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Old February 9th 08, 06:49 AM posted to rec.radio.amateur.antenna
Cecil Moore[_2_] Cecil Moore[_2_] is offline
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First recorded activity by RadioBanter: Mar 2007
Posts: 3,521
Default Derivation of Reflection Coefficient vs SWR

Keith Dysart wrote:
Are you sure?


Rs Vg Pfor--25w Vl
+----/\/\/-----+----------------------+
| 50 ohm 23.08w--Pref |
| 48.08w / 1.92w
Vs 45 degrees \ Rl
100 cos(wt) 50 ohm line / 1 ohm
50w \ load
| |
+--------------+----------------------+
gnd

As a matter of interest, let's return to the 45 degree
line, the one to which I objected previously.

The forward power and reflected power are the same as
in the previous example but now the dissipation in Rs
is equal to the sum of the forward power and reflected
power. (It would be nice if all cases were as straight
forward as this special case.)

This is indeed the one special case where everything you
have been saying is true. There is no redistribution of
energy because there is no interference. There is no
interference because at Vg, Vfor and Vref are 90 degrees
out of phase.

These concepts are covered in my magazine article at:

http://www.w5dxp.com/energy.htm
--
73, Cecil http://www.w5dxp.com