[TowerTalk] 10M phased verticals

[Jim Lux]

On 11/29/11 10:45 AM, Paul Christensen wrote:
> I just modeled a 10m four-square in 4Nec2.  I used 60 #14 AWG radials
> 5/8-wave long over average soil, and 5/8 wave radiators.  The F/B is
> terrible at 1/4-wave spacing.

how did you set the element currents?  Explicitly with type 6 sources? 
or with a matching network/transmission lines?

F/B being bad is generally the result of the phases/amplitudes being 
wrong (small errors fill in the nulls)



   At best, it's about 12dB at an elevation of
> 45 degrees.  As would be expected with a 5/8wave vertical, two lobes are
> present.  Maximum FS with this ground occurs at 15 degrees elevation with a
> secondary lobe at about 60 degrees elevation.  The second lobe is within 3dB
> of the primary lobe.  Reducing radial length to either 1/4 or 1/2 wave has
> minimal effect on pattern.  There may be other combinations of spacing and
> source phase with 5/8 wave verticals that yield better pattern results.
>
> I'm not sure why anyone would want to use 5/8-wave verticals on HF.   We
> tend to equate 5/8-wave with maximum 0-degree elevation gain (usually from
> VHF/UHF antenna literature).  If someone has a compelling reason to use
> 5/8-wave *vertical* radiators on HF, I would like to hear about it.
>