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Old October 21st 04, 11:48 PM
Cecil Moore
 
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Tom Donaly wrote:
Who said anything about a circuit model?


I'm going to present an example, step by step. Please contribute
something technical in response.

It's a simple lossless quarter-wave matching section example.

------50 ohm feedline---+---1/4WL 600 ohm feedline---7200 ohm load
Pfor1=100w-- Pfor2=352w-- 100w
--Pref1=0w --Pref2=252w
Vfor1=70.7v-- Vfor2=460v-- Vload=849v
--Vref1=0v --Vref2=389v
Ifor1=1.414A-- Ifor2=0.766A-- Iload=0.118A
--Iref1=0A --Iref2=0.648A

Vref2 is 180 degrees out of phase with Vfor2 and thus they subtract.

Iref2 is in phase with Ifor2 and thus they add.

The impedance at '+' is (Vfor2-Vref2)/(Ifor2+Ifor1)

The impedance at '+' is (460v-389v)/(0.766A+0.648A) = 70.7V/1.414A = 50 ohms

Note that the impedance seen at the match point is:

Vfor1/Ifor1 = (Vfor2-Vref2)/(Ifor2+Iref2)

So Tom, do you find anything wrong with this network analysis? If so,
please be technically specific. (Sorry, your feelings don't matter.)
--
73, Cecil http://www.qsl.net/w5dxp


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