Owen Duffy wrote:
To do that, you need to determine the position of the standing wave
pattern with respect to the load, and a typical reflectometer style
SWR meter does not do that.

Yes it does, if one has the ability to vary the length of the feedline
until a current maximum point (minimum SWR) is known to be located at
the balun/choke. I do it everytime I get on the air. That's how I tune
my antenna system and I don't use any conventional tuner at all.

It is misleading to suggest that a reflectometer style SWR meter alone
is useful for determining the impedance of a load connected to the
meter by a length of transmission line, save possibly the case when
VSWR=1 and the line is low loss and Zo is the same as the calibration
Z of the SWR meter.

Not misleading at all. I do it all the time. I know the exact length,
velocity factor, and Z0 of my feedline. I know an SWR current maximum
point is located at my choke. I know if it is greater than, less than,
or equal to 50 ohms. It is a rather simple-minded process to accurately
estimate the antenna feedpoint impedance given everything I know. You
should try it sometime. Even if I didn't know if the current maximum
impedance was lower than or higher than 50 ohms, there would only be
two possible antenna impedances. EZNEC has a perfect track record in
predicting which of those two antenna impedances actually exists.
--
73, Cecil http://www.qsl.net/w5dxp