In a message dated 10/21/02 11:15:41 AM Eastern Daylight Time,
[email protected] writes:
My experience with many shapes of top hats is that it DOES
> reduce the radiation measured in the far field.
Is that in comparison with no top loading at all, or purely
horizontal top loading?
That's in comparison with horizontal top loading.
If a drooping top hat is all one can manage, it's generally better than none
at all. However, consider that the far field radiation will be proportional
to the sum of the vertical components of the current flow, and you can see
that current in the downward segments will subtract somewhat from the end
result. The trick is to make sure that the top loading is effective enough
that the increased magnitude of overall current is enough greater to offset
the partial cancellation.
John
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