If the hat has the purpose of substantially loading a short element in the most
efficient possible way, then it has to be at the top of the element.
If the hat has instead the purpose of loading an element whose lenght (phisical
or electrical) is already close to resonance, in other words if the hat is
small, then the hat works like a fine tuning device, without affecting in
practice the antenna performances/characteristics.
Because of the above, when the hat is small, or better to say when the loading
required for final antenna resonance is not big, the position of the hat is not
necessarily at the extreme top of the element.
> My question is: Does a tophat always have to be at the top? Or could
> it be a "Collar", half way
> up the vertical and maybe called a "Scarf"?
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