First normalize the load impedance by dividing by the
characteristic impedance, and find this point on the chart.
When working in terms of reactance X, an inductive load
will be located on the top half of the chart, a capacitive load
on the bottom half. It's the other way around when working
in terms of susceptance B [Siemens].
Draw a straight line from the center of the chart through the
normalized load impedance point to the edge of the chart.
Anchor a compass at the center of the chart and draw a
circle through the normalized load impedance point. Points
along this circle represent the normalized impedance at
various points along the transmission line. Clockwise
movement along the circle represents movement from the
load toward the source with one full revolution representing
1/2 wavelength as marked on the outer circle. The two
points where the circle intersects the horizontal axis are the
voltage maxima (right) and the voltage minima (left).
The point opposite the impedance (180° around the circle) is
the admittance Y [Siemens]. The reason admittance (or
susceptibility) is useful is because admittances in parallel
are simply added. (Admittance is the reciprocal of