[BC] efficiency vs height

[Phil Alexander]

On 25 May 2005 at 11:03, PeterH5322 at aol.com wrote:

> 
> >> Best overall performance for a high-powered station with a non-sectional 
> >> radiator is at 5/9-lambda, which is 0.556. This is 200 degrees.
> >
> >But doesn't this assume a very thin radiator?
> 
> No, it assumes a radiator of conventional uniform cross-section, about 3 
> feet.

I don't know how general it is, but that doesn't sound like the tall,
high power radiators I've seen. Usually, 6 ft minimum and often more.

> >IOW, if a very large face is used won't 195 physical approximate 200 
> electrical?
> 
> Sure, as one would expect of a radiator with a very large uniform 
> cross-section, about 9 feet.

Exactly!
 
> Physical height may be of significance to tower erectors and to the FAA, 
> but whenever I use the term "height", I always mean electrical height, 
> and nothing else, unless otherwise qualified.

However, the FCC seems to do a direct physical height to electrical
height conversion, without regard for face width. Your way makes far
more sense to me.


Phil Alexander, CSRE, AMD
Broadcast Engineering Services and Technology 
(a Div. of Advanced Parts Corporation) 
Ph. (317) 335-2065   FAX (317) 335-9037





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