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Huh?
Humor me, in what way does that equation constitute proof? Where is the source impedance in that equation? An SWR meter will correctly indicate the SWR on a transmission line if the transmission line connected to its output equals the design impedance of the meter, regardless of the source impedance. If the transmission line connected to its output doesn't equal the design impedance of the meter, the meter won't correctly indicate the SWR on the the transmission line, again regardless of the source impedance. Why does this seem so complicated? Roy Lewallen, W7EL Reg Edwards wrote: Source impedance DOES affect the amount of energy moving in and sloshing around in a transmission line. It DOESN'T affect the ratio of forward to reflected waves, and therefore DOESN'T affect the SWR. =========================== But it DOES affect the indicated SWR and so the indicated SWR is incorrect. It is the meter which is at fault ! It is designed to indicate correctly only when the source is 50 ohms. Here's the proof - Rho = (50-Zt) / (50+Zt) - which you may have seen before. SWR, of course, is calculated from Rho and the meter scale is calibrated accordingly. If the source is not what the meter expects then it gives the wrong answers. And its faithful worshippers believe it! --- Reg, G4FGQ |
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