With cellular boost, a longer arm of the law

Tools to amplify signals bring mobile data to patrol cars in a sprawling Arizona county

The history of the Yavapai County Sheriff’s Office goes back to 1864, and until recently its paper-based records system had not changed very much since those days. But when Sheriff Steve Waugh took office in 2005, he wanted to bring it up to date.

“One of the things he was adamant about was that we were going to migrate to a mobile data environment,” said Lt. Brian Hunt, who heads the department’s Technical Services Bureau.

That was easier said than done. With 8,100 square miles, Yavapai County, which stretches from the South Rim of the Grand Canyon to the suburbs of Phoenix, is larger than Rhode Island, Delaware and Connecticut combined, and larger than either Hawaii, New Jersey or Massachusetts. “You have a large coverage area and many challenges that Mother Nature has thrown our way that make communications challenging,” Hunt said.


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Cellular coverage is as good as can be expected in a remote area that size, which means it is spotty. But satellite communication was too expensive to be practical and there were areas without radio coverage. Building a radio repeater network for an area that large was out of the question. So the department had to fall back on the existing cellular infrastructure.

“It immediately became apparent that we were going to use cellular for putting our records management system out there,” Hunt said. “We were going to get the best service with commercial cellular, but we knew we would have to find a way to enhance the quality of the signal.”

That was done with cellular boosters from Wilson Electronics to amplify the signals from cellular air cards in mobile laptop PCs mounted in 120 vehicles that patrol the rural areas of Yavapai County. The system has been in the field since 2009 and the deployment was completed in March 2010.

The system has brought the office rapidly into mobile modernity. “We have the connectivity we would not reliably have with just the air cards,” Hunt said. “There are still areas where there are no signals and communications are still as they were in 1864. But those areas are smaller,” and for the most part deputies no longer have to drive 80 or 100 miles to a substation to find a networked computer to file paperwork or gather information.

The mobile communications enabled by the signal boosters is for data rather than voice, and is not used primarily for communications. “We have no intention of replacing two-way police radio,” Hunt said. But the data link enables a secondary communications channel through instant messaging and e-mail that reduces the amount of traffic on the police radio system and allows officers to keep in touch in areas outside of radio coverage.

Deputies seldom have to work in the remaining dead zones except on search and rescue missions. “We do venture into those areas occasionally,” Hunt said . “These are areas where people who don’t want to be found go.”

The boosters do have limitations, but they help in the gray area where signal strength is too low to provide reliable connections. “There has to be a signal to begin with,” said Wilson chief operating officer Joe Banos. “If there is no signal, no amount of amplification will help you.”

Wireless dumb pipes?

The system is not without controversy. Some carriers have objected to the use of third-party RF equipment that uses their licensed spectrum. “They don’t want to become wireless dumb pipes,” Banos said.

But phones and modems using the carrier’s service have permission to use that spectrum, and Wilson’s position is that it is the phone or modem that generates the signal, not the booster. “All the booster is doing is making the signal stronger,” Banos said.

The Federal Communications Commission has proposed rules governing cellular boosters that would spell out how the equipment can operate.

The booster can provide power for the uplink from the modem of 2 to 4 watts, Banos said. A cell phone typically operates at about .2 watts, but “at no point do we exceed the industry standards for the system.”

Alternatives to cellular service in an area as extensive and remote as Yavapai County were not practical. A radio network covering terrain that ranges from desert to 8,000-foot mountain peaks would require too much new infrastructure. “If you had the money and the ability to acquire land on top of mountains to build the microwave sites, it is still not possible to get the kind of service to push the kinds of data we wanted to,” Hunt said.

Satellites out of reach

Satellite phones were an option, “like space travel is an option,” he said. “It can be done, but I can’t do it.” To be practical there would have to be a phone for each car, and the county could not afford 120 of them. “We wanted to have standardization of technical resources available in the field,” to all officers, and that mean leveraging existing commercial infrastructure.

The Yavapai Sheriff’s Office uses Verizon cellular service through a state contract. The company has the most comprehensive coverage in the Southwest, even if that coverage is not 100 percent complete, Hunt said.

“Verizon has been great to work with,” he said. “We didn’t ask them to expand the network. It’s about as good as we hoped it could be,” and the company did help with the selection and testing of cellular modems. But in the summer of 2009 as he was field testing the equipment it became apparent that the modems by themselves would not be adequate to support the Internet resources and the records management system from Spillman Technologies that the department wanted to push to its deputies.

“Within the initial few hours of having the equipment, it became apparent to me it would be a deal breaker if we could not field the booster addition to the system,” he said.

Fielding the system proved to be simple. The booster box was mounted in the trunk of the patrol car, with a cable linking it to the modem and the antenna mounted outside the car. “It’s not rocket science,” Hunt said. “And it’s cop proof.” With 120 units in operation for more than a year, “I’ve had zero problems.”

Hunt’s advice to other departments faced with similar challenges is to try it before you buy it. “The most important thing is you’ve got to field-test whatever solution you are considering,” he said.

Secondly, take advantage of existing commercial resources, such as cellular service, when possible. “It was more responsible for us to pay our way and use commercial resources rather than have a capital outlay,” he said.

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