Sylvan,
Why did you put crossed 29* ft CONTINUOUS conductors
*(14 ft guy, across 1 ft tower face, plus 14 ft guy = 29 ft)
1.5 ft BELOW your Beam ? These crossed wired will act as
closely spaced directors on 20M and reflectors on 15 and 10M !
To MINIMIZE interaction between a Yagi and guy wires, the
FIRST Insulator should be as CLOSE to the Tower as possible.
Wires between insulators should be less than 1/3 WL
at the HIGHEST Frequency on the tower
(<12 ft Guy for 10M, INSULATED at BOTH ENDS).
I use TWO and sometimes THREE 12 Guy sections
for each guy connected to my towers before going to
27, 40, (and sometimes 54 ft on tall towers).
A friend once told me his tribander worked great on 10
and 20M but seemed less effective on 15M. His top guys
were 10 ft below the beam with insulators 10 ft from the tower.
The guys formed a NEAR RESONANT Continuous wire
( 10 + 1 + 10 ft = 21 ft) acting as a 15M Parasitic Director
0.2 WL BELOW the Driven Element of his Tribander.
Adding a single insulator to each of your guys, about 3 ft
from the tower, just might help with your problem. Another
insulator placed to provide two 10-12 sections in series
would be even better.
Tom N4KG
On Tue, 16 Apr 2002 Sylvan Katz <jskatz@sk.sympatico.ca> writes:
> Steve
>
> Thanks for the response.
>
> Is the C31 on top of the tower and the above the guys?
> What does the swr do when you key the xmtr and rotate the antenna?
> If it changes, then the culprit is typically the guys.
>
> Yes - the C31 is about 1.5 ft above the top of the tower. The guys,
> four of them, are attached directly to the metal plate at the top of
the
> tower. I have an insulator in each guy about 14 ft from the top of the
tower.
> The problem I am experiencing is not being able to get the SWR on 20
and
> 15 down within spec. I have exchanged a number of emails with Natan at
F-12
> and he figures the problem is related to the fact that the 14 ft guys
> sections electrically connected to each other via the tower plate
> (about 1.5 ft across) is detuning the C31 and causing the swr
problems.
> Oh and I do not see any swr change as I rotate the antenna.
>
> Any advice before I endeavor to make a change is really appreciated.
>
> .. sylvan
>
> Ô¿Ô¬
> ----------------
> Sylvan Katz, VE5ZX
> Saskatoon, SK
> "A Novel Perspective of Amateur Radio Contesting" at
> http://www.dynamicforesight.com/~ve5zx
>
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