Re: question about wire antenna and tuner



Cecil Moore wrote:
Jim Kelley wrote:

Correct, except for the part about destructive interference redistributing reflected energy. Please note the absence of any such claim in the cited (or any other) reference.


Please note the presence of constructive interference in
the cited reference: "... the photons are redistributed to
regions that permit constructive interference ...", which
implies an equal magnitude of destructive interference
elsewhere in order to avoid violating the conservation of
energy principle. It is akin to the gain of an antenna.
Constructive interference in one direction is matched
by an equal magnitude of destructive interference in
another direction.

More to the point, the Z-match reflects energy back toward the antenna.


Yes, as "constructive interference" energy which requires
destructive interference elsewhere to balance the
energy equation. Since there are only two directions
available in a transmission line, any constructive
interference toward the load must be balanced by an
equal magnitude of destructive interference toward the
source.

Quoting Reflections II, by Walter Maxwell, page 4-3:
"The destructive wave interference between these two
complementary waves causes a complete cancellation of
energy flow in the direction toward the generator.
Conversely, the constructive wave interference produces
an energy maximum in the direction toward the load,
resulting from the sum of the two reflected waves
and the source wave."

For a non-reflective thin film coating, these two
reflected waves are known as the internal reflection
and the external reflection.

Physical objects redistribute energy. Interference simply describes its spacial distribution.

73, ac6xg




.

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