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Car keyring

  1. Jul 15, 2004 #1
    Ok, I saw this guy trying to unlock his car with his radio controlled keyring with no luck, he put the device next to his head and it worked. The keyring was the same distance to the car in both cases give or take 1/4 meter. Would the same happen if you put the keyring next to a conductive metal antenna of some sort, this has been bugging me after I first watched it on top gear (uk television prg). Any insights?
  2. jcsd
  3. Jul 15, 2004 #2


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    Nothing special would happen. The antenna would absorb a very small part of the RF emitted in a (more less) spherical pattern. His putting it next to his head probably had nothing to do with his success -- the evelation might have helped though.

    - Warren
  4. Jul 15, 2004 #3
    Having worked on a number of remote entry systems I would say it probably de-tuned the oscillator in the transmitter. Or the range is very marginal. Sometimes works, sometimes doesn't.
  5. Jul 16, 2004 #4


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    Zero data but I've had numerous experiences where I was able to get this to work, both car alarm tranmitters and keyless entry systems and RF remote controls in the home like the one Sony included in their early DSS receivers. I'd "heard" that touching the tranmitter allows your body to act as a crude antenna. I usually use my left hand though, not my head. :-)
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