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Old December 1st 03, 05:25 AM
Art Unwin KB9MZ
 
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Cecil Moore wrote in message ...
Art Unwin KB9MZ wrote:
In my case when modeling my particular dipole I can make tremendous
strides in efficiency if I attach wires at the end of the dipole that hang
to the ground
But when comparing gain say at 15 degrees horizontal there is no
worthwhile increase in gain ie less than 10% of the difference !


Art, a *gain* in efficiency is as good as an increase in gain. :-)


Cecil I believe you are missing the point.Either that or you have a
motive for such an answer.
An increase in efficiency will provide an equivalent gain at its 'max
directivity point' but the gain at a low angle has increased by a very
small amount. With my dipole antenna say at 40 % efficiency would be
equivalent to a beverage antenna at 15 degrees.
If I upped the efficiency of my antenna say to 80% then yes, you would
see
the gain at 90 degrees increase in a worth while manner but when you
examine an overlay with the beverage at 15 degrees you would be hard
put to see any difference. Draw the radiation patterns with both
circles meeting at the ground level and you will see what I am getting
at.( I am looking at horisontal polarisation now that provides
different ground losses for polarisation antenna forms , the beverage
being very close to ground)
Art