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8157Re: [loopantennas] Re: Loop reflector

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  • Andy
    Jan 18, 2011
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      > I(t) will not work like a quabic quad for a couple of reasons
      > 1. Main element only 1/8 wavelength from ground causing distortion
      > of pattern
      > 2. Reflector is therefore much less than 1/8 from main element
      > causing distortion of pattern
      > 3. Reflector is considerably less than 1/8 wavelength from ground
      > causing even more distortion of the pattern and it's probably not going
      > to work like a reflector at all even in the slightest being more or less
      > cancelled out by the effects of ground

      You are right that its pattern won't be exactly the same as a
      free-space quagi tipped on its side.

      But yagi antennas (as a general class of antennas with a radiator and
      one or more passive parasitic elements) can be made with all kinds of
      inter-element spacings. There are the NIST spacings, or you can
      optimize for bandwidth, or you can optimize for maximum gain/length,
      etc. There is no one yagi design. And there are perfectly good
      compact yagis with far less than 1/8 wavelength spacing ... and they
      do work. Yes, the pattern will be different than a longer yagi, and
      the bandwidth may not be the same, but they too are quite acceptable

      There indeed is some interaction between the reflector loop and the
      earth beneath it, just as there is between every antenna and earth,
      and that is somewhat of an unknown (due in part to the variability of
      soil types). It's not right to say that one cancels out the other.

      The fact that people have been making "cloud burners" for decades,
      some adding low reflector wires under their antennas, and many finding
      that it helps, can't be discarded either. I think it is definitely
      wrong to say that it "won't work like a reflector at all even in the

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