On Mon, 28 Nov 2005 17:54:35 GMT, "Jerry Martes"
wrote:


that VSWR *cant* be measured. I claim that VSWR *can* be measured and that
VSWR can be used to identify the impedance terminating the transmission
line.

Jerry, unless you redefine the term "impedance", you cannot generally
measure impedance with a typical reflectometer style SWR meter.

Impedance is a complex quantity (ie with real and imaginary parts).
There are an infinite number of different impedances (being
combinations of the real and imaginary parts) that could cause a given
SWR on a given line in most cases. (The exception is the case when
VSWR=1, you do know the impedance, it is the nominal Zo for which the
instrument was calibrated.)

Whilst you can work out the SWR that will result from a specific
impedance on a specific Zo line, you cannot do the inverse, you don't
have enough information.

Owen
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