On Mar 28, 7:38 pm, Cecil Moore wrote:
Keith Dysart wrote:
Once again the hypothetical equality
Preflected = Pdissipated + Pre-reflected
229.6 = 872 + 0
does not hold.

I have pointed out your errors and misconceptions
3-4 times and you have refused to correct them.
This is the last time I am going to waste my
time.

The source is a 2A Norton with a shunt 450 ohm
resistor. During steady-state, the source sees
75 ohms. Adding 1WL of 75 ohm lossless line doesn't
change anything but for the Nth time, points out
your errors and misconceptions.

source--1WL 75 ohm line--+--1000' 450 ohm line--75 ohm load
Pfor1-- Pfor2-- Pload
--Pref1 --Pref2

Taking your numbers, Pload = 220.4w, Pfor2 = 450w, and
Pref2 = 229.6w

Obviously Pfor1 = Pload = 220.4w and Pref1 = ZERO

The joules/sec into the impedance discontinuity must equal
the joules/sec out of the impedance discontinuity. Let's
see if they do.
Pfor1 + Pref2 = Pref1 + Pfor2
220.4 + 229.6 = ZERO + 450
450 joules/sec = 450 joules/sec

There you have it. You simply made a mistake. There is NO
violation of the conservation of energy principle. The
same conditions that exist at the impedance discontinuity
also exist at the source. Total destructive interference
toward the source is accompanied by total constructive
interference toward the load. Every sliver of energy is
accounted for. You analysis is, once again, simply wrong.
--
73, Cecil http://www.w5dxp.com

I didn't catch this first time round, but better late then never.

As you say, adding 1 wavelength of 75 Ohm line will not change
the steady state.

So the condition on the right side of the inserted 75 Ohm line
section will be reproduced on the left side of the line section.

This means that reflecting back into the generator from the
left end of the 75 Ohm line will be the same Pref2 = 229.6 W
that exists on the right side of the 75 Ohm line section.

If you doubt, do the same energy analysis for the left end of
the line that you did for the right end. The generator is
putting 450 W forward into the connection to the 75 Ohm line,
229.6 W is being reflected and 220.4 W is entering the 75 Ohm
line. All is in balance at the connection at the left end
as it is at the right end. But 229.6 W are going back into
the generator. Where do these Watts go?

Using your analytical approach it may help if you put a one
wavelength section of 450 Ohm line between the generator
and the 75 Ohm line section previously inserted. This will
not change the steady state result but may make it easier
to visualize the reflected 229.6 W.

....Keith