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Re: progress

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  • capntripps2000
    The pattern is less affected the lower the frequency AND the lower the loop is in height. My 1/4w circumference 80/160M magnetic loop is 1 meter above the
    Message 1 of 8 , Feb 11, 2010
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      The pattern is less affected the lower the frequency AND the lower the loop is in height.

      My 1/4w circumference 80/160M magnetic loop is 1 meter above the ground at its lowest side and the 4NEC2 models show the patter is very oval in shape, which makes it good enough for general non-directional use. Raise the loop higer and the patter does start to become more directional.

      Andrew



      >
      > Generally speaking (again hi hi ) the answer is yes. Imbalance in the loop
      > feed does affect the radiation pattern to a degree. So for example ... if
      > one is designing a loop direction finder then care is taken to balance in
      > all aspects, the feed system, symmetry in construction, and the use of a
      > shield. In other uses ... such as an efficient small loop for xmit/rcv ...
      > balance is not critical.
      >
      >
      > >Best wishes
      > >
      > >Richard Bown
      >
      > Jim
      >
      >
      >
      >
      >
      > [Non-text portions of this message have been removed]
      >
    • richard
      On Thu, 11 Feb 2010 13:14:42 -0500 Jim Dunstan wrote: Am I correct that the directivity of a mag loop is the same quad element, ...
      Message 2 of 8 , Feb 11, 2010
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        On Thu, 11 Feb 2010 13:14:42 -0500
        Jim Dunstan <jimdunstan@...> wrote:> >Am I correct that the directivity of a mag loop is the same quad element,
        >
        > Generally speaking a full size loop or 1 wavelength (usual in a quad
        > element) has maximum reception broadside or perpendicular to the
        > plane. However small loops (usually defined as 1/10 wavelength or less)
        > have the null broadside to the loop or perpendicular to the plane. The
        > reason I say 'generally' is that when the small loop is tuned the pattern
        > is shifted to some degree.
        >
        >


        >
        > Generally speaking (again hi hi ) the answer is yes. Imbalance in the loop
        > feed does affect the radiation pattern to a degree. So for example ... if
        > one is designing a loop direction finder then care is taken to balance in
        > all aspects, the feed system, symmetry in construction, and the use of a
        > shield. In other uses ... such as an efficient small loop for xmit/rcv ...
        > balance is not critical.
        >
        >


        >
        > Jim
        >
        >
        Thanks Jim

        I'll fit the Balun on and see if it make a lot of difference, The coax feed to the loop will be
        buried, so it would be nice to get as much RF off the braid and to protect it from the XYL with
        the mowing machine.

        Its definitely working well in its current position as I'm seeing S9+ signals with it.

        --
        Best wishes

        Richard Bown

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