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Old March 27th 05, 09:52 PM
Dave Platt
 
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In article bkE1e.110371$Ze3.24514@attbi_s51,
wrote:

Right..... so what creats it, this "squeezing" that you talk about and from
where
does this "squeezing force come from in an "appropiate"array?


There is no "force" in the usual sense of pressure on a physical
balloon. That's because the "balloon" is not an object. It's simply
a mathematical abstraction - a drawing of lines of equal RF power
levels on a graph having a certain set of axes.

To think that there's a specific 'force' squeezing the 'balloon', is
somewhat like trying to travel from east to west by pulling yourself
along the lines of longitude. Hey, the lines are there on the globe,
they're there on the map, why can't I just walk along the lines?

There's nothing "pushing" on the "boundaries" of the lobe, because
there is no lobe in the physical sense. It's not a separate and
distinct object.

To understand why there's a change in the shape that we visualize (and
that's all that the lobe shape is - a selective visualization), we
have to step down to the underlying phenomenon and see what's changing.

Because the conventional "lobe shape" is simply the result of plotting
the strength of the RF energy coming from the antenna, the answer is
simple. The lobe's shape is changing, because the amount of RF energy
being transmitted in the different directions is changing...

.... and *that* happens because the phase-and-location details of the
various radiators (and re-radiators) in the antenna system are being
altered.

Different radiator and re-radiator locations, intensities, and phases...

.... cause different "sum of vectors" results ...

.... which changes the strength of the RF received ...

.... which, when we walk around and try to locate the points
having equal RF field strength, means that we walk along
different paths ...

.... which means that we draw the lines on the map in
different places ...

.... which means that the "lobes" now have a different
shape.

--
Dave Platt AE6EO
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