Motorola RADIUS GM300 User Manual

TheGM300wasMotorola'snextstepintheMaxTrac/Radiusmobileproductlines.Theschematicsareremarkablysimilar.Youcaneveninterchange

TheGM300controlheadisquitesimilartotheMaxTrac.Thereisanadditionalcircuitboard,solderedtothelogicboardpins,thatthecontrolhead

Forcomparison,here'stheinsideviewofaMaxTrac.Noticethelackofshieldingandnofilterboardbetweenthelogicboardandcontrolhead.

TheGM300logicboardissignificantlydifferentfromtheMaxTraclogicboard.ItcancontroltheRFboard'slocal/DXcircuit.Theaudiopowera

TheGM300audioamplifierdrivesbothsidesoftheloudspeaker.ThereforeyoumustNOTgroundeitherpin1orpin16oftheaccessoryconnector.You

and9.6Vreading,andalignthepoweramplifieranddeviationcircuits.Note:peoplehaveusedtheMaxTraclabRSStoblankGM300radios.Theythenin

Bytheway,theRSSknowsaboutonlyone"panelnumber"fortheseradios:5,anditcoverstheRadiusGM300productandmodelsMxxGMC00D2xx

Manuals and RSS:GM3008-channelOperator'sCard,6880902Z26GM30016-channelOperator'sCard,6880902Z41GM300Owner'sManual,6

BacktothetopofthepageMaxtracIndexMotorolaIndexBacktoHomeThiswebpage,thiswebsite,theinformationpresentedinandonitspagesand

Model Numbers:ThefirstsixcharactersareprettymuchstandardMotorolaconvention.TheIFfrequencyisusually45.1MHzbutifyouhavemultipler

AtypicalmodelnumberwouldbeM44GMC09C3A_.Thisisa40watt,UHFradio,45.1MHzIF,narrowspacing(12.5kHz),16channels,expandedlogicboard,

NotethatarevisiontotheservicemanualshowstwoVHFranges:136-162MHzand146-174MHz.Also,thepowerlevelsarecontinuouslyvariablethroug

Logic Board Jumpers:Clickontheimagetoenlargeit.HLE8275A UHFPowerAmp 403-433MHz,25-45WattsHLE8267A UHFPowerAmp 438-470MHz,01-10WattsH

ThesearequitevisibleonthephotooftheGM300logicboardbelow.NotethatsomeofthesejumpersarealsopresentonMaxTracsandhavethesamef

Notethatthe8-channelradiosignalsareslightlydifferentthanthe16-channelradiosignals.Thatmaybeduetothemaskedvs.expandedlogicboar

Theaccessoryconnectorandpinsarealsowell-documentedintheMaxTracsection.Notethatmanyaccessorypinsontheexpanded(four-layer)logicbo

Pins4,8,12,14canbeconfiguredforCOR.Pins6,8,9,12,14canbeconfiguredforChannelSelect.SoyoucanputCORonpin4andCSontheothers.The