Use a large enough nylon rope (5/8 - 3/4") and you might be ok.
However, think about what the rope tension becomes as a section of tower
gets out of vertical. It is impossible to pull a horizontal pole
upright with a rope parallel to the ground - it takes infinite force.
As the temp guyed section starts to lean (worst case directly opposite
one guy) the tension starts to increase towards infinity, the rope
stretches and the tower leans more, until down it comes. Nylon rope as
the other two guys are a long spring helping to pull the tower over!
Think of EHS and wire rope as a very short spring. The tension is gone
as soon as the tower moves a few inches (except for the weight of the guy).
The perfect (worst case & likely) setup is you at the top, tram lines to
slide the beam up, and gin pole above the tower top to hoist the beam
onto the mast, all adding more load force against a single guy. The top
guy on a 90' tower is 115' long so 8% or 10' of stretch swings the top
30 feet out of column 10' and down it and you and beam and gin pole comes.
There is a great tower stress analysis at
http://wiki.contesting.com/index.php/Guyed_tower_study It explains a
lot about how tower/guy systems behave.
On 4/3/2011 7:32 AM, email@example.com wrote:
> I use nylon rope all the time for tower work and for supporting temporary
> antennas and I have never seen the stretch that you describe Roger.
> Actually I like a little stretch when installing large antennas as it allows
> for a little height adjustment while on the tower. According to the
> internet, nylon rope stretched 10-15% when under a load equal to 30% of it's
> breaking strength.
> John KK9A
> To: firstname.lastname@example.org
> Subject: Re: [TowerTalk] Temporary guys
> From: K8RI on TT<email@example.com>
> Date: Thu, 31 Mar 2011 00:27:02 -0400
> On 3/30/2011 6:13 PM, firstname.lastname@example.org wrote:
>> I am curious how temporary guys could stretch so much to lay a tower on
>> side, perhaps the guy anchors were very far away? The Trucker's Hitch is
>> great advice, I have used this knot to for securing tower or reels of
>> hardline when transporting them home.
> When experimenting with a phased array I used Nylon rope to guy a
> temporary 40 meter vertical made from relatively light weight steel
> masting (the old TV masting). In 24 hours that antenna was leaning a
> good 60 degrees from vertical. You could walk over and take hold of the
> Nylon does not make even a good temporary solution to holding an
> antenna. However after it's been stretch out in the elements for a
> couple of weeks there is very little stretch left. OTOH I still would
> not trust it.
> Roger (K8RI)
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