Sept. 10 — After the first round of testing, AT&T has not found the source of the interference that allegedly was being caused by its 850 MHz GSM service to public safety communications in Oakland.
The city claims that its one-year-old digital public safety, which operates between 851 MHz and 854 MHz, is being interfered with by AT&T’s GSM service, which operates between 824 MHz and 849 MHz and between 869 MHz and 894 MHz, according to IDG News Service.
“All of us have an interest in identifying the true technical cause of the City of Oakland public safety system’s interference issue, and in ensuring a properly functioning system,” said John Britton, AT&T spokesman. “AT&T takes interference concerns seriously and has a comprehensive process for public safety entities to report concerns so we can work together and take appropriate actions.”
Despite its intentions, AT&T’s relationship with public safety officer David Cruise has deteriorated. In a letter, dated Sept. 5, to the Oakland City Attorney, the carrier complained that Cruise was not cooperating with the investigation into the interference. In fact, Cruise abruptly ended a meeting on the interference when he found out that AT&T’s counsel was in attendance.
“While our objective has been to quickly resolve questions about potential interference at the 16 sites identified by the city, we are concerned that Cruise does not share that goal,” according to the AT&T letter.
After agreeing to joint testing on Aug. 21, Cruise pulled his support four days later. Cruise also initially rejected using public safety radios in the interference tests. Additionally, specific information about the where and when the interference was experienced by the public safety system has been withheld by the city.
“Cruise refused and continues to refuse to provide AT&T with non-confidential information about the locations and times of the interference that was allegedly on the city’s public safety radios,” according to the letter. “Cruise has not yet provided information … that would enable AT&T to identify potential problem areas where the public safety signal low or other problems may exist.”
Even so, AT&T has completed testing at the 16 sites in question using an independent third-party and a test plan agreed upon with the city’s public safety systems advisor.
The results demonstrated that AT&T’s cellular signal is operating within FCC requirements at 15 of these sites. The carrier did find and fix an issue with one located outside the City of Oakland, but it said that site could not have produced the interference in question.
“We’ve proposed doing additional testing at these 16 cell sites using actual radio handsets from the City of Oakland. However, the City’s public safety systems advisor has not agreed to additional testing or identified specific locations or times when interference allegedly occurred. AT&T continues to try to assist in this effort,” Britton said.
In the meantime, AT&T will continue taking keeping its 2G 850 MHz frequencies out of service at the 16 sites where the interference allegedly occurred, while continuing to sleuth the potential causes for the interference. The carrier’s 2G 1900 MHz, 3G and 4G service throughout the area continues to operate normally.