On Jan 29, 2012, at 10:19 AM, Lizeth Norman wrote:
> Hi all!
> I'm helping a friend set up a 40 m dipole on his tower. It hangs at
> approximately 30ft. The dipole is in a flat top configuration. There is
> some droop on the ends, but not too much. We have tried it at the 33' per
> side length as well as 30' per side. Neither gives reasonable swr. Both
> show 3:1 +. The cable is tested good (into my bird load) at 100 watts.
> Tried using a balun, and not using a balun. The tower is heavily grounded.
> Any ideas to try?
> Norm n3ykf
Sure. Check, the SWR across the band. Is it higher at 7.3, or 7.0? Is
there a lower SWR in the middle?
If it looks like the lowest SWR is below the band, then shorten the antenna by
6" and remeasure. Repeat as necessary.
If it looks like the lowest SWR is above the band, then lengthen the antenna
and remeasure. Repeat as necessary.
73,
Ken WA8JXM
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