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Old-school AM walkie talkie

Discussion in 'Amplitude Modulation' started by W0RIO, May 7, 2019.

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  1. WZ5Q

    WZ5Q Ham Member QRZ Page

    I did some research on it and came across quite a bit of information.
    Interesting reading indeed.
     
  2. AC0OB

    AC0OB Subscriber QRZ Page

    As did I but it wasn't explained in the equipment literature.

    This paper https://arxiv.org/pdf/physics/0606109.pdf

    seems to indicate that "Quasi-electrostatic " implies treating the AC as if it were DC in a specific domain or in a specific instant in time.


    Pheel
     
  3. W2VW

    W2VW Ham Member QRZ Page

    That contraption can't possibly work. There's no 9:1 balun and there isn't even a microprocessor.
     
    K5UJ and AC0OB like this.
  4. WZ5Q

    WZ5Q Ham Member QRZ Page

    That is the same conclusion I had gotten from other sources.

    Rather interesting once you get into the tech of it. It basically uses the magnetic near-field for communications in leu of the more commonly used electromagnetic far-field radiation. The reasoning for using such a low operating frequency is that the effective range is only within one wavelength of the antenna.
     
    Last edited: May 9, 2019
  5. AC0OB

    AC0OB Subscriber QRZ Page

    Agreed.

    My colleagues and I tend to think this term is kinda nutty.

    A system is either Dynamical, i.e. changing or moving, or it is static, no change-no movement.

    I guess the term, while somewhat impressive but imprecise, is simply a shorter term than stating:

    "a physical system where the effects of charges and currents do not extend to spatial infinity but have short-range boundary conditions." :D

    This VLF equipment does make sense for spelunking since cave walls will act as ducting for those long-waves.

    Of course, back in 1960, Harold Wheeler suggested "Crustal Communications" via 1.5 kHz RF waves.

    https://nvlpubs.nist.gov/nistpubs/jres/65D/jresv65Dn2p189_A1b.pdf


    Pheel
     
    Last edited: May 9, 2019

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