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October 29, 2002 International Loran Association
Design and Test of theFirst Article Accufix 7500 Transmitter
Presented by Mark Danieli
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Need for New Transmitter
• Factors leading to decision for new transmitter
• Goals for new transmitter
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Factors Leading To Decision For New Transmitter
• TTX not supportable in near term
• TTX/SSX do not support additional capabilities (i.e. IFM)
• Cost reduction associated with fewer personnel requirements
• Unmanned Stations
• Remote Control
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Goals for New Transmitter
• Increase individual HCG output power through component improvements
• Modernize Control Console - TCS
• Make the number of DHCs variable and assignments flexible
• Future incorporation of IFM has minimal impact on system architecture
• Maximize commonality with existing USCG assemblies
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Accufix 7500 Transmitter Overview
HCG
TCS
Timer
RemoteControl &Monitoring
Tailbiter
Output Network
Tailbiter
Output Network
RF SwitchAntennaSwitch
MPT
Phase
5MHz
MP3605-9.VSD
HCG
PGA
PPDUAC IN
Antenna Tuning
Status&
Alarms
ANTFEEDBACK
PGA
DHCFeedback
Position Interlock
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Improved Architecture
• Prime Power Distribution Unit
• Pulse Generator Assembly
• Switch Network Assembly
• Coupling Cabinet Assembly
• Transmitter Control Subsystem (TCS)
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Prime Power Distribution Unit
• Provides emergency shutdown, at the site and via remote control
• Configuration dependent on the number of HCGs in transmitter
• Each subsystem has a dedicated breaker
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Pulse Generator Assembly
• PGA consists of 4 HCGs
• Component modernization:– Fire detection module linked to TCS
• HCG Assembly – Power Supply Reengineering
• Card Cage / Circuit Boards • Backplane PCB• Module connections• Increased Capacitance (Droop)
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Pulse Generator Assembly (Con’t)
• Megatron Charger Assembly– A4 Resistor Board– Connector Replacement
• Megatron Assembly– Oil filling Connector– Snubber Board Addition – Higher Power Diode– Connector Replacement
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Switch Network Assembly
• 3 second switchover
• Switch modules interchangeable
• New lightning arrestor
• Redundant DHC and Antenna current feedbacks
• Service Life Extension Program (SLEP)
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Coupling Cabinet Assembly
• Total Redesign – symmetric
• Reduced footprint
• Modular
• Electrically a hybrid between the 6500 and the AN/FPN-64
• Circuit breakers now used in place of fuses
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Benefits
• Increased Output Power/higher efficiency
• Increased flexibility
• More robust ECD control
• Improved Timing Stability
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Work In Progress
• Ongoing development
• Future software enhancements– Refined fail soft– Signal Quality Analyzer (SQA)
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Factory System Acceptance Testing
• Performance Measurements
• Test and Demonstration Tasks
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Transmitted Signal Performance Measurements
• Envelope Shape Measurements– Amplitude measurements for positive and
negative phase-coded pulses
• RF Zero Crossing Measurements– Specifications relates more the timing accuracy
of the output pulses rather than to phase accuracy
• Spectrum & Harmonics Measurements
• Power Input Measurements
• IAW COMDTINST M16562
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Performance Measurements
32 HCG Cape Race Accufix 7500 Wildwood
Antenna Current 715 AMPS 680 AMPS
P2P ECD VAR < .45 sec < .15 sec
P2P Timing Error < 25 nsec < 10 nsec
Phase Mod 2nd 3rd 4-12
~150 nsec ~100 nsec ~50 nsec
~75 nsec ~50 nsec ~35 nsec
Input 65 kW 59 kW
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Test and Demonstration Tasks
• Single Rate Test
• Dual Rate Test
• HCG Failure Recovery Test
• Switch-over Test
• 120-Hour Burn-In Test
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