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8134Re: [loopantennas] Re: Loop reflector

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  • Steve Ellington
    Jan 5, 2011
      I'm glad you spoke up.
      Here is a link to an Eznec model of an 80m horizontal loop. I've never heard anyone claim a loop had the same pattern as a dipole until now.
      At typical heights, this loop has a circular pattern and vertical radiation is straight up. At greater, 1/2 wavelength, heights the pattern will show a bit of a bulge opposite the feedpoint and a lower angle. Of course the pattern changes for the harmonics but never the same as a dipole. It's a great multiband antenna and very common.

      ----- Original Message -----
      From: Andy
      To: loopantennas@yahoogroups.com
      Sent: Wednesday, January 05, 2011 6:23 PM
      Subject: Re: [loopantennas] Re: Loop reflector

      > ... Think of a 1 wavelength
      > horizontal loop as two half wave dipoles spaced 1/4 wavelength apart- it is
      > obvious this is not omni and will have classic construction and destruction
      > azimuth pattern.

      OK ... but now think of it as four shortened (quarter wave) dipoles in a square.

      Now it's not so obvious that it might have classic dipole radiation

      Thinking that a loop is like two dipoles in parallel, is a real stretch.

      And in fact a good 1 wavelength loop radiates nothing like a dipole!

      Bend a circular loop into a square or triangle, and it's not quite so
      omni anymore; but it's still close enough for government work.


      [Non-text portions of this message have been removed]
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