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U.S. Government Sometimes Jams Keyless Car Locks?
PizzaFace writes "The Washington Post reports that in certain towns (generally near military bases), on certain days (such as the day an aircraft carrier returns to port), keyless car entry systems and remote garage door openers mysteriously fail. While some frustrated motorists blame aliens, the FCC says the jammed frequencies belong to the U.S. military. The good ol' Post even tracks down a government contractor who all-but-confirms the source of the interference."
Mine don't work in the parking lot on the military base I work on, but the work fine at home.
"Anyone who is capable of getting themselves made President should on no account be allowed to do the job."-THG
Too bad part 15 of the FCC's guidelines can't apply. The whole "may not cause harmful interference" section might have been nice. My dad parked on a Navy base with his keyless entry-equipped Oldsmobile for a few years up in Washington. Whatever they had running was so strong, it completely fried the system.
I had a sucky sig.
I used to work with an engineer who was a former air force tech on the Looking Glass. The Looking Glass missions were a group of USAF command/control aircraft that was always airborne to provide a redundant facility to the Strategic Air Command (SAC) in the unlikely event SAC ceased to exist from a USSR strike.
He explained on several occasions that one of their amusements was lowering a long antenna and jamming garage door frequencies and other civilian applications (e.g. keyless door locks). I couldn't imagine why the air force would want to interfere with garage doors and he never had a good explanation other than they were told to do that and the crew always found it amusing.
Urban legend? Looking Glass crew tall tale told to amuse their friends? Who knows, but they certainly had the ability to try and lord knows many friends have had their garage doors open by themselves in the middle of the night.
I used to work in a lab where we did some (non-military, non-secret) radio work and it would sometimes cause problems in the car park. The problem seems to be that the receivers in the cars are built "on the cheap" using ceramic resonators rather than quartz crystals, so they are not very selective. That is, rather than being sensitive only to the frequency that the remote is transmitting on, they are also sensitive to adjacent (and not so adjacent) frequencies. They could easily be swamped by a powerful transmitter several MHz away, whereas a better-designed receiver would be imune. So I blame the remote manufacturers.
The particular frequencies used depend on where in the world you are; the U.S. uses one set and the rest of the world uses another. Here in the "rest of the world" most remotes operate at 433 MHz. This is not far from TV frequencies - ever find your car remote doesn't work if you're parked next to a TV transmitter? Newer systems will probably be using 868 MHz (rest of world) or 913 (U.S.); this bit of the spectrum is better regulated and it would be difficult to get away with not using a crystal-based receiver. So hopefully these problems will go away.