On Jun 8, 6:28*pm, K1TTT wrote:
interference is nothing but what you observe after you superimpose two
or more waves. *the general principle at work is superposition, giving
it more specific names like destructive or constructive interference
is just describing the result that you observe.

Yes, interference is the result of superposition. Sometimes
superposition results in wave cancellation which is destructive
interference that redistributes the energy in the canceled waves in
the opposite direction in a transmission line - the only direction
that supports constructive interference. The point is that at an
impedance discontinuity in a transmission line, in the absence of a
local source, destructive interference in one direction *requires*
constructive interference in the other direction. That's how a Z0-
match redistributes all the reflected energy back toward the load
while none reaches the source. It is exactly how a 1/4WL thin-film
coating cancels reflections on a piece of non-reflective glass.

The important thing is that a power density equation exists that
predicts the energy flow as a result of superposition.

Maybe if you reviewed "Sec 4.3 Reflection Mechanics of Stub Matching"
in "Reflections", it will be more clear?
--
73, Cecil, w5dxp.com