wireless elec from RF

Discussion in 'Wireless & RF Design' started by notanEE, Oct 22, 2010.

  1. notanEE

    Thread Starter New Member

    Oct 22, 2010
    i'm trying to capture RF from a radio station putting out 50,000 watts to an antenna, and converting the dc power to ac. any suggestions?

    how would i proceed? from an antenna to a diode to an inverter?

    i read that tesla powered his pierce arrow car with a wireless radio signal.
  2. beenthere

    Retired Moderator

    Apr 20, 2004
    Sounds kinda magical. doesn't it? You might think that everybody would be doing it by now.

    It happens that those 50,000 watts only amount to just over 60 horsepower. That is not nearly as impressive as the 50 KW figure. Radio signals are attenuated by distance, as well. An antenna radiating 50 KW at one meter will have the output diminished by the square of the distance from the antenna (inverse square power law). 10Km away, the power you can receive is only .5 watt.

    That is why radio receivers are very sensitive and nobody powers diddley from a transmitter.
  3. skeptic

    Active Member

    Mar 7, 2010
    Also in the U.S., doing that is illegal.
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    It isn't illegal to receive, only transmit on controlled bands, or broadcasting wideband noise, such as a spark gap transmitter.
  5. t_n_k

    AAC Fanatic!

    Mar 6, 2009
    I guess if one rolled up with a great big RF tank circuit and strategically placed it a few yards from a transmitter tower and put a large hole in the radiation pattern when running their appliances, someone in charge would be bound to get upset. I know it's somewhat fanciful, but I'll bet there's an urban myth built around that scenario.
  6. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    Yeah, the whole "Free Energy by plugging into somebody else's outlet" concept that seems to be big these days.