• Croquette@sh.itjust.works
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    5 months ago

    How do you think you are changing the resonant frequency? By modifying it’s capacitive impedence, i.e. creating a capacitor with yourself and the antenna.

    And you know what we call the difference of electric potential between two points? Voltage.

    When you say that capacitance is geometry, you are right. The distance between two objects, be it you and an antenna or two planks of wood, affect the capacitive impedance.

    • piecat@lemmy.world
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      5 months ago

      … Was this written by ai

      I’m an rf engineer and I swear it feels like I’m having a stroke reading your comments

      • Croquette@sh.itjust.works
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        5 months ago

        As the distance increase between two surfaces, the capacitance diminishes and the voltage between the two increase, so that C=QV is always true.

        The resonant frequency is determined by the impedence, i.e. capacitive and inductive impedence.

        You can’t affect inductive impedance of the antenna because you are not a coil and do not emit EMR. But you can change the capacitance between you and the antenna by moving closer or further away.

        • piecat@lemmy.world
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          5 months ago
          1. as the distance increases the capacitance reduces. But C=Q/V doesn’t mean you’re not inducing any potential into the antenna… You’re adding to the load… C=ε*A/d is the equation that says capacitance will decrease with distance, but that isn’t going to induce any voltage in this case.

          2. yes this is what I’m saying.

          3. in the very near field, conductive tissue, ie a body, will have Eddy currents. Your body has an ε term as well as σ. You can definitely load an antenna. The R term will dominate but there will be some effect on inductance.