Reg Edwards wrote:
And what on earth has it to do with a Smith Chart?

The phase angle between the total voltage and total
current can be had from the Smith Chart. Here's a
procedure that I use that works well for ladder-line
fed dipoles.

1. Model the antenna feedpoint impedance. Plot it
as a point on the Smith Chart. Draw an SWR circle
through that point.

2. Knowing the length of the ladder-line and the VF,
follow the SWR circle toward the source for the
appropriate wavelength(s). Mark that point as the
calculated impedance seen by the 50 ohm SWR meter.

3. Measure the 50 ohm SWR. The difference in the
calculated lossless SWR and the actual SWR reading
indicates the variations plus losses.

The above exercise gets me into the ballpark (almost)
every time.
--
73, Cecil, W5DXP