P25 Coverage Below the Capital – DC Water’s New DAS Network

  • Post on May 7th, 2015

As originally written and published on MissionCritical Communications

Beneath the streets and buildings of our nation’s capital, about 3 miles of tunnels, galleries and confined spaces DC Water deployed a distributed antenna system (DAS) to provide coverage for first responders working in its 3 miles of wastewater tunnels. By Manuel Ojeda are used to treat the wastewater and sewage for the District of Columbia’s 640,000 residents and 17.8 million annual visitors. The District of Columbia’s Water and Sewer Authority, known as DC Water, manages the most advanced wastewater treatment facility in the United States within these underground tunnels.

Until recently, whenever DC Water employees entered that environment below the surface, radio communications came to a halt. A new distributed antenna system (DAS) went live last September and effectively replaced an antiquated and failing 25-year-old installation with a modular, scalable and forward-looking design that integrates with the districtwide system used by other D.C. government agencies, such as police and fire.

DC Water is the third-largest agency using the District of Columbia government’s radio communications system. Now that its underground tunnels have a comprehensive network that staff and first responders can rely on, many other district agencies have taken notice and are anxious to enjoy the same benefits at their own facilities.

DAS Underground

The DAS, built with DC Water frequencies, covers the underground tunnels housing DC Water’s treatment facilities and other operations and includes various pieces of modular hardware from SOLiD. The installation includes 18 remotes with 700 and 800 MHz public-safety amplifiers all connected via a single strand of fiber to an optical distribution unit that connects with a head-end chassis.

Each piece of equipment is stored in National Electrical Manufacturers Association (NEMA)-rated enclosures painted a bright red to help first responders identify the DAS hardware during major incidents and emergencies. Each remote unit was installed in locations deemed the most ideal for DC Water’s coverage needs while maintaining as much distance as possible from the processing facilities.

As the needs of DC Water change, the communications needs also change. The system supports two-way public-safety radio communications, but the agency plans to add cellular and other data capabilities in the future. As such, the agency requires a DAS design and hardware that will enable it to expand, reroute and enhance its communications capabilities for many years to come.

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