有线电视共用天线系统安装工艺标准（installation standard of catv common antenna system）

'有线电视共用天线系统安装工艺标准（InstallationstandardofCATVcommonantennasystem）InstallationstandardofCATVcommonantennasystem1,scopeofapplicationThisstandardappliestocabletelevision,satelliteTV,closed-circuittelevisionandcommonantennasysteminstallationworks.2、constructionpreparation2.1materialsTheselectionofreceivingantennafor2.1.1CATVsystemshallbebasedondifferentreceivingchannels,receivingsatellites,fieldstrengthandreceivingringsAswellascableTVsystemfacilities,scaleselection,opencircuitantennaandsatelliteantenna,tomeettherequirementsofreceivingimagequality,andHaveproductqualificationcertificate.2.1.2allkindsofironpartsshouldbegalvanized.Corrosiontreatmentshallbecarriedoutwhengalvanizingisnotallowed.Suchastheuseofwireand8#Steelwireropeandallkindsofironpipes,angleiron,channelsteel,flatiron,roundsteel,14#tiewire,wireropecard, flowerbasketbolt,pullringZincplatingshallbeadoptedforequaltreatment.Allkindsofmachinescrews,metalexpandingbolts,woodscrews,washers,springmatsandsoonshouldbegalvanized.The2.1.3userterminalboxistheportthatthesystemconnectswiththeusertelevisionset,andtheuserterminalboxisdividedintothebrightandthedarkboxesPlasticboxtwo.Userterminalpanelsocket,singleholeanddoubleholesocket,socketimpedanceis75,andshouldhaveproductsCertificate。2.1.4TVcableshallhaveahighperformancePEfoamcablewithgoodshieldingperformance.ItiscomposedofcoaxialinnerandouterconductorgroupsTheproducthasacharacteristicimpedanceof75ohmsandshallhaveaproductqualificationcertificate.Doubleshieldedcablesmaybeusedtointerferewiththesiteenvironment;Fortheoverheadcable,theself-supportingcableshallbeadopted,andtheoutdoorcableshallbemadeofblacksheathcable.2.1.5branch,distributorandotherpassivecomponents:accordingtothedesignrequirements,choosedifferentspecificationsofthedevice,andshouldhaveproduct qualificationcertificate.2.1.6accordingtothedesignrequirements,selectthecorrespondingtypeandperformanceofantennaamplifier,mixer,waveseparator,trunkamplifier,Branchedtrunkamplifier,extendedamplifier,distributionamplifier,cabinet,chassis,tuner(LNB),receiver,modulator,Demodulator,purifyingpowersupply,etc..Shouldchecktheequipmentandequipmentappearanceisintact,thefittingsarecomplete,andthenproceedElectricaltesting,checkwhetherthedeviceandequipmentworkproperly,productspecificationsandtechnicalinformationiscomplete,andshouldhaveproductcertification(importedproductsshouldbeprovidedwithcommodityinspectioncertificate).2.1.7othermaterials:weldingrod,waterproofelbow,solder,flux,connector,insulator,antennafoundation,embeddedbolt,avoidThunder,etc..2.2implementsandequipment2.2.1measuringinstrument:fieldstrengthmeter,testantenna,multimeter,megohmmeters,monitor,compass,anglemeasuringinstrument,suchasa. 2.2.2constructionequipment:electricdrill,electrichammer,pliers,screwdriver,electricknife,electriciron,electricwelder,jointspecialtool,Level,bigrope,safetybelt,highladder,middleladderandtoolbag.2.2.3liftingequipment:crane,downchain.2.3operatingconditions2.3.1withthecompletionofthecivilstructure(beforeroofwaterproofinganddecoration),thesatellitereceivingantennafoundationandtheburiedpipearepreburied.2.3.2withthestructuralwalls,buriedpipeanduserboxhasbeencompleted.2.3.3civilconstruction,interiordecoration,paint,pulpliveallconstruction,coaxialcablelaying,deviceinstallationiscomplete.Installationofequipmentin2.3.4front-endroomshallbeginconstructionafterthefollowingconditionsaremet:Inthecomputerroom,thecivilengineeringdecorationisfinished,andtheoverheadfloor(orantistaticfloor)iscompleted.~220Vequipmentpowersupplyand~380Vequipmentpower(antenna, motor),powersupplypipe,wire,boxallcompletedconstruction.Thecaseofthecaseisstable.Thefeedersandtheirpipelinesandslotsintheengineroomhavebeenlaiddownandintroducedintothecabinetofthemachineroom.Roomair-conditioning,lighting,etc.afterthecompletionofconstructionfacilitiesmaintenancesocketattachment.Specialearthingterminalsarereservedinthecomputerroomforearthingtheequipmentintheengineroom.2.4technicalpreparation2.4.1constructionunitsmusthavetheconstructionqualificationofsystemengineering.2.4.2designdocumentsandconstructiondrawingscomplete,Thedesignconformstotherequirementsofthestate,industry,localstandardsandconstructionunitsThroughtherelevantindustrymanagementapproval.2.4.3designersgivedetailedtechnicalclarificationoftheconstructionpersonnel.2.4.4constructionsitesurveybeforeconstruction,tomeetthe requirementsofsystemengineeringconstructionanddrawings.3,operationprocess3.1processSiteselectionAntennainstallationFrontendequipmentandroomequipmentinstallationTransportpartinstallationUserterminalinstallationGroundinginthesystemSystemcommissioningandacceptance3.2operationmethod3.2.1siteselection3.2.1.1receivethescenetomeettheopenandspaciousconditions,shouldavoidreceivingthedirectionoftransmissionofradiowaves,shieldingandsurroundingmetalComponent,andavoidsomepossibleinterferencefactors,suchas:highvoltagepowerlines,elevatorroom,aircraftchannel,microwavedry Interferencebelt,industrialinterference,etc.,anddonotbetooclosetotheroad.3.2.1.2antennaheightshouldberaisedasfaraspossible,whichcanavoidtheshadowareaaroundthetallbuildingsandincreasethereceivinglevel,Itisbeneficialtoimprovethecarriertonoiseratioofthesystem.Theinstallationpositionofthe3.2.1.3satellitereceivingantennacanalsobechoseninthenonblockingground,whichcanbeusedtoblockthemicrowaveinterferenceTheutilitymodelcanreducethewindloadontheroofofthesatellitereceivingantennaandimprovethesafetyoftheinstallationofthesystem.The3.2.1.4sitelocationshouldbemoderate,shouldbechoseninthecenterofthewholesystem,soastoreducetheradiationofthelayingoftrunkaround.Transmissionlengthoflesstrunk.Thedistancebetweenthefrontengineroomandtheantennareceivingstationshallbelessthan50meters.Beforeinstallinganantenna,3.2.1.5shouldusetestantennaandtestinstrumenttosurveythesceneandselectthebestimagequality Locationandmountingheight.3.2.2antennainstallation:Installationof3.2.2.1satellitereceivingantenna:Installationprinciple:theproductspecificationshallbestrictlyfollowedandoperatedbyprofessionaltechnicians.Antennalightningprotection:iftheantennaisintheprotectionrangeofthelightningrodofthebuilding,theantennadoesnotneedtobeequippedwithalightningrodBesides,alightningrodisarrangedatthetopofthemainreflectingsurfaceandthetopoftheauxiliaryreflectingsurface,andtheheightofthelightningrodshallcoverthewholemainreflectingsurface(see)Fig.3.2.2.1-1)orthelightningrodshallbemountedseparately,andthemountingheightshallbeensuredthattheantennaiswithinitsprotection(seeFig.3.2.2.1-2).Lightningrodgroundingshouldbeindependentoftheline,strictlyprohibitthelightningrodgroundingandindoorreceivingequipmentgroundwiresharing.LightningarresterLightningarresterLightningarrester LightningrodSecondaryreflectorMainreflectorFoundationpierFigure3.2.2.1-1satellitereceivingantennalightningrodinstallationdiagram1Figure3.2.2.1-2satellitereceivingantennalightningrodinstallationdiagram2AntennaFoundation:accordingtotheantennamanufacturerstoprovideproductinformation,andaccordingtotheantennaweightandwindloadandotherindicators,embeddedbasicscrewBoltandbaseplate,andshallensurethattheplaneheightsofthebasepiersremainthesame.Columnhoisting:aftercorrectingthesizeandpositionoftheembeddedbolt,firstlifttheantennapostandfixitontheembeddedboltTightentheflatwasher,springwasheranddoublemother.Applythebutterevenlytotheexposedpartofthebolttopreventthemetalfromrusting.Theassemblyoftheantennasurface:accordingtotheserialnumberofthefactoryassembly,theassemblyprocess,thescrewsshouldnotbetightenedatonce,tobealltheantenna surfaceAfterthecompletionoftheassembly,unifiedfastening,inordertopreventdamagetotheantennasurfaceintheinstallationprocess,affecttheaccuracy.Thewholeliftingoftheantennasurface:theassembledantennasurfaceisintegrallyhoistedonthemainantennapostwhichisinstalled,andisconnectedwiththebolt.stayIntheprocessofassembly,attentionshallbepaidtotheload-bearingpointsontheantennasurfaceframe,soastopreventtheloadcenterfrombeingbiasedduringtheliftingprocessCausetheantennasurfacetotiltordamagetheantennasurface.Iftheantennadiameterisgreaterthan(including)4meters,theantennahoistingschemeshallbeprogrammedProjectconstruction.Antennaselection:maximumreceivingdirectionofsatelliteantennaistoadjustthepitchangleandtheazimuthangle,tomonitorimagenoiseforatleast(ornot)andpayattentiontothebalanceofimagequalityofdifferentTVsatellitechannels.3.2.Itis30degrees~45degrees;iftheantennapoleistoohigh, doublelayercablecanbeused.ThepositionofthecableshallbeavoidedfromtheelectromagneticwavereceivedbytheantennaTo.(4)theanchormustbefirmlyconnectedwiththebuilding,andthecableshallnotbefixedontheroof,ventilationpipe,waterpipeandothercomponents.Installationofthe3.2.2.4antenna(1)theantennaitselfshouldbecarefullyinspectedandtestedbeforeerectingtheantenna.ThedipoleoftheantennashouldbeplacedhorizontallyandadjacentvibrationsThepartsshouldbeparallelandthevibratorshallbefixedwithspringcushionandcushionfirmlyfastened.Thefeedersshouldbefixedsoasnottoswingwiththewind,Andleaveawaterproofbendatthejoint.(2)thecheckedantennaisassembledonthecrossarm,andallthecomponentsoftheantennaareassembledThehorizontalarmoftheantennaisassembledandhoistedtoapredeterminedposition,andthestaffontherodisconnectedwiththeantennaclipfirmly.(3)eachchannelantennaisassembledontheantennapoleinproperpositionaccordingtotheabovemethod;theprinciple highfrequencyantennaisontheuppersideandthelowerchannelTheantennaisbelow,andthedistancebetweenthelayerandthelayerisgreaterthanlambda/2.(4)byobservingthereceivingimageofthemonitorandreadingthemeasuringvalueofthefieldstrength,anddeterminingtheoptimumreceivingpositionoftheantenna,theskywillbesetLinefixation.(5)outdoordevicesandequipmentshallbewaterproof.3.2.2.5groundproduction:buildinglightningprotectionnet,steelavailableon4mm*25mmormorethan10mmdayswillbeflatThemainrod,thebaseandthelightningprotectionnetworkofthebuildingareconnectedintoawhole.Theantennamustbewithintheprotectiveangleofthelightningrod.EarthresistancevalueShouldbelessthan1,specificproceduresaredetailedinthe"lightningprotectionandgroundinginstallationprocessstandards"intherelevantchapters.Installationof3.2.3frontendroomequipment:3.2.3.1operationflow CabinetstabilizationequipmentinstallationEquipmentwiringandidentificationEquipmentgroundingPoweronofequipment3.2.3.2stablecabinet:locationofequipmentandcabinetaccordingtotheplanelayoutofengineroom.Underthecabinet,thecorrespondingpositionwillbeanti-staticTheplateisslottedtoensurethatthecableunderthefloorisintroducedintothecabinet.Whentherackheightexceeds1.8meters,andthenumberofequipmentinstallationisgreaterthanthegroundWhentheplateisloaded,thecabinetisfirmlymountedonthechannelsteelandfixedwithaboltandanantilockwasher,soastopreventthecabinetfrombeingtooheavyDamagetoplateandequipment.Thecabinetshouldbeverticalandstable.Whenthecabinetisplacedsidebyside,thegapbetweenthetwocabinetsshallnotbegreaterthan2mm;Thecabinetpanelshallbeinthesameplaneandparalleltothedatumline.Thefrontandbackdeviationsshallnotbegreaterthan2mm. 3.2.3.3equipmentinstallation:theequipmentinstalledonthecabinetshallbearrangedinanorganiccombinationaccordingtotheusefunction(seeFigure)3.2.3.3).Fixtheequipmentonthecabinetbyusingscrews,gasketsandspringgasketsarrangedinarandomcabinet.ThetopandbottomofeachdeviceSpaceshouldbekept1U(orgreaterthan50mm)spacetoensurethattheequipmentupanddowntokeeptheaircirculation,coolingspace,Thegapismadeofaspecialblankpanelpackage.Fornon-19"standardcabinetmountingequipment,standardtraycanbeinstalledColormonitorshallbeequippedwithspecialTVset,specialtrayandpanelmount.Program1receiverProgram1modulatorProgram2receiverProgram2modulatorprogram4modulatorProgram4receiverProgram3modulator Program3receiverProgram6modulatorProgram6receiverProgram5modulatorProgram5receiverPreamportrunkamplifiermixerProgram7modulatorProgram7receiverReserveFig.3.2.3.3sketchmapofequipmentlayoutofcabinet3.2.3.4devicecablingandidentification:(1)thegroundlinetroughisusuallyusedinthemachineroom,andthecableisintroducedatthebottomofthecabinet.Cablelayingshouldbestraightwithoutkinking,nottiedInthecableinletandoutletslot,shouldbetiedatthecorner,andpayattentiontotheradiusofthebend,thecablecannotbebroken. (2)whenthecabletrayisadopted,thecableshouldbebroughtintothecabinetatthetopofthecabinet.(3)usingTVcableandFtypespecialplugtoconnecttheequipmentaccordingtothedrawing.ThepowersupplyoftheengineroomisledtothepurifiedpowersupplyAfter,Andthenfortheuseofequipmentintheroom.TheTVcableandpowerlineofthebackofthecabinetshallberespectivelydistributedonbothsidesofthecabinetInthegroove,thebundleistiedbytheloop.Theequipmentinstalledinthecabinetshallidentifythechannelreceivedbytheequipment,andtheendsofthecableshallbemorethanenoughMeasureandmakeapermanentmark.3.2.3.5equipmentgrounding:theoutdooroverheadcableshouldbepassedthroughthearresterbeforeitcanbeintroducedintotheroomequipment.InthecomputerroomMetalsheatharrester,cabinet/box,metalshell,cableequipment(orshield)shallbeconnectedtothetotalroomgroundingbusOn.Thegroundresistanceofthefrontgroundingunitisnomorethan1ohms. The3.2.3.6deviceisenergized.3.2.4transportsectioninstalled:3.2.4.1activedevices(suchastrunkamplifiers,branchtrunkamplifiers,extendedamplifiers,distributionamplifiers)Install:(1)thetrunkamplifier,branchtrunkamplifier,extendedamplifieranddistributionamplifiershallbeinstrictaccordancewiththeconstructiondrawingsCarryoutconstruction.(2)whenitisinstalled,theTVcableneedstobeelevatedthroughthepole;thefieldtypeamplifierismountedonthepoleorabout1metersWithintheplace,andshallbefixedonthecableline,fieldamplifiershouldbeusedinsealingrubbergasketsealing,andtheuseofThecastaluminumshellwithgoodheatdissipationshallbemadeofmeshmetalhighfrequencyshieldingring,andensuregoodcontactwiththegroundPartsshouldhavegoodwaterproofandcorrosionresistance,andtheoutsideshouldbewaterproofwithrubbersleeve.Amplifiersandotherdevicesthatdonothavewaterproofconditions Partsshouldbeinstalledinwaterproofmetalbox.(3)darkloading:accordingtothedesignofdrawings,aswitchboardisplacedinsidetheTVbox,andallthecomponentsintheboxarefixedbymachinescrewsOnthedistributionboardinthebox,theequipmentonthedistributionboardisledfromthebackofthepaneltothefrontofthepanel.PutitinthedoorpanelinsidetheboxThesystemdiagramoftheequipmentintheboxandindicatethedirectionofthecableandthesignalinputandoutputlevelforfuturemaintenanceandinspection.(4)poweramplifiershallbeleftintheamplifiercase.3.2.4.2cablelaying:(1)thelengthoftrunkcablesshallbeselectedorcustomizedaccordingtothedesignlengthofthedrawingssoastoavoidthetransmissionofthemaincableCablesplicing.(2)whenthecableislaidthroughthepipe,itshallclearthepipefirstandtiethecablewiththereservedstripinthepipePullthecableintothepipe.(3)overheadcablelaying,cablewireshouldbefixedonthe cablerodwithasplint,andthenputthecardinthecablecablehookHangingon.Thespacingofthehookshouldbe0.5m~0.6m.Keepacertainsagaccordingtoclimaticconditions.(4)whenanaerialcableoracablelayingalongthewallisintroducedintotheground,asteelpipeisusedwherethegroundisnotlessthan2.5mProtection;steelpipeshallbeburiedintheground0.3m~0.5M.(5)theerectionofcablesalongthewallshallbeprovidedwithwallsupportsandsupportsonthewall,andtheslingsshallbesecuredtothecrossmember,andthenshallbeattachedtothecablesHangthecablecardonthesling.Thedistancebetweenthewallsisgenerallynotgreaterthan6m.(6)whenthecableisburieddirectly,itmustusearmoredandburiedcable,anditsburieddepthshallnotbelessthan0.8M.tightThecableshouldbecoveredwithfinesoil,10cm,coveredditchcoverplate,andmarked.Itshouldbeburiedbelowthefrozengroundincoldareas.Installationofthe3.2.4.3branchallocator: ThebranchdistributorshallbeinstalledinabranchdistributorboxoramplifiercaseandfixedwithamachinescrewinthecaseswitchboardTheboxsizeshallbedeterminedaccordingtothequantityoftheequipmentinthebox.ThecaseismadeofironandcanbeequippedwithasinglefanordoublefanboxdoorReservedearthingbolt,distributionboardinthebox.3.2.5distributionnetworkpartialinstallation:distributionnetworkpartoftheinstallation,includingthedistributionofamplifierinstallation,branchdistributorinstallation,powerCablingandinstallationofuserterminals.Installationof3.2.5.1userterminals:Checktherepairboxmouth:checktheboxmouthhasunevenplace,shouldbetimelymaintenancesmooth.Thecassetteoutsidethemouthshouldbeflushwiththewallbox;Theelevationshallcomplywiththedesignspecifications,withoutspecialrequirements,TheTVsubscriberterminalis300mmawayfromtheground,awayfromthestrongcurrentsocketHorizontaldistance500mm;plaincaseshouldbefirm. CablesheathCableshieldCableinsulationmediumcablecorewireLinecardFigure3.2.5.1userterminalcrimpingdiagram(2)linecrimping:firstcutthecablejointinto100~150mmlength,thenthe25mmcableisinsulatedoutsideThesheathisstrippedoff,thentheouterwirecoppernetisbrokenupandwovenintobundles,leavingtheinsulatedplatformof3mmandthe12mmcoreline,andpressingthecorelineinTheterminalpressesthecoppernetwiththeOmegacard.Asshown:(3)fixingtheboxcover:theimpedanceoftheusersocketis75,andthepanelisfixedbymachinescrews.3.2.6systemgrounding3.2.6.1shieldinganddevicemetalgrounding:toreduceinterferenceinthecablesystemdevice(includinghighfrequencyinterferenceandAlternatingcurrentinterference)andpreventlightningstroke, themetalshellofthedeviceneedstoshieldtheearth,allconnected,andgoodgrounding.The3.2.6.2metallineshallbeconnectedwiththegroundingofthelightningprotectionofthebuildingasawhole.3.2.6.3systemmaintenancepersonnelregularlydolightningprotectiongroundinginspection.3.2.7systemtesting3.2.7.1antennadebugging(1)theerectionoftheopencircuitantennashallcheckwhethertheinstallationpositionofthereceivingchannelsisnormal;thepitchofthesatelliteTVantennaandIsthepositionoftheazimuthnormal?.(2)thefieldlevelmeterisusedtomeasurethelevelofthereceivedsignaloftheantenna,andthedirectionoftheantennaisfinetuned,sothatthelevelindicatorofthefieldstrengthinstrumentreachesthemaximumBig.Atthesametimetoobservethereceivedtelevisionpicturequalityandsoundquality,noghosting,nosnow,nonoise(oroccasionalnoise,Butdonothateit,fixedantenna,andtheantennasignaldownthefeeder,lashingneat. 3.2.7.2frontenddevicedebugging(1)theTVsignalsofeachchannelareconnectedintothemixer,andthefieldtesterisusedtotestthemixerentrance,andtheoutputofeachchannelisadjustedLevelvaluesothattheoutputlevelofeachchannelislessthan2dB.Iftheadjustmentknobofthemixerisnotadjusted,theelectricityof2dBcannotbereachedWhenadjusted,anattenuatorcanbeaddedtoachannelwithahighlevelvalue.(2)adjustthereceivingfrequencyandotherparametersofthesatellitereceiver,andadjusttheoutputlevelofthemodulatortothedeviceThenominallevelvalueistestedbytheoutputdetectionportofthemixer,andthenthechanneltuningknobandamplifierofthemixerareadjustedappropriatelyOutputlevel,andfinallythemixeroutputleveldifferenceis+1dB,andthelevelvalueconformstothedrawingdesignrequirements(ifthereisnodrawingdesign)Indicatorsshouldbecalculatedandallocatedbeforeconstruction,andthelevelvaluesofactiveequipmentshouldbecalculated.(3)debugthepreamplifier(ortrunkamplifier)ofthecomputerroom:adjusttheoutputleveloftheamplifieraccordingtothe designrequirementsofthedrawingAbalancingknob(orreplacementofanappropriateattenuationvalue)designedtoachievethelevelvalueofadrawing,usuallypractice,amplifierTheoutputlevelshouldnotbegreaterthan100dB.Forsystemswithlargescaleandlongtransmissionlink,alowerlevelisrecommendedTheleveldifferenceofadjacentchannelislessthan0.75dB,theleveldifferencebetweeneachchannelislessthan2dB.(4)whenthefront-enddeviceisdebugged,thesignalistransmittedtothetrunksystem.3.2.7.3trunkamplifierdebugging:accordingtothedesignofthelevelofthevalueofthetest,adjusttheoutputlevelandoutputlevelSlope。Iftheimagegeneratesintermodulationinterference,theoutputleveloftheamplifierishigherthanthemaximumoutputpoweraftertheallocationofthesystemindexLevelingshallbereassignedandadjustedaccordingtothedesignvalueofreaccountingtheamplifieroutputlevel.Commissioningofthe3.2.7.4distributionnetwork:adjusttheoutputlevelandslopeofthedistributionamplifieraccordingtothedesignrequirementsofthedrawings.Ineachsystem TheuserterminalistestedtoseewhethertheuserterminallevelisuptothesystemdesignrequirementsandthatthedesignrequirementscannotbemetproperlyAdjusttheoutputlevelandslopeofthedistributionamplifierandthepassivedevicesuchasbranchdistributortoachievethedesignrequirements.systemTheuserterminalleveliscontrolledat64+4dB,andthecolormonitorisusedtoseeiftheimagequalityisclear,whetherthereissnoworastripPattern,alternatingcurrentinterference,etc..3.2.8systemacceptance:fieldtest,andfillinthefrontendtestrecord,amplifierleveltestrecord,userterminalleveltestRecordtherecordsandcheckwiththerelevantmanagementdepartment.4,finishedproductprotection4.1wheninstallingopencircuitantenna,mainpoleandsatelliteantennaontheroof,thebuilding,roofwaterproofanddecorationshallnotbedamagedandmaintainedFieldcleaning.4.2,setintheceilingofthebox,box,intheinstallationofcomponentsshouldnotdamagethekeelandceiling. 4.3repairingtheslurryshallnotcontaminatethesurfaceofthedeviceandpreventwaterfromenteringtheinteriorofthedevice.4.4theuseofhighTishi,donottouchthebrokendoorsandwindowsandwalls.5,shouldpayattentiontoqualityproblems5.1nosignalTreatmentmeasures:(1)failureoffront-endpowersupplyorfailureofactiveequipment.Thepowersupplyvoltageormeasurementinputsignalshallbechecked(whetherornot).(2)thefaultofthereceivingantennasystem.Shortandopentransmissionlines,plugconnections,frontendconvertersandfrontendantennaamplificationshouldbecheckedSuchdevice.(3)thepowersupplyfailureofthelineamplifier.Checkwhethertheinputplugisopen,andthendetectthepower,insurance,power,etc.Theoutputsignalandthepowersupplyofeachamplifierarecheckedattheendofthesignalsource. (4)trunkcablefault,checkwhetherthecablefromthefirstendtotheamplifieratalllevelsisopenorshort,andcheckallkindsofcableplugHead.The5..2signalisweak,andallsignalshavesnow.Thisphenomenonisthatthesignallevelhasnotreachedthestandardlevel.Treatmentmeasures:(1)thefaultoftheantennareceivingsystemcheckswhetherthesignalreceivedbythefrontendisclearandwhethertheantennafacesdeviation.(2)thefront-endequipmentisoutoforder,whethertheinputandoutputoftheactiveequipmentisnormalornot,iftheequipmentisnormal,thecable,feederandsoonThereisnoshort-circuitphenomenon.(3)thetransmissionlineisfaulty.TheoutputsignalofeachamplifierandthepowersupplyoftheamplifierarecheckedfromthesourcetothedirectionoftheprogramsourceIsthepowernormal?.(4)whetherthereisashortcircuitinthepassivedeviceinthedistributionnetworkandwhetherthecableisdamagedornot. 5.3imageghostingHandlingmeasures:belongstotheantennareceivingquestion.Amonitorisusedtoobservetheimagequalityofareceivedtelevisionsignal,ifitisapreghostingimage,Becausetheintensityofthereceivedsignalistoostrong,itisnecessarytoprocessthesignalatthefrontofthesignalThereceptionsignalofthefrontendisreflectedbythesurroundingbuildings,andthepositionoftheantennashouldbeadjustedsoastoavoidtheghostingcausedbythereflection.5.4,theimageappearsstripe,transverseinterference:Handlingmeasures:theoutputlevelofanactivedevicesuchasanamplifieristoohigh,exceedingthemaximumoutputleveloftheamplifier,orexceedingthatoftheamplifierIndicatorforsourcedeviceallocation.Appropriateloweringlevel.5.5someoftheimagesarestripedinterference,andsomeimagesareclearHandlingmeasures:thelevelofthechannelsistoolarge,causinghighlevelchannelstointerferewithlowlevelchannels.Levelshouldbeleveled. 5.6,imagesappearACrolling,crosschannelinterferenceHandlingmeasures:systemshielding,groundingisnotdonewell,atfault,aswellasprioramplifiersandsplitters,andshieldedenclosuresofcablesEvenasawhole,reliablegrounding.'