While Bruce's ideas have merit for testing an antenna, the Cushcraft
A-4S and other beams do not require testing/pruning etc. The book
values are fine and will work just fine.
I would add that modern, computer-designed beams do not require such
testing at all. I have been there, done that and verified such over
many years.
Bill, N3RR
Bruce Richards wrote:
>
> I have found over the years that if you can not put it up at least 1/4 wave
> above ground for testing/adjusting clear of other objects, it is better to
> support the antenna in a way that it stands on the reflector and points
> slyward.
> This works very well, and can be done by tying a rope between two trees or
> other
> items, and throwing a second rope over it in a clear area. Tie the second rope
> to the director end and raise the antenna to "near" vertical. This works well
> on
> all antennas, except Logs. Your SWR will be within .1 and .2 of what it will
> be
> at the top of the tower.
>
> Joe Natale wrote:
>
> > I just built the A4S/A744 Cushcraft 4 el tribander with 40m kit. I built it
> > on a mast about 4' above the ground using the band center dimensions. The
> > 1:1 SWR points are: 6.9, 14.050, 21.3 and 28.7. Do I tune it to resonance at
> > it's present position 4' above ground or put it up on the tower as is and
> > take my chances? It is going to be at the top of a 72' aluminum tower. The
> > manual is very vague on these issues. This is my first beam and can use your
> > advice. Thanks in advance.
> >
> > --
> > FAQ on WWW: http://www.contesting.com/towertalkfaq.html
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> >
>
> --
> -------------------------------------------------------------
> Bruce Richards / WD4NGB (No Good Bum)
> 50 miles Northwest of Nashville Tn.
> DX Web Page http://home.sprynet.com/sprynet/wd4ngb
> Space A DX Group http//www.geocities.com/Nashville/9846
>
> --
> FAQ on WWW: http://www.contesting.com/towertalkfaq.html
> Submissions: towertalk@contesting.com
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--
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