Specifications

Section-1 Introduction
October 17, 2013
1‐4
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1.5 TransmitterSystemMajorSubassemblies
UAXtransmittersfeaturesolid‐statedesignandutilizeFET‐basedpoweramplifier(PA)modulestoamplifytheRF
signal.InadditiontoRFdrivepowerfromtheLPU,thesePAmodulesutilize50VDCpowersuppliedbyswitchmode
powersupply(PS)modules.BoththePAandPSmodulesarehot‐pl
uggableandmaybeinsertedandremovedfrom
thetransmitterwhileitisontheairwithout riskofdamage.Each50VDCpowersupply feedsonePAmodule.
Note
Unplugging PA modules or PS modules that are non-redundant, such as those in the LPU, will take the
transmitter off the air.
Figure 1-1 Basic VAX Transmitter System
ThebasicUA
Xtransmitterconsistsoftwomajorsubassemblytypes:theLPU(LowPowerUnit)andthePAB(Power
AmplifierBlock)chassis.Thequantitiesofthesebasicbuildingblocksvaryaccordingtothepowerleveland
redundancydesired.ConsultTable1‐3pa
ge1‐9foralistingoftheLPUandPABquantitiesversusthetransmitter
model.
Ina
dditiontotheLPUandPABsubassemblies,aseriesofexternalRFcomponents,suchasfilters,directional
couplers,andtransmissionlines,arepresentatthetransmitteroutput.