A gem of a system upgrade

Aug 1, 2008 12:00 PM, By Howard W. Newton, P.E.

In-building coverage boost pays off during mall robbery, shootout

On March 9, 2008, a heavily armed 27-year-old man allegedly robbed a jewelry store in the Mission Viejo Mall, smashing jewelry cases and brandishing weapons. Orange County (Calif.) Sheriff's Department deputies responded to the call and within minutes were pursuing the perpetrator. The chase culminated in a gun battle and a shooting of the robber by officers. Fortunately no officers, mall employees or visitors were hurt.

The response was aided greatly by a distributed antenna system (DAS), supported by bidirectional amplifiers and a backup battery system, which enabled officers using the county's 800 MHz radio system to receive signals well within the mall — something that previously had been a major problem.

The 800 MHz Countywide Coordinated Communications System (CCCS) is used by all local public-safety agencies (law enforcement officers, firefighters, paramedics and lifeguards) and by government agencies on a 24-hour basis. The system is managed by the Sheriff-Coroner Communications Division (SCCD) — under the direction of Robert Stoffel — which oversees system design and engineering and frequency management, as well as the installation, maintenance, and programming of communications and electronic equipment (including microwave equipment; 911 dispatch equipment; mobile and portable radios; and surveillance, alarm, sound, video and control systems).

The SCCD consists of 91 personnel organized in three areas that specialize in specific technical applications, including the Technical Services Unit, the Engineering Section and the Emergency Communications Section. Each group maintains a staff of engineers, technicians and support staff to provide a high level of technical expertise to various public-safety functions, including city and county law enforcement, emergency services, lifeguard operations, park rangers, public-works agencies, courts, jails and probation facilities.

Within the Engineering Section is the Radio and Microwave Unit (RMU), which maintains the CCCS backbone that consists of 21 remote sites, six trunked simulcast cells and several intellirepeaters that provide 15 dB or greater coverage countywide. The highly fault-tolerant system initially cost $84 million to field in 1999.

The CCCS is Orange County's state-of-the-art, analog/digital trunked, public-safety interoperable radio communications system. More than 19,000 subscribers use the system, resulting in approximately 20 million transmissions per year.