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#1
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Shucks, I have an antenna that's no bigger than a baseball, and it gives
better than a 1.5:1 SWR over more than the whole HF band when I connect it directly to my transmitter. If I hang it up real high, the SWR gets better yet. Roy Lewallen, W7EL Richard Harrison wrote: Art wrote: "My present antenna, which is for 160 m and above, is about the size of two shoe boxes and is less than 2:1 swr (50 ohm) across the band when situated at the tip of my tower." Outstanding! An effective antenna needs to be an appreciable portion of wavelength in some dimension. If Art`s antenna is an appreciable portion of 525 feet it can radiate well on 160 meters. Any length of wire carrying an RF current is capable of radiation. Significant radiation from a short wire requires much current. With a garbage can lid for a reflector, a helical antenna can be made. Were it 3 feet across in diameter (0.9 meter) the helix might work on 3 meters as the diameter needs to be about 0,3 lambda. Terman gives helical antenna information on page 909 of his 1955 opus. His best bets for small antenas are the corner reflector and the Yagi. Best regards, Richard Harrison, KB5WZI |
#2
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Roy Lewallen wrote:
Shucks, I have an antenna that's no bigger than a baseball, and it gives better than a 1.5:1 SWR over more than the whole HF band when I connect it directly to my transmitter. If I hang it up real high, the SWR gets better yet. Roy Lewallen, W7EL Well heck, I have one the size of 2 shoe boxes that will handle a KW from 160m through 70cm with less than 1.35:1. Bird made it. Decades old and still works perfectly. tom K0TAR |
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