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L.A. Building's Lights Interfere With Cellular Network, FCC Says 158

Posted by timothy
from the can't-you-hear-me-now? dept.
alphadogg writes "When a certain Los Angeles office building lights up, it's a dark day for nearby cellphone users, according to the Federal Communications Commission. Fluorescent lights at Ernst & Young Plaza, a 41-story tower near the heart of downtown, emit frequencies that interfere with the Verizon Wireless 700MHz network, the agency said in a citation issued against the building owner. The FCC's message comes through loud and clear in the filing: the building owner could be fined up to $16,000 a day if it keeps using the interfering lights, up to a total of $112,500. The alleged violation could also lead to 'criminal sanctions, including imprisonment,' the citation says."
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L.A. Building's Lights Interfere With Cellular Network, FCC Says

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  • by Anonymous Coward on Sunday February 09, 2014 @10:39AM (#46202729)

    Isn't this a case where the manufacturer of the fluorescent fixtures needs to fix them so they don't emit interference? Don't electronics of that type have to go through FCC testing?

  • by jeffb (2.718) (1189693) on Sunday February 09, 2014 @11:00AM (#46202859)

    Cheap switching power supplies crank out plenty of harmonics, and you don't need a very high percentage of the power lighting an entire high-rise to overwhelm cellular signals.

    As for compliant lights (and drivers), I think most certifications specify "when installed according to specifications". For an industrial-scale lighting installation, I'd bet there are plenty of places where contractors could cut corners on grounding or shielding, throwing a product out of compliance.

    I'm no expert, though, so I'll defer to those who are.

  • by quetwo (1203948) on Sunday February 09, 2014 @11:01AM (#46202865) Homepage

    It's not that the lighting system uses 700 Mhz, but that the ballasts or other high-energy equipment that is used to power these lights leak RF in the 700Mhz band. Cheap electronics are noisy and they leak out RF like crazy. Hell, just last week I found an old CRT monitor that was flooding out the aeronautical band at about 9,000 mV -- enough for my meter to go crazy over a football field-length away.

    Most likely the electronics are not grounded properly, or they aren't properly shielded. That is why the UL and and FCC require certifications on most classes of devices in order to catch this stuff. Of course, with our global economy it is easy to order cheap crap from Asia or elsewhere that was never tested by the UL or FCC.

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