I'm not sure I understand the point you're trying to make. Nothing I've
said disputes in any way that the input impedance of a shorted quarter
wave stub is high. I'm quite able to make transmission line calculations
and arrive at correct results.

You're certainly correct that there's very little net current at the
open end of the stub. Yet there are waves traveling in both directions
right through that point. Don't believe it? Then check the current
anywhere else along the stub. How did it get there without going through
the "open" at the input end?

Roy Lewallen, W7EL

Richard Harrison wrote:
Roy Lewallen, W7EL wrote:
"Those traveling waves, and hence their sum, cannot cause a reflection
of other waves, or alter those waves in any way."

Let`s reason together on the situation in a quarter-wavelength
short-circuited transmission line stub. I maintain it has a hard short
on its far end and a high impedance on its near end.

A high impedance means just what it says. You can put a high voltage on
it and the resulting current is small.

Reflection from a short-circuit results in a 180-degree voltage phase
reversal at the short.

A round-trip on a 1/4-wave stub produces an additional 180-degree phase
reversal.

This means thats volts returning to the open-circuit end of the stub are
about of the same phase and magnitude as when they started out.

Nearly identical voltages appear at the same pair of terminals from
opposite directions. Significant current flows in either direction? I
think it does not.

Where voltage causes insignificant current flow, we have a high
impedance.

That is why King, Mimno, and Wing on page 30 of Transmission Lines,
Antennas and Wave Guides say:
"Since the input impedance of a short-circuited quarter-wavelength
section of transmission line is a very high resistance, short-circuited
stubs may be used to support the line."

Best regards, Richard Harrison, KB5WZI

Roy Lewallen wrote in
:

anywhere else along the stub. How did it get there without going through
the "open" at the input end?

Ah, a total re-reflector!

Owen