On Tue, 08 Jun 2004 16:43:04 -0500, Cecil Moore
wrote:

Walter Maxwell wrote:
This means that the system is matched and thus the re-reflected
voltage equals the reflected voltage.

No! NO! NO! The voltage re-reflected from any physical impedance
discontinuity equals the reflected voltage times the physical reflection
coefficient. That is the S-parameter term s22(a2). s22 is the physical
reflection coefficient. a2 is the reflected voltage incident upon port 2.

If the reflected voltage is 70.7V and the physical voltage reflection
coefficient is 0.5, then the re-reflected voltage is 35.35V. This is
all explained in HP's AN 95-1 on S-parameter analysis.

Cecil, when a mismatched line is matched at the input with a tuner the
reflection coefficient at the matching point in the tuner is 1.0 when the tuner
is matched, thus the re-reflected voltage wave must be equal to that of the
reflected wave. My statements are all based in these conditions.

These conditions are in effect when using an antenna tuner, so any equations
that work in general must work with the tuner setup. When the tuner is matched
the re-reflected voltage is in phase with the source wave. Then, according to
the conditions Steve set forth to use Eq 13 this equation should be viable for
use with conditions set up with the tuner, but it doesn't. You say this equation
is valid, so can you come up with the correct answers using it with a tuner
matching the mismatched line?

Unfortunately, my S-parameter texts are behind in Florida, and I've forgotten
the significance of the 'a' and 'b' terms.