Monday, August 27, 2012

Oakland police radio culprit: cell towers


Oakland police radio culprit: cell towers

Updated 10:32 a.m., Tuesday, August 21, 2012
Oakland officials say they and federal investigators have discovered a major source of disruption to the city's police radio communications system: interference from cell phone towers.

Specifically, officials said, cell phone towers operated by AT&T Wireless have been interfering with the city's public safety communications frequency and causing radio failures among police and firefighters on city streets.

AT&T, notified by the city of the problem last week, is cooperating and has partially disabled 16 towers. A company spokesman said the impact on customers will be minimal, affecting only those on the company's oldest phones.

The towers constantly interfered with the radios, but the problems became particularly pronounced when a police car was within a quarter to a half mile of a tower, said David Cruise, Oakland's public safety systems adviser.

"If the officer is in an area close to one of their cell sites, essentially the cell site overpowers their radios," he said.

The number of officers reporting no radio connection, however, dropped immediately after the frequency was curbed at the first cell site, Cruise said.

The city's public safety radio communications system has suffered repeated failures. Officers routinely have been unable to connect to dispatchers or to communicate with other officers.

In addition, the radios do not work in hundreds of buildings, including the basement of Oakland police headquarters. The night President Obama visited Oakland in July, police radios went down, although after the president had left town.

More issues to inspect

Cruise emphasized that cell tower interference was only one part of the city's examination.

"Our investigation is continuing," Cruise said. "This is not the end of it, for sure. There are plenty more issues we're looking at. We're working on plans to remove all of them."

Cruise said the city will be looking at cell phone towers of other companies, particularly T-Mobile, which uses a frequency that might also interfere with police radios.

Oakland and the Federal Communications Commission had been investigating the police radio communications problems. The city mapped locations of radio blackouts, said Cruise, who was hired on Aug. 2, partly to help resolve the issues.

Public safety priority

An analysis of the maps led investigators to believe cell phone interference was playing a role. The FCC confirmed the interference on Thursday. The next night, AT&T shut down the problem frequency. FCC rules give public safety agencies priority in communications, according to city officials.

AT&T cell towers emit three different frequencies - 850 MHz, 1900 MHz and 700 MHz - said John Britton, a company spokesman. In addition, it operates three different cellular networks - 2G, 3G and 4G.

The company temporarily shut down the 850 MHz frequency for 2G customers. The 2G network is the company's oldest, meaning relatively few customers would be affected, Britton said. Those on 2G are using some of the company's oldest phones and would still be supported in the affected areas on the 1900 MHz frequency.

"AT&T would never do anything to jeopardize law enforcement," Britton said. "This spectrum has been out there since the 1990s. Thursday or Friday was the first time we were notified by Oakland. We reacted quickly."

Britton said the company does not disclose how many towers it has in Oakland, but did say it has more than a thousand towers in the Bay Area.

Limiting interference

Interference from cell phone towers is not unique to Oakland. Sprint Nextel is spending well over a billion dollars nationally to relocate public safety radio frequencies, a project known as re-banding.

Sprint Nextel paid $10.5 million in direct costs to move Oakland's $7.5 million radio system to a frequency further from its network, Cruise said. Oakland moved to the new frequency in July 2011, Cruise said.

The company that installed the Oakland radio system did check for interference, but it's unclear how close it got to each of the cell towers, he said.

"Unless they drove close to a cell site, they wouldn't have seen this," Cruise said.
Matthai Kuruvila is a San Francisco Chronicle staff writer. E-mail: 



Read more: http://www.sfgate.com/crime/article/Oakland-police-radio-culprit-cell-towers-3802585.php#ixzz24lCgIRhb

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