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camera is crystal radio when placed on top of oscillator in broken tube radio?

Discussion in 'General Electronics Discussion' started by dietermoreno, May 29, 2013.

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  1. dietermoreno


    Dec 30, 2012
    Camera is crystal radio when placed on top of oscillator in broken tube radio?

    I was attempting to record what the broken tube radio looked like on the inside with my camcorder, and something really cool happened, I heard radio transmissions very quietly on my camcorder that I didn't hear with my ears next to the broken radio.

    So just like guitar amp acting as radio, loose solder connection inside cheap camcorder is acting as a rectifying junction and when it is placed on top of the oscillator, the oscillator doesn't even need any power and the oscillator still emits weak RF that is picked up by my camcorder and rectified?

    Someone please tell me if I've gone off the deep end and should check in to a mental hospital for hearing voices if this is 100% nonsense.
    Last edited: May 29, 2013
  2. BobK


    Jan 5, 2010
    I was thinking the same thing as I read your post.

  3. poor mystic

    poor mystic

    Apr 8, 2011
    Might be demodulating the IF.
    In which case the tuning dial on the radio will change the station you hear on the camera.
    Last edited: May 30, 2013
  4. dietermoreno


    Dec 30, 2012
    I am unable to determine if turning the tuning dial changes the station demodulated by the camera, because the voices are unintelligible, just loud enough to detect voices, and I am not familiar with the voices of the DJs in Jacksonville, FL like I am familiar with the voices of the DJs in Chicago.

    By the way, I am visting my family in Jacksonville, FL and I took a look at the radio while my mom and my step dad were at work.

    I doubt that the camera is picking up the IF, because the radio wasn't even turned on (not a good idea to turn on the radio and poke around inside it considering that it appears that the tubes get their B+ voltage from simply soldering to the chassis which means that the chassis is live with B+ voltage) so there's no IF if there's no non linear mixer.

    While were on the subject of the old broken tube radio, I think I found out why all I hear is mains hum when I turn it on -- there's no ground.

    Next to the antenna wire is a jack labled "ground". The ground jack has no wire connected to it. So it appears that the radio doesn't use the mains outlet ground and instead wants a separate connection to ground, and there is no ground wire connected. The same effect occurred connecting an antenna and a 15pF coaxial guitar cable to a penny to a guitar cable going into my guitar amp -- if I didn't connect one half of the dipole antenna to the ground shield of the guitar cable going into my guitar amp, then all I heard was mains hum, and when I connected to ground then I hear music.

    So my feet standing on the ground are acting as ground allowing the camera to have ground to demodulate the signal, and if I turned on the radio then my feet would also provide a path for the B+ voltage of the chassis to go to ground and electrocute me.

    Well I do know that there are some antenna farms a few miles down I-295 when we drove that way going out to dinner 2 days ago.

    In fact, at night I can see the blinking red lights of the antenna farms over the tops of the trees when my mom drives me out of her subdivision and onto a wide street half a mile away that has its right of way cleared of trees to make room for shopping centers and parking lots.

    Radio interference at home in Chicago area on guitar amp and radio interference in Florida on camcorder. It appears that on crappy electronics there will be radio interference in every metropolitan area of the U.S.
    Last edited: May 30, 2013
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