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Cecil Moore wrote:
Roy Lewallen wrote: Did anyone understand it? If so, would someone else please try to explain it to me? Where does that 18 watts of "reverse power" go, and why? Bob Lay, w9dmk, could explain it but he's off on a camping trip. I think the QEX editors can now explain it also. 18 watts is rejected by the mismatched load. It was part of a forward wave that contained energy and momentum. That energy and momentum MUST be conserved according to the laws of physics. The reflected wave heads back toward the source at the speed of light and part is re-reflected as Pref2*rho^2. rho at the source is zero; the source matches the transmission line Z0. So the "part" which is re-reflected is zero, by your calculations. The remaining Pref(1-rho^2) part (which is all of it, since none was re-reflected) engages with Pfor1*rho^2 in an equal magnitude/opposite phase wave cancellation as explained by Walter Maxwell on page 23-9 of "Reflections II". That part of Walt's text is talking about voltage and current waves. I'm familiar, thanks, with how they interact. You're the one talking about waves of average power -- since none of the reverse power wave is re-reflected, what happens to it? Where does the power go? Out the source resistor? I believe you said that 11.52 watts of it did. What happened to the rest? Since energy and momentum cannot be cancelled, the two cancelled waves conserve energy and momentum by heading back toward the load at the speed of light as a re-reflection of energy which joins the forward wave energy. What two waves head back toward the load? None of the alleged reverse power wave is reflected, by your own calculation. Where did it go? What's the other "cancelled wave" and where did it come from? What's its magnitude? Roy Lewallen, W7EL |
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