On Monday 21 October 2002 15:42, [email protected] wrote:
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.
Thanks, that was the picture I'd arrived at. Does the current really taper
away to zero at the open ends or is that effect swamped by ground capacitance
when it's only 0.5% of a wavelength above ground?
Thanks,
Steve
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