User's Manual

GPA-1 manual
Caution; only use authorized antennas that meet the FCC license requirements.
Use of unauthorized antennas, cables, and/or coupling devices not conforming
with ERP/EIRP for outdoor/indoor will void the licensee’s license to operate.
Introduction
TheGPA‐1isanRFpoweramplifierdesignedforuseinthe150‐174MHzfrequencyrangeatupto40
Watts.Itisintendedtoserveasa100%dutycycleamplifierforMDSSD1operatinginpoint‐to‐multipoint
repeaterorbaseapplications.
1.4 ProductDescription
TheGPA‐1poweramplifierconsistsofanRFamplifierandPCBmountedtoaheatsink,withaDCPower
interface,powercontrolinterface,andinput/outputRFconnectionsonthesidewallsofthechassis.DC
powerissuppliedtotheamplifierfromaregulatedandfilteredDCsourcecapableof
supplying10‐16Vdc
atamaximumcurrentof8Amperes.TheDCpowersourceshouldbecurrentlimitedorhaveaprotective
fuseorcircuitbreaker.
1.5 PowerControlLoop
TheGPA‐1amplifieroperatesinINTmode.InInternalmode,afeedbackcircuitwithintheamplifier
controlstheoutputpower.ThesetpointissetbypotentiometerR112,locatedwithintheamplifier.
Further,thePAperformsTX/RXswitchingtoprovidealowlossreceivepathwhennottransmitting.The
TX/RX
controlisperformedbyRFdetectionwithinthePA.
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