Evaluation and Upgrade of a
Digital Microwave Communications System

The US Navy operates an air combat maneuvering instrumented range, the Charleston Tactical Air Crew Training System (TACTS), off the Georgia coast. During training exercises, aircraft telemetry is relayed from tactical aircraft to a series of offshore platforms. A multi-hop digital microwave communications network relays the data between the platforms and the system operations center at the Marine Corps Air Station at Beaufort, South Carolina.

The microwave network was failing to meet reliability and availability requirements, making the range unusable for pilot training. The Howland Company was asked to evaluate the system and propose corrective measures.

System operators reported that propagation issues over the 47-mile microwave hop from the central offshore platform to the 1200-foot onshore tower were the source of frequent full-blown system crashes. We evaluated the microwave path, inspected the equipment configuration and measured transmit and receive signal levels over the RY1-R2 hop and identified several issues that limited the effectiveness of the network. We proposed replacing non-standard radios with commercially available models, repositioning preselector filters, and a new dual frequency space diversity configuration at both sites. After the Navy implemented these changes, the system performed at the required 99.995% reliability.

  

Charelston TACTS tower and platform locationsSkidaway Institute of Oceanography
Map of the TACTS network

Links:

External Link  Beaufort TACTS Range page at GlobalSecurity.org.

External Link  Bergey Windpower, supplier of the high-reliability wind turbines which provide electric power to the TACTS platforms, has a page on their role in the project here (archived page).

pdf  "'Top Gun Towers' to Be Renovated", article about TACTS upgrades from a 2003 issue of Navy Civil Engineer magazine.

         
  TACTS onshore terminal 1200' tower, site RY1--fortunately, it's equipped with an elevator
 --THC Photo by Jim Howland     TACTS offshore relay platform, site M2R6
 --Photo by Cheryl Breeden
The 1200-foot tower at site RY1, linking the offshore
towers to the system operations center.
  One of the offshore platforms. This is site M2R6, linking
three other sites to site R2.