Satellite television is a service that delivers television programming to viewers by relaying it from a communications satellite orbiting the Earth directly to the viewer's location. The signals are received via an outdoor parabolic antenna commonly referred to as a satellite dish and a low-noise block downconverter .
85-704: SKYNET Direct to Home (DTH), is a pay TV operator that provides nationwide satellite television in Myanmar . Owner Shwe Than Lwin Media Co., Ltd. is part of a conglomerate with diverse interests in Myanmar, they launched the broadcaster in November 2010. SKYNET DTH broadcasts a total 80 channels via Apstar 7 satellite, provide internet services in the Pacific Asia region, and employ more than 2000 staff. Owner and chairman of SKYNET DTH
170-489: 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-tuned oscillator with some filter circuitry) for downconversion to an intermediate frequency. The channel selection
255-470: 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
340-528: A limited radio frequency bandwidth in a defined geographic area. It may for example be defined as the maximum aggregated throughput or goodput , i.e. summed over all users in the system, divided by the channel bandwidth and by the covered area or number of base station sites. This measure is affected not only by the single-user transmission technique, but also by multiple access schemes and radio resource management techniques utilized. It can be substantially improved by dynamic radio resource management . If it
425-408: A maximum symbol rate of W symbols/s, and in that the modulation efficiency can not exceed N (bit/s)/Hz. If digital single-sideband modulation is used, the passband signal with bandwidth W corresponds to a baseband message signal with baseband bandwidth W , resulting in a maximum symbol rate of 2 W and an attainable modulation efficiency of 2 N (bit/s)/Hz. If a forward error correction code
510-572: 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 K u -band satellites simultaneously. 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
595-414: A rooftop parabolic receiving dish (" satellite dish "), which reflects the weak signal to the dish's focal point. Mounted on brackets at the dish's focal point is a feedhorn which passes the signals through a waveguide to a device called a low-noise block converter (LNB) or low noise converter (LNC) attached to the horn. The LNB amplifies the weak signals, filters the block of frequencies in which
680-694: 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
765-481: A single channel or single user. However, the fact that one can "layer" multiple channels on the same frequency band means that the system spectrum utilization for a multi-channel CDMA system can be very good. The spectral efficiency can be improved by radio resource management techniques such as efficient fixed or dynamic channel allocation , power control , link adaptation and diversity schemes . A combined fairness measure and system spectral efficiency measure
850-487: A single dish) pointing to different satellites. A common solution for consumers wanting to access multiple satellites is to deploy a single dish with a single LNB and to rotate the dish using an electric motor. The axis of rotation has to be set up in the north–south direction and, depending on the geographical location of the dish, have a specific vertical tilt. Set up properly the motorized dish when turned will sweep across all possible positions for satellites lined up along
935-445: 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 K u 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
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#17328479299301020-402: A special type of LNB. There are also LNBs available with a multi-switch already integrated. This problem becomes more complicated when several receivers use several dishes or several LNBs mounted in a single dish are aimed at different satellites. The set-top box selects the channel desired by the user by filtering that channel from the multiple channels received from the satellite, converts
1105-420: A specific frequency range, so as to be received by one of the transponders tuned to that frequency range aboard that satellite. The transponder then converts the signals to K u band , a process known as "translation," and transmits them back to earth to be received by home satellite stations. The downlinked satellite signal, weaker after traveling the great distance (see path loss ), is collected by using
1190-412: 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. Uplink facilities transmit the signal to
1275-529: A transponder is transmitting at and on what polarisation it is using, the satellite receiver has to switch the LNB into one of four different modes in order to receive a specific desired program on a specific transponder. The receiver uses the DiSEqC protocol to control the LNB mode, which handles this. If several satellite receivers are to be attached to a single dish a so-called multiswitch must be used in conjunction with
1360-457: A wider frequency range of 2–2150 MHz. The satellite receiver or set-top box demodulates and converts the signals to the desired form (outputs for television, audio, data, etc.). Often, the receiver includes the capability to selectively unscramble or decrypt the received signal to provide premium services to some subscribers; the receiver is then called an integrated receiver/decoder or IRD. Low-loss cable (e.g. RG-6 , RG-11 , etc.)
1445-503: A wireless network, high link spectral efficiency may result in high sensitivity to co-channel interference (crosstalk), which affects the capacity. For example, in a cellular telephone network with frequency reuse, spectrum spreading and forward error correction reduce the spectral efficiency in (bit/s)/Hz but substantially lower the required signal-to-noise ratio in comparison to non-spread spectrum techniques. This can allow for much denser geographical frequency reuse that compensates for
1530-567: Is Sino-Burmese businessman, Kyaw Win. Launching SKYNET DTH with 24 channels, including Spanish La Liga , Italian Serie A , German Bundesliga , French Ligue 1 , Hero I-League , Indian Super League , American Major League Soccer , Australian A-League , NBA , CCL , Saudi Professional League , Saudi Super Cup , Myanmar National League and other sports and entertainment and expanding to 80 channels with media rights for competitions held by UEFA ( Euro 2012 , UEFA Champions League , Europa League ). SKYNET DTH started broadcasting all matches of
1615-401: Is Walt Disney Asia Pacific), Lifetime, CNN, BBC and more. As of June 2024, the total number of channels is 80. Satellite television A satellite receiver decodes the desired television program for viewing on a television set . Receivers can be external set-top boxes , or a built-in television tuner . Satellite television provides a wide range of channels and services. It is usually
1700-440: Is also affected by the source coding (data compression) scheme. It may be used in analog cellular networks as well. Low link spectral efficiency in (bit/s)/Hz does not necessarily mean that an encoding scheme is inefficient from a system spectral efficiency point of view. As an example, consider Code Division Multiplexed Access (CDMA) spread spectrum , which is not a particularly spectral-efficient encoding scheme when considering
1785-414: 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. Depending on which frequency and polarization a transponder is using, the satellite receiver has to switch the LNB into one of four different modes in order to receive a specific "channel". This
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#17328479299301870-490: Is defined as a measure of the maximum goodput, retransmissions due to co-channel interference and collisions are excluded. Higher-layer protocol overhead (above the media access control sublayer) is normally neglected. The system spectral efficiency of a cellular network may also be expressed as the maximum number of simultaneous phone calls per area unit over 1 MHz frequency spectrum in E /MHz per cell , E/MHz per sector , E/MHz per site , or (E/MHz)/m . This measure
1955-441: 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
2040-425: Is handled by the receiver using the DiSEqC protocol to control the LNB mode. If several satellite receivers are to be attached to a single dish, a so-called multiswitch will have to be used in conjunction with a special type of LNB. There are also LNBs available with a multi-switch already integrated. This problem becomes more complicated when several receivers are to use several dishes (or several LNBs mounted in
2125-413: Is not a factor, the largest link spectral efficiency that can be supported by the available SNR is generally used. In digital wireless networks , the system spectral efficiency or area spectral efficiency is typically measured in (bit/s)/Hz per unit area , in (bit/s)/Hz per cell , or in (bit/s)/Hz per site . It is a measure of the quantity of users or services that can be simultaneously supported by
2210-773: Is referred to as baseband . This baseband comprises the video signal and the audio subcarrier(s). The audio subcarrier is further demodulated to provide a raw audio signal. Later signals were digitized television signals or multiplex of signals, typically QPSK . In general, digital television, including that transmitted via satellites, is based on open standards such as MPEG and DVB-S / DVB-S2 or ISDB-S . The conditional access encryption/scrambling methods include NDS , BISS , Conax , Digicipher , Irdeto, Cryptoworks , DG Crypt , Beta digital , SECA Mediaguard , Logiways , Nagravision , PowerVu , Viaccess , Videocipher , and VideoGuard . Many conditional access systems have been compromised. An event called sun outage occurs when
2295-452: Is the net bit rate (useful information rate excluding error-correcting codes ) or maximum throughput divided by the bandwidth in hertz of a communication channel or a data link . Alternatively, the spectral efficiency may be measured in bit/symbol , which is equivalent to bits per channel use ( bpcu ), implying that the net bit rate is divided by the symbol rate (modulation rate) or line code pulse rate. Link spectral efficiency
2380-473: Is the only remaining satellite broadcasting in analog signals. The satellites used for broadcasting television are usually in a geostationary orbit 36,000 km (22,000 mi) 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
2465-433: Is typically used to analyze the efficiency of a digital modulation method or line code , sometimes in combination with a forward error correction (FEC) code and other physical layer overhead. In the latter case, a "bit" refers to a user data bit; FEC overhead is always excluded. The modulation efficiency in bit/s is the gross bit rate (including any error-correcting code) divided by the bandwidth. An upper bound for
2550-464: Is used to connect the receiver to the LNBF or LNB. RG-59 is not recommended for this application as it is not technically designed to carry frequencies above 950 MHz, but may work in some circumstances, depending on the quality of the coaxial wire, signal levels, cable length, etc. A practical problem relating to home satellite reception is that an LNB can basically only handle a single receiver. This
2635-528: Is used, the spectral efficiency is reduced from the uncoded modulation efficiency figure. An upper bound for the spectral efficiency possible without bit errors in a channel with a certain SNR, if ideal error coding and modulation is assumed, is given by the Shannon–Hartley theorem . Note that the goodput (the amount of application layer useful information) is normally lower than the maximum throughput used in
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2720-650: The Relay 1 satellite was the first satellite to transmit television signals from the US to Japan. 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 . The world's first commercial communications satellite, called Intelsat I and nicknamed "Early Bird",
2805-638: The Air KBZ Myanmar Lethwei World Championship, Premier League , IPL from the 2013-14 season after acquiring rights from FA. SKYNET DTH also have media rights of FIFA competitions, enabling SKYNET to broadcast live the FIFA World Cup 2018 . It also has media rights to all of WWE , which broadcasts RAW , Smack Down Live , NXT and other pay-per-view shows from WWE. The 2021 Myanmar coup d'état saw SKYNET DTH stop broadcasting some international channels, like Fox Network (now
2890-563: 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
2975-537: The C-band (4–8 GHz) from FSS type satellites, requiring the use of large 2–3-meter dishes. Consequently, these systems were nicknamed "big dish" systems, and were more expensive and less popular. Early systems used analog signals , but modern ones use digital signals which allow transmission of the modern television standard high-definition television , due to the significantly improved spectral efficiency of digital broadcasting. As of 2022, Star One D2 from Brazil
3060-481: The C-band frequencies and the dishes required were large; typically over 3 meters (10 ft) 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 K u -band transponders on FSS -type satellites. The higher frequency K u -band systems tend to resemble DBS systems and can use
3145-573: 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. On October 18, 1979, the Federal Communications Commission (FCC) began allowing people to have home satellite earth stations without a federal government license. The front cover of
3230-618: The attack on HBO's transponder Galaxy 1 by John R. MacDougall in April 1986. One by one, all commercial channels followed HBO's lead and began scrambling their channels. The Satellite Broadcasting and Communications Association (SBCA) was founded on December 2, 1986, as the result of a merger between SPACE and the Direct Broadcast Satellite Association (DBSA). Spectral efficiency Spectral efficiency , spectrum efficiency or bandwidth efficiency refers to
3315-405: The geostationary orbit directly above the equator. The dish will then be capable of receiving any geostationary satellite that is visible at the specific location, i.e. that is above the horizon. The DiSEqC protocol has been extended to encompass commands for steering dish rotors. There are five major components in a satellite system: the programming source, the broadcast center, the satellite,
3400-456: The information rate that can be transmitted over a given bandwidth in a specific communication system. It is a measure of how efficiently a limited frequency spectrum is utilized by the physical layer protocol, and sometimes by the medium access control (the channel access protocol). The link spectral efficiency of a digital communication system is measured in bit / s / Hz , or, less frequently but unambiguously, in (bit/s)/Hz . It
3485-466: The intermediate frequency ranges of 950–2150 MHz to carry the signal from the LNBF at the dish down to the receiver. This allows for the transmission of UHF signals along the same span of coaxial wire at the same time. In some applications ( DirecTV AU9-S and AT-9), ranges of the lower B-band and 2250–3000 MHz, are used. Newer LNBFs in use by DirecTV, called SWM (Single Wire Multiswitch), are used to implement single cable distribution and use
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3570-469: The satellite dish , and the receiver . "Direct broadcast" satellites used for transmission of satellite television signals are generally in geostationary orbit 37,000 km (23,000 mi) above the earth's equator . 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
3655-507: The symbol rate can not exceed 2 B symbols/s in view to avoid intersymbol interference . Thus, the spectral efficiency can not exceed 2 N (bit/s)/Hz in the baseband transmission case. In the passband transmission case, a signal with passband bandwidth W can be converted to an equivalent baseband signal (using undersampling or a superheterodyne receiver ), with upper cut-off frequency W /2. If double-sideband modulation schemes such as QAM , ASK , PSK or OFDM are used, this results in
3740-496: The 10.7-12.7 GHz band, but some still transmit in the C-band (4–8 GHz), K u -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 K u -band or 24 C-band transponders, or more for K u / 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
3825-424: The 1979 Neiman-Marcus Christmas catalogue featured the first home satellite TV stations on sale for $ 36,500. The dishes were nearly 20 feet (6.1 m) 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,
3910-578: The US most condominiums, neighborhoods, and other homeowner associations tightly restricted their use, except in areas where such restrictions were illegal. These restrictions were altered in 1986 when the Federal Communications Commission ruled all of them illegal. 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. The necessity of these restrictions would slowly decline as
3995-427: The above calculations, because of packet retransmissions, higher protocol layer overhead, flow control, congestion avoidance, etc. On the other hand, a data compression scheme, such as the V.44 or V.42bis compression used in telephone modems, may however give higher goodput if the transferred data is not already efficiently compressed. The link spectral efficiency of a wireless telephony link may also be expressed as
4080-466: The attainable modulation efficiency is given by the Nyquist rate or Hartley's law as follows: For a signaling alphabet with M alternative symbols, each symbol represents N = log 2 M bits. N is the modulation efficiency measured in bit/symbol or bpcu . In the case of baseband transmission ( line coding or pulse-amplitude modulation ) with a baseband bandwidth (or upper cut-off frequency) B ,
4165-480: 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
4250-457: The company reactivates it. Some receivers are capable of decrypting the received signal itself. These receivers are called integrated receiver/decoders or IRDs. Analog television which was distributed via satellite was usually sent scrambled or unscrambled in NTSC , PAL , or SECAM television broadcast standards. The analog signal is frequency modulated and is converted from an FM signal to what
4335-544: 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
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#17328479299304420-519: 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
4505-526: The dishes got smaller. Originally, all channels were broadcast in the clear (ITC) because the equipment necessary to receive the programming was too expensive for consumers. With the growing number of TVRO systems, the program providers and broadcasters had to scramble their signal and develop subscription systems. In October 1984, the U.S. Congress passed the Cable Communications Policy Act of 1984 , which gave those using TVRO systems
4590-691: 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 K u 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
4675-565: The first satellite in history. 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. Launched in 1962,
4760-534: 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
4845-488: The indoor receiver to the satellite television dish and LNB, and that the technology for handling the signal at L-band and UHF was far cheaper than that for handling the signal at C-band frequencies. 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
4930-501: The lower link spectral efficiency, resulting in approximately the same capacity (the same number of simultaneous phone calls) over the same bandwidth, using the same number of base station transmitters. As discussed below, a more relevant measure for wireless networks would be system spectral efficiency in bit/s/Hz per unit area. However, in closed communication links such as telephone lines and cable TV networks, and in noise-limited wireless communication system where co-channel interference
5015-471: 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 . The term television receive-only , or TVRO, arose during
5100-417: 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
5185-432: The maximum number of simultaneous calls over 1 MHz frequency spectrum in erlangs per megahertz, or E /MHz . This measure is also affected by the source coding (data compression) scheme. It may be applied to analog as well as digital transmission. In wireless networks, the link spectral efficiency can be somewhat misleading, as larger values are not necessarily more efficient in their overall use of radio spectrum. In
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#17328479299305270-432: The next satellite to avoid interference; for K u 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 K u -band satellites. C-band transmission is susceptible to terrestrial interference while K u -band transmission is affected by rain (as water is an excellent absorber of microwaves at this particular frequency). The latter
5355-404: The only television available in many remote geographic areas without terrestrial television or cable television service. Different receivers are required for the two types. Some transmissions and channels are unencrypted and therefore free-to-air , while many other channels are transmitted with encryption. Free-to-view channels are encrypted but not charged-for, while pay television requires
5440-475: The quality of the coaxial wire. The shift to more affordable technology from the 50 ohm impedance cable and N-connectors of the early C-band systems to the cheaper 75 ohm technology 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 another lower intermediate frequency centered on 70 MHz where it
5525-493: The residence using cheap coaxial cable . To transport the signal into the house at its original K u band microwave frequency would require an expensive waveguide , a metal pipe to carry the radio waves. The cable connecting the receiver to the LNB are of the low loss type RG-6 , quad shield RG-6, or RG-11. 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
5610-466: The right to receive signals for free unless they were scrambled, and required those who did scramble to make their signals available for a reasonable fee. 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
5695-434: The satellite over a narrow beam of microwaves , typically in the C-band frequency range due to its resistance to rain fade . Uplink satellite dishes are very large, often as much as 9 to 12 metres (30 to 40 feet) in diameter to achieve accurate aiming and increased signal strength at the satellite, to improve reliability. The uplink dish is pointed toward a specific satellite and the uplinked signals are transmitted within
5780-475: The satellite television channel for down conversion to a lower intermediate frequency centered on 70 MHz, where it was demodulated. This shift allowed the satellite television DTH industry to change from being a largely hobbyist one where only small numbers of systems costing thousands of US dollars were built, to a far more commercial one of mass production. In the United States, service providers use
5865-404: The satellite television signals are transmitted, and converts the block of frequencies to a lower frequency range in the L-band range. The signal is then passed through a coaxial cable into the residence to the satellite television receiver, a set-top box next to the television. The reason for using the LNB to do the frequency translation at the dish is so that the signal can be carried into
5950-718: The satellite's transponders drowns out reception. 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. Signals are transmitted using K u band (12 to 18 GHz) and are completely digital which means it has high picture and stereo sound quality. 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
6035-428: 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
6120-603: 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 9 to 12 meters (30 to 40 feet) in diameter. The increased diameter results in more accurate aiming and increased signal strength at
6205-409: The signal to a lower intermediate frequency , decrypts the encrypted signal, demodulates the radio signal and sends the resulting video signal to the television through a cable. To decrypt the signal the receiver box must be "activated" by the satellite company. If the customer fails to pay their monthly bill the box is "deactivated" by a signal from the company, and the system will not work until
6290-418: The sun lines up directly behind the satellite in the field of view of the receiving satellite dish. 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
6375-417: 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
6460-471: The use of gallium arsenide FET technology enabled the use of smaller dishes. Five hundred thousand systems, some costing as little as $ 2000, were sold in the US in 1984. Dishes pointing to one satellite were even cheaper. People in areas without local broadcast stations or cable television service could obtain good-quality reception with no monthly fees. The large dishes were a subject of much consternation, as many people considered them eyesores , and in
6545-433: The viewer to subscribe and pay a monthly fee to receive the programming. Modern systems signals are relayed from a communications satellite on the X band (8–12 GHz) or K u band (12–18 GHz) frequencies requiring only a small dish less than a meter in diameter. The first satellite TV systems were a now-obsolete type known as television receive-only . These systems received weaker analog signals transmitted in
6630-633: Was Canada 's geostationary Anik 1 , which was launched on 9 November 1972. 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
6715-473: Was controlled typically by a voltage tuned oscillator with the tuning voltage being fed via a separate cable to the headend, but this design evolved. Designs for microstrip -based converters for amateur radio frequencies were adapted for the 4 GHz C-band . Central to these designs was concept of block downconversion of a range of frequencies to a lower, more easily handled IF. The advantages of using an LNB are that cheaper cable can be used to connect
6800-399: Was demodulated. An LNB can only handle a single receiver. This is due to the fact that the LNB is mapping two different circular polarisations – right hand and left hand – and in the case of the K u -band two different reception bands – lower and upper – to one and the same frequency band on the cable, and is a practical problem for home satellite reception. Depending on which frequency
6885-432: Was established in 1980. Early satellite television systems were not very popular due to their expense and large dish size. The satellite television dishes of the systems in the late 1970s and early 1980s were 10 to 16 feet (3.0 to 4.9 m) in diameter, made of fibreglass or solid aluminum or steel , and in the United States cost more than $ 5,000, sometimes as much as $ 10,000. Programming sent from ground stations
6970-519: 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. The first domestic satellite to carry television transmissions
7055-445: 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. Eventually HBO allowed dish owners to subscribe directly to their service for $ 12.95 per month, a price equal to or higher than what cable subscribers were paying, and required a descrambler to be purchased for $ 395. This led to
7140-519: 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
7225-631: Was relayed from eighteen satellites in geostationary orbit located 22,300 miles (35,900 km) above the Earth. 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 . Between 1981 and 1985, TVRO systems' sales rates increased as prices fell. Advances in receiver technology and
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