Its not related to a J-pole, the DB Products dipoles are simply a center fed dipole with a fat grounded element and the driven element is a folded monopole. Probably much lower impedance than a typical dipole of 72 ohms in free space due to its girth but when placed really close to a tower leg the impedance gets pulled way down.?
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I recently picked one up at a swap meet and used some excellent info from this group and tuned it for 6m.?
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