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UHF Crystal Radio

Discussion in 'Home Brew' started by vu2nan, Dec 26, 2015.

  1. vu2nan

    vu2nan Active Member

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  2. vu2nan

    vu2nan Active Member

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    Here's an update.

    ................Later on, another Yagi Beam was rigged up with a second OA85 providing the return path for the audio instead of the coil.
    [​IMG]
    UHF Yagi Beam Crystal Radio
    with 2 diodes - Schematic

    Signal strength was as good on that one too.


    [​IMG]
    Two UHF Yagi Beam Crystal Radios

    73,

    Nandu.
     
  3. vu2nan

    vu2nan Active Member

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    #3 vu2nan, Jan 20, 2016
    Last edited: Jan 20, 2016
  4. vu2nan

    vu2nan Active Member

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    Yet another update!

    The terminal block arrangement made it convenient to replace the folded dipole with a full wave loop.

    [​IMG]
    UHF Full Wave Loop Crystal Radio

    Likewise with an AWX antenna.

    [​IMG]
    UHF AWX Antenna Crystal Radio

    Results were as good as with the folded dipole.

    73,

    Nandu.
     
  5. vu2nan

    vu2nan Active Member

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    The latest update!

    A second Yagi Beam was then rigged up, with another diode providing the return path for the audio, instead of the coil.

    The signal strength was not as good. During trials, a chance shorting of the second diode gave a considerable increase in signal strength.

    [​IMG]
    Single-diode UHF Yagi Beam
    Crystal Radio - Schematic


    The diode and capacitor were hence discarded. Performance of this single-diode UHF crystal radio is quite good.

    73,

    Nandu.
     
  6. vu2nan

    vu2nan Active Member

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