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On Dec 3, 5:49 pm, "Tom Donaly" wrote:
Cecil Moore wrote: K7ITM wrote: Cecil, I posed two very specific examples for you to work out to show us that you can actually correctly find the phase shift for travelling waves, as you promised you could and would. Sorry, Tom, when I came to the word "superconductor", I stopped reading your posting. Please try to stick to the real world of amateur radio next time. Anyone at anytime can come up with some impossible esoteric example that defies solution. Such examples are a "vexations of the spirit" and I don't waste the little time I have left on such nonsense. Please go find another victim for your tarbaby. In other words, you can't do it. Why don't you just say so? 73, Tom Donaly, KA6RUH It's his tarbaby, not mine. My description was just for an inductively loaded antenna, and a capacitively loaded antenna. I was simply describing a method by which I could make a very small high-Q coil; the small capacitor can be had from DigiKey. The obvious question is, does the size of the reactive loading component matter? Then, if so, why, and to what degree? What is it that loads (tunes) the antenna? Is it primarily the inductance of the coil, or is it parasitic effects such as the coil's capacitance to the outside world? Would the antenna be properly loaded with pure inductance, or does it _require_ the parasitic capacitance of the coil to the outside world? By the way, there's another way I can place an inductive reactance at a point in the antenna, in a way that it's not coupled to the outside world: I can make the antenna conductor be the outside of a piece of coaxial cable, and use the coaxial inside as a shorted stub which reflects a pretty good (fairly high Q) inductive reactance back to a particular point such as a quarter of the antenna length back from each end, where the stub connects across a gap in the outer conductor. Can I use such an inductive reactance to tune the antenna? Will there then be a difference in current at each end of the gap across which that reactance connects? If there is not, and we're dealing with a standing-wave antenna, how do we account for all the "electrical degrees" we need to--or do we really even need to be counting "electrical degrees"? (Joseph Boyer's wonderful article, "The Antenna-Transmission Line Analog," is highly recommended here...) Others are welcome to ponder all that while Cecil tries to unstick himself from his tarbaby. Cheers, Tom |
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