On Jun 24, 5:17*am, Keith Dysart wrote:
I assume you will claim that there is now “constructive
interference” rather than the previous “destructive interference”,
but the line conditions are the same. How does the “reflected
power” know if it should construct or destroy? The phase is the
same.

That's easy to answer. The Norton equivalent is a current source so
currents should be used in the calculations. The phase angles between
the two current components are 180 degrees different from the phase
angles between the two voltage components. If the interference between
voltages is constructive, the interference between currents will be
destructive. Hint: the reflected current phasor is 180 degrees out of
phase with the reflected voltage phasor because of the direction of
travel of the reflected wave. As a result of directional convention,
the power in the reflected wave is negative.

So destructive interference for forward/reverse voltages is
constructive interference for forward/reverse currents and vice versa.
An SWR voltage maximum (constructive voltage interference) is an SWR
current minimum (destructive current interference) and an SWR voltage
minimum (destructive current interference) is an SWR current maximum
(constructive voltage interference).
--
73, Cecil, w5dxp.com