Satellite tv for pc tv is a system of supplyingtelevision programming utilizing broadcast alerts relayed from communication satellites.
Thesignals are acquired through an outside parabolic reflector antenna normally known as asatellite dish and a low-noise block downconverter.
A satellite tv for pc receiver then decodes the desiredtelevision programme for viewing on a tv set.
Receivers might be exterior set-top packing containers,or a built-in tv tuner.
Satellite tv for pc tv offers a variety of channelsand companies, particularly to geographic areas with out terrestrial tv or cable tv.
The direct-broadcast satellite tv for pc tv sign might be both older analogue alerts,or newer digital alerts, each of which require a suitable receiver.
Digital alerts mayinclude high-definition tv.
Some transmissions and channels are free-to-air or free-to-view,whereas many different channels are pay tv requiring a subscription.
Know-how Satellite tv for pcs used for tv alerts aregenerally in both naturally extremely elliptical or geostationary orbit 37,000 km above theearth's equator.
Satellite tv for pc tv, like different communicationsrelayed by satellite tv for pc, begins with a transmitting antenna positioned at an uplink facility.
Uplinksatellite dishes are very massive, as a lot as 9 to 12 meters in diameter.
The increaseddiameter ends in extra correct aiming and elevated sign energy on the satellite tv for pc.
The uplink dish is pointed towards a particular satellite tv for pc and the uplinked alerts are transmittedwithin a particular frequency vary, in order to be acquired by one of many transponders tunedto that frequency vary aboard that satellite tv for pc.
The transponder 'retransmits' the signalsback to Earth however at a unique frequency band, sometimes within the C-band or Ku-band orboth.
The leg of the sign path from the satellite tv for pc to the receiving Earth station iscalled the downlink.
A typical satellite tv for pc has as much as 32 transpondersfor Ku-band and as much as 24 for a C-band solely satellite tv for pc, or extra for hybrid satellites.
Typical transponders every have a bandwidth between 27 and 50 MHz.
Every geostationaryC-band satellite tv for pc must be spaced 2° from the subsequent satellite tv for pc to keep away from interference;for Ku the spacing might be 1°.
Because of this there’s an higher restrict of 360/2 = 180geostationary C-band satellites or 360/1 = 360 geostationary Ku-band satellites.
C-band transmissionis prone to terrestrial interference whereas Ku-band transmission is affected byrain.
The latter is much more adversely affected by ice crystals in thunder clouds.
From time to time, solar outage will happen when the solar traces up instantly behind the geostationarysatellite the reception antenna is pointing to.
This can occur twice a yr at aroundmidday for a two-week interval within the spring and within the fall, and impacts each the C-bandand the Ku-band.
The road-up swamps out all reception for a couple of minutes as a result of sunemitting microwaves on the identical frequencies utilized by the satellite tv for pc's transponders.
The downlinked satellite tv for pc sign, fairly weak after touring the nice distance, is collectedwith a parabolic receiving dish, which displays the weak sign to the dish's focus.
Mounted on brackets on the dish's focus is a tool referred to as a feedhorn or collector.
The feedhorn is basically the flared front-end of a bit of waveguide that gathers thesignals at or close to the point of interest and 'conducts' them to a probe or pickup related to a low-noiseblock downconverter or LNB.
The LNB amplifies the comparatively weak alerts, filters the blockof frequencies through which the satellite tv for pc tv alerts are transmitted, and converts theblock of frequencies to a decrease frequency vary within the L-band vary.
The evolution ofLNBs was one in every of necessity and invention.
The unique C-Band satellite tv for pc tv systemsused a low-noise amplifier related to the feedhorn at the point of interest of the dish.
Theamplified sign was then fed through very costly and typically 50 ohm impedance gasoline filledhardline coaxial cable to an indoor receiver or, in different designs, fed to a downconverterfor downconversion to an intermediate frequency.
The channel choice was managed, typicallyby a voltage tuned oscillator with the tuning voltage being fed through a separate cable tothe headend, however this design advanced.
Designs for microstrip primarily based converters foramateur radio frequencies have been tailored for the four GHz C-Band.
Central to those designswas idea of block downconversion of a variety of frequencies to a decrease, and technologicallymore simply dealt with block of frequencies.
Some great benefits of utilizing an LNB are that cheapercable could possibly be used to attach the indoor receiver with the satellite tv for pc tv dishand LNB, and that the expertise for dealing with the sign at L-Band and UHF was far cheaperthan that for dealing with the sign at C-Band frequencies.
The shift to cheaper technologyfrom the 50 Ohm impedance cable and N-Connectors of the early C-Band techniques to the cheaper75 Ohm expertise and F-Connectors allowed the early satellite tv for pc tv receivers touse, what have been in actuality, modified UHF tv tuners which chosen the satellite tv for pc televisionchannel for down conversion to a different decrease intermediate frequency centered on 70 MHzwhere it was demodulated.
This shift allowed the satellite tv for pc tv DTH business to changefrom being a largely hobbyist one the place receivers have been inbuilt low numbers and full systemswere costly to a much more business one in every of mass manufacturing.
Direct broadcast satellitedishes are fitted with an LNBF, which integrates the feedhorn with the LNB.
In the US, service suppliers use the intermediate frequency ranges of 950-2150 MHzto carry the sign to the receiver.
This enables for transmission of UHF band signalsalong the identical span of coaxial wire on the similar time.
In some purposes, ranges thelower B-Band and higher 2250-3000 MHz, are used.
Newer LNBFs in use by DirecTV referredto as SWM, See additionally Single Cable Distribution, use a much less restricted frequency vary of 2-2150 MHz.
The satellite tv for pc receiver or set-top field demodulates and converts the alerts to the specified kind.
Typically, the receiver consists of the aptitude to unscramble or decrypt the acquired sign;the receiver is then referred to as an built-in receiver/decoder or IRD.
The cable connectingthe receiver to the LNBF or LNB must be of the low loss sort RG-6, quad defend RG-6or RG-11, and so on.
RG-59 is just not advisable for this software as it isn’t technicallydesigned to hold frequencies above 950 MHz, however will work in lots of circumstances, dependingon the standard of the coaxial wire.
A sensible drawback regarding satellitehome reception is that mainly an LNB can solely deal with a single receiver.
That is dueto the truth that the LNB is mapping two totally different round polarizations – proper hand andleft hand – and within the case of the Okay-band two totally different reception bands – decrease andupper – to 1 and the identical frequency band on the cable.
Relying on which frequencya transponder is transmitting at and on what polarization it’s utilizing, the satellite tv for pc receiverhas to change the LNB into one in every of 4 totally different modes to be able to obtain a particular desiredprogram on a particular transponder.
That is dealt with by the receiver utilizing the DiSEqC protocolto management the LNB mode.
If a number of satellite tv for pc receivers are to be hooked up to a single disha so-called multiswitch should be used at the side of a particular sort of LNB.
There are additionally LNBs accessible with a multiswitch already built-in.
This drawback turns into morecomplicated when a number of receivers are to make use of a number of dishes pointing to totally different satellites.
A typical answer for shoppers desirous to entry a number of satellites is to deploy asingle dish with a single LNB and to rotate the dish utilizing an electrical motor.
The axisof rotation needs to be arrange within the north-south course and, relying on the geographicallocation of the dish, have a particular vertical tilt.
Arrange correctly the motorized dish whenturned will sweep throughout all potential positions for satellites lined up alongside the geostationaryorbit instantly above the equator.
The disk will then be able to receiving any geostationarysatellite that’s seen on the particular location, i.
that’s above the horizon.
The DiSEqC protocol has been prolonged to embody instructions for steering dish rotors.
Requirements Analog tv distributed through satelliteis normally despatched scrambled or unscrambled in NTSC, PAL, or SECAM tv broadcast requirements.
The analog sign is frequency modulated and is transformed from an FM sign to what isreferred to as baseband.
This baseband contains the video sign and the audio subcarrier(s).
The audio subcarrier is additional demodulated to offer a uncooked audio sign.
If the sign is a digitized tv sign or multiplex of alerts, it’s sometimes QPSK.
On the whole, digital tv, together with that transmitted through satellites, is basedon open requirements similar to MPEG and DVB-S/DVB-S2 or ISDB-S.
The conditional entry encryption/scrambling strategies embrace NDS, BISS, Conax, Digicipher,Irdeto, Cryptoworks, DG Crypt, Beta digital, SECA Mediaguard, Logiways, Nagravision, PowerVu,Viaccess, Videocipher, and VideoGuard.
Many conditional entry techniques have been compromised.
Classes of utilization There are three main sorts of satellitetelevision utilization: reception direct by the viewer, reception by native tv associates,or reception by headends for distribution throughout terrestrial cable techniques.
Direct to the viewer reception consists of direct broadcast satellite tv for pc and tv receive-only,each used for properties and companies together with inns, amongst different properties.
Direct broadcast through satellite tv for pc Direct broadcast satellite tv for pc, also referred to as"Direct-To-Residence" can both check with the communications satellites themselves that ship DBS serviceor the precise tv service.
Most satellite tv for pc tv prospects in developed televisionmarkets get their programming by way of a direct broadcast satellite tv for pc supplier.
Alerts aretransmitted utilizing Ku band and are fully digital which suggests it has excessive image andstereo sound high quality.
Programming for satellite tv for pc tv channelscomes from a number of sources and will embrace dwell studio feeds.
The published centre assemblesand packages programming into channels for transmission and, the place obligatory, encryptsthe channels.
The sign is then despatched to the uplink the place it’s transmitted to the satellite tv for pc.
With some broadcast centres, the studios, administration and uplink are all half ofthe similar campus.
The satellite tv for pc then interprets and broadcasts the channels.
A lot of the DBS techniques use the DVB-S normal for transmission.
With pay tv companies,the datastream is encrypted and requires proprietary reception tools.
Whereas the underlyingreception expertise is analogous, the pay tv expertise is proprietary, usually consistingof a conditional-access module and good card.
This measure assures satellite tv for pc televisionproviders that solely authorised, paying subscribers have entry to pay tv content material butat the identical time can permit free-to-air channels to be considered even by the individuals with standardequipment accessible available in the market.
Tv receive-only The time period Tv receive-only, or TVRO,arose through the early days of satellite tv for pc tv reception to distinguish it from commercialsatellite tv uplink and downlink operations.
This was the first methodology of satellite tv for pc televisiontransmissions earlier than the satellite tv for pc tv business shifted, with the launch of higherpowered DBS satellites within the early 1990s which transmitted their alerts on the Kuband frequencies.
Satellite tv for pc tv channels at the moment have been meant for use by cabletelevision networks slightly than acquired by house viewers.
Early satellite tv for pc tv receiversystems have been largely constructed by hobbyists and engineers.
These early TVRO techniques operatedmainly on the C band frequencies and the dishes required have been massive; sometimes over three metersin diameter.
Consequently TVRO is also known as "large dish" or "Huge Ugly Dish" satellitetelevision.
TVRO techniques are designed to obtain analogand digital satellite tv for pc feeds of each tv or audio from each C-band and Ku-band transponderson FSS-type satellites.
The upper frequency Ku-band techniques are usually Direct To Homesystems and might use a smaller dish antenna due to the upper energy transmissionsand larger antenna achieve.
TVRO techniques have a tendency to make use of bigger slightly than smaller satellitedish antennas, since it’s extra doubtless that the proprietor of a TVRO system would have a C-band-onlysetup slightly than a Ku band-only setup.
Extra receiver packing containers permit for various sorts ofdigital satellite tv for pc sign reception, similar to DVB/MPEG-2 and 4DTV.
The slender beam width of a traditional parabolic satellite tv for pc antenna means it could possibly solely receivesignals from a single satellite tv for pc at a time.
Simulsat or the Vertex-RSI TORUS, is a quasi-parabolicsatellite earthstation antenna that’s able to receiving satellite tv for pc transmissions from35 or extra C- and Ku-band satellites concurrently.
HistoryEarly milestones In 1945 British science fiction author ArthurC.
Clarke proposed a world-wide communications system which might perform by way of threesatellites equally spaced aside in earth orbit.
This was revealed within the October 1945 issueof the Wi-fi World journal and received him the Franklin Institute's Stuart BallantineMedal in 1963.
The primary satellite tv for pc tv alerts fromEurope to North America have been relayed through the Telstar satellite tv for pc over the Atlantic oceanon 23 July 1962.
The alerts have been acquired and broadcast in North American and Europeancountries and watched by over 100 million.
The primary geosynchronous communication satellite tv for pc,Syncom 2, was launched on 26 July 1963.
Launched in 1962, the Relay 1 satellite tv for pc was the firstsatellite to transmit tv alerts from the US to Japan.
The world's first business communications satellite tv for pc, referred to as Intelsat I and nicknamed"Early Chook", was launched into geosynchronous orbit on April 6, 1965.
The primary nationalnetwork of tv satellites, referred to as Orbita, was created by the Soviet Union in 1967, andwas primarily based on the precept of utilizing the extremely elliptical Molniya satellite tv for pc for rebroadcastingand delivering of tv alerts to floor downlink stations.
The primary business NorthAmerican satellite tv for pc to hold tv transmissions was Canada's geostationary Anik 1, which waslaunched on 9 November 1972.
ATS-6, the world's first experimental instructional and DirectBroadcast Satellite tv for pc, was launched on 30 Might 1974.
It transmitted at 860 MHz utilizing widebandFM modulation and had two sound channels.
The transmissions have been centered on the Indiansubcontinent however experimenters have been capable of obtain the sign in Western Europe usinghome constructed tools that drew on UHF tv design strategies already in use.
The primary in a collection of Soviet geostationary satellites to hold Direct-To-Residence tv,Ekran 1, was launched on 26 October 1976.
It used a 714 MHz UHF downlink frequencyso that the transmissions could possibly be acquired with present UHF tv expertise ratherthan microwave expertise.
Starting of the satellite tv for pc TV business, 1976-1980The satellite tv for pc TV business, within the US, developed from the cable tv business as communicationsatellites have been getting used to distribute tv programming to distant cable tv headends.
Residence Field Workplace, Turner Broadcasting System, and Christian Broadcasting Community have been amongthe first to make use of satellite tv for pc tv to ship programming.
Taylor Howard of San Andreas,California grew to become the primary particular person to obtain C-band satellite tv for pc alerts along with his home-builtsystem in 1976.
Within the US, PBS, a non-profit public broadcastingservice, started to distribute its tv programming by satellite tv for pc in 1978.
In 1979 Soviet engineers developed the Moskva system of broadcasting and delivering of TValerts through satellites.
They launched the Gorizont communication satellites later thatsame yr.
These satellites used geostationary orbits.
They have been geared up with highly effective on-boardtransponders, so the scale of receiving parabolic antennas of downlink stations was reducedto four and a pair of.
On October 18, 1979, the Federal Communications Fee beganallowing individuals to have house satellite tv for pc earth stations with out a federal authorities license.
The entrance cowl of the 1979 Neiman-Marcus Christmas catalogue featured the primary homesatellite TV stations on sale for $36,500.
The dishes have been practically 20 ft in diameter,and have been distant managed.
The value went down by half quickly after that, however there wereonly eight extra channels.
The Society for Personal and Business Earth Stations, anorganisation which represented shoppers and satellite tv for pc TV system house owners was establishedin 1980.
Early satellite tv for pc tv techniques have been notvery fashionable as a result of their expense and huge dish dimension.
The satellite tv for pc tv dishesof the techniques within the late 1970s and early 1980s have been 10 to 16 ft in diameter, madeof fibreglass or strong aluminum or metal, and in the US value greater than $5,000,typically as a lot as $10,000.
Programming despatched from floor stations was relayed fromeighteen satellites in geostationary orbit positioned 22,300 miles above the Earth.
TVRO/C-band satellite tv for pc period, 1980-86 By 1980, satellite tv for pc tv was effectively establishedin the USA.
On 26 April 1982, the primary satellite tv for pc channel within the UK, Satellite tv for pc Tv Ltd.
Its alerts have been transmitted from the ESA's Orbital Check Satellite tv for pcs.
Between1981 to 1985, TVRO techniques' gross sales charges elevated as costs fell.
Advances in receiver technologyand the usage of Gallium Arsenide FET expertise enabled the usage of smaller dishes.
500,000techniques, some costing as little as $2000, have been bought within the US in 1984.
Dishes pointingto one satellite tv for pc have been even cheaper.
Folks in areas with out native broadcast stationsor cable tv service might receive good-quality reception with no month-to-month charges.
The largedishes have been extra fashionable in rural areas, and residents sometimes positioned them prominentlyin entrance yards.
Growing recognition prompted jokes of the satellite tv for pc dish being the stateflower of predominately rural US states, together with West Virginia and Vermont.
The big disheswere a topic of a lot consternation, as many individuals thought of them eyesores, and in theUS most condominiums, neighborhoods, and different house owner associations tightly restrictedtheir use, besides in areas the place such restrictions have been unlawful.
These restrictions have been alteredin 1986 when the Federal Communications Fee dominated all of them unlawful.
A municipalitycould require a property proprietor to relocate the dish if it violated different zoning restrictions,similar to a setback requirement, however couldn’t outlaw their use.
The need of those restrictionswould slowly decline because the dishes obtained smaller.
Initially, all channels have been broadcast inthe clear as a result of the tools essential to obtain the programming was too expensivefor shoppers.
With the rising variety of TVRO techniques, this system suppliers and broadcastershad to scramble their sign and develop subscription techniques.
In October 1984, the U.
Congress handed the Cable Communications Coverage Act of 1984,which gave these utilizing TVRO techniques the appropriate to obtain alerts totally free except they werescrambled, and required those that did scramble to make their alerts accessible for a reasonablefee.
Since cable channels might stop reception by large dishes, different corporations had an incentiveto supply competitors.
In January 1986, HBO started utilizing the now-obsolete VideoCipher IIsystem to encrypt their channels.
Different channels makes use of much less safe tv encryption techniques.
The scrambling of HBO was met with a lot protest from house owners of big-dish techniques, most of whichhad no different possibility on the time for receiving such channels, claiming that clear signalsfrom cable channels can be troublesome to obtain.
Ultimately HBO allowed dish ownersto subscribe on to their service for $12.
95 per thirty days, a worth equal to or higherthan what cable subscribers have been paying, and required a descrambler to be bought for$395.
This led to the assault on HBO's transponder Galaxy 1 by John R.
MacDougall in April 1986.
One after the other, all business channels adopted HBO's lead and started scrambling their channels.
The Satellite tv for pc Broadcasting and Communications Affiliation SBCA was based on December 2,1986 as the results of a merger between SPACE and the Direct Broadcast Satellite tv for pc Affiliation.
Videocipher II used analogue scrambling on its video sign and Information Encryption Standardbased encryption on its audio sign.
VideoCipher II was defeated, and there was a black marketfor descrambler units which have been initially bought as "check" units.
Late 1980s and 1990s to current By 1987, 9 channels have been scrambled, however99 others have been accessible free-to-air.
Whereas HBO initially charged a month-to-month price of $19.
95,quickly it grew to become potential to unscramble all channels for $200 a yr.
Dish gross sales wentdown from 600,000 in 1985 to 350,000 in 1986, however pay tv companies have been seeing dishesas one thing constructive since some individuals would by no means have cable service, and the industrywas beginning to recuperate in consequence.
Scrambling additionally led to the event of pay-per-viewevents.
On November 1, 1988, NBC started scrambling its C-band sign however left its Ku band signalunencrypted to ensure that associates to not lose viewers who couldn’t see their promoting.
A lot of the two million satellite tv for pc dish customers in the US nonetheless used C-band.
ABCand CBS have been contemplating scrambling, although CBS was reluctant as a result of variety of peopleunable to obtain native community associates.
The piracy on satellite tv for pc tv networksin the US led to the introduction of the Cable Tv Client Safety and CompetitionAct of 1992.
This laws enabled anybody caught participating in sign theft to be finedup to $50,000 and to be sentenced to a most of two years in jail.
A repeat offendercan be fined as much as $100,000 and be imprisoned for as much as 5 years.
Satellite tv for pc tv had additionally developed in Europe nevertheless it initially used low energy communicationsatellites and it required dish sizes of over 1.
On 11 December 1988 Luxembourglaunched Astra 1A, the primary satellite tv for pc to offer medium energy satellite tv for pc protection toWestern Europe.
This was one of many first medium-powered satellites, transmitting signalsin Ku band and permitting reception with small dishes.
The launch of Astra beat the winnerof the UK's state Direct Broadcast Satellite tv for pc licence holder, British Satellite tv for pc Broadcasting,to the market.
Within the US within the early 1990s, 4 massive cablecompanies launched PrimeStar, a direct broadcasting firm utilizing medium energy satellite tv for pc.
Therelatively robust transissions allowed the usage of smaller dishes.
Its recognition declinedwith the 1994 launch of the Hughes DirecTV and Dish Community satellite tv for pc tv techniques.
Satellite tv for pc Tv for the Asian Area, an organisation primarily based in Hong Kong which nowprovides satellite tv for pc TV protection to Asia and Australia, launched satellite tv for pc TV to theAsian area.
It started broadcasting alerts utilizing the AsiaSat 1 satellite tv for pc on 1 January1991.
On March four, 1996 EchoStar launched DigitalSky Freeway utilizing the EchoStar 1 satellite tv for pc.
EchoStar launched a second satellite tv for pc in September1996 to extend the variety of channels accessible on Dish Community to 170.
These techniques providedbetter photos and stereo sound on 150-200 video and audio channels, and allowed smalldishes for use.
This vastly lowered the recognition of TVRO techniques.
Within the mid-1990s,channels started shifting their broadcasts to digital tv transmission utilizing theDigiCipher conditional entry system.
Along with encryption, the widespreadavailability, within the US, of DBS companies similar to PrimeStar and DirecTV had been reducingthe recognition of TVRO techniques for the reason that early 1990s.
Alerts from DBS satellites are higherin each frequency and energy and subsequently require a lot smaller dishes than C-band, andthe digital modulation strategies now used require much less sign energy on the receiver thananalogue modulation strategies.
Every satellite tv for pc can also carry as much as 32 transponders in theKu band, however solely 24 within the C band, and a number of other digital subchannels might be multiplexed orcarried individually on a single transponder.
Advances in noise discount as a result of improvedmicrowave expertise and semiconductor supplies have additionally had an impact.
Nevertheless, one consequenceof the upper frequencies used for DBS companies is rain fade the place viewers lose sign duringa heavy downpour.
C-band satellite tv for pc tv alerts are much less liable to rain fade.
See additionally Dish HomeCommercialization of area Free-to-airFTA Receiver Microwave antennaMolniya orbit Satellite tv for pc dishSatellite tv for pc subcarrier audio Satellite tv for pc tv by regionSmart TV: offers tv through web connectionSMATV References Exterior linksHistory Steve Birkill's Historical past of C-Band and EarlySatellite tv for pc TV Channels and satellite tv for pc fleetsLyngemark Satellite tv for pc Charts Worldwide satellite tv for pc locationsEutelsat satellite tv for pc fleet Eutelsat TV channel guideSES fleet info and map SES information to receiving Astra satellitesSES information to channels broadcasting on Astra satellitesLinowsat PID-Lists and Videobitrate Charts Monitoring and utilitiesOnline Satellite tv for pc Calculations On-line Satellite tv for pc Finder Primarily based on Google MapsDish Alignment Calculator with Google Maps BasicSatellite tv for pc–TV C-Band FAQ Record Basic frequency allocation info,primarily for U.