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Are people radio transmitters?

  1. Aug 18, 2010 #1
    Are human beings radio wave transmitters? I recently moved to a new town and started listening to a new station on 101.9 fm. Found their broadcast plagued by static interference. Tried all the usual suspects, but it really looks like I am the source. When I approach the tuner the static increases, as I go away it decreases. Its not possible to put the tuner in another room, so is there some way I can shield the tuner from this effect? Thank you for your help.

    Graham Lawrence
  2. jcsd
  3. Aug 18, 2010 #2
    You are acting as a reflector and secondary aerial for the static.

    If you can work out where it is coming from you may be able to shield it somewhat with aluminium foil.

    100 Megacycles gives a wavelength of 3 metres though so I wouldn't hold out too much hope.

    Better to find the source of the interference and have it stopped - in most countries it's illegal to interfere with broadcast transmissions.

    PS - Unless you are creating static electricity in huge quantities (nylon carpet?). In that case it should stop if you keep still
  4. Aug 18, 2010 #3
    Same exact thing has been happening to me for years with the station I listen to after I bought a new radio (the old one didn't have the problem). I just can't approach my radio.

    To answer your question, humans are radiation transmitters, but in much higher frequencies than a radio resonates at, so you are not the source of the cause. I don't know what causes this.
  5. Aug 18, 2010 #4
    Just thinking out load (or however I should call it), couldn't it be that your body is creating some kind of capacitor and therefore messing with the signal. I've encountered this phenomenon in a funny way, when a LED was turning on with only one electrode connected and me (beleive me, I was insulated) touching the other. It was very dim but I could actually measure 1.4 volts across me! In a discussion with my friends we pretty much concluded that my body was acting as a coupling capacitor with the earth.
  6. Aug 19, 2010 #5
    Your were grounding it, creating a difference in potential.

    But how would this effects a radio just by getting close to it?
  7. Aug 19, 2010 #6
    It's more likely that you were simply picking up a local radio transmitter and the acids on your skin were acting as a crude rectifier with the metal contact to turn the RF signal into a dc voltage.

    When I'm working with my Tesla coil I have to be really careful not to touch anything metal in my workshop because the powerful RF signal from the coil being picked up by my body is enough to create a fat spark a millimetre or two long and the shock I get from it is seriously unpleasant.
  8. Aug 19, 2010 #7
    I want a Tesla coil :)
  9. Aug 19, 2010 #8


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    Perhaps you can gain some insight by reading about the operating principle of a Theremin. A Theremin is a music instrument that is designed to be sensitive to how close the hand is to the antenna. Pitch and volume are controlled by moving the hand closer to or away from the antennas for pitch and volume respectively.
  10. Aug 19, 2010 #9
    We concluded that I was acting as a capacitor because the phenomenon only happened if the LED electrode (either cathode or anode) was connected (respectively) to the output of an SMPS.
  11. Aug 19, 2010 #10
    Thank you, but this confuses me. If there is an external source of static, why doesn't the tuner's own antenna pick it up along with the station signal?
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