Hmmm,
I think that an additional rope would work ok AS LONG AS the rope remained dry.
Most antennas prefer to be away
from conductive surfaces. Water and ice/snow tend to have some conductive
properties until totally distilled and I
have never seen any distilled stuff falling from the sky!
Also you would be putting additional stress on the center insulator thingy
(especially when the rope was wet). Water
starts to get heavy when maintained in absorbant materials like rope!
Antennas in trees are always subject to a lot of variable stresses. I just
'live' with it (I use coaxial inverted Ls in my
trees and plan on replacing them every couple of years with the ones that cross
multiple trees (160M) being the
ones that have the shortest life expectancy. I also use a bungy cord at one
end to take up some of the slack when
the wind blows...but I find that the bungy cords also have a short life so I
try to inspect them every couple of weeks.
The coaxial inverted Ls do not seem to mind being close to the trees. I see
not differences when the trees are wet
or when the leaves are on or off.
I have a pair of 160M, a pair of 75M, a 4-square on 40M and on 20M. These have
only been up a maximum of 6
months at this QTH, but experience at other QTHs with this type of antenna
gives me a good idea of the effects of
stress.
73 and good luck
-- Bruce, WA3AFS
On 11 Oct 2006 at 14:15, Eugene Hertz wrote:
> Ok, this may be the simplest question I will ever ask here so here goes.
>
> During my research for OCF dipoles, I have read about some horror stories of
> dipoles breaking or coming apart due to the stress of wind, weight and other
> factors. Especially I've heard that the carolina windoms, with their extra
> weight in the center caused by the matching unit, the isolator, and the
> length of feedline can cause a big sag at the feedpoint. Several folks I've
> corresponded with indicated that they attempted to "lift up" the feedpoint as
> high as possible by putting more tension on the wires (legs) to hoist it
> higher. This was for people that did not have a convenient center mounting
> location like a tower or tree or house.
>
> In thinking about this, it seems that these antennas have lots of phyiscal
> stress on them from both gravity as well as tension on the ends of the wires
> in the horizontal plane to try to counteract gavity.
>
> My thought was this: By using one rope (dacron etc) to connect leg1 to a tree
> and another rope to connect to leg2 to a tree (with pulleys and weights, of
> course), this is putting lots of "horizontal" stress on these wires and the
> center matching conductor/insulator thingy. This force is always trying to
> pull apart the antenna.
>
> Why not take one very long rope, thread it through the leg1 insulator, the
> center insulator/matching unit and then the leg2 insulator? Surely the two
> ends of the wires would have to be attached somewhat taught to the rope, but
> this could be done with some black wire-ties along the length of each wire.
> Or tie some knots in the rope somehow to hold the insulators in place.
>
> My thought was, this would all but eliminate any horizonatal stress normally
> put onto these wires and we would be left only with the stress of gravity
> vertically. I would imagine too, that this would help keep the center up a
> big better than nothing going through the center point.
>
> Any thoughts? Could this work? What am I missing?
> Eugene
>
>
>
>
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