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Weather satellite APT antenna



  I built an antenna for receiving NOAA 17 images and am impressed with it.
The antenna seems to be quite insensitive to "manufacturing tolerances'.
The one I made last week end seems to work very well.  It is a prototype
that I expected to use as a "first try" and could then be modified to
produce better performance.   But, this concept continues to be tolerant of
major physical variations.  There may not be a need for improving this Cross
antenna concept.
  I am now building yet another configuration and have others in mind to
evaluate.
 
  The antenna is basically two dipoles, crossed spaced apart, and fed in
phase.    The best performance so far is obtained with a pair of the two
dipoles.  Thats now four dipoles spaced about 1/8th wave, slanted about 60
degrees from vertical.  It looks alot like a Lindenblad thats squished and
elongated.
 
  I dont have exact instructions to describe how to duplicate this antenna.
I do have the notes and photographic records of "what I did".    I sure
would like to show someone with a little antenna experience how to build
this elliptically polarized hemispheric coverage antenna.   Its value can be
judged only by the performance others achieve.   I may be too easily
satisfied.
 
  This week  NOAA 17  has consistently recorded decent images whenever it is
above 2 degrees elevation.   I can usually hear it as soon as it gets only 1
degree above the horizon.   
 
  I can be contacted at   j.jmartes @verizon.net
 
             Jerry
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