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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

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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

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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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HCG Power Supply

6500 Series 7500 Series Control Logic Boards

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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

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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

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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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Summary

• 16 HCG Transmitter for USCG LSU – FSAT completed in October 02– Installation completed in November 02

• 48 HCG Transmitter for LORSTA George, WA– FSAT in December 02– Installation in January 03

• 16 HCG Transmitter for LORSTA Kodiak, AK– In process

• USCG Support