THE BIRTH OF SATELLITECOMMUNICATIONS

Twenty·fiVe years ago worldwide communicat ions entered a newere . Telstar, the wor ld 's first commerc ia l communica tions sat ellite ,was lau nched on July 10 , 1962. and the first live television sign a ls

via satellite were received by British Telecom 's Goonhilly ea rthstation in the early hours of the following morn ing .

Fig . 1. Th.Otym pus S81 e1~leis one of the l"'gesl end rnoll

po--"u l in th e worid , Photograph counttuy o f Briti$ll~.

Fig. 2 . A sma. seC-lion of Goonhi.y Down s E/Ilth SI8IiO<l: in lhelo. eg. ouod Aerie l No.1 . Photog,aph c-outtesy of B,itish Telec om .

rnunicetions satellites,At the same time iI was an­ncunced that sarellite earth sta­lions would be bu ilt in Englandand France "lor tl':.e rece ptionand transmission of telephone,telegraph and lelevision signalsacross the Atlantic usingsatellites to be launche d byNASA during 1962 and 1963."Work began shortly afterwar dsto build the UK's first satellitestation al Goonhilly Downs inCornwall. The site was chosenbecause it was as far west aspossi ble to ob tain the maximum

peri od of visibility to the UnitedStates via the satell ite, 10 beremo te from sources of elec ­tricaI inte rfere nce, and 10 pro­vide an onob scu red view to thehor izon for the longest possi blecontact withthe satellite.In less than a year from gainingacc ess to the site the station wasready. A massive, steerabledish ant"'nna, weighing 870tonne s with a as.9m dish hadbeen buill. All of the equi pmenton the stalion was of Britishde sign and manufacture. withthe exception 01one Ame ricantransminingIdystronvalve.The British desiqn was the odd­man-out amonq the three earthstations to be usedfor the tests.BoththeAmeri can stalion at An­dover, Maine, and the Fren chstation at Pleurneur Bodou inBritanny wer e equipped withhom antennas housed inrado mes.T heB ritish stationhadcost around £800,000 to cern­plete . abou t a quan er of thecost of the Ame rican and theFrench stations.In early July 1962 it was an­nounc ed that Telstar would belaunched from Cape Ca naveralon eithe r July 10or II.The successful launch tookplace a1 8.35 GMT on Tuesday,July 10, and the desired orbitwas achieved. With Telstarcirc ling the earth at heigh tsvarying be tween 590and' 35OQmiles ,it waspossibletoachievethree or four periods duringeach 24 hears when mutual

i~"!,!!'!!!J!!!!!!!!g~~ I visib ility between Goonhillyand Andover lasted for 30to 40mmutes.During these periods the anten­na at Goonhilly had to be ac­cura tely manoeuvred to followthe sate llite from the moment itrose above the horizon until itagain disappeared from view.The signa] e ans mmed from theante nna to the satellite was con -

Th e early Telstardemonst rations andtest sIn the Sprint;! of 19tH it wasjointly announced in the UnitedKingdom, the USA and Francethat the USNaricnalAerona uticsand Space Administration(NASA), the French Centre forTelec ommunications Studiesand British Telecom, as itspredecessor Post Office Tele­comm unications, would co­ope rate in a programme fortransatl antic testinq of com-

In October 1945, the magazineWireless World published anarticle by ArturC Clarke, todayprobab ly better known as theautor of 2(X)J-A space Odyssey,e ntitle d Extra-terrestrial re­lays- can rocket stations giveworldwide radio coverage ?Arthur C Clarke commented inhis article : "Many may considerthe solution propose d in thisdiscussion too farfetched to betaken very seriously." Yet hisidea was 10 prove the blue-printfor today's satellite communi­catio nsnerwork.He accurately predicted theor­bital velocity lhat a rocketwould need to become an ar­tificial satellite, or secondmoon, circlinq the world withno expenditure of power. Healso predicted that a satellitecircling the earth above theequator ill a certain heightwould appear to be stationaryto the earth and that three suchsatelli tes could give globalradio coverageHe further predicted that deve l­o pment of rocket technology.starte d by the Ge rmans duringthe second world war, wouldsoon make it possible to place asatellite inorbil.

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Telecom Interna tional-BTl· 2handles more than three mi.llionminutes cf telephone calls.jele­vision pictures . data , facsimile,and telex , every day throughGoonhilly and its other inter­conti ne ntal links.Abo ut 90per ce nt of the world 'stelephones-some 600 millionof them-in 113countries canbe dia lled direct from theUK- Telep hone servic es areprovided to more than 200countries and each day morethan 500,000 calls are connec­ted from the UK to the othe rccunmes

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excellent quality and werebroadcast as recei ved tmpug h·ou t the USA.On July 12 the first two-waytransatlan tic telep hony testswere made, showinq that qood­quality . stable telephone cir­cuits with low noise levels hadbeen achi eved These testswere 10 be followed two dayslater by the lirsttransatlantictele phon e call and photo-tel­eq raphy (facsimile) transmission via sate lliteOn Iulv 14 during orbit 34, thed irect or gene ral of the PostO!­nee. Sir Ronald German, spokefrom his home in Londo n to thepresident of Amer ican tel e ­phone and Teleqra ph Co(AT&T).Mr. Eugen e McNeel y, in

'1~!".l":":!:l:l:!l.-C::::::;;::ii~~~' INew York. Simultaneously, one~ pair of channels was used (0

send facsimile pictures be­tween London and New York.On July 15tests 10 assess theability of a communications sat­e llite to carry large num bers oftele phone circui ts were carri edout during orbit 43. Thesedemon strated that at least 600flrst-qrade intern ationalcircuusshould be possib le by satelliteThe first transmission s ofco lourtelevision signa ls by sate llitewere made lrom Goonhilly dur­ing orbits 60 and 61 on july 16.With the cooperancn of theBBC's research and de siqnsdepartment , who provided acolou r slide scanner and moni ­tor eq uipment , the signals. on525--line NTSC standards. com­prise d captions, test cards andstill pictures to asse ss colour

iZIOi':!!!!!!!==iI.iiiii:~~~~ I quality. The transm issions wereinitially made from Goonhilly tothe satellite and back 10Goonhill y but we re also re­cei ved in Andover , Andoverre ported: "Colour-good; pic­ture quality -excellent",During orbit 87 on July 19satel·lite communications wer eopened up to the pres sTwenty-fourcallswere madeb<{the British pre ss from Flee tBuildinq in London , to theAmerican press in New York.On July Z3 durinq orbill25 an18-minute long programmefrom the Europe an Broad ­casting- Union was transmitte dfrom Goonhill y to Andover. Theproqramm e consiste d ofscenes from many Europe anco untries and wastransminedby the Eurovision link toGoonhilly, from Goonhilly 10thesate llite . and was received atAndover and broadcastthrougho ut the USJ\.

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~~~~~~dO;n~od:;:O; ~~~~: 3so a.bsolute precision wasnec essary, To maintain uus ac­curacy in hiqh wind meant thatthe antenna had to be massiveand sturdy , morde r to move theantenna so accurately it wasequipped with e lectri c motorsof some 100horse powe r. How­ever , the engi neerinq designresuned in such qood balanceand smooth moveme nt of theantenna that normaly less thantwo horse power was requir edunde r reasonable weathe r con­d itions.The primary purpose of theTelstar satellite tests was to ac­quire data on which to basethefuture design of satel liteSV$lerns for comm erctal ope r­ation. However. during- thepe riod from July 10 10 July 21 anum ber of demonstrationswe re carri ed out which i1.lustrated the poIentiali ties ofsateUitesystems for world·widetelecommunicationslnthe eany hours ot luly II thefirst usable or bits were the sixthand seve nth and the first at­temp t at television receptionwas made. Rece ption wasdecid edly poor. Some exp ert swere quick to blame Goo n­hilly's unique antenna design,and The Times describe d theexpe riment as "an almost totalfailure': Some experts said theantenna was too he avy andcumbersome 10 accura telytrack the satellite, othersblamed the drivin g mechanism.The prob lem proved to be thatone component had be en fi"edthe wrong way round and it wasa twenty-minu te job 10 correctit. The effec t 01the incorrec t fit,ting had been to reverse thed irectio n of the wave polariz­ation of the antenna, relative tothat of the satellite, introducin ga serious weakening of theslTenqth of signals re ce ivedThe prob lem arose be cause ofan amb iguity in the acceptedde finition of the sense ct rc­tation of rad io waves; a difficultywhich had been encounte redbolh in the USJ\.and the UK inthe pe riod just before the tests,With the con ection made, ex­ce llent pictures were recei vedon orbit 15 during the eveningof July 11. and during orbit 16the first live television trans­mission between Europe andthe USA was made fromGoonhilly to Andover . The pic­ture sand soun d rece ived at An· Fig, S. The la18st ol th . a n ta nnas (No. 10) ta b. Ins ta lled atdove r were reported to be of I GoOllhilly Downs. Photogr aph courre sey of Britis h TBlecom

~~~it~~ I~~~i~~~~:~~~~h~~ Iand Andover was used to pro­vide telep hone circuits for meUS Information Agency involv­illg conversations betwee n"notable persons " ill 20pairs ofcities ill the USA and Europe forthe Agency's " People-to­People" proqrnnme- The cir ­cuits were reported as ex­cellentThe Teislartests confirmed thatcommurucallons satellitescould provide high-quality,stable circuits for television andmulti-channel telephony. Theperformance of GoonhiUyearthstation was reported as ex­ce llent in every re spect , andthe equipm ent, almost all ofwhich was of a unique newdesign , had worked well. Infact, Goonhilly's antennadesign was to prove, as hadArthur C. Clarke's idea, to bethe blue-print for the future.

Fig. 6 . A British Te lecom rigger uamines the ' lee lwor k o f Go onh illyEarl SUllie n ' . a n l_ No.6. PhotOgraph cvune_r of Brirish-.m.

rece ive the siqnals from thesatellites, ended ill the Lizard.on the flatexpanse ofGoonhillyDowns,

The Lizard offered an unim·paired view of the Atlantichorizon, giving- the longestpossible contact with the low­orbiting satellites then beillgused. It suffered fromIinle elec­meal and radio interference;was well placed to connectwith inland communications,power supplies and transpo rtlinks; and had a climate with

moderate rainfall,hltie seasonalvariation ill tempera ture andonly occasional snow •Equ ally important was thegeoloqy of the area. Theserpe ntine bedr ock reaching athousand feet dee p would givevital suppo rt to the massiveweight of the antennas.Within a year of oblainingposse ssion of the site, the firstantenna, the control room andits associated equ ipment wereinstalled and ready for the firsttests which would use the

Fig . 7. A Mc tion of lhe control ar ea al Goonhilly Down •. "" oro.graph cvune.er o f Bri tish Telecom.

mand for sate llite communi­canons. BrillSh Telecomannounce d plans in August19a3to built a third earth stationin London's Docklands.primar­ily for sate llite TV distributionand specialised business ser ­vices . The London Telepo n . inNon h Woolwich, opened foropera tion in February the nextyear - Iessthansixmonlhsaftersite clear ance be gan .Aerial 1 at Goonhilly, inuiallyused for TV circui ts, is now be-

tic route. Aerial 6 is Goonhilly 'slargest dish with a diameter of32m. It was also the first "dual­frequency" antenna , able toboth transmit and receive ontwo frequencies simultan eously--<loublinqpotentiaicap,acilY.Itentered service in September1985.While aerial 6 was beinq built.Aerial 7 was also being brou ghtinto service to provide lease dTV servic es to NOI1hAmericaWith continuing grow th in de-

I ;';PhU;;:_af~:le~~~net~~~ico:to aircraft in flight-which isdue to start by the end of thisyeMMeanw hile Aerials 8, 9 and 10have bee n built. These aresmall-dish antennas below 14min diameter. They are used forresearch and develcpmeru, andto provide monito ring and con­trc l facilities on the more than130sate llites currenliy in useToday. development at Goon·hilly continues. Aerial 6, thebig gest antenna, has beenequipped to operate to thelatest deve lopme nt in satellitecommunications -Time Div­ision Multiple Access /DigitalSpeech Interpolation (TDMA!OSI). TOMA/ OSI means thatsigna ls from the station aregroup ed and sent by timerathe r tha n freque ncy, so that,on the principle that dur ing theaverage telephone ccnver­sation either party is onlyspeaking lor one third 01 thetime 01the call,otherqroupsolsignal s can be se nt along thesame cha nnels during thelapse s of conversationWhile British Telecom's earthstation at Goonhilly providesvital links for fOdayan d tomor ­row, it has nOl forqonen itspast-i, past that goes back farbeyond Marconi 's early expenments.The Lizard Peninsula isde signaled as an Area ofOutslaIldinq Natural Beauty andGoo nhilly Downs was c era­wall's first National NatureReserve. In deve lopinq theearth station, British Telec omspent E200,OOO landsca ping thescheme to form natural-lcckinq

r;;-- - ...,,-- - - - - - - - - - , mound s, or bunds. inside andoutside the station's boun d­aries . Localh eathers, qorseandwillow were planted in thestation, in kee pinq with thenatural charac ter of the Downs .With little intrus ion from thepublic, amidst the sile nt giantsof Goonhilly's antennas, thelocal Dora and fauna have beenab le to Dourish. makingGoo nhilly not only a pioneer inhig tHechnoloqy but afso a~'s paradise.

h.i.9h.~. rbit ing ,satellite. in "g.e~ 1 8staucnarv crbit'',AI1hur C Clarke had proposedin his 1945 paper that sate llites,c lIClinq the earth above theequa tor at i, certam heiqht,would appear 10 be stationaryto the eanh's surface -theirperiod of orbit would eu ctlymatch that of the earth's naturalrotation. That distan ce was22,300 miles abcNe the equator .After INTELSAT I's successfullaunch to this height , comm er­cial service opened in June1!l6SAnh ur C Clarke had also pro­pose d that thre e sate llites inge ostationary or bit could giveworld-wide radio coverage.A second sate llite-INTELSATIl-cwa s launched in December1966, and at the same time,Aerial I at Goonhill y, whichnow no longer needed to tracklow·orbiting sate llites acrossthe sky,had an extra re flectingsurface adde d, pushing itswe ight up to 1100tonnesSatellite communications hadnow truly ente red comm erc ialoperation , As the dem and for

==~TV:~. te~h:: ~~;h~ ' I;~~:~"vh':~eI~I:~f:;:;Yc:,~:;rb:~n:':Ct~elGoonhilly with the addition ofJl.erial 2 in l968.By 1969 three geostationarysate llites were in orbit, fulfillingAn hur C Clarke's prophesyof global communications.INT£LSA.T III was position edaboYethelndianOceanandde­mand lor satellite co mmuni·canons wtththe Far East qrew.'lb meet this need Aerial 3 wasbro uqht into servi ce in 1972.Aerial" was added in 1978, tomeet an eve r·increasing de­mand for communic ationsacross the Atlantic. This wasalso one ol lhe first antennas inthe world to use the 11/14 GHzfrequenc y as soon as it be cameavailable for business satellitecommunications.Demand lor satel litecommuni­cationsqrew by 20 pe r cent a~ar during the l97Osandearly

198Os. Funher satellites wereput into orbil and in October1978 a second earth station wasbrought into service by BritishTelecom at Madley inHere fordshir e.Demand for specialist sencesalso qrew during this pe riodand in 1983Aerial 5at Goonhillywas comp leled to presi de setel­lite se rvice s 10 ships at sea.

~i~:, :':;;Ie t~imp:~d~~w: ~~io~~ :e;em8"::";; n7:::~~~ I~~~:~~~:;~~~:::':~~capacllYonthebusytransatlan- 1 courr 8q ofBririlhT8I8com .

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