Cecil Moore wrote:
Roy Lewallen wrote:
And, if you assume the line is lossless, the voltage and current are
in phase every 90 degrees along the line regardless of the amount of
mismatch.

If the line has losses, the SWR circle becomes an SWR spiral
but the spiral still crosses the purely resistive axis like
the circle does, just not at the same points.

Does your answer imply that the number of degrees between
purely resistive crossings is not equal to 90 degrees when
the line is lossy? (Not a trick question)

After further thought, I think Roy's point is that a lossless
transmission line has a purely resistive Z0 so the voltage
and current are in phase every 90 degrees. Z0 is not purely
resistive for ordinary transmission lines. But real-world
distortionless lines are indeed lossy while possessing a
purely resistive Z0.
--
73, Cecil http://www.qsl.net/w5dxp