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télécommunication par satellite

Sous la rubrique Services de télécommunication par satellite à Bolton ON, des Pages Jaunes, découvrez et comparez rapidement les informations et les coordonnées des entreprises locales qui s'y trouvent. International Telecommunication Union (ITU). A communications satellite is an artificial satellite that relays and amplifies radio telecommunication signals via a transponder; it creates a communication channel between a source transmitter and a receiver at different locations on Earth. Two satellite types are used for North American television and radio: Direct broadcast satellite (DBS), and Fixed Service Satellite (FSS). Télécommunication par satellite et la technologie vsat 1. Il y a maintenant plus de 200 stations terrestres de télécommunication par satellite dispersées dans le monde. This orbit provides a long dwell time over Russian territory as well as over Canada at higher latitudes than geostationary orbits over the equator.[29]. 3. PwC a réalisé une analyse commerciale comprenant une évaluation du marché des services par satellite dans la région et une analyse technique des besoins en matière d'acquisition de systèmes par satellite. Le premier satellite de Télécommunications américain, appelé Project SCORE, a suivi un an plus tard le 18 décembre 1958. In addition, satellites in low earth orbit change their position relative to the ground position quickly. This is carried out under the auspices of the International Telecommunication Union (ITU). THEME: TELECOMUNICATION PAR SATELLITES ET LA TECHNOLOGIE VSAT Présenté par: Joseph KAPOU 2. ($126 bn), Marché global des communications par satellites en 2016, Part des revenus du marché Satcom générée dans le downstream en 2015. Improvements in submarine communications cables through the use of fiber-optics caused some decline in the use of satellites for fixed telephony in the late 20th century. There are two major classes of communications satellites, passive and active. Satellite radio offers audio broadcast services in some countries, notably the United States. In various patterns, these satellites make the trip around earth in anywhere from 2 to 8 hours. The data rate is typically much lower than in satellite Internet access. 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. Après de premières tentatives en 1960 avec le satellite Écho-1, mis au point par J. R. Pierce, ingénieur des Bell Telephone Laboratories, la première transmission réussie a lieu le 11 juillet 1962 avec le satellite Telstar, entre une antenne située dans l'État du Maine (États-Unis) et une autre à Pleumeur-Bodou (Bretagne, France). Tous droits réservés "PwC" fait référence au réseau PwC et/ou à une ou plusieurs de ses entités membres, dont chacune constitue une entité juridique distincte. [22], A direct extension of the passive experiments of Project West Ford was the Lincoln Experimental Satellite program, also conducted by the Lincoln Laboratory on behalf of the United States Department of Defense. Thus, for areas close to the North (and South) Pole, a geostationary satellite may appear below the horizon. Les nombreuses applications dérivées de la communication par satellite assurent des solutions de continuité, de sécurité et d’accessibilité auprès d’entités publiques et privés. Communications satellites are used for television, telephone, radio, internet, and military applications. Its period is one half day, so that the satellite is available for operation over the targeted region for six to nine hours every second revolution. Region 1: Europe, Africa, the Middle East, what was formerly the Soviet Union, and Mongolia, Region 2: North and South America and Greenland, Region 3: Asia (excluding region 1 areas), Australia, and the southwest Pacific, This page was last edited on 19 April 2021, at 20:44. (Elevation is the extent of the satellite's position above the horizon. Remote islands such as Ascension Island, Saint Helena, Diego Garcia, and Easter Island, where no submarine cables are in service, need satellite telephones. Examples of these are the Astra, Eutelsat, and Hotbird spacecraft in orbit over the European continent. A MEO satellite's longer duration of visibility and wider footprint means fewer satellites are needed in a MEO network than a LEO network. The Molniya orbit is highly inclined, guaranteeing good elevation over selected positions during the northern portion of the orbit. [37] Typically military satellites operate in the UHF, SHF (also known as X-band) or EHF (also known as Ka band) frequency bands. [25], When Intelsat was launched, the United States was the only launch source outside of the Soviet Union, who did not participate in the Intelsat agreements. Passive satellites only reflect the signal coming from the source, toward the direction of the receiver. Initially available for broadcast to stationary TV receivers, by 2004 popular mobile direct broadcast applications made their appearance with the arrival of two satellite radio systems in the United States: Sirius and XM Satellite Radio Holdings. Using Global Positioning System (GPS) technology as a reference, these antennas automatically re-aim to the satellite no matter where or how the vehicle (on which the antenna is mounted) is situated. [20], An immediate antecedent of the geostationary satellites was the Hughes Aircraft Company's Syncom 2, launched on 26 July 1963. Le Centre de Télécommunication par Satellite. Thus there is a trade off between the number of satellites and their cost. NASA and ISRO[34][35] have also launched experimental satellites carrying Ka band beacons recently.[36]. The launch of Sputnik 1 was a major step in the exploration of space and rocket development, and marks the beginning of the Space Age.[8]. MEO and LEO are non-geostationary orbit (NGSO). 4. Allocating frequencies to satellite services is a complicated process which requires international coordination and planning. The downlink follows an analogous path. Due to launch costs, most current 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. Spacecom, Maroc Télécommunication par satellite, un nouvel outil de développement au Maroc. 2. Le développement d’activités humaines dans des régions urbaines et rurales entraine un besoin grandissant de développement en Technologies de l’information et de la communication. Optimisation du système de télécommunication par satellite de l'ASECNA (Agence pour la Sécurité de la Navigation Aérienne en Afrique) et Madagascar ( Télécharger le fichier original ) par Romaric GUIGUI-NDACKO Université de Bangui République Centrafricaine - Ingénieur des travaux télécoms 2008 : précédent sommaire suivant This allocation of bands minimizes the risk of signal interference. In areas where tall buildings, bridges, or even parking garages obscure the signal, repeaters can be placed to make the signal available to listeners. As satellites in MEO and LEO orbit the Earth faster, they do not remain visible in the sky to a fixed point on Earth continually like a geostationary satellite, but appear to a ground observer to cross the sky and "set" when they go behind the Earth beyond the visible horizon. Therefore, to provide continuous communications capability with these lower orbits requires a larger number of satellites, so that one of these satellites will always be visible in the sky for transmission of communication signals. The satellite also executed several realtime transmissions before the non-rechargeable batteries failed on 30 December 1958 after 8 hours of actual operation. 86 Bis Quai Blanqui 94140 Alfortville France Tél. • Le besoin croissant de communication entre individus nous a conduit à un développement des artères filaires. In areas with a relatively high population density, it is easier and less expensive to reach the bulk of the population with terrestrial broadcasts. Quels sont les avantages d'une constellation LEO. [12][13], NASA's satellite applications program launched the first artificial satellite used for passive relay communications in Echo 1 on 12 August 1960. Ce satellite utilisait un magnétophone à cassette pour enregistrer et rediffuser des messages vocaux. The Molniya orbit is designed so that the satellite spends the great majority of its time over the far northern latitudes, during which its ground footprint moves only slightly. [10][11], The direct successor to SCORE was another ARPA-led project called Courier. Molniya orbits can be an appealing alternative in such cases. [5] In October 1945, Clarke published an article titled "Extraterrestrial Relays" in the British magazine Wireless World. Une confirmation vous sera envoyée par email à cette adresse. This experiment sought to establish the feasibility of worldwide broadcasts of telephone, radio, and television signals. Nos conclusions ont abouti à une stratégie basée sur des scénarios impliquant l’acquisition de satellites propriétaire, la mise en place de constellations de satellites, la location de capacités ou de services de satellite et un travail en collaboration entre pays européens. Other services, such as Music Choice or Muzak's satellite-delivered content, require a fixed-location receiver and a dish antenna. Des applications vitales pour l’économie globale. Communication signals were bounced off the satellite from one point on Earth to another. ", "Design of the first artificial satellite of the Earth", "United States Aeronautics and Space Activities - 1st Annual Report to Congress", "United States Aeronautics and Space Activities 1960", "TELSTAR 1: The First Satellite to Relay Signals from Earth to Satellite and Back", "United States Aeronautics and Space Activities 1962", "NASA Compendium Of Satellite Communications Programs", "IADC Space Debris Mitigation Guidelines", "Indian GSLV successfully lofts GSAT-14 satellite", "DIRECTV's Spaceway F1 Satellite Launches New Era in High-Definition Programming; Next Generation Satellite Will Initiate Historic Expansion of DIRECTV", India's first 'military' satellite GSAT-7 put into earth's orbit, "Satellite Data Telecommunication Handbook", The future of communication satellite business, Consultative Committee for Space Data Systems, https://en.wikipedia.org/w/index.php?title=Communications_satellite&oldid=1018781591, Telecommunications-related introductions in 1962, Short description is different from Wikidata, Wikipedia articles needing clarification from January 2016, Wikipedia articles with multiple identifiers, Creative Commons Attribution-ShareAlike License, The region below medium orbits is referred to as, In 2013, the first four of a constellation of 20 MEO satellites was launched. 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. Satellite phones connect directly to a constellation of either geostationary or low-Earth-orbit satellites. It 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. Satellite communications also provide connection to the edges of Antarctica and Greenland. In all cases, the antenna must have a clear view to the satellites. [6] The article described the fundamentals behind the deployment of artificial satellites in geostationary orbits for the purpose of relaying radio signals. For example, the satellites in the NPOESS (civilian) orbit will cross the equator, going from south to north, at times 1:30 P.M., 5:30 P.M., and 9:30 P.M. Communications Satellites are usually composed of the following subsystems: The bandwidth available from a satellite depends upon the number of transponders provided by the satellite. To facilitate frequency planning, the world is divided into three regions: Within these regions, frequency bands are allocated to various satellite services, although a given service may be allocated different frequency bands in different regions. In addition, there are important differences in the onboard and ground equipment needed to support the two types of missions. Some of the services provided by satellites are: The first and historically most important application for communication satellites was in intercontinental long distance telephony. Thus, a satellite at the horizon has zero elevation and a satellite directly overhead has elevation of 90 degrees.). De plus, de nouveaux marchés tels que la connectivité en vol, le M2M, et l’Ultra HD, vont maintenir la croissance du secteur des satellites de télécoms. [7], The first artificial Earth satellite was Sputnik 1. Nos partenaires. Amateur radio operators have access to amateur satellites, which have been designed specifically to carry amateur radio traffic. Le satellite est défini, par le Règlement des radiocommunications (RR) de l’UIT, comme un : « corps qui tourne autour d’un autre corps de masse prépondérante et dont le mouvement est principalement déterminé, d’une façon permanente, par… Notices gratuites de Architecture D Un Systeme De Telecommunication Par Satellite PDF Plusieurs de ces constellations fournissent des services de téléphonie (La téléphonie est un système de télécommunication qui a pour but la transmission de son et en...) sans fil par satellite… MEO satellites are visible for much longer periods of time than LEO satellites, usually between 2 and 8 hours. Typically the orbit of a medium earth orbit satellite is about 16,000 kilometres (10,000 mi) above earth. A group of satellites working in concert is known as a satellite constellation. L’environnement commercial international du secteur des satellites de télécommunication est relativement stable avec peu d’acteurs détenant la majorité des parts de marché. Pour plus de détails, il vous suffit de nous contacter : ... Télécommunication par satellite Détails Visioconférence Détails Ingénierie Informatique Détails. Some satellites also provide data-forwarding services using the X.25 or similar protocols. Ce document a été mis à jour le 27/05/2013 Dans le cadre de notre réseau PwC - Stratégie et réseau, PwC travaille avec l'industrie de la communication par satellite, comprenant les acteurs déjà établis tout comme les acteurs du NewSpace, Photo: NASA | ESA | CNES | SpaceX | Blue Origin | RocketLab | Maxar Technologies, Associé Consulting - Responsable activité spatiale, PwC France et Maghreb, © 2012 - 2021 PwC. TS : Télécommunication par satellite SEA : Sciences spatiales et sciences de l’atmosphère T&SIG : Télédétection et Systèmes d’information Géographique This is typically known as link budgeting and a network simulator can be used to arrive at the exact value. Satellite phone systems can be accomplished by a number of means. Le centre de télécommunication par satellite de Pleumeur-Bodou (CTS), situé dans les Côtes-d'Armor, est le téléport à l'origine de la première transmission télévisée en mondovision via le satellite … La technologie VSAT. Une telle croissance et ampleur est basée sur plusieurs indicateurs tels que la masse totale envoyée en orbite ainsi que les revenus générés par les acteurs du secteur. Examples of military systems that use communication satellites are the MILSTAR, the DSCS, and the FLTSATCOM of the United States, NATO satellites, United Kingdom satellites (for instance Skynet), and satellites of the former Soviet Union. There are also regions of some continents and countries where landline telecommunications are rare to nonexistent, for example large regions of South America, Africa, Canada, China, Russia, and Australia. TELECOMMUNICATIONS PAR SATELLITE APPLICATIONS MILITAIRES date 28/02/2011 Page 5 •1945 : Arthur C. Clarke introduit le concept de communication par satellite. This will be the case with the CASCADE system of Canada's CASSIOPE communications satellite. [2] Most communications satellites are in geostationary orbit 22,236 miles (35,785 km) above the equator, so that the satellite appears stationary at the same point in the sky; therefore the satellite dish antennas of ground stations can be aimed permanently at that spot and do not have to move to track the satellite. Fixed Service Satellites use the C band, and the lower portions of the Ku band. Like LEOs, these satellites do not maintain a stationary distance from the earth. Les télécommunications par satellite sont l’aboutissement de recherches techniques et économiques visant à réaliser des communications de capacités toujours plus grandes à des coûts les plus faibles, face à la concurrence exercée par la fibre optique et … 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. Courier 1B was launched on 4 October 1960 to explore whether it would be possible to establish a global military communications network by using "delayed repeater" satellites, which receive and store information until commanded to rebroadcast them. In this way a constellation of three Molniya satellites (plus in-orbit spares) can provide uninterrupted coverage. GLOSSIAIRE. au Professeur Marcelo Kohen, co-directeur de thèse, qui m’a guidée par la pertinence et la qualité de ses remarques et soutenue par ses encouragements tout au long de mon travail. Une visite à la station terrestre de télécommunication par satellite de BT est une expérience véritablement impressionnante. L’utilisation des satellites de communications (satcoms) a connu une croissance fulgurante ces 50 dernières années pour devenir aujourd’hui le secteur le plus important de l’industrie spatiale. The various services are proprietary signals, requiring specialized hardware for decoding and playback. There are also services that will patch a radio signal to a telephone system. Les satellites de télécommunications sont essentiels à un large panel d’activités commerciales, gouvernementales, et de loisirs. Because of their low altitude, these satellites are only visible from within a radius of roughly 1,000 kilometres (620 mi) from the sub-satellite point. These mobile satellite antennas are popular with some recreational vehicle owners. [21] Its successor, Syncom 3, launched on 19 July 1964, was the first geostationary communications satellite. [clarification needed], A low Earth orbit (LEO) typically is a circular orbit about 160 to 2,000 kilometres (99 to 1,243 mi) above the earth's surface and, correspondingly, a period (time to revolve around the earth) of about 90 minutes.[30]. DBS technology is used for DTH-oriented (Direct-To-Home) satellite TV services, such as DirecTV, DISH Network and Orby TV[33] in the United States, Bell Satellite TV and Shaw Direct in Canada, Freesat and Sky in the UK, Ireland, and New Zealand and DSTV in South Africa. Even though only about half of the dipoles properly separated from each other,[19] the project was able to successfully experiment and communicate using frequencies in the SHF X band spectrum. Les systèmes de communication par satellite appliqués au SCS des pêches utilisent des satellites géostationnaires ou orbitaux. [4], The concept of the geostationary communications satellite was first proposed by Arthur C. Clarke, along with Mikhail Tikhonravov and Sergey Korolev building on work by Konstantin Tsiolkovsky. On November 9, 1972, Canada's first geostationary satellite serving the continent, On May 30, 1974, the first geostationary communications satellite in the world to be, After the launches of the Telstar through Westar 1 satellites, RCA Americom (later GE Americom, now, Communication Payload, normally composed of, Engines used to bring the satellite to its desired orbit, Power subsystem, used to power the Satellite systems, normally composed of. Ships at sea, as well as planes, often use satellite phones.[32]. Dans le cadre … Historiquement, le contrôle des satellites de télécommunication étaient effectué par des agences publiques gouvernementales et intergouvernementales. Because of this, the terms FSS and DBS are more so used throughout the North American continent, and are uncommon in Europe. Il peut utiliser une orbite géostationnaire, une orbite polaire basse ou une orbite de Molniya.. Pour des services fixes, les satellites de communications apportent une technologie complémentaire à la fibre optique qui compose les câbles sous-marins. Syncom 2 was the first communications satellite in a geosynchronous orbit. Each service (TV, Voice, Internet, radio) requires a different amount of bandwidth for transmission. By 2000, Hughes Space and Communications (now Boeing Satellite Development Center) had built nearly 40 percent of the more than one hundred satellites in service worldwide. 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. Command and Control subsystem, which maintains communications with ground control stations. However, due to their relatively small distance to the Earth their signals are stronger. [38][39] It may be based on a secondary payload of a weather satellite (as in the case of GOES and METEOSAT and others in the Argos system) or in dedicated satellites (such as SCD). The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated geographical points. Communications satellites usually have one of three primary types of orbit, while other orbital classifications are used to further specify orbital details. L’évolution des exigences des utilisateurs privés comme publics, engendre la nécessité de redéfinir les stratégies de développement des acteurs du domaine des télécommunications. Puis le secteur a traversé un processus de privatisation en Amérique du Nord et en Europe pour être de nos jours contrôlé dans sa quasi-totalité par des opérateurs privés. Radio services are usually provided by commercial ventures and are subscription-based. [26][27] Subsequent Intelsat launches in the 1960s provided multi-destination service and video, audio, and data service to ships at sea (Intelsat 2 in 1966–67), and the completion of a fully global network with Intelsat 3 in 1969–70. Other land use for satellite phones are rigs at sea, a back up for hospitals, military, and recreation. [25] The Soviet Union launched its first communications satellite on 23 April 1965 as part of the Molniya program. Military planners had long shown considerable interest in secure and reliable communications lines as a tactical necessity, and the ultimate goal of this project was the creation of the longest communications circuit in human history, with the moon, Earth's natural satellite, acting as a passive relay. After achieving the first transoceanic communication between Washington, D.C. and Hawaii on 23 January 1956, this system was publicly inaugurated and put into formal production in January 1960. Since the satellite is so far above Earth, the radio signal is attenuated due to free-space path loss, so the signal received on Earth is very, very weak. 1. A direct broadcast satellite is a communications satellite that transmits to small DBS satellite dishes (usually 18 to 24 inches or 45 to 60 cm in diameter). 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. 9 mile(s) from Goonhilly Earth Station, A visit to BT's satellite earth station is a truly awe-inspiring experience. CONCLUSION ANNEXES. Thus, Arthur C. Clarke is often quoted as being the inventor of the concept of the communications satellite, as well as the term 'Clarke Belt' employed as a description of the orbit. Le premier satellite artificiel, le Spoutnik 1, équipé d'un émetteur radio embarqué, a été lancé par l'URSS le 4 octobre 1957. This is in contrast to the geostationary orbit, where satellites are always 35,786 kilometres (22,236 mi) from the earth. This is because it revolves around the Earth at Earth's own angular velocity (one revolution per sidereal day, in an equatorial orbit). In this example, almost any type of satellite can be used. [4] Passive satellites were the first communications satellites, but are little used now. Satellite communications are still used in many applications today. A total of nine satellites were launched between 1965 and 1976 as part of this series. Avec l’ouverture du Maroc sur le marché international, le secteur des télécommunications est appelé à avancer à grands pas afin de pouvoir soutenir le développement économique du pays. Les centraux locaux transportent les appels jusqu'à une station terrienne (aussi appelée téléport), d'où ils sont émis en direction d'un satellite géostationnaire. Calls are then forwarded to a satellite teleport connected to the Public Switched Telephone Network . Historique. [23][24], In the United States, 1962 saw the creation of the Communications Satellite Corporation (COMSAT) private corporation, which was subject to instruction by the US Government on matters of national policy. Some satellites have been launched that have transponders in the Ka band, such as DirecTV's SPACEWAY-1 satellite, and Anik F2. Avec plus de 700 satellites en orbite dédiés aux télécommunications, le secteur spatial joue un rôle primordial dans la réponse aux besoins croissants de connectivité. The ground control Earth stations monitor the satellite performance and control its functionality during various phases of its life-cycle. Nombre de satellites de communication en orbite en 2017, €119 bn La télécommunication par satellite présente quelques propriétés importantes par rapport aux réseaux terrestres, citer les. Free-to-air satellite TV channels are also usually distributed on FSS satellites in the Ku band. In applications that require many ground antennas, such as DirecTV distribution, the savings in ground equipment can more than outweigh the cost and complexity of placing a satellite into orbit. [9], The first satellite purpose-built to actively relay communications was Project SCORE, led by Advanced Research Projects Agency (ARPA) and launched on 18 December 1958, which used a tape recorder to carry a stored voice message, as well as to receive, store, and retransmit messages. [3] Communications satellites use a wide range of radio and microwave frequencies. Pour plus d'information, rendez-vous sur le site www.pwc.com/structure, Surveillance et sécurité des objets spatiaux, L’utilisation première des infrastructures spatiales, Des applications vitales pour l’économie globale, Des marchés prometteurs qui restent à développer, Un marché ouvert à la compétition internationale, Enjeux commerciaux et technologique issus d’une demande croissante de capacité, Évaluation des besoins en capacité de communication par satellite des services d'urgence, Conseil stratégique et technique pour une société satellitaire en expansion en Afrique et au Moyen-Orient, Analyses de rentabilisation des stratégies novatrices de mise en marché auprès d’opérateurs de satellites, Etudes de cas de constellations de satellites, Analyses de potentiel du marché secondaire pour opérateur satcom, Évaluation du potentiel de croissance externe des acteurs satellites résultant des stratégies de diversification, Évaluation de l'impact potentiel de nouvelles plateformes sur l'industrie manufacturière des satcoms, comme les drones de haute altitude et les ballons, Évaluation des impacts des programmes gouvernementaux de satcom, Evaluation et optimisation de la performance technique et économique du portefeuille de produits, Déploiement des meilleures pratiques de cout de conception, Mise en place de modèles d'ingénierie «good-enough», Ingénierie système par gestion des exigences et de la configuration, Définition des leviers favorisant la collaboration entre les opérateurs de satellites et les acheteurs de capacité, Analyse d'impact de l'utilisation d'outils numériques pour soutenir la production en séries de méga-constellations. Même concurrencée par les câbles optiques terrestres ou sous-marins, l'application qui est toujours la plus importante pour les satellites de communication est la téléphonie internationale. a) Definition. As 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. L’offre de PwC permet d’accompagner nos interlocuteurs face aux évolutions du domaine, à travers notamment l’analyse des impacts du déploiement de méga-constellations, l’évaluation des besoins spécifiques en terme de communications gouvernementales, ou encore la définition d’une stratégie de diversification pour les opérateurs privés. Two such constellations, intended to provide satellite phone services, primarily to remote areas, are the Iridium and Globalstar systems. Syncom 3 obtained a geosynchronous orbit, without a north–south motion, making it appear from the ground as a stationary object in the sky. PwC a travaillé avec la Commission européenne à l'évaluation des besoins, à la conception et à la mise en œuvre d'un nouveau programme phare au même niveau de Galileo et Copernicus dédié aux communications par satellite sécurisées pour les organisations de services d'urgence (maritime, policière, civile, humanitaire et Services d'action extérieure). It was also used in its Ku band form for the now-defunct Primestar satellite TV service. Direct broadcast satellites generally operate in the upper portion of the microwave Ku band.

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