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Cecil Moore wrote:
AI4QJ wrote: Going further, I am still trying to consider how the extra angle can also be absorbed "into" an impedance discontinuity. I have started a phasor diagram of it but it is not finished yet. Maybe a Smith Chart explanation will work. All lines are lossless. On a Smith Chart normalized to 100 ohms, lay out the 10 degrees of 100 ohm line from the infinity point, i.e. the open-circuit point. The reactance value is tan(90-10) = 5.67. That means the reactance value is 5.67*100 = -j567 ohms which has to be the value at the impedance discontinuity. Now on a Smith Chart normalized to 600 ohms, lay out the x degrees of 600 ohm line from the zero point to the point where -j567/600 is located. Read the number of degrees required. It is Arctan(567/600) which is equal to ~43 degrees. The phase shift at the impedance discontinuity is therefore 90-10-43 = 37 degrees. Wrong. In the first place, you obviously don't know the criterion for resonance. In the second place you just assume the number 90 without any reason. In the third place, the number 37 has only your assumption for the necessity of a 90 degree phase shift to justify its existence. As I wrote before, this is pretty poor shooting for a professional symbol slinger. 73, Tom Donaly, KA6RUH |
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