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TheseinstructionsarewrittenbytwousersonRCGroups:jj604andDaedalus66.WehavenoconnectionwithLemonRX.

LemonRXandOrangeRXarebrandnames.Spektrum,DSM2,DSMX,X-BUS,Airware,STi,andtheTelemetrylogoareTradeMarksofHorizonHobby.Thesenamesareusedheresimplyasdescriptionsofthoseitems.

NOTE:AnyDSM2andDSMXlogoshavebeenobliteratedinthephotographstoavoidanyTrademarkissues.

InstructionsforLemonRXReceivers1.TheDistinctionbetweenDSM2andDSMX.........................................................................12.Binding................................................................................................................................................23.WhattheLEDsMean.....................................................................................................................34.AntennasandSatellites...............................................................................................................45.ConnectionsandSwitchesontheVariousLemonReceivers......................................66channelDSM2-compatible......................................................................................................66channelDSM2-compatibleUltra-Light..............................................................................76channelDSM2-compatibleMicroLight.............................................................................76channelDSMX-compatible.....................................................................................................87channelDSMX-compatiblestabilizer.................................................................................88and10channelreceivers........................................................................................................98channelDSMX-compatiblePPMreceiver......................................................................10SatelliteReceivers.......................................................................................................................10

6.Failsafe.............................................................................................................................................11

1.TheDistinctionbetweenDSM2andDSMXLemonRXmakesbothDSM2-compatibleandDSMX-compatiblereceivers,thoughincreasinglytheirrangeofproductsemphasizesDSMXcompatibility.TheDSMXprotocoldevelopedbySpektrumincludesfrequencyhoppingformorereliableoperationinareasofhighpotentialinterferencefromother2.4GHztransmitters,butreceiversusingtheolderDSM2protocol,alsobySpektrum,continuetoworkwellinallbutthemostdemandingconditions.

Lemon“DSMX-compatible”receiversworkwithanyDSMX-compatibletransmitterandarebackwardcompatiblewitholderDSM2-typetransmitters.

Lemon“DSM2compatible”receiversworkwitheitheraDSM2-compatibletransmitteroraDSMX-compatibletransmitteroperatingonDSM2.MostrecentSpektrumDSMXtransmitterssupportbothmodesandwillautomaticallydetectaDSM2receiveratbindtime(NolongertrueintheEU–seebelow).

EUUpdate.AsignificantchangeofregulationsintheEuropeanUnionrequiresthattransmitterssoldthereafterJanuary1,2015NOTincludeDSM2modulation.Consequently,newDSMXtransmittersnowsoldintheEUsupportonlyDSMX-typereceivers.TransmitterssoldpreviouslythatincludeDSM2capabilitywillcontinuetobefullylegalforuse.

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DXeUpdate.TheEUrequirementsdonotdirectlyaffectotherpartsoftheworld,butthenew(2015)low-costSpektrumDXetransmittersupportsonlyDSMX,whereveritissoldintheworld.OtherSpektrumtransmitters,includingnewonesreleasedinearly2016,continuetosupportbothDSMXandDSM2exceptintheEU.

2.BindingBindingistheprocessof“locking”thereceivertoitsowntransmitter(and,whererelevant,toaparticularmodelmemorywithinthetransmitter)sothatitignoresanyothers.Bindingisthefirststepinsettingupanyreceiver.Ensurethetransmitterandreceiverareseparatedby3-6ft/1-2morthetransmittermay“swamp”thereceiver.Occasionally,itmaybenecessarytohaveasmuchas10ft/3mseparationtoachievebinding.Generallyyoushouldonlyneedtobindonceand,afterbinding,normallink-upshouldnotrequiremorethanacoupleoffeetofseparation.

Step1.PowerupthereceiverinbindmodeFormostreceivers:putthebindplugontothebindpins.For6-channelUltraLightandMicroLightreceivers,pressandholdinthebindbutton.Connectasuitablepowersourcetothereceiverthrottleservopins.Thiscanbe:

• areceiverpackbattery(generally3.45–7.2v)1;or• astand-aloneBEC;or• thethrottleconnectionfromyourspeedcontroller(ESC)withinbuiltBEC

(iftheESCisinamodel,disconnectthemotororremovethepropeller).

TheredLEDonthereceiverwillflashrapidlytoindicatebindmode.Ifitdoesn’t,youhaveaproblem(suchasreversedpowerconnector).MakeabsolutelysuretheLEDisflashingrapidlybeforegoinganyfurther.

Step2.TurnontransmitterinbindmodeOnsometransmittersbindmodeisactivatedbyholdingtheTrainerbutton/switchorbindbuttonwhilepoweringup.Othersrequiregoingintoamenutoenablebindmode.Ifindoubt,readthemanual.

Whereappropriate,continuetoholdtheswitch/buttonuntilthereceiverLEDstopsitsrapidflashing.Releaseitatthatpointandthebindprocesswillcomplete.AsolidlightontheLEDindicatessuccessfulbind.

Sometransmitterswilldisplayonscreenorannouncethetypeofbind(DSM2orDSMX)andtheframerate(normally22mS).

Step3.PowerdownandtestRemovepowerfromthereceiver,removethebindplug(veryimportant!)andswitchthetransmitteroff.

Turnthetransmitterbackon,thenapplypowertothereceivertocheckthatthereceiveroperatesproperlyandservosrespondtothetransmittercontrols.

1Checkindividualspecificationsassomereceiversmayworkwithinadifferentvoltagerange.

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NOTES:1. Ifasatelliteisused,itmustmatchthemainreceiver;thatis,aDSM2-

compatiblereceivershouldhaveaDSM2-compatiblesatellite,andlikewiseforDSMX-compatibleunits.

2. IfyourreceiverusesasatellitethenbindingMUSTbedonewiththesatelliteconnected.BothreceiverandsatelliteLEDsshouldflashrapidlyatthebeginningofthebindprocess,thenbecomesolid.

3. Bindingcanbedonewithorwithoutservos.Servospluggedinthewrongwayroundmaypreventbinding,socheckthisifyouhavedifficulty.

4. IfyouexperiencedifficultygettingaDSM2-onlyreceivertobindwithaDSMXtransmitter,tryforcingthetransmitterintoDSM2mode(iftheoptionisavailable).

5. Alwaysperformarangecheckafterbinding,usingtherangecheckfunctiononyourtransmitter.Thisattenuatestransmitterpowersothatrangeisreducedbyafactorofabout30.WithSpektrumtransmitters,fullcontrolinrange-checkmodeat30yds./25m(roughly30pacesformanyadults)indicatesamplerangefornormalvisualflying.Itisgoodpracticetoperformarangecheckatthebeginningofeveryday’sflyingtoensureeverythingisworkingproperly.

3.WhattheLEDsMeanAllLemonreceiversandsatelliteshavearedLED.Some,includingthe7-channelstabilizer,alsohaveLEDsofothercolors.

1. ArapidlyflashingredLEDindicatesthereceiverisinBindmode2. AsolidredLEDindicatesnormalradiolinkbetweenreceiverand

transmitter.3. NoredLEDmeansthereisnoradiolink.4. AslowlyflashingredLEDonareceiverinDSM2compatiblemode

indicatesthattherehasatsomestagesinceitwaspoweredupbeenapowerlossorsignificantvoltagedrop(howeverbrief),oftencalleda“brownout”.Theflashingmayindicateaninadequatereceiverpowersupplyoritmaymeansimplythattheoperatorfailedtoturnoffthetransmitterwhenpoweringdownthereceiver.Itdoesnotindicatearangeorsignallossissue.ReceiversinDSMX-compatiblemodedonotprovidethis“brownoutwarning”.

5. Onthe8/10-channelDSM2compatibleand10-channelDSMXcompatiblereceiversarapidlyflashingGreenLEDatpowerupindicates11mSframeratemode.

6. Onreceiversequippedwithafailsafebutton,asolidgreenLEDindicatesthatuser-defined(preset)failsafehasbeenset.NogreenLEDonthesereceiversindicatesthatfailsafeisinthedefaultmode,inwhichlossofsignaltriggersremovalofallpulsesfromtheoutput.Thisisexplainedinthesectiononfailsafe,startingonpage11.

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7. The7chStabilizedreceiverhasbothredandgreenLEDsthatareusedtoindicatebindingandstabilizationstatusaswellasreceiverversion.Seetheseparateinstructions(availableontheLemonwebsiteorintheRCGroupsLemonInstructionsthread)forinformationonsettingupthestabilizer.

8. The7chTelemetryenabledPPMreceiverhasred,greenandblueLEDsthatareusedtoindicatebinding,stabilizationandPPMstatus.Seetheseparateinstructions(availableontheLemonwebsiteorintheRCGroupsLemonInstructionsthread)forinformationonsettingupthisreceiver.

4.AntennasandSatellitesAllLemonreceiversare“fullrange”,includingthe“Light”series.InpracticeLemonreceiversmatch,orbetter,therangeofcomparableSpektrumDSM2/DSMXandotherDSM2/DSMX-compatiblereceiversunderthesameconditions.Howevertherangeofanyreceiverisaffectedbythenumberofantennas(aerials)andtheirorientation,aswellasbytheinstallationinthemodel,makingcomparisonsdifficult.

SomeLemonreceiversandsatelliteshaveoneshortactiveantennawire,whileothersalsohaveasecondidentical“reflector”wire.Somecomewithlongertwindiversityantennasorhavethemasanoption.Forthestrongestandmostreliablereceptionthereareanumberofgoodpracticestofollow.Forreceiversandsatelliteswithshortwireantennas:1. Thewire(s)shouldstickreasonablystraightoutfromthereceiver/

satellite;wheretherearetwo,theyshouldbeinanapproximatelystraightline.Antennasthatarebentalongthereceiver/satelliteboardmayhaverangereducedby10-15%.

2. Ifasatelliteisconnected,itshouldbelocatedasfaraspossiblefromthemainreceiver,notrightnexttoit.

3. Ifasatelliteisconnected,mostreliablereceptionisobtainedwhenthesatelliteantennaandmainreceiverantennaareatrightangles.

Thelargernon-diversityreceivers(e.g.,7,8-and10-channel)donothaveasecondshortantennawire,asthecircuitboardservesthereflectorfunction.

Asmallreceiverwithonlyasingleantennawire(includingsatellite-enabledreceiverswhenoperatedwithoutasatellite)willgenerallyhavelessrangebyabout10-15%thananequivalenttwinshortantennawireversion.Thisisstillamplerangefornormalflying.Forreceiversandsatelliteswithdiversityantennas:Receiversandsatelliteswithdiversityhavetwoantennasmadeofcoaxialcablewiththelast32mmofouterinsulationandconductivesheathremovedtocreateawhiteorsilveractiveportion(theantennaproper).

Theantennacablesareconnectedtoanelectronicswitchthatselectstheonecurrentlywiththestrongeravailablesignal.Thereceiverwillswitchantennasveryquicklyifthesignalfromtheoneitisusingstartstodropinstrengthbelowthesignalfromtheotherantenna.Theswitchingoccurswithin300mSandnosignalislostduringtheswitchingperiod.Thisantenna-switchingstrategyiscommonlycalled“diversity”intheRCworld.

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Somereceiversalsohaveaconnectortoallowtheuseofasatelliteforadditionalsignalrobustnessthroughanotherformofdiversity.Thesatellitemaybeeitherashortantennatypeoronewithdiversityantennas,buttheprotocolsofreceiverandsatellite(DSM2orDSMX)mustmatch.Asatellitedoesnotsignificantlyincreasethemaximumpossiblerange.Rather,asaseparatestand-alonereceiveritincreasestheprobabilitythatareliablesignalwillbeobtainedatalltimesnomattertheorientationofthemodel.Themainreceiverselectsthestrongerofitsownbestsignalorthatofthesatellite.Notethatifboththereceiverandthesatellitehavediversityantennasthisgivesuptofourseparatesignalsourcesforthereceiver/satellitecombination.Theantennasweuseforradiocontrolradiate(andreceive)inalldirections,butthesignalismuchweakerofftheendsoftheantenna(theactiveportionofthecable)than"broadside"toit.Thinkofanancientnavalbattlewheretheshipshadverylittlefirepowerforeandaftbecausemostoftheircannonwerepointedoutthesides.Toachievethemostreliablepossiblelinktothemodel,therefore,whatwewanttoavoidaresituationsinwhichthetransmitterandreceiverantennasareend-ontoeachother.Forthetransmitter,theadvicetothepilotissimple:don'tpointtheantennaatthemodel.2Forthereceiver,thingsaremorecomplicatedbecausethemodelisconstantlychangingitsorientationrelativetothetransmitter.Asinglereceiverantennawillinevitablybepointedatthetransmittersomeofthetimeandthusinarelativelyweakorientationforreception.Thisiswherediversitycomesin.Ifthereceiverhastwoactiveantennaspositionedatrightanglestoeachother,theycanneverbothbepointedatthetransmittersimultaneously.Thereceiverjusthastoselecttheantennathatisgivingthebettersignalrightnow.That'swhatdiversityswitchingdoes.

DiversityimprovesthereliabilityoftheRFlinkinotherways.Ifthetworeceiverantennasarewellseparated,atleastoneshouldhaveaclearviewofthetransmitter,minimizingtheriskofsignalblankingbyconductivematerialsonboardthemodel.Aswell,withantennasatrightangles,oneofthemshouldbesomewherenearparalleltothetransmitterantenna,thusroughlyaligningpolarizationforastrongersignal.Conductivematerialssuchasfoilcoverings,batteries,metalcomponentsandcarbonfibercanabsorbandshieldtheincomingradiosignal.Radiosystemson2.4GHzhaveaveryshortwavelengthandaresusceptibletothis.Receiverantennasneedtobeplacedsothatthiseffectisminimized.

InsummaryWhatallthismeansfortheinstallationofareceiverissimple.

Ifthereceiverhasdualdiversityantennas,makesuretheactivetipportionsareseparatedasfaraspracticalfromeachotherandfromconductivestufflike

2SomeSpektrumtransmittersovercomethisissuebyincorporatingdualdiversityantennasorientedatrightangles.TheDX9and2016versionoftheDX6areexamples.

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battery,wiringandcarbonfiber.3Aligntheseportionssotheyareatrightanglestoeachotherandreasonablystraight.Thecoaxcableportionoftheantennascanbecurvedtoachievethisbutmustnotbesharplybent.

Ifasatelliteisconnected,itshouldbewellawayfromthemainreceiver,notrightnexttoit.Alignitsothesatelliteantenna(s)andatleastonemainreceiverantennaareroughlyatrightangles.

Takeallthisseriouslybutdon'tgetparanoid.Theinstallationdoesn'thavetobeperfecttosupportanadequatelystrongRFlink.Ourmodernreceiversdoaremarkablejobofpickingupthesignal,evenwithjustasimplesingleantenna.Diversityisnotessentialinmostcasesbutcanbethoughtofasextrasecurityforwhenthegoinggetstough.

And,asalways,rangetestingisessential.Itshouldbedoneverythoroughlybeforethefirstflightofanewinstallation,withreceptiontestedfromalldirectionsbywalkingaroundthemodel.Ifcontrolbecomeserraticfromanydirectionat25mrangeit’stimetoreviewandimprovetheinstallation.Oncethesetupisproven,aquickrangecheckat30pacesbeforethefirstflightofthedayisallthat’sneededtocheckthatthingsareworkingastheyshould.

5.ConnectionsandSwitchesontheVariousLemonReceiversTheavailablerangeofLemonreceiverscontinuestoevolve,withemphasisonDSMXcompatibility,butthefollowinginformationshouldbehelpfulevenasthemixchanges.ChecktheLemonRXwebsiteforcurrentlyavailableunits.

Lemonreceivershaveconnections,plugorientationandswitchfunctionidentifiedonthePCboardorcase.Thepositivepinsforallchannels(andthebindslot)areconnectedtogether,asareallthegroundpins;powercanbeappliedtoanysetofpinsandifnecessaryaY-cablecanbeused.

6channelDSM2-compatible

Endpinandstraightpinversionsaresimilar.

3Helicopters,multicoptersandglidersthatuselotsofmetalorcarbonfiberconstructionrequireparticularcareinlocatingreceiversandsatellitestoensurethatatleastoneantennareceivesaclearsignalregardlessoforientation.

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6channelDSM2-compatibleUltra-LightWithJST-ZH1.5mmpitchconnectors.TheseconnectorsarethesameasSpektrumAR6300Nanolitereceiverstyle.

6channelDSM2-compatibleMicroLightWithJST-SH1.0mmpitchconnectors.TheseconnectorsarethesameasSpektrumAR6400Brickstyleforlinearservos.

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6channelDSMX-compatible

OnlyuseaDSMX-compatiblesatellitewiththisreceiver.Itisalsoavailableinadiversityantennaversion.

7channelDSMX-compatiblestabilizerSeeseparateinstructionsfordetailsofhowtosetupthe7-channelstabilizer.

OnlyuseaDSMX-compatiblesatellitewiththisreceiver.

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8and10channelreceiversThesereceivershavebeenmadeinDSM2-compatibleandDSMX-compatibleversions.Useonlythematchingtypeofsatellite.

Onthesereceiversaconnectornexttothebindconnectorislabeled“UART”.Thisisaserialconnectionthatcanprovidedatatootherexternaldevicessuchacontrolleroron-screendisplay.Itisnotusedwherethereceiverstandsalone.

Toenablean11mSrefreshrateforhigh-speeddigitalservos,abindplugisinsertedinthisconnectorduringbinding(seebelow).

Using11mSFrameRateBothDSM2-compatibleandDSMX-compatibleversionsofthe8-channeland10-channelreceiverscanbesettofunctionin11mSmode.Thisshouldonlybedonewhenallservosaredigitalandcapableofan11mSrefreshrate.

1. InsertbindplugsintoboththeBindandUARTconnectorsonthereceiver.2. Providepowertotheunit.TheredLEDshouldflashrapidly.3. Enablebindmodeintransmitter(ensuringadistanceseparationofatleast

3-6feet/1-2metersfromreceiver).4. WhenthereceiverbindsandtheLEDissolid,powerdownandremove

bothbindplugs.5. Everytimefromnowonwhenthereceiverispowered,aquicklyflashing

greenLEDindicates11msframerateisenabled.6. Tocancel11mSmode,rebindnormallywithouttheUARTbindplug.

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8channelDSMX-compatiblePPMreceiver

Thisreceiverdoesnotallowforconnectionofservosoraspeedcontrol.ItisdesignedtoprovideaPPM(alsocalledcPPM)streamsuitableforusebyaflightcontroller(orinawirelesstrainersystemorflightsimulator).

UsingthePPMstreamwithaFlightControllerThisreceiver,anditsDSM2-compatiblepredecessor,outputschannelpulsesinthesequencesentbythetransmitter,normallyTAER.Itcannotcorrectforincompatibilitiessuchasthatbetweenatransmitter(suchastheSpektrumDX8),whichusesthestandardSpektrumTAERchannelorder,andaflightcontrollersuchasNAZAthatrequirestheso-calledFutabasequenceofAETR.FortransmitterssuchastheSpektrumDX9,FrSkyTaranisorTurnigy9XR,inwhichthechannelassignmentscanbechanged,thisisnotanissue.TheabilitytoallowtheusertoswitchbetweenTAERandAETRreceiveroutput(giventransmitterchannelorderofTAER)isnowavailableonthe7channelTelemetryenabledDSMX-compatiblediversityPPMreceiver.Seeseparateinstructionsfordetailsofhowtosetupthatreceiver.

SatelliteReceiversTheLemonDSMXandDSM2-compatiblesatelliteslooksimilarbuttheplastichousingismarkedwiththeletters“DSMX”or“DSM2”(obliteratedinthephoto).Thecorrectsatelliteshouldbeusedwithareceiver.

Notethatthesatellitemustbeattachedtothereceiverforbinding.Bothwillshowasolidredlightwhenbound.

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6.Failsafe4Theprimarypurposeoffailsafeistominimizetheriskofinjuryanddamageshouldthereceiverlosesignalwhilethemodelispoweredup,whetherflyingorontheground.Thekeysafetyrequirementisthatthemotorbeshutdownonlossofsignal.

ThreetypesoffailsafeareusedbythevariousLemonreceivers:

1.Throttle-onlyPre-setOnlossofsignal,thethrottlegoestoapresetpositiondeterminedbythepositionofthethrottlestickduringbinding.Otherchannelsreceivenopulsesandthusservosstayintheircurrentpositions.ThisissimilartotheSpektrum“SmartFailsafe”approach.

Tosetthecorrectthrottlefailsafetheusermustplacethethrottlestickinfulllowpositionwhenbinding.Thisisveryimportant!

ThistypeoffailsafeisusedonlybytheLightseriesof6-channelDSM2-compatiblereceivers.

2.NoPulseModernspeedcontrols(ESCs)goautomaticallytoOFFifnocontrolpulsesareavailable.ThisimportantsafetyfeaturecanbeusedtoachievefailsafebehaviorifonlossofsignalthereceivercutsoffpulsestotheESCandotherchannels.Thisresultsinthemotorshuttingdownandtheservosnotmoving.

Anadvantageofthisapproachisthatitdoesnotrelyontheoperatortoensurethatthethrottlestickisatlowpositionwhenbinding.However,itisnotsuitableforusewithamodelpoweredbyaninternalcombustionengine(gloworgasoline),orwithanESCthatlacksautooff.ThistypeoffailsafeisusedbytheLemon7-channelstabilizer.

NoPulseFailsafeisthedefaultforthe6-channelDSMX-compatible,7-channelTelemetryenabledDSMX-compatiblePPMreceiver,8and10channelDSM2-compatibleandDSMX-compatiblereceivers,and8-channelPPMreceivers(boththecurrentDSMX-compatibleversionandtheearlierDSM2-compatibleunit).

3.User-DefinedFailsafeThistypeoffailsafeallowstheoperator,afterbindingthereceiver,tosetthedesiredfailsafepositionsofallchannels.Thisallowsforsuchspecialfailsaferequirementsashavingaglidergointoaspiralwithspoilersdeployedinordertopreventaflyaway.Likewise,multicoptersmayhaveafailsafecommandtoreturnhomeusingGPS.User-DefinedFailsafe,alsoknownasPre-setFailsafe,isausersetoptiononthe6channelDSMXcompatible,7-channelTelemetryenabledDSMXcompatiblePPMreceiver,and8and10channelreceivers,includingthePPMunits.Asexplainedabove,thedefaultforthesereceiversisNoPulseFailsafe.

4Thissectionhasbeenrevisedtocorrectsomeinformationinthefirstversionoftheinstructions.

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SettingUser-DefinedFailsafe.Whereuser-definedfailsafeisavailable,thereceivercanbesettouseitasfollows:1. Powerupthetransmitterandreceiver(whichshouldalreadybebound).

DoNOThavethetransmitterinbindmode.2. Applythebindplugtothereceiverbindpins(withpoweron).3. Setthetransmittercontrolstothedesiredfailsafepositions.4. Pressinthefailsafeswitchonthereceiverbriefly.5. TheGreenLEDonthereceiverwillturnontoindicatethatfailsafe

positionshavebeenstored.Henceforth,wheneverthereceiverispoweredup,thegreenLEDwillindicate“user-definedfailsafe”.Ifsignalislost,thereceiverwilloutputthepre-setpositionsafterapproximately3secondsandmaintainthemuntilavalidsignalisagainreceived.

Testthefailsafesettingsbyturningoffthetransmitter,aftertakingallnecessaryprecautions,suchasremovingpropellersorrestrainingthemodel.

Toreturntothedefaultno-pulsefailsafewiththesereceivers,simplyrebindthereceivernormally.NOTICE This manual is provided to help you understand and use the Lemon RX receivers. The authors are not associated with Lemon RX and this is not a Lemon RX publication.

You can freely quote from, redistribute and/or modify this manual; in doing so please acknowledge the source and any changes.

The manual is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. In using this manual, you agree that you accept all responsibility.

For more information on the Lemon RX receivers, see

http://www.rcgroups.com/forums/showthread.php?t=1773138

http://www.lemon-rx.com/shop/index.php?route=common/home

Written by RCGroups users jj604 and Daedalus66 March 2015, February 2016

LemonRXmanual_V2.docx