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About Hi-Q

Solid State Power Amplifier (SSPAR) Program

The Problem

The Omega pulse modulated VLF transmitter site at LaMoure, ND. was decommissioned as a navigation broadcast by the U.S. Coast Guard in 1997, and the Navy acquired the station for conversion to an MSK modulated Fixed Submarine Broadcast System (FSBS) communications station. The helix house and radio station equipment needed to be interfaced with a new 500kW Rockwell Collins solid state amplifier. For cost considerations, as much of the existing Omega antenna tuning and matching equipment as practical needed to be reused in the final configuration.

Hi-Q's Solution

Hi-Q provided top level system design and equipment arrangement, using the requirements dictated by the SSPAR solid state transmitter and existing Omega equipment. Hi-Q engineers commissioned the completed system, including all proof-of-performance testing. Additional services delivered included:

  • Performed comprehensive measurements of the existing antenna electrical parameters to be used in the design of the antenna tuning and matching equipment and the selection of the radio station's new operating frequency.
  • Prepared detail design, modified, and tested one of the existing Omega antenna tuning variometers for use as the variable antenna coupling inductor in the new antenna tuning and matching system.
  • Combined two of the existing Omega antenna tune variometers and motor drives to provide the required tuning resolution for the RF system automatic tuning function.
  • Provided the design and the required modifications to the helix house for the installation of an existing surplus antenna tuning variometer from the Annapolis radio station for use in this application.
  • Specified the architecture and wrote the software for the computer control of the complete transmitter including the solid state amplifiers, and an automatic tuning and loading system to provide accurate and reliable tuning of the complete RF system without intervention of the operators.
  • Prepared maintenance schedule and procedures for the complete transmitting system.

Since the initial installation and commissioning, Hi-Q has developed many performance, reliability, and maintainability improvements to the SSPAR transmission system. Most notably were the addition of an Antenna Base Arc detector, improved arc detector interface circuits. Hi-Q has also developed comprehensive training for the SSPAR transmission system that is still in use to this day. Hi-Q continues to provide logistics support, emergent on call problem analysis, depot level repair and engineering guidance/consultation for the LaMoure, ND transmitter site.


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