[Antennas] gain vertical

[Alex Eban]

>>>you got your own answer in the last part of the email!
The theoretical isotropic antenna is considered to be placed at the center
of a sphere and sending its energy in such a way as to cover ( illuminate))
the internal surface of the sphere as evenly as possible. On the other hand,
a directional antenna puts the available energy over a small section of the
sphere's internal surface. The same energy spread over a smaller area,
generates a much higher signal level simply by rising the energy density.
This is equivalent to covering the original area with a much higher signal
energy. It doesn't matter whether the energy is concentrated over a small
patch of the sphere's surface, or is distributed over a ring around the
antenna. In this case the energy is taken from the areas found at high
radiation angles where it does no good for ground coverage.
The physical effects involved are the same in ALL cases of directional
antennas.
Any antenna array, whether, gets "gain" by reducing the surface of the
covered area, ALWAYS!
Alex	4Z5KS

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