Ian White GM3SEK wrote:
If you measured the impedance of that incorrect antenna, and then
replaced the antenna with a dummy load of the same impedance (a resistor
of the correct value, in series with an inductor/capacitor of the
correct value) then your transmitter will not know the difference.

It is true that transmitters are dumb as a stump. However,
a human being should be smart enough to realize that the
virtual impedance, which is only a voltage to current ratio
has been replaced by an impedor with a resistor, inductor,
and/or capacitor.

The impedor *causes* the load conditions. That virtual voltage
to current ratio is a *result* and not the cause of anything.
To get down to the actual cause of the conditions, the human
being needs to know whether the load impedance is virtual or
not.

Why do you imply that a virtual impedance can *cause* the
conditions seen by a source but deny that a virtual impedance
can *cause* 100% re-reflection? Seems a contradiction.
In fact, virtual impedances cannot cause anything. The
voltage to current ratio associated with a virtual impedance
is a *result* of something physical. Choosing to ignore that
physical "something else" cause has gotten lots of folks into
logical trouble.

In the huge majority of applications, both amateur and professional, it
IS possible to separate those two topics cleanly and completely. It
seems perverse to tangle them together unnecessarily.

It seems perverse to say the antenna system can be replaced
by a resistor and inductor or capacitor and nothing changes.
How about the radiation pattern? Does that change?

It should be
absolutely no surprise that, when summed to an infinite number of terms,
this series produces exactly the same results as the steady-state model
- exactly the same pattern of standing waves, and exactly the same load
impedance presented to the transmitter.

How about the total energy in the steady-state system? The
number of joules pumped into the system during the transient
state is *exactly* the amount required to support the forward
and reflected power readings.

The important conclusion from this more detailed time-dependent analysis
is that re-reflections at the transmitter have NO effect on the final
steady-state pattern of standing waves.

This is based on a rather glaring rule-of-thumb assumption,
that any standing wave energy dissipated in the source was
never sourced to begin with. Born of necessity, that is a
rather rash assumption. Thus some people sweep the reflected
energy dissipated in the source under the rug and forget
about it, hoping that nobody ever lifts the rug and points
out the conservation of energy principle.

I await the inevitable photon explanation.

None needed. If anyone wishes to introduce additional complications
where none are necessary, then of course they're at liberty to do so.
But when invited to join in, everyone else is at liberty to decline.

Optical physicists did not have the
luxury of dealing with voltages. As a result of dealing with
power densities, they learned a lot more than RF engineers
know to this very day. Optical physicists have never asserted
that reflected waves are devoid of ExB joules/sec or that
EM waves are capable of "sloshing around".
--
73, Cecil http://www.w5dxp.com