Úvod
O AntennaAmplifier
AntennaamplifierisgenerallycalledMastheaderAmplifierinEnglish,anditisalsocalledPre-amplifierorAntennaAmplifier,Amplificador,etc.insomeEuropeanandAmericancountries.UHF,broadband,lownoiseamplifierbetweenantennaandfeeder.TocompensateforthelossofthetransmissiondistancebetweentheantennaandtheTV,andtoensurethatthedistributorobtainsthenecessaryinputpowerinthesharedantennasystem.
Whenwereceivelong-distanceTVprogramsorterrestrialhigh-definitionTVprograms,theTVsignalisgenerallyweak.Atthistime,weneedtouseamulti-unitTVantennawithstrongdirectivityandhighgain,andtheantennaSetitupashighaspossibleandinanopenplace.Ifyoufeelthatthereceivingsituationisnotidealenough,youneedtoinstallanantennaamplifierbetweentheantennaandtheTVtoincreasethereceivingsensitivity,sothattheTV’simageisstableandthesoundisgood.
Afterusingtheantennaamplifier,itislikeaddinga"telescope"totheTV.ItcanamplifytheweakTVsignalreceivedbytheantenna,butofcourse,intheprocessofreceiving,morethanjustamplifyingIt'saTVsignal,anditalsoincludesallkindsofnoiseandinterference.UsuallyundertheantennaamplifiercanamplifytheTVsignaltotentimesormore.Theantennaamplifierisactuallyasuperhigh-bandamplifier.Thereceivingchannel,frequencyrangeandoverallgainofvarioustypesofantennaamplifiersaredifferent.
Payattentiontotheproblem
(1)PayattentiontotheinstallationpositionTheantennaamplifierusuallyconsistsoftwoparts:theamplifyingpartandthepowersupply.Whentheantennafeederlineisshort(generallyreferstotheuseofindoorantennas),theantennaamplifiercanbeplacednexttotheTV;whentheantennaissetuphigherandthefeederlineislonger,thetwopartsshouldbeplacedseparately,andtheamplifyingpartshouldbesealedbyawaterproofboxLater,itisbesttoinstallitattheendofthesupportrod1~1.5mawayfromtheantennaelement,andthepowersupplypartcanbeplacedneartheTV,whichcanimprovethesignal-to-noiseratiooftheTVsignal.
(2)Channelsmustmatch.Antennaamplifiersaregenerallydividedintotwocategories:VHFandUHF.TheVHFtypecanamplifytheTVsignalofchannels1to12,andtheUHFtypecanamplifytheTVsignalofchannels13to68.Wheninuse,theantennaamplifiershouldmatchtheTVchanneltobereceived.
(3)PayattentiontoimpedancematchingTheoutputimpedanceoftheantennaamplifierandtheoutputendoftheantennaandtheinputimpedanceoftheTVshouldallmatch.Thefeedershouldnotbetoolong,thatistosay,theantennashouldnotbeerectedtoohighortoofar.Otherwise,althoughtheantennaamplifierisaddedtotheTV,theincreasedsignalwillbeseverelyattenuatedduringthetransmissiontotheTV,resultinginlittleimprovementinthereceivingeffect.Inaddition,theinputandoutputfeedlinesoftheantennaamplifiercannotoverlaporbetooclosetoavoidfeedbackorinterference.
(4)Thegainmustbeselected.Thegainofvarioustypesofantennaamplifiersisdifferent,generallytherearehighandlowpoints.High-gainantennaamplifiersusuallyhaveagainof30to60dB,andinconjunctionwithamulti-channelYagiantenna,theycanreceiveTVprogramshundredsofkilometersaway.Thelow-gainantennaamplifierhasagainof20-40dBandcanreceiveprogramsdozensofkilometersaway.Itisnecessarytomakeaproperchoicewhenchoosing,butitisnotthatthehigherthegain,thebetter.
(5)Checktheinstallationeffect.Iftheimagereceivedbytheindoorcableispoor,andgoodresultscanbeobtainedwheninstallinganoutdoorantenna,youcanstillusetheindoorantennaafterusingtheamplifier.Ifafterinstallingtheantennaamplifier,theTVviewingeffectdoesnotchangesignificantly,ortheviewingeffectisworsethanbefore,itiscausedbyaninstallationerror,andyoushouldcheckitcarefullybeforecorrectingitaccordingtothecorrectinstallationmethod.
(6)Goodantennasandlightningprotectionequipment,suchasTVuserswhouseoutdoorantennas,needtoinstallanantennaamplifier,andagoodmulti-elementantennamustbeusedtocooperatewithit,andlightningprotectionequipmentmustbeinstalledtopreventLightningstrikes.
Kritéria pro posuzování předností
Za prvé, signál a hluk by měly být malé
Zadruhé, citlivost by měla zůstat zachována
Třetí by mělo být lepší ve voděodolnosti
Čtyři objemy menší
Fivemetalshellje lepší
Šest úspory energie
Sevenwiring je pohodlný
Velmi známá značkah2>
Zámoří:Antiference,Global,Johansson,Fracarro,Fringe,Ikusi,IkusiLabgear,Maxview,Paragon,Philex,Proception,Televes,Triax,Vision,Wolsey
ButmostoftheaboveproductsaremainlyProducedinSoutheastAsia,especiallyinChina.
Domestic:Boligo,Seebest,Wanshida,Wanshibao,Jiaxun
ThesebrandsarealsotheOEMsofmanyforeignbrands,andsomeofthebrands'productqualitycanbestraightforward.Referstofirst-lineforeignbrands.
Architecturediagram
Thisillustrationtellstheuserhowtoconnectfromtheantennatotheamplifiertothepowersupplytotheuser.Butthislegendisnotclearenough.Becausetheantennaamplifierisalsocalledpreamplifier,itisbecausetheantennaamplifierisinstalledlessthan30cmbelowtheantenna,andthegeneralpowersupplywillbeinstallednexttotheTV,sothatthesignallinecanbedirectlyinsertedintotheTV.IfmultipleTVsreceiveaprogramononeantenna,thepowersupplyisgenerallyplacednearthebranchdistributor.Asforwhethertowatchhigh-definitionTVprogramsoranalogprograms,itdependsontheconfigurationofyourTV.Atpresent,mid-to-high-endflat-panelTVshavebuilt-interrestrialhigh-definitionset-topboxmodules,someofwhicharecalledall-in-ones,andthetechnologyisverymature.Comparedwithbroadcastandtelevisionsignals,terrestrialhigh-definitionprogramsarefree,andtheinitialinstallationcostisrelativelylow.Aslongasyouchoosehigh-qualityantennasandantennaamplifiers,youcanreceiveultra-high-definitionprogramsinmpg-2orevenmpg-4format.
Applicationexample
Inthisexample,themostbasicequipmentsuchasthehomeantennaamplifier7322andbranchdistributorofJohanssoninBelgiumareused.TheEuropeantestreportindicatedthatHDTVcanbereceivedinopenconditions,evenifitisonthesideofthehighway,closetothemobilebasestationorSanyin,etc.,itcanstillachieveaclearervideosignal,withidealgainandanti-interference.,Especiallyintermsofanti-mobilesignalinterference,itisworthyofrecognition.DirectTV,theworld'slargestproviderofsatelliteTVlivebroadcastsandterrestrialhigh-definitionprograms,iscooperatingwiththisbrand.
Samozřejmě, že existují některé domácí značky, které mohou dosáhnout této kvality.