Had a look at the refs. I'm curious, did you actually read the
sentence that Roy wrote?

Cheers,
Tom

Richard Clark wrote in message . ..
On Tue, 12 Aug 2003 02:48:49 -0700, Roy Lewallen
wrote:

Almost correct.

The transmitter output impedance has no effect whatsoever on the line's SWR.

Roy Lewallen, W7EL


Hi Roy,

Entirely incorrect.

Transmitter output impedance that does not conform to transmission
line Z, when presented with a mismatched load through that line, adds
mismatch uncertainty in the form of an indeterminate SWR and
indeterminate Power to the load.

This has already been demonstrated twice. This has long been
documented with NBS/NIST references going back 4 decades. There is
nothing mysterious about it at all, and it conforms to the rather
simple principles of wave interference so poorly presented by Cecil in
months past.

The authoritative site:
http://www.boulder.nist.gov/div813/index.html

Direct reference:
"Juroshek, J. R.; A Direct Calibration Method for Measuring
Equivalent Source Mismatch; Microwave J., pp. 106-118;
October 1997

Obscure references:
http://www.boulder.nist.gov/div813/r...00S_n2nNet.pdf
"With vector measurements of the generator and meter reflection
coefficients Ãg and Ãm, respectively, the power of the incident
signal am can be related to the power of the source."

http://www.boulder.nist.gov/div813/r...FRad_ARFTG.pdf
which describes radiometer calibration (perhaps too exotic for this
group)
"tests are based on two assumptions. First, the network responds
linearly to our signal ( no power compression), and second, the
radiometer is sufficiently isolated from the source impedance."
...
"One of the assumptions made in deriving eq. (2) was that the
output from the radiometer is not dependent on the source
impedance. In the construction of the radiometer, two isolators
are inserted at the input of the radiometer to isolate the
radiometer from the source."
...
"The mismatch uncertainty depends strongly on the poorly known
correlation between uncertainties in the measurements of different
reflection coefficients, and so we use the maximum of the
uncertainties obtained by assuming either complete correlation or
no correlation whatsoever."

"Forthcoming Paper: Influence of Impedance Mismatch Effects on
Measurements of Unloaded Q Factors of Transmission Mode Dielectric
Resonators"
IEEE Transaction on Applied Superconductivity

"Analysis of Interconnection Network and Mismatch in the
Nose-to-Nose Calibration
Automatic RF Techniques Group , June 15-16, 2000 , Boston, MA -
June 01, 2000
"We analyze the input networks of the samplers used in the
nose-to-nose calibration method. Our model demonstrates that the
required input network conditions are satisfied in this method and
shows the interconnection errors are limited to measurement
uncertainties of input reflection coefficients and adapter
S-parameters utilized during the calibration procedure. Further,
the input network model fully includes the effects of mismatch
reflections, and we use the model to reconcile nose-to-nose
waveform correction methods with traditional signal power
measurement techniques."

As I mentioned, obscure references. However, given the impetus of
their discussion is long known (and that I have already provided the
original references they rely on), NIST presumes the investigators
already have that basis of knowledge.

73's
Richard Clark, KB7QHC