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Old October 30th 05, 06:48 PM
Richard Clark
 
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Default Antenna gain question

On 30 Oct 2005 10:41:53 -0800, "lu6etj" wrote:

Imagine an inner radiant spherical surface with a finite and uniform
density radiant energy.
Aim a directional antenna with a directivity of, for example, one
stereoradian on any direction.
How is it able to such an antenna to receive equal quantity of energy
of a smaller portion of the sphere than an antenna that is able to
receive the energy taken place by the entirety sphere?


Hi Miguel,


You are quite right. Only an isotropic antenna can take all the
energy as only an isotropic could have transmitted it. The uniform
distribution and the spherical geometry force this solution even
though it is a practical impossibility.

The real question is, how did that energy get turned around to come
back?

73's
Richard Clark, KB7QHC