350-Watt Digital VHF LB Transmitter
Table of Contents
DT325B, Rev. 0
ii
September 12, 2008
TABLE OF CONTENTS (continued)
Section
Page
4.2 VHF Low Band Amplifier Tray..................................................................4-5
4.2.1 Phase Shifter Board......................................................................4-6
4.2.2 Filter/Amplifier Board....................................................................4-6
4.2.3 VHF Low Band Amplifier Board.......................................................4-7
4.2.4 Overdrive Protection Board............................................................4-7
4.2.5 3 Way Splitter Board ....................................................................4-7
4.2.6 VHF Low Band Output Amplifier Pallets ...........................................4-7
4.2.7 3 Way Combiner ..........................................................................4-8
4.2.8 AGC Control Board .......................................................................4-8
4.2.9 +28 VDC Switching Power Supply ..................................................4-9
4.2.10 Current Metering Board...............................................................4-9
4.2.11 Operation of the VHF Amplifier Tray .............................................4-9
4.3 External Boards...................................................................................4-10
4.3.1 Triple Peak Detector Board ..........................................................4-10
4.3.2 Isolation Relay Board..................................................................4-11
CHAPTER 5 DETAILED ALIGNMENT PROCEDURES
5.1 System Preparation ...............................................................................5-1
5.2 Module Replacement..............................................................................5-1
5.3 VHF Amplifier Tray.................................................................................5-1
5.3.1 AGC Control Board .......................................................................5-1
5.3.2 Phase Shifter Board......................................................................5-2
5.3.3 Filter/Amplifier Board....................................................................5-2
5.3.4 VHF Low Band Amplifier Board.......................................................5-2
5.3.5 Overdrive Protection Board............................................................5-2
5.3.6 3 Way Splitter Board ....................................................................5-2
5.3.7 VHF Output Amplifier Pallets..........................................................5-2
5.3.8 3 Way Combiner Board .................................................................5-3
5.4 Calibration of the Output Power of the VHF Amplifier Tray .........................5-3
5.5 Setting Up the Output Power of the Transmitter .......................................5-3
5.5.1 Setting Up of AGC 1 .....................................................................5-3
5.5.2 Setting Up of Overdrive Threshold..................................................5-4
5.5.3 Axciter Relay K2 Sample Values.....................................................5-5
5.5.4 Upconverter/Downconverter Adjustment ........................................5-5
5.6 System Calibration of Forward & Reflected Powers using the Driver/
Amplifier LCD Display ............................................................................5-5
5.6.1 Forward Power Calibration.............................................................5-5
5.6.2 Reflected Power Calibration ...........................................................5-5
APPENDICES
APPENDIX A DT325B w/AXCITER SYSTEM DRAWINGS
APPENDIX B DRIVER/AMPLIFIER CHASSIS ASSEMBLY DRAWINGS
APPENDIX C VHF LOW BAND AMPLIFIER TRAY DRAWINGS
