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8130Re: [loopantennas] Re: Loop reflector

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  • Andy
    Jan 5, 2011
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      > A horizontal 1 wavelength loop, if up sufficently high, has a radiation
      > pattern almost identical to a half wave dipole- that is a figure 8 pattern.

      Where did you hear that?

      A full wavelength loop, in free space, has a pattern that looks like a
      dumbbell: two major lobes in opposite directions (perpendicular to the
      loop), and a null going a full 360 degrees around it in the plane of
      the loop.

      A half wave dipole has a pattern like a donut, which is almost exactly
      the opposite.

      So I'm trying to figure out what orientations of the loop and of the
      dipole you are envisioning.

      Most half wave wire dipoles are horizontal, and tend to have maximum
      signal broadside to the wire, and nulls off the ends (except for
      interaction with the earth or ionospheric reflections). A full wave
      loop at any height is essentially nondirectional with respect to its
      axis. Its primary radiation is straight up and straight down, so it
      makes a good antenna for high angle signals; though if you mount it a
      half wave above earth, it may get a null going straight up due to
      cancellation with its reflection.

      Andy
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