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Indoor ceiling loop antenna

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  • mojavedxer
    I am planning to redo my current makeshift indoor antenna to something more permanent. 1. If I run a wire around the perimeter of the radio room in a loop
    Message 1 of 2 , Sep 1, 2010
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      I am planning to redo my current makeshift indoor antenna to something more permanent.

      1. If I run a wire around the perimeter of the radio room in a loop configuration. Will multiple turns help lower the resonance of the antenna or is it a waste of time, I am planning to use a 1" space between the turns.

      2. What would be the best way to connect a coax feed line in a loop configuration. 9/1 un/un or 4/1 balun.

      3. Would a antenna tuner be beneficial in this case. This antenna would be used for reception only,

      4. since grounding is not available. Would creating two 20' radials running against the baseboards of the radio room help lower the noise level.
    • John Popelish
      ... More turns increases the total inductance and electrical length of the loop. Both effect5s lower the self resonant frequency. Increased space between the
      Message 2 of 2 , Sep 1, 2010
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        mojavedxer wrote:
        > I am planning to redo my current makeshift indoor antenna
        > to something more permanent.
        >
        > 1. If I run a wire around the perimeter of the radio room
        > in a loop configuration. Will multiple turns help lower
        > the resonance of the antenna or is it a waste of time, I
        > am planning to use a 1" space between the turns.

        More turns increases the total inductance and electrical
        length of the loop. Both effect5s lower the self resonant
        frequency. Increased space between the turns lowers the the
        turn-to-turn capacitance and also lowers the loop
        inductance. Both effects raise the self resonant frequency
        of the loop.

        > 2. What would be the best way to connect a coax feed line
        > in a loop configuration. 9/1 un/un or 4/1 balun.

        You might consider a transformer coupling made with a
        ferrite bead. This works best if the loop tuning is on the
        loop side of the transformer.

        > 3. Would a antenna tuner be beneficial in this case. This
        > antenna would be used for reception only,

        Resonating the antenna at the received frequency will not
        only increase the signal strength at that frequency, it will
        lower the signal strength of frequencies on each side of
        that frequency, decreasing interference.

        > 4. since grounding is not available. Would creating two
        > 20' radials running against the baseboards of the radio
        > room help lower the noise level.

        A loop antenna much shorter than a half wavelength does not
        generally benefit much from ground planes or ground
        connections. There need be only a ground connection at the
        receiver to carry away static charge.

        Keep in mind that a horizontal loop has maximum sensitivity
        for propagation that has a vertical magnetic component (that
        passes parallel to the axis of the loop). But this is not a
        common or efficient mode for most radio wave broadcasts,
        because that puts the E field component parallel to the
        ground, where is is most absorbed by the soil. I think you
        would be better served by circling a wall with the loop,
        though you may need to make two loops, one on each wall
        meeting at a corner, and switch between them, depending on
        the direction to the transmitter. There is no loop
        configuration that has the omni directional pattern of a
        vertical whip, E-field antenna. this is both a benefit (to
        null a strong interfering signal) and a detriment (can't use
        a single, fixed loop to receive from any direction).

        --
        Regards,

        John Popelish
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