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Art, KB9MZ wrote:
"Are you suggesting using a capacitive coupling instead of an inductor?" The dipole is about the simplest standing wave antenna. Its system must be resonant to allow full current in the antenna. The best arrangement for a dipole is a centerfed balanced pair of wires in a straight line that is self-resonant but this is only possible at discrete frequencies. If an antenna is too short to be resonant, it may be resonated by adding to its inductance or its capacitance, or both, if the antenna can`t be lengthened. My remark was only a reiteration of common knowledge. Coils are lossy and capacitors tend to be nearly lossless. Cecil has shown how an all-wave system with small losses can be made that doesn`t even require a tuner. He uses a variety of selected ladder line lengths to maximize antenna current. Another option is to use a balanced dipole with a balanced line connected with the transmitter through a tuner. Bill Orr, W6SAI has a suggestion for reducing the range of impedances the tuner must handle. It is to make the sum of the dipole length and the feedline length into preferred sums. These are 110, 133, 177, or 212 feet. He shows how to make the dipole, balanced line, and tuner in his book "Wire Antennas". He calls the dipole, line, and tuner: "A Universal H-F Antenna System", to cover 3.5 to 29.7 MHz with one antenna. Best regards, Richard Harrison, KB5WZI |
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