Cecil Moore wrote:
walt wrote:

Richard, it's very uncommon, but on this issue I'm having a difficult
time following you. The only reason that I can conclude for my lack of
understanding is that our definition of 'interference' must be
divergent. So I'll just drop the discussion--OK?


I am ignorant of any technical words (if they exist)
for what I am about to describe so bear with me.

Interference can have totally different outcomes so I
have to ask, are there different kinds of interference?

For instance, the interference between the forward wave
and reflected wave that causes standing waves has no
effect on either the forward wave or the reflected wave.
In an unchanging Z0 environment, the forward wave and
reflected wave pass like ships in the night. For want
of a better term, I will call this type of interference
"temporary interference".

The other type of interference occurs when reflections
are eliminated at a Z0-match or a non-reflective thin-
film. This is *wave cancellation* between two coherent
waves of equal magnitude and opposite phase traveling
in the same path in the direction. For want of a better
term, I will call that type of interference "permanent
interference" since the two waves are canceled and
disappear. Their energy components are redistributed.

Are there any technical words to differentiate between
the two types of interference?

When you think of interference as being the instantaneous sum of waves
at a given position and time, then there is really only one kind of
interference to be had - though there are a variety of results which
can be obtained from it. It is useful to bear in mind that fields,
voltages, and currents are what give physical form to the waves in
transmission lines. Whether in a transmission line, or free space it
is the fields which interfere - not power, or energy.

73, Jim AC6XG