Myron A. Calhoun wrote:
"--I`m not learning much."

Alas, I`d wager I don`t have anything new for Professor Calhoun, but
from some of the postings, what I write may be new in part to someone.

Current is defined as movement of electrons through a conductor.
Obviously, an incomplete definition. As we know, there is beam current
in the vacuum of a CRT, and that at r-f, skin-effect forces most
electrons to the surface so that most electron movement is on or very
near the surface of the conductor rather than "through" it.

When currents of equal amplitude and opposite direction meet at various
points along a perfect transmission line, as they might after a perfect
reflection of the incident wave, one might measure zero amps at
cancellation points along the line. These would be distributed
periodically as the waves, in fixed phase relation and equal and
opposite currents, coincide. The measurement of zero amps occurs because
the ammeter is measuring both currents simultaneously. If a directional
coupler is used to measure the current in each direction separately, it
will be found that the currents traveling in opposite directions are
passing through each other without effect. Standing waves are more
manifestation than anything else.

There was a PBS TV Channel appeal tonight. It Quoted Einstein as saying:
"Nothing happens until something moves".

Incident and reflected waves move on a transmission line but standing
waves are stationary and don`t move. So, it is the incident and
reflected waves that make something happen. Not the stationary waves.

Circulating energy within a transmission line causes standing waves.
Without a reflection, they don`t exist. Energy must be accepted by an
antenna to be radiated. It is best if it is accepted on the first pass
so that there are no more losses on additional passes. A perfect match
at the antenna accepts energy on the first pass. A mismatched antenna
produces an SWR. Magnitude of the SWR is an indication of how much
mismatch there is.

Best regards, Richard Harrison, KB5WZI