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  • #16
    Bringing long ferrite rods up to a search-coil can give different results depending on orientation. I have always brought the end of the rod towards the centre of the coil, with the rod perpendicular to the plane of the coil -- that seems to give consistent behaviour. But if you have the rod flat, (so both ends of the rod are the same distance from the coil) , the orientation of the rod seems important, so I never use rods that way.

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    • #17
      Originally posted by Skippy View Post
      Bringing long ferrite rods up to a search-coil can give different results depending on orientation. I have always brought the end of the rod towards the centre of the coil, with the rod perpendicular to the plane of the coil -- that seems to give consistent behaviour. But if you have the rod flat, (so both ends of the rod are the same distance from the coil) , the orientation of the rod seems important, so I never use rods that way.
      In which direction should the RX signal be relative to the TX? + or - ?
      So 1.jpg or 2.jpg ? (on previous page)​

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      • #18
        All the ferrites I have produce either 0° or 180° responses. Skippy is right, orientation matters, especially with DD coils. He may also be right, that there may be some lossy ferrites that give oddball phase shifts.

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        • #19
          Originally posted by Carl-NC View Post
          All the ferrites I have produce either 0° or 180° responses. Skippy is right, orientation matters, especially with DD coils. He may also be right, that there may be some lossy ferrites that give oddball phase shifts.
          Hi Carl, Is it necessary to put a resonance capacitance on the RX coil for a detector that will work with a single frequency?
          Does the resonant capacity work as a band pass filter?
          Even if we resonate the RX at one frequency, it is operating at the frequency of the TX.
          What is the difference of resonance capacity in analog and digital?
          In TX, more amplitude is obtained at the resonant frequency, but the RX coil will not work at its own resonant frequency anyway. It will work at the TX frequency, then what does the capacity do?​

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          • #20
            You do not need to resonate the RX coil. Yes, it works as a BPF and reduces thermal noise and EMI. I don't understand the last two questions.

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