On 10/5/2018 11:15 AM, Joe Subich, W4TV wrote:
The longer inverted L moves the maximum current up into the vertical
section resulting in a higher feed impedance and more efficiency.
The higher the maximum current (to a point), the less loss in the
dirt. Further, the radiated field is proportional to the integral
of the current so putting the maximum current half way up the vertical
portion of the inverted L results in maximum radiated (vertical
polarized) field.
... Joe, W4TV
I did some modelling on this topic and found that making the
horizontal part on an inverted L longer does not increase the
vertically polarized wave that comprises the useful radiation.
It instead increases the useless horizontally polarized
radiation. Now if you have a top loaded vertical (T shape)
then more wire upstairs does mean more useful signal out.
There is a price to be paid for using an inverted-L vs
symmetrical top loading. (I realize not everyone can achieve
the latter.)
73
Rick N6RK
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