On 8/15/2010 7:11 PM, R. Kevin Stover wrote:
> The thing that makes a self supporting tower self supporting is the big
> block of rebar reinforced concrete under it. Adding guys to a self
> supporting tower may actually make it fail because of loads introduced
> by the guys that were never intended by the manufacturer.
This really isn't what he asked. If I interpreted his post correctly,
he's asking about installing temporary guys to eliminate the tower sway
while working on it. If the Phillystran guys are tensioned just enough
to eliminate the sway, it should add little vertical load and very
little pull on the legs. "As long as the additional vertical load plus
the weight being added does not exceed the tower's ratings" I see no
problem with it. The tower has a maximum vertical load which should be
in its ratings.
I would not leave the temporary guys in place except during work.
Guyed towers use a "yoke around the tower" to take the side pull rather
than the legs (like most hams attach them.) A yoke could be constructed
for this tower as well, but with care as it must not add any bending
moment, or cut into the tower legs. But again, it's temporary.
I'd certainly not use steel in this instance.
When ever I add sections to a tower they go up with light weight,
temporary guys on them http://www.rogerhalstead.com/ham_files/work.htm
. Yes this was before full climbing harness. Note the temp guys from
the section I'm on and from the top of the new section which hang almost
straight down. These make the sections rock solid when climbing, but
they certainly would not be sufficient for a windy day with anything on
> When the wind blows across guys, that force is transferred as a downward
> force through the tower to the base. Rohn 25/45/55 were designed to be
> guyed. I'm quite sure the Heights aluminum tower was not.
> As the list moderator is so fond of saying "do what the manufacturer
> says to do".
> On 8/15/2010 5:35 PM, Steve Sala wrote:
>> What is it that makes a standalone tower stand alone? without guys? I have
>> a used Heights tapered aluminum tower which I am going to install sort of
>> close to the shack to put my Vhf/Uhf yagis on to minimize feedline length.
>> Is it because the taper makes the shape sort of triangular which, I bet, is
>> the most stable of geometric shapes (compared to a Rohn 25-45, etc. which
>> all sections are non-tapered)?
>> Would I affect anything by adding a set of guys so I don't panic as much
>> when I climb it to install the sections and then the rotator and yagis?
>> Even though the hole in the ground holding the three long bolts would be
>> about 7 feet deep by 4 feet wide, minimizing movement is an objective while
>> I am up there. I was thinking of three Phillystran guys that I connect to
>> ground anchors when I am on the tower and then either removing them from the
>> ground anchors for operation or keeping them on for extra stability.
>> This Heights tower is going to be 60 feet tall although it originally was
>> 112 tall. A friend topped it off later at 60 feet with a new flat plate so
>> he it would not interfere with his astrophotography in his yard.
>> Nine Mile Falls, WA
>> TowerTalk mailing list
TowerTalk mailing list