From: WarmSpgs@aol.com
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Date: Mon, 21 Oct 2002 11:42:02 EDT
To: rsgb_lf_group@blacksheep.org
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Subject: Re: LF: RE: Re: Re: Ant Questions
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In a message dated 10/21/02 11:15:41 AM Eastern Daylight Time, 
steve@eltac.co.uk 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