Richard Harrison wrote:
Which is cause and which is effect? Often what is cause and what is
effect can be interchanged. Volts across a resistor produce a current.
Current in a resistor produces a voltage drop. Take your pick of cause
or effect.

A resistor's resistance *causes* a certain V/I ratio. If there exists
a V/I ratio and no resistor, then the V/I ratio is the *cause* of the
resistance (or impedance). In other words, a resistorless resistance
cannot be the cause of anything. It is always an effect, often from
interference, and is usually lossless. Note that anything that suffers
from I^2*R dissipation is a resistor by this definition. That includes
a piece of copper wire.

A reflection may be caused by a phase reversal between voltage and
current.

We are past discussing reflections. The present argument is: Given two
coherent waves traveling in the same path with the same magnitude and
opposite phases, wave cancellation results from destructive interference.

The laws of physics tells us that energy cannot be destroyed and if
destructive interference exists, an equal magnitude of constructive
interference is required to exist. The destructive interference in
a Z0-matched system is toward the source. The constructive interference
in a Z0-matched system is toward the load. The energy components involved
in those two types of interference are traveling in opposite directions.

The conclusion is obvious. The reflected energy involved in the wave
cancellation process heads back toward the load just as explained on
the Melles-Griot web page. That there is such a large well-organized
good old boy conspiracy trying to hide these simple facts of physics
speaks volumes about the sad state of amateur radio.

http://www.mellesgriot.com/products/optics/oc_2_1.htm
--
73, Cecil, W5DXP