User ManualTable of ContentsGENERAL INFORMATION5DESCRIPTION5EQUIPMENT FURNISHED6SEA 245 MF/HF Single Sideband Transceiver6Transceiver Mounting Bracket6Microphone and Microphone Clip6Power Connector6SEABUSS Connector, 9 pin PHOENIX type, female6Accessory Connector, 14 pin PHOENIX type, female6SEA 245 Operator's Manual6TRANSCEIVER UNIT SPECIFICATIONS6MECHANICAL INFORMATION6DIMENSIONS:6WEIGHT:6ELECTRICAL SPECIFICATIONS:6TRANSMITTER7RECEIVER7O10OPERATION10WARM UP CAUTION10FRONT PANEL CONTROLS10ROTARY CONTROL10KEYPAD10LCD DISPLAY10PROPAGATION10BANDWIDTH LIMITATIONS11M12MODE AND FREQUENCY CONTROL12GENERAL12TRANSMITTER MODE SELECTION12RECEIVE MODE SELECTION12SEA 245 FREQUENCY LISTING132 MHZ VOICE BAND134 MHZ VOICE BAND166 MHZ VOICE BAND188 MHZ VOICE BAND1912 MHZ VOICE BAND2116 MHZ VOICE BAND2318 MHZ VOICE BAND2522 MHZ VOICE BAND2525 MHZ VOICE BAND28DSC FREQUENCIES284 MHZ TELEX BAND306 MHZ TELEX BAND318 MHZ TELEX BAND3312 MHZ TELEX BAND3516 MHZ TELEX BAND4118 MHZ TELEX BAND4822 MHZ TELEX BAND5025 MHZ TELEX BAND56CAUTION! FREQUENCY TOLERANCE58SETTING THE TRANSMITTER FREQUENCIES59THE MASTER CLOCK OSCILLATOR59ENABLING CARRIER REINSERTION59I60INSTALLATION60MOUNTING THE TRANSCEIVER60A TYPICAL INSTALLATION60THE TRANSCEIVER UNIT REAR PANEL CONNECTION AND FUSES60THE POWER CONNECTOR60THE RF CONNECTOR61THE PARALLEL INTERFACE PLUG61THE SEABUSS INTERFACE CONNECTOR62THE RS232 DB-9 INTERFACE CONNECTOR63FUSING63THE GROUND CONNECTION64T65THEORY OF OPERATION65GENERAL65THE RECEIVER66BLOCK DIAGRAM67RECEIVE RF CIRCUITRY AND FIRST MIXER67THE 45 MHz IF68THE SECOND MIXER/POST AMPLIFIER68THE A/D CONVERTER68THE CODEC68THE DIGITAL SIGNAL PROCESSOR69THE RECEIVER AGC SYSTEM69THE RECEIVER AUDIO CIRCUITY69THE TRANSMITTER71BLOCK DIAGRAM71THE MICROPHONE AUDIO CIRCUITRY71THE AUDIO LINE RECEIVER/TRANSMITTERS72THE CODEC AND DIGITAL SIGNAL PROCESSOR72THE QUADRATURE MODULATOR7245 MHz IF AND SIGNAL MIXER73THE LOW PASS FILTER AND TRANSMITTER PREAMPLIER73THE TRANSMITTER PREDRIVER73THE TRANSMITTER DRIVER74THE TRANSMITTER POWER AMPLIFIER74THE OUTPUT LOW PASS FILTERS74THE ALC CIRCUITRY75THE MASTER CLOCK OSCILLATOR AND SYNTHESIZER SYSTEM75BLOCK DIAGRAM75THE MASTER CLOCK OSCILLATOR75THE FIRST LOCAL OSCILLATOR SYNTHESIZER75THE SECOND LOCAL OSCILLATOR SYNTHESIZER78THE 2187.5 kHz MONITOR RECEIVER78BLOCK DIAGRAM78RECEIVER RF CIRCUITRY AND FIRST MIXER78THE 455 kHz IF AMPLIFIER81THE SECOND MIXER/POST AMPLIFIER81THE LOCAL OSCILLATOR CIRCUITRY81THE POWER SUPPLY CIRCUIT82GENERAL82BLOCK DIAGRAM82THE MAIN POWER CONTROL CIRCUITRY82+10 VOLT REGULATOR AND THE +10VTX SWITCH84+12 VOLT RAIL AND THE +12VTX/+12VRX SWITCHES84+5 VOLT REGULATORS84+3.3 VOLT REGULATOR84+12VTX RAIL84THE +24VTX RAIL AND PA BIAS SYSTEM85THE MAINBOARD CONTROLLER AND DSP PROCESSORS85GENERAL85BLOCK DIAGRAM85CLOCK DISTRIBUTION85MICROCONTROLLER OPERATION87DSP OPERATION87CODEC OPERATION88T89THE SEA 245 FRONT PANEL/CONTROLLER SYSTEM89GENERAL89THEORY OF OPERATION89KEYBOARD SUPPORT90THE LCD DISPLAY AND DISPLAY LIGHTING90THE SQUELCH FUNCTION90BILATERAL AUDIO CIRCUITRY91SEABUSS DATA CIRCUITRY91Size: 395 KBPages: 91Language: EnglishOpen manual
