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InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IBTheShoppingListforyourHome-BrewMMDVMRepeaterProjectusingMotorolaCDM1250

UhfradiosBeforeweattemptgettingstartedonthisproject,youwillfirstneedgoshoppingforafewessentialsbeforebeginning:

1. RaspberryPi3(Amazon)$39-45ea2. RaspberryPiCase(Amazon)$6.00-$20ea3. PowersupplyforRaspberryPi(Amazon)$8.00-$10.004. ArdueinoDueorDueClonegetspowerfromthepiUSB.(Amazon)$18.50-$25.00ea5. ArdueinoDueCaseGeauxRobot(Amazon)$12.006. Scan-DiskUltraClass10MicroSDCardwithadaptor32GB(Amazon)$15.00ea7. MMDVMrev1.0.1withpigtail(BruceGivenVE2GZI)[email protected]$60.00+

$10.00Shipping8. HLN9457Aquantity2(E-Bay)$8.00-15.00ea9. PincrimperKineeDupont(Amazon)$20.0010. Solder(Amazon)$6.00-$10.0011. SolderingIronWellerWES51RecommendedfortheHAMandhisorherprojectsworth

themoney(Amazon)$99.9512. HeatGun(Amazon)$20.00-$40.0013. HeatshrinkmultiplesizesIrecommendaheatshrinkkit(Amazon)$10.0014. 47kOhmresistortogetherwitha250K10turntrimmerPotbothtobeconnectedin

seriestogetherandtoPIN11RXaudioontheCDM.BothpartscanbesourcedonAmazonforlessthan($10.00ea)thiswillallowforthefinetuningoftheflatRXaudiotoachieve.9–1vpk:pkofthereceiversIF.ThereasonforthetrimmeriswehavefoundmultipleCDMradiosrequiredifferentamountsofpaddingrangingfrom50K–300Knonearealikeandnoneperformthesamethisisbecausetheradioswereneverdesignedwithsuchtighttolerancesinmind.

15. Cat5estrandedusedforinterfacingtheCDMradiostotheMMDVMboardyourlocalhardwarestore

16. CDM1250RadiosModel:AAM25RKD9AA2AN.403-470MHZ45WQty2(E-Bay)$75-$150

17. MotorolaPowerCablesHKN4137AQty2(E-Bay)$10.0018. JumpersMini-UHFMale:NMaleforradiosLMR240threeFtQty2(E-Bay)$14.00ea19. DuplexerBPBRpreferredifgoingtocommsiteifathomeorlowlevelNotchDuplexer

willwork.Hilltopduplexersgofor($250.00-$500)Notchduplexers($50-100)Essentialssourceonyourownorborrowfromafriend

20. 25amp12VDCSwitchingpowersupply21. Servicemonitor22. OScopewithprobe23. ProgrammingcableforCDMradios24. MototolaCPSrev06.12.09orearlier

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IBAhomebrewrepeatercompleteforunder$700asopposedto$5000industrialnottobadandtheyworkwellDownloadyourimageandsetupthePiandArdueinointerfacingtotheBrandmeisterDMR

NetworkTherearemanyimagesavailable,howevertheoneIhaveusedhasalltheessentialsandworksverywell.IusetheDMR-UTAHmmdvm_Pixel_DMR-UTAH:https://drive.google.com/uc?export=download&id=0BxeyR6_rxGV1Mk12X2owVUpBSVEThisimagehasthetooltouploadthefirmwaretotheArduinoandalltheessentialspre-loadedintotheimagesomyreferencestogettingthingsgoinginthistextwillpertaintothisimage

1) NowthatyouhaveyourPiassembledtheimageloadedontoyourSDcardandyourArduinoassembledandinterfacedtothepi,youwillneedtosettheMMDVMboardontheArdueino.ItwillsitverycloseandsnugagainsttheArdueinoboardthisisnormal.IfyoumustremovetheboardfromtheArdueinoexercisecautionandgoslow.

2) ThenextstepisinterfacingtheArdueinoDUEwiththeRaspberryPi3.3) PlugtheUSBcablethatisdesignedtoconnecttotheArdueinoDUEintooneofthe4

USBplugsontheFrontoftheRaspberryPi.4) TheNextstepistoconnecttothepropermicroUSBportontheArdueino.The

Ardueinohastwoofthemthisisthemostimportantstepandtheonetonotoverlookasoneportworksandtheotherdoesnot.ConnectthemicroUSBtotheportclosesttothebarrelontheArduinoalsoknownastheProgrammingPort.ThisportserverstwopurposesitistheporttheArdueinogetsitspowerfromaswellastheportthatinterfaceswiththepiforcommunicationbackandforthfortheservicessuchasMMDVMHost,MMDVMCalandtheArdueinoIDEfirmwareprogram.

5) Powerupyourpi.TheUsernameis:pithepasswordis:raspberry6) GotothestartmenuthentothefolderHamRadioselecttowardsthebottomUpdate

all.Thiswilldownloadthelatestfirmware,MMDVMHost,andMMDVMCalrepositorydirectlyfromtheGitHubandinstallitonyourPiandplacethemintheappropriatefoldersforyou.

7) GotostartmenuthentothefolderHamRadioselectStopMMDVMHostbackgroundservicesfollowthesamesteponcemoreandSelectStopMMDVMHost.

8) GototheHamRadiofolderandselectthetopicontitledArdueinoIDE.ThisprogramqueuesupthesoftwareandfirmwaretobeloadedonyourArdueinoDUEboard.

9) Oncetheapplicationisrunning,youwillseeabuttonthatlookslikeanarrowgoingtotherightitiscalledupdateconfigurationhitthatandyouwillburnthefirmwaretoyourDUEandMMDVM.

10) Youwillneedtoaccessafilenamed:MMDVM.ini.TheMMDVM.inifileistheconfigfilethattellstheMMDVMHostsoftwareyoursettinngsandcontainsinformationsuchas:repeatercallsign,etc.Thisfileislocatedinthefollowingdirectory:/home/pi/MMDVM.ini

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

11) DoubleclickonfilemanagerandgototheHomedirectorythentothesubdirectoryPiyouwillseethefile:MMDVM.inidoubleclickitandbegineditingit.[General]Callsign=yourcallsignTimeout=180Duplex=1#ModeHang=10RFModeHang=10NetModeHang=3Display=NoneDaemon=0[Info]RXFrequency=446000000TXFrequency=441000000Power=45Latitude=yourlatitudeindecimalLongitude=yourlongitudeindecimalHeight=yourantennaheightinmetersLocation=cityandstateDescription=descriptionofyourrepeaterURL=yourwebsiteURL[Log]#Logginglevels,0=NologgingDisplayLevel=1FileLevel=1FilePath=/mnt/ramdiskFileRoot=MMDVM[CWId]Enable=1Time=10[DMRIdLookup]File=DMRIds.datTime=24[Modem]Port=/dev/ttyACM0#Port=\\.\COM3TXInvert=0

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

RXInvert=0PTTInvert=0TXDelay=100DMRDelay=0RXLevel=16TXLevel=50#CWIdTXLevel=50#D-StarTXLevel=50#DMRTXLevel=50#YSFTXLevel=50#P25TXLevel=50OscOffset=0#RSSIMultiplier=1#RSSIOffset=10Debug=0[D-Star]Enable=0Module=CSelfOnly=0[DMR]Enable=1Beacons=1Id=yourrepeateridColorCode=1SelfOnly=0#Prefixes=234,235CallHang=3TXHang=4#Blacklist=#DstIdBlackListSlot1RF=#DstIdBlackListSlot2RF=#DstIdWhiteListSlot1RF=#DstIdWhiteListSlot2RF=#DstIdBlackListSlot1NET=#DstIdBlackListSlot2NET=#DstIdWhiteListSlot1NET=#DstIdWhiteListSlot2NET=TGRewriteSlot1=0TGRewriteSlot2=0BMAutoRewrite=0BMRewriteReflectorVoicePrompts=0

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

DirectDial=0TargetTG=9#RewriteMapSlot1=#RewritemapSlot2=[SystemFusion]Enable=0RemoteGateway=0[P25]Enable=0NAC=293[D-StarNetwork]Enable=0GatewayAddress=127.0.0.1GatewayPort=20010LocalPort=20011Debug=0[DMRNetwork]Enable=1Address=74.91.118.251Port=62031Jitter=300#Local=3350Password=passw0rdRSSI=0Slot1=1Slot2=1Debug=0[SystemFusionNetwork]Enable=0LocalAddress=127.0.0.1LocalPort=3200GwyAddress=127.0.0.1GwyPort=4200Debug=0[P25Network]Enable=0GatewayAddress=127.0.0.1

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

GatewayPort=42020LocalPort=32010Debug=0[TFTSerial]#Port=modemPort=/dev/ttyAMA0Brightness=50[HD44780]Rows=2Columns=16#ForbasicHD44780displays(4-bitconnection)#rs,strb,d0,d1,d2,d3Pins=11,10,0,1,2,3#DeviceaddressforI2CI2CAddress=0x20#PWMbacklightPWM=0PWMPin=21PWMBright=100PWMDim=16DisplayClock=1UTC=0[Nextion]#Port=modemPort=/dev/ttyAMA0Brightness=50DisplayClock=1UTC=0IdleBrightness=20[OLED]Type=3Brightness=0Invert=0file:///usr/share/applications/mmdvm-mmdvmhost_service_restart.desktop

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

12) GotoStartthanHamRadiothentoStartMMDVMHostthiswillgetyourinitialinterfaceonthenetwork

13) Goto:brandmeister.network14) Selectrepeaters15) SearchforyourrepeaterIDafterafewminutesyoushouldseeyournodeontheMaster

serverifyouseethisyouhavebeensuccessfulinconnectingtothenetwork

InterfacingtheCDM1250RadioswiththeMMDVMModemthisisthewiringharnessprocess

TheCDMradiohasa20pinaccessoryconnectoronthebackoftheradio.However,wecanusethe16pinaccessoryconnectorausedwiththeGM300radiusradiosandMaxtracradios.Whenweplugthisin,thelasttwopinstotherightandleftarenotusedonlytheinner16withthelockingtabbeingincenter.ThepinsIwillbereferringtoarethenumbersonthe16pinconnectorandnotthe20pinsastheCDMusesthesameprogramnumberingfortheinner16pins.

Pin5=TransmitAudioConfigureinCPStoFLATTXaudioPin3=PTTConfigurepininCPSto(DataPTT)ActiveLowPin10=+12vdcforignitionsenseConfigurepinCPStofollowignitionandconnectto+12vdcPin11=ReceiveAudioConfigureinCPStoFLATReceiveAUDIOPin7=GroundPin8=CarrierDetectWiringforthe8pinplugislabeledasfollows).Pin(1)CTRLnotusedinthiscasePin(2)COS/STAT_1coscarrierfromtheRXradiopin(3)RXAudioconnectyourvariable47k-300ktrimmerOhminserieswiththeRXaudiofrom

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IBthediscriminator.TheaudiothatcomesfromtheCDMistoohotandneedspaddingforittoworkwiththeCDMdon’tskipthisstepyouwillpullyourhairoutifyoudoanditwon’twork!!pin(4)RXGNDpin(5)TXGNDpin(6)TXAudiopin(7)PTTpin(8)STAT_2notusedinthiscaseConfigurationoftheMotorolaCDMinMotorolaCPSthesestepsareveryimportant

RadiopersonalityconfigurationWithintheconventionalpersonality,wecansetthebandwidthofthestation(s)togetthebestandeasiesttuningresultsofaudiolevels,werecommendthatyouprogramboththereceiveandtransmitradiosforwidebandor25KHz.Thisisnotaproblemwiththeemissionmaskofthemodebecausewhenwelookatitonaspectrumanalyzerweareonlyutilizing12.5KHzbandwidthbasedupontheTXtuninglevelsoftheMMDVM.Wehavefoundthatwhenyounarrowtheradiosyouenablethefilterswhichmakethetuningandadjustmentsverydifficulttoachievesatisfactoryresults.

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

RadioConfiguration

ThisisthesectionunderradioconfigurationaftertheradiowasreadwherewesettheReceiveAudioandTransmitAudiotoFlattallthewayacrosstheboard.Thisisanessentialstepasthedigitalwaveformrequiresaudiotobeasflataspossibletominimizeerrorsandbiterrorswhichiscommonlyreferredtoaspacketloss.

ConfigurationoftheConventionalPersonalityAdvancedTab

MakesureunderEmphasisSelection,youselectnoneasindicatedinthebelowpicture.BecausewewantreceiveandTXaudiotobeasflataswepossiblycanhaveitaddingemphasismakesthetuningofthereceiveandtransmitalmostanimpossibility.

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

PinAssignmentsinCPS

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

ThissteptellstheradiowhichporttoutilizewhencommunicatingtotheMMDVMmodemalsoanotherimportantsteptonotoverlook

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

PowerSettingofRadioThisexampleisfora25WRadio

Becausetheseradiosaremobiletheywereneverdesignedtorunat100%dutycycleIrecommendsettingtheHighpowerleveltobetween50-60%offullpowerandLopowerto25-30%thiswillensurethatthePAdoesn’tfailbeforeyouareready.IalsorecommendgettingafantoplaceonthePAunittokeepitcool.

SettingtheTransmitaudiolevels

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IBGotoStartthenaccessHamradioclickonMMDVMCalselectDMRaudiosettinggrabyourservicemonitorsetuptomonitorovertheairyourfrequencyandhaveitsetupwhereyoucanseedeviationlevelsinKHzmodeVersion:1"MMDVM20161230(D-Star/DMR/SystemFusion/P25/RSSI/CWId)"Thecommandsare:H/hDisplayhelpIToggletransmitinversioniTogglereceiveinversionP/pTogglePTTinversionQ/qQuitRIncreasereceivelevelrDecreasereceivelevelTIncreasetransmitleveltDecreasetransmitlevelDDMRDeviationMode(Adjustfor2.75KhzDeviation)dD-StarModeS/sRSSIModeV/vDisplayversionofMMDVMCal<space>ToggletransmitOncethatisdonehitthespacebartokeytheradioyouwillseeanotetoadjustdeviationto2.75Khzyouwillalsoheara1000KhztonebeinggeneratedadjusttheTXpottillyouattain2.75KHzdeviationandtheTXaudioisset.Thiseffectivelysetsupthetransmitstageoftheradioforwhatisknowas1stcarrierdrop-outandplacesallthepowerintothesidebandsoftheDMRcarrier.Onaservicemonitorsettothefrequencysetdispersionto15KhzandyoushouldseethiswhiletheradioistheDMRCalibrationmodewhiletransmitting.Youshouldseethemaincarrieriscompletelydroppedoutornulledthisisreferredtoasfirstcarrierdropout.

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

SettingtheReceiveLevelsWhenhookingupyourO-Scope,makesureitiscalibrated.Whenmeasuringaudiovoltage,connecttheprobetopinA11ontheArdueinoandadjusttheRXPOTtothepointwhereyousee1vacpk:pkfromthereceiversIF.

PinA11wheretheprobeistouchingIfyoucannotgetthe1vpktopkduetothefactthatthereceiveaudiooutistoohighcomingfromthereceiver,itwillbecomenecessaryforyoutoincreasetheinseriesresistoronRXaudiountilyoucangetthereceiversIFleveltothe1vpktopkorslightlylesssothattheDMRwave

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IBforcanevolvetothelevelrequiredtobewithinspecification.Wehavefoundthatdependinguponyourradiowehaveseeninseriesresistorsrequiredinrangeof:47k:300k,Itbecomesevermorecleartheneedforthisduetothefacttheseradioswereneverdesignedtodowhatwearerequiringthemtodoandtheirtoleranceswerenotbuilttosuchatightspecification.Therefore,becauseofthisdisparity,itisbesttouseatrimmerpotratedat250kinserieswitha47kohmresistortogiveyoutheminandmaxrangeasfoundwithMotorolaCDMseriesradios.Onceyouachieveyourdesiredresult,measuretheimpedanceandyoucanreplacethepotwithafixedresistororsimplyleaveitaloneinplace.

RXAudiothisiswhereyouwillputyourresistanceinserieswiththeMMDVMRXAudioConnectiononPin3ofthepigtailIrecommendusinga47Kohmresistorinserieswitha250ktrimmerPottoachievetherangeof50k-300kohmstoachievethedesiredresultsperyourradio.

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

WhenyougenerateaDMRsignal,youwillbegintoseethesignalitisimportanttonotethattheDMRwaveforordigitalsignaltendstoevolvearound300mv-440mvpeaktopeak.AsseenbelowinthepictureoftheO-ScopeshowinganalogreceiverIFrelativetothatoftheDMRwaveform.Ifyouhavesuccessfullyachievedthis,youaregoodtogo.

WehavefoundsettingtheRXLevellocatedinthemodemsectionoftheMMDVM.inifiletobebetween15-50dependingupontheamountofresistanceyourequiretoachieveyourdesiredresults.

WrappingthingsupGotoStartMenu,Hamradio,StartMMDVMHostbackgroundserviceGotoStartMenu,Hamradio,MMDVMHostBackgroundConsoleYoushouldseeyourpiArdueinologintothenetworkonceconnectedkeyyourradio.YoushouldseetheheadersandpacketsgoingacrossthescreenwhenyouaredoneitshouldsaycalldurationandBERrateifyourBERis<0.9%youaregoodifitsabove1%slowlyadjusttheRXlevelupanddownintheMMDVM.inisaveandrestartservice.

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

[Modem]Port=/dev/ttyACM0#Port=\\.\COM3TXInvert=0RXInvert=0PTTInvert=0TXDelay=100DMRDelay=0RXLevel=16AdjustthisTXLevel=50AdjustthisHookingupRSSIDataTappointfromtheMotorolaCDMtotheMMDVMboardfor

reportingvaluetotheBrandmeisternetworkOntheCDMyouwillneedtoconnectajumperfromPin15ontheCDM

TothispinontheMMDVMboard

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

attachtheotherendofthejumpertothistestpointontheMMDVMThenextstepistomodifytheconfig.hfilelocatedin:/home/pi/MMDVM/config.hTheconfigurationfileshouldlooklikethis:

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

ThenextstepistomodifytheMMDVM.inifilelocated:/home/pi/ApplicationsThefileshouldlooklikethis:

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

NowyouwillneedtoputthecalibratedRSSIvaluesfortheCDMradiointotheRSSI.datfile.Thefileislocated:/home/pi/Applications/MMDVMHost/RSSI.datThefileshouldlooklikethis:----------------------------------------------------------------------------------------------------------------#ThisfilemapstherawRSSIvaluestodBmvaluestosendtotheDMRnetwork.Anumberofdata#pointsshouldbeenteredandthesoftwarewillusethosetoworkoutthein-betweenvalues.##Theformatofthefileis:#RawRSSIValue dBmValue##Forexample#1134 -90#1123 -100#1000 -109346 -137381 -124443 -115485 -110560 -100629 -90698 -80740 -75787 -70819 -65830 -60832 -55

InterfacingtheMMDVMtoapairofCDM1250UhfRadiosBy:MarkKWardN6IB

InsidelookofCompletedConcept


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