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Old June 27th 05, 01:38 PM
Cecil Moore
 
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Richard Harrison wrote:
Bob, W9MDK wrote:
"The above paragraph, however, was a rather difficult to ubderstand
reading,---."

I responded that the load would not accept volts and amps in a ratio
which does not fit its load impedance. Perhaps we should reason together
some more. The transmission line delivers power to the load at its Zo.
When the load impedance is different, there is a surplus of either volts
or amps. The surplus nust be reflected because the load can`t take it.
That`s all.


Another way of saying the same thing:

The mismatched load rejects voltage in the form of Vref and rejects
current in the form of Iref. Thus Vload is the phasor sum of Vfor
and Vref. Iload is the phasor sum of Ifor and Iref. The
result is that (Vfor+Vref)/(Ifor+Iref) = Zload.

If Z0 and Zload are purely resistive and Zload Z0 then:

Zload = (Vfor+Vref)/(Ifor-Iref)

Vfor and Vref are in phase, Ifor and Iref are 180 deg out of phase,
because we need a higher voltage and a lower current for RL Z0.

If Z0 and Zload are purely resistive and Zload Z0 then:

Zload = (Vfor-Vref)/(Ifor+Iref)

Vfor and Vref are 180 deg out of phase, Ifor and Iref are in phase,
because we need a lower voltage and a higher current for RL Z0.
--
73, Cecil http://www.qsl.net/w5dxp

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