P-H_Electronics_LA-500M_Service-User_Manual操作说明书手册

MODEL LA-50OM SPITFTREPage 1APPLICATIONThe Spitfire has been designed as a compact portable ormobile RF linear amplifier capable of operating at 1000watts PEP input SSB.Features tn this new compact designpermit ease of operation and compatability with the manytransceivers now on the market.When used with the Dc toDC power supply,model PS-1000B,the unit becomes a kilo-watt mobile linear amplifier.When used with the modelPS-1000 A.C.power supply,the LA-50011 becomes a compacttable top SSB kilowatt amplifier.No internal changesare required when going from the Ac to DC power supplies;thus the unit may be quickly removed from the vehicle forbasestation operation.DESCRIPTIONThe Spitfire utilizes six inexpensive type 12JB6 tubes,high mu-triode connected,in grounded grid circuitry.A70 ohm pad is provided across the input to present a moreconstant load impedance to the exciter.The pi-networkfeatures pre-set antenna loading for each band 80 through10 metera,permitting simplified tuning of the amplifier.Relay switching functions are provided to connect the ex-citer to the amplifier input;and the amplffier output tothe antenna when transmitting;and to connect the antennaback to the exciter or transceiver while receiving.Thisrelay can be actuated by the vox circuit in the exciterused。Th1g●l1 minate8 the need【or two coax.1a1 relays nor-mally required when a transceiver is used with an amplifier.The aireraft type post light is used for meter 1lluminationand.as a pilot light.Since the unit was designed far con-tinuous handling,the cabinet and handle are chrome platedto retain their appearance.The radical departure from conventional construction per-mits free air convection'cooling of the components andamplifier tubes,thus elimineting the necessity of a cool-ing fan.The 1/8 inch aluminum support plate for the tubesserves as a heat sink,keeping the base seal temperatureslow.A zener diode 'in the Dc cathode path provides amplif-ier bias.Bias generated in this fashion i8 ripple freeand atable under the varlable loads imposed by 88B type ofoperation.The 1/8 inch aluminum rear panel serves as a heatsink for the zener diode.