Table-sizedStarlinksatellites, however, needtobein a lowEarthorbittoprovidefor 20 millisecondlatencies, whichiscriticalforsmoothlyplayinginternetgamesorsurfingtheweb, andas a resulttheircoverageismuchsmaller.
Well, inessence, wehave 1,280 antennasarrangedin a hexagonalhoneycombpatternwitheachstackofcoppercirclesbeing a singleantennacontrolledbythemicrochipsonthePCB.
Thismassivearrayworkstogetherinwhat's called a phasedarrayinordertosendandreceiveelectromagneticwavesthatareangledtoandfrom a Starlinksatelliteorbiting 550 kilometersabove.
Wesend a 12 gigahertzhigh-frequencyvoltage, orsignal, tothefeedwire, whichis a voltagethatgoesupanddownin a sinusoidalfashion, goingfrompositivetonegativeandbacktopositiveonceevery 83 picoseconds, 12 billiontimes a second, or 12 gigahertz.
Well, asmentionedearlier, a 12 gigahertzsignalisappliedtothecopperfeedwire.
前述したように、12ギガヘルツの信号が銅の給電線に印加される。
Whenthevoltageisatthebottomofitssinusoidal, ortrough, wehave a concentrationofelectronspushedtotheendofthefeedwire, thuscreating a zoneofnegativechargewhichcorrespondstothemaximumnegativevoltage.
However, whenwereversethevoltagetothecopperfeedwire 42 picosecondslater, wehave a concentrationofpositivecharges, or a lackofelectronsattheendofthewire, andthustheelectronsinthepatchflowtotheotherside.
Atthesametime, electronsflowingfromonesideofthedisktotheother, whichisanelectriccurrent, generate a magneticfieldwith a strengthanddirection, orvector, perpendiculartothefringingelectricfieldvector.
Thequickexplanationisthatbyhavingthesepatternsofconstructiveanddestructiveinterference, it's asifwetook a singleantenna, multiplieditby 1280, andthenplaced a wholebunchofmirrorsaroundit, andleftonly a singleholeforthemainbeamtoexitthrough.
Toreallyunderstandtoday's frontiertechnologies, andtohelpyoubecome a revolutionaryengineerandentrepreneurlikeElonMusk, youhavetobeversedin a widerangeoffieldsinscienceandengineering.
As a quickrefresherfrombefore, here's anarrayof 1280 antennasandwefedthemallwiththesame 12 GHzsignalinordertocreate a laser-likebeampropagatingperpendiculartoDishi.
Thesolutionistophaseshiftthesignalsenttooneantennawithrespecttotheotherantennaand, as a result, thetimingofthepeaksandtroughsemittedfromoneantennaisdifferentfromtheother.
Well, DISHIandthesatelliteindeedsend a signalthatlookslikethis.
DISHIと衛星は確かにこのような信号を送っている。
However, theyvarytheamplitudeandthephaseofthetransmittedsignalandthenassignorencode 6-bitbinaryvaluestoeachdifferentcombinationorpermutationofamplitudeandphase.
With 6 bits, thereare 64 differentvalues, andthusweneed 64 differentpermutationsofamplitudeandphase.
6ビットでは64通りの値があるので、振幅と位相の64通りの順列が必要になる。
However, insteadoflistingallthepermutations, it's moreeasilyvisualizedbyarrangingthe 64 differentvaluesin a graph, called a constellationdiagram, asshown.
However, notethatthisdatatransferissharedbetweendownloadandupload.
ただし、このデータ転送はダウンロードとアップロードの間で共有されることに注意。
Sincethisparticularantennacan't transmitandreceivedataatthesametime, about 74 millisecondsofeverysecondisusedtosenddatafromDISHItotheStarlinksatellite, and 926 millisecondsisusedtosenddatafromthesatellitedowntoDISHI.