Manypeople can't mount a 40 meter antenna far enough away from other objects to eliminate detuning effects. See for yourself how bad this is with a 2 meter mobile station and an SWR meter--then scale things up dimensionally by a factor of 20. Thus, for proper performance, low-frequency antennas often need to be tuned in-place. When they're
Homebrew2 meter Yagi construction. • 2 1/4 inch x 48 inch Steel rods (I know they'll rust, it's just temporary to get it to work, I'll get aluminum later) I don't have any coaxial cable (don't know the best type to get) and don't know how to match the impedance of the cable to the antenna.
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