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Old February 7th 08, 11:33 PM 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

John KD5YI wrote:
I disagree. If the current through the 50 ohm source resistor is 0.039216,
then the power in the 50 ohm source resistor cannot be 0.03845w. Namely
because 0.039216 * 0.039216 * 50 = 0.076895w (eye-squared-are, matey).
Either your power is wrong or your current is wrong. My own calculations
show that your current is correct. Therefore, your energy analysis appears
to be in error.


You seem to have forgotten that since 0.039216 is the maximum
value of current you need to divide the 0.076895w by two.

0.076895w/2 = 0.03845 watts

If we used the RMS value of the current, i.e. 0.039216/1.414
equals 0.027734a, then 50(0.027734)^2 = 0.03845 watts and
all is well.
--
73, Cecil http://www.w5dxp.com