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Roy Lewallen wrote:
Yes, many, and they've been discussed here at length. That this concept is wrong can and has been shown by theory, modeling, and measurement. I made and posted measurements on this newsgroup in November 2003 which demonstrated clearly that the presumption is false. By now, even you know that standing wave current phase is fixed and unchanging and that those delay measurements of yours are invalid whether made on a wire or on a coil. The loading coil isn't making the antenna act like a physically longer antenna. Of course not! The loading coil is making the antenna act like an electrically longer antenna by adding a phase shift through the coil. The electrical lengthening is what resonates the antenna feedpoint to a pure resistance. In the extreme case of a physically short inductor at the feedpoint, it's simply modifying the feedpoint impedance and has no effect whatever on the antenna's radiation. Nobody has ever said it affected the antenna's radiation so that has been and is still just a straw man. As the inductor gets longer, it does become some part of the antenna, but adding an inductor which resonates, say, a 45 degree physical radiator doesn't make the antenna act like a 90 degree physical radiator. Of course not and nobody has ever said it does. It increases the electrical length and brings the forward and reflected waves into phase with each other. That's why the the feedpoint impedance is resistive. -- 73, Cecil http://www.qsl.net/w5dxp |
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