Walter Maxwell wrote:
Cecil, why are you avoiding trying to understand the basis for his erroneous
concept of adding forward and reflected voltages to obtain total forward
voltage? You don't even respond to my discussion on this point.

I'm not trying to avoid it, Walt. Dr. Best simply doesn't do that. V1 is
a *forward-traveling voltage*. V2 is a *forward-traveling voltage*. Their
sum is VFtotal, the *total forward-traveling voltage*. He does NOT add a
forward voltage to a reflected voltage. V2 is the *forward-traveling* re-
reflected voltage equal to VR2(RHO).

When the reflected voltage is acted upon by the reflection coefficient, it
becomes a forward-traveling voltage. That you think Dr. Best is adding forward
and reflected voltages, is the source the present misunderstanding. The
individual Poynting Vector for V1 points toward the *load*. The individual
Poynting Vector for V2 points toward the *load*. V1 and V2 are coherent
component waves, both flowing toward the load so, of course, they superpose.

Again, consider the following *matched* configuration where RHO is
the reflection coefficient and TAU is the transmission coefficient.

XMTR---Z01---x---1/4WL Z02---load
VF1-- VF2--
--VR1 --VR2

There are four superposition components that occur. Two of them are
traveling toward the load and two of them are traveling toward the
source.

V1 = VF1(TAU) traveling toward the load
V2 = VR2(RHO) traveling toward the load

Adding these two forward-traveling voltages yields VF2 = V1 + V2

V3 = VF1(RHO) traveling toward the source
V4 = VR2(TAU) traveling toward the source

Adding these two rearward-traveling voltages yields VR1 = V3 + V4
which, in a matched case is zero because V3 = -V4.

VF1 breaks up into two components, V1 toward the load and V3
toward the source.

VR2 breaks up into two components, V2 toward the load and V4
toward the source.

Collect and superpose the two forward-traveling terms and you get
the total forward-traveling voltage.

Collect and superpose the two rearward-traveling terms and you get
the total rearward-traveling voltage.
--
73, Cecil http://www.qsl.net/w5dxp



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