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Human 'Antenna' with Regenerative Receiver

  1. Aug 23, 2012 #1
    I have constructed a small one-transistor regenerative receiver, and I have been getting weird results with reception. I have noticed that simply touching parts of the radio, such as the antenna or around where the antenna is attached, will provide great reception. However, when I am not touching the radio it gets rather poor, if any reception. I am mystified by the fact that replacing the antenna with a resistor, inductor, or even a polyethylene capacitor will also provide great reception given that I am holding onto it, and not touching any conductive parts. Reception fails if I touch a ground plane while holding onto the component. I am not sure what phenomena is causing this and why, and I was wondering if anyone might be able to tell me more.

    I have provided the electrical diagram of the regenerative receiver (a modified clapp oscillator)
     

    Attached Files:

  2. jcsd
  3. Aug 23, 2012 #2
    The human body is a conductor, are you simply increasing the size of the antenna?
     
  4. Aug 23, 2012 #3

    NascentOxygen

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    Staff: Mentor

    You're guaranteed hours of fun! :smile:
    Any large conductive body (e.g., you) is capacitively coupled to Earth. So wherever you touch the radio you are earthing that point. A small radio receiver such as you have here needs a good earth, together with an antenna, to perform reliably and well. If you are in a strong reception area the antenna may not need to be large, a metal window frame may suffice.

    Radio signals move from the antenna to earth, so the better each is, the stronger the signal driving your receiver. It is not really worried if you swap their connections, it's the strength that is important.

    You are able to increase the regeneration until it whistles?
     
  5. Aug 23, 2012 #4
    Okay, thanks, that makes a lot of sense now that I think about it. I'll try earthing it and see if that helps. I can increase the regeneration until is whistles/screeches.
     
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