still exist on FSS satellites (more so for reception and re-distribution by cable TV and DBS systems, instead of for DTH viewers) makes TVRO systems for DTH viewing a still-viable option for satellite TV, often being a much-cheaper alternative to DBS, as far as monthly subscription fees are concerned. TVRO-oriented programming packages sold by companies such as National Programming Services, Bigdish.com, and Skyvision, are often quite a bit cheaper than their DBS equivalents. Motorola still makes digital 4DTV receivers for DTH TVRO use, and analog TVRO receivers are still available. Motorola Inc. ... 4DTV is the name of the digital TVRO communications satellite receiver box manufactured by Motorola. ...


However, the hardware for a brand-new TVRO system (dish and receiver, along with a VideoCipher or DigiCipher descrambler, or an integrated receiver/decoder (IRD) like a 4DTV system, instead of a separate receiver and descrambler/decoder) nowadays costs quite a bit more than a DBS system (about US$1500–2000, including installation). But most older used TVRO systems can be had almost for free, due to most people converting over to DBS systems over the years. Unlike DBS, big-dish TVRO satellite TV also provides a plethora of unscrambled and unencrypted channels such as Classic Arts Showcase, and feeds of syndicated TV shows for reception by local TV stations. VideoCipher is a brand name of analog scrambling equipment for satellite television invented in 1983 by Linkabit systems, which was bought out by MA/COM in 1985. ... DigiCipher 2, or simply DCII, is the name of the digital signal compression standard used on many communications satellite television and audio signals. ... An integrated receiver/decoder is an electronic device used to receive and decode digital signals. ... Classic Arts Showcase is a television channel promoting the fine arts. ... In the television industry (as in radio), syndication is the sale of the right to broadcast programs to multiple stations, without going through a broadcast network. ...


Free-to-air satellite TV channels are also usually distributed on FSS satellites in the Ku band. The Intelsat Americas 5, Galaxy 10R and AMC 3 satellites over North America provide a quite large amount of FTA channels on their Ku band transponders. Free-to-air is a phrase used to describe television and radio broadcasts which are available without subscription and without decryption (pay-TV). ... Intelsat Americas 5 (IA-5) (formerly Telstar 5) is a communications satellite in the Clarke orbit at 97 degrees west, above a point in the Pacific Ocean several hundred miles west of the Galapagos Islands. ... AMC-3 is a geostationary communications satellite owned by SES-Americom. ... North American redirects here. ... An Ontario Highway 407 toll transponder In telecommunication, the term transponder (short-for Transmitter-responder and sometimes abbreviated to XPDR, XPNDR or TPDR) has the following meanings: An automatic device that receives, amplifies, and retransmits a signal on a different frequency (see also broadcast translator). ...


The American Dish Network DBS service has also recently utilized FSS technology as well for their programming packages requiring their SuperDish antenna, due to Dish Network needing more capacity to carry local television stations per the FCC's "must-carry" regulations, and for more bandwidth to carry HDTV channels. DISH Network is a direct broadcast satellite (DBS) service that provides satellite television, audio programming, and interactive television services to households and businesses in the United States, owned by parent company DISH Network Corporation. ... The SuperDish was deployed by Dish Network in November 2003 as a means to provide more channels for subscribing customers. ... FCC redirects here. ... High-definition television (HDTV) means broadcast of television signals with a higher resolution than traditional formats (NTSC, SECAM, PAL) allow. ...


Satellites for communication have now been launched that have transponders in the Ka band, such as DirecTV's SPACEWAY-1 satellite, and Anik F2. NASA as well has launched experimental satellites using the Ka band recently. The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. ... SPACEWAY-1 is part of DirecTV’s constellation of direct broadcast satellites. ... The Anik satellites are geostationary communications satellites launched by Telesat Canada for television in Canada. ... For other uses, see NASA (disambiguation). ...


The definitions of FSS and DBS satellites outside of North America, especially in Europe, are a bit more ambiguous. Most satellites used for direct-to-home television in Europe have the same high power output as DBS-class satellites in North America, but use the same linear polarization as FSS-class satellites. Examples of these are the Astra, Eutelsat, and Hotbird spacecraft in orbit over the European continent. Because of this, the terms FSS and DBS are more so used throughout the North American continent, and are uncommon in Europe. SES Astra SA, is a corporate subsidiary of SES, based in Betzdorf, in eastern Luxembourg, that owns and operates the Astra series of geostationary satellites, which transmit approximately 1100 analogue and digital television and radio channels via 176 transponders to 91 million households across Europe. ... Eutelsat S.A. is a French-based satellite provider. ... Hot Bird is the common name of a family of 5 satellites operated by Eutelsat, located at 13 degrees East over the Equator (orbital position) and transmitting in free-to-air towards 98 million households in Europe, North Africa &, the Middle East. ...


See broadcast satellites for further information on FSS and DBS satellites in orbit. This is the list of broadcast satellites — radio and television networks and backhauls, and for DBS. Listings are from west to east (increasing longitude) by orbital position, starting and ending with the International Date Line. ...


Mobile satellite technologies

Initially available for broadcast to stationary TV receivers, by 2004 popular mobile direct broadcast applications made their appearance with that arrival of two satellite radio systems in the United States: Sirius and XM Satellite Radio Holdings. Some manufacturers have also introduced special antennas for mobile reception of DBS television. Using GPS technology as a reference, these antennas automatically re-aim to the satellite no matter where or how the vehicle (that the antenna is mounted on) is situated. These mobile satellite antennas are popular with some recreational vehicle owners. Such mobile DBS antennas are also used by JetBlue Airways for DirecTV (supplied by LiveTV, a subsidiary of JetBlue), which passengers can view on-board on LCD screens mounted in the seats. Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... “RV” redirects here. ... For the Jet Blue database used in Exchange Server and Active Directory, see Extensible Storage Engine. ... LiveTV is the leading provider of innovative, low-cost in-flight entertainment products and services to commercial aircraft markets worldwide. ...


Amateur radio

Amateur radio operators have access to the OSCAR satellites that have been designed specifically to carry amateur radio traffic. Most such satellites operate as spaceborne repeaters, and are generally accessed by amateurs equipped with UHF or VHF radio equipment and highly directional antennas such as Yagis or dish antennas. Due to the limitations of ground-based amateur equipment, most amateur satellites are launched into fairly low Earth orbits, and are designed to deal with only a limited number of brief contacts at any given time. Some satellites also provide data-forwarding services using the AX.25 or similar protocols. Amateur radio station with modern solid-state transceiver featuring LCD and DSP capabilities Amateur radio, often called ham radio, is both a hobby and a service that uses various types of radio communications equipment to communicate with other radio amateurs for public service, recreation and self-training. ... Look up Oscar in Wiktionary, the free dictionary. ... For the album by the post-hardcore band Fugazi, see Repeater (album). ... This article is about the radio frequency. ... Very high frequency (VHF) is the radio frequency range from 30 MHz to 300 MHz. ... In biology, antenna (plural: antennae) refers to the sensing organs of several arthropods. ... A Yagi-Uda antenna. ... AX.25 is a data link layer protocol derived from the X.25 protocol suite and designed for use by amateur radio operators. ...


Satellite Internet

After the 1990s, satellite communication technology has been used as a means to connect to the Internet via broadband data connections. This can be very useful for users who are located in very remote areas, and cannot access a wireline broadband or dialup connection. Satellite Internet services are used in locations where terrestrial Internet access is not available and in locations which move frequently. ... Broadband in telecommunications is a term that refers to a signaling method that includes or handles a relatively wide range of frequencies, which may be divided into channels or frequency bins. ...


Military uses

Communications satellites are used for military communications applications, such as Global Command and Control Systems. Military communications are links between battlefield units, including connections to a higher command or home country. ... Global Command and Control System (GCCS, often pronounced GEEKS by the Air Force, Army and Navy, GUCKS by the Marines and in DISA spelled out G-C-C-S) is a system of Command, Control, Communications, Computers, and Intelligence (C4I) systems and applications. ...


See also

Commercialization of space is the use of outer space for the purpose of generating a profit, either by a corporation or state. ... DTN, formerly known as Data Transmission Network, is a subscription-based service for the delivery of real-time weather, agricultural and commodity markets information. ... DVB, short for Digital Video Broadcasting, is a suite of internationally accepted, open standards for digital television maintained by the DVB Project, an industry consortium with more than 300 members, and published by a Joint Technical Committee (JTC) of European Telecommunications Standards Institute (ETSI), European Committee for Electrotechnical Standardization (CENELEC... DigiCipher 2, or simply DCII, is a digital signal compression standard used on many communications satellite television and audio signals. ... Free-space optical communication involves the use of optical links across the space between two points, either within the Earths atmosphere, or in outer space. ... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... ICO Satellite Management, LLC, formerly ICO Global Communications, plans to offer S-band mobile satellite services (MSS) via a satellite in geostationary orbit and auxilliary ground-based relays. ... Intelsat, Ltd. ... The Intersputnik International Organization of Space Communications commonly known as Intersputnik is an international satellite communications services organization founded on November 15, 1971 in Moscow by the Soviet Union along with a group of eight formerly socialist states (Poland, Czechoslovakia, East Germany, Hungary, Romania, Bulgaria, Mongolia, and Cuba). ... An Iridium phone (without the aerial) The Iridium satellite constellation is a system of 66 active communication satellites and spares around the Earth. ... Early milestones in the history of communications satellites. ... This is a list of all companies currently operating at least one commercial communication satellite or currently has one on order. ... The following is a list of types of orbits: // Box orbit Circular orbit Ecliptic orbit Elliptic orbit Highly Elliptical Orbit Graveyard orbit Hohmann transfer orbit Hyperbolic trajectory Inclined orbit Osculating orbit Parabolic trajectory Capture orbit Escape orbit Semi-synchronous orbit Subsynchronous orbit Synchronous orbit Geocentric orbit Geosynchronous orbit Geostationary orbit... MILSTAR satellite. ... Earth-Moon-Earth is a radio communication which relies on the propagation of radio waves from an earth based transmitter directed via reflection from the surface of the moon back to an earth based receiver. ... A spy satellite (officially referred to as a reconnaissance satellite or recon sat) is an Earth observation satellite or communications satellite deployed for military or intelligence applications. ... Sky Digital mini-dish Astros mini-dish. Special dish for up to 16 satellite positions (Ku-band) Satellite dish antenna for C-Band Satellite Dishes installed on an apartment complex A satellite dish is a type of parabolic antenna designed with the specific purpose of transmitting signals to and... A satmodem is a modem used to establish data transfers using a communications satellite as a relay. ... A satellite telephone, satellite phone, or satphone is a mobile phone that communicates directly with orbiting communications satellites. ... Satellite television is television delivered by way of communications satellites, as compared to conventional terrestrial television and cable television. ... // A satellite radio or subscription radio (SR) is a digital radio signal that is broadcast by a communications satellite, which covers a much wider geographical range than terrestrial radio signals. ... Spacebus™ [1] is the name given to a family of geostationary telecommunications satellites developed starting in the 1980’s by Aerospatiale now Thales Alenia Space, in its Space Centre in Cannes Mandelieu. ... The Symphonie satellites[1] are the first communications satellites built by France and Germany and the first in the world which were three-axis stabilized on geostationary orbit. ... A cross-section of a submarine communications cable. ... Syncom (for synchronous communication satellite) started as a 1961 NASA program for active geosynchronous communication satellites, all of which were developed and manufactured by Hughes Space and Communications. ... Teledesic was a 1990s proposal to build a commercial broadband satellite constellation for Internet services. ... TELKOM-2 is a C-band geosynchronous communications satellite built by Orbital for Indonesias state-owned telecommunications company, PT Telekomunikasi Indonesia Tbk (PT Telkom). ... The original Telstar had a roughly spherical shape. ... VSAT is short for Very Small Aperture Terminal. ... X*Press X*Change is an obsolete computer-based newsticker-style newsfeed service that existed during the late 1980s and much of the 1990s. ... Palapa was a series of communication satellites owned by Telkom, an Indonesian telecommunication company. ...

External links


  Results from FactBites:
 
Communications satellite - Wikipedia, the free encyclopedia (2507 words)
A communications satellite (sometimes abbreviated to comsat) is an artificial satellite stationed in space for the purposes of telecommunications.
A satellite in a geostationary orbit appears to be in a fixed position to an earth-based observer.
A direct broadcast satellite is a communications satellite that transmits to small DBS satellite dishes (usually 18" to 24" in diameter).
  More results at FactBites »

 
 

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