As stated originally the boom length in the formula is in wavelengths.
A 47' boom is about .7 wavelength on 40 meters. The formula predicts
a spacing of .84 wavelenth or about 56 feet.
73
Tom Rauch wrote:
>
> Hi Brian,
>
> I don't understand what the following means. Is something wrong?
>
> > I queries WX0B about the rule of thumb regarding "optimum" stacking
> > height.
> >
> > Here was his response:
> > ***********************************
> > For HF antennas over ground, W2PV did the math correctly and the
> > formula is SQ rt of boom length is the widest stacking distance you
> > should use on a yagi. The results are in boom lengths just as you
> > state.
>
> My 40 meter yagi has a 47 foot boom. Optimum stacking distance
> for gain is ~90 feet, depending on array mean height.
>
> Using that formula, I should stack my 40 meter beams sqrt of 47,
> or 7 feet apart MAXIMUM?? A 1 WL boom antenna would stack
> at .7WL...which also would be much less than optimum
> ....although getting closer.
>
> Was something stated or conveyed incorrectly above, or is
> something missing? It clearly is not correct.
> 73, Tom W8JI
> W8JI@contesting.com
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