Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Radio Grounding Theory

  1. Jun 8, 2010 #1
    So, I've heard it said that when you use a hand-held radio, your body acts as a ground.
    Let's say I wanted to go on an adventure with my homemade flying machine (lawn chair and weather balloons). Obviously, my friends would like to know how the world looks and feels from that height. I choose to use my hand-held radio to tell them everything.

    The question is: "Would my hand-held radio still work?" Do I need to ground it to something?
  2. jcsd
  3. Jun 8, 2010 #2
    The radio has a built in ground plane, yes it will work.
    Make sure you keep it vertical ;)
  4. Jun 8, 2010 #3
    I think the idea that radios need a ground comes from many years ago when radio was used mostly at lower frequencies and the antennas were so long they required the earth as the other half of the antenna. At the higher frequencies that today's portables use, the antennas are long enough to efficiently create the electric and magnetic fields without a ground.

    And no, the portable does not use your body as a ground. The antenna is a tuned circuit. If it required the user's body in order to work, it would work differently with each different user.
  5. Jun 8, 2010 #4
    So, I guess this holds true for radios with a 1/4 wavelength antenna?
    What about a lower frequency signal like VHF?

    From what you guys were saying, it sounds like whatever works on the ground works in the air.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook