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Cecil, W5DXP wrote:
"My statement was limited entirely to lumped inductors, a purely imaginary conceptual model." Sorry I didn`t get the picture. An inductor that provides no phase shift is similar to a capacitor that holds no charge. Inductors and capacitors store energies in their magnetic and electric fields. Current lags in the inductor and leads in the capacitor. Pure reactances have a 90-degree phase shift between applied voltage and resulting current by definition. An inductor sans phase shift is salt without savor or sugar without sweetness. Lumped inductance means coiled in place of straight wire, to me. Reference to toroidal coils in this thread implied to me an absence of external field, for which I chose a shielded coil with a straight-axis for my example. I agree with Cecil that a 90-degree antenna which includes only a 45-degree length of wire needs another 45-degree phase-shift in its length to reach the full 90-degrees. As the coil is in series with a resistance, and the resistance the coil experiences depends upon its position between drivepoint (low-resistance) and far end (high resistance) at the end of the element, the inductance required to produce the same required phase shift, varies with its position in the element. Where the resistance is low, so is the required inductance. Where the resistance is high, so is the required inductance, and it is all for the same number of degrees that the antenna is short. Best regards, Richard Harrison, KB5WZI |
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