Cecil Moore wrote:
Roy Lewallen wrote:
2. I don't understand the mechanism which causes waves to bounce.

I don't understand the mechanism which causes waves to slosh.
Would you mind posting the sloshing equation?

Cecil,

I am not Roy, but I will answer your question.

It is really *very* straightforward. As I hope you will agree, a
standing wave is characterized by voltage and current that are in
quadrature, both in time and in space. In other words, the current loops
are spaced 1/4 wave from the voltage loops, and the current maximum
occurs 1/4 cycle ahead of (or behind) the voltage maximum.

Let's look at conservation of energy, one of your favorite topics.

At some arbitrary starting time, the voltage loop is at a maximum, and
the current is zero. At that time all of the energy in the standing wave
is contained in the capacitive or E^2 term. The physical location of
that energy is centered on the voltage loops.

As the cycle proceeds, the voltage decreases and the current increases.
After 1/4 cycle the current is at a maximum and the voltage is zero.
Now all of the energy in the standing wave is contained in the inductive
or H^2 term. The physical location of that energy is centered on the
current loops.

There are two important observations. First, the location of the
standing wave energy has physically moved by 1/4 wave during the 1/4
cycle. That is the "sloshing" that some of us use as a description. Call
it what you like.

The second observation is that the standing wave is not at all static.
Energy is moving back and forth at the speed of light in the medium.

Some people like to treat standing waves as poor distant cousins to
"real" waves, or perhaps only as "envelopes". It is their option to do
so, but it misses the actual behavior of standing waves and "sloshing"
energy.

The equations can be found in many places, such as Johnson's book on
Transmission Lines and Networks.

73,
Gene
W4SZ