Hey, thanks, Brian!
Yes, I have read the suggestion that the last few feet before the anchor
be EHS, and you can then use a Loos gauge on it to determine the
tension.
The tower is designed to be guyed, and there are guy fixtures welded to
the top of each section. The manufacturer recommends that the bottom
section be guyed, and the top sections in any high-wind area; so the top
two sets of guys are optional; but here in Highlands County, I looked up
the wind speed value for which I should guy, and it is 100 mph.
Hurricane Irene just about came right through here a couple weeks ago,
but veered East at the last minute and we only got about 40mph winds and
a little rain. But it could happen any time. Of course, if I knew she
were coming, I could crank it down and it would handle just about
anything then.
I'll see what the manufacturer says. Surely they must have to have some
guy tension values in mind: hope so, anyway. In the absence of other
advice, I think I would tension the bottom guys to about 400#, and the
others to about 100# or so. I think.
Dick Spindler
----- Original Message -----
From: alsopb <alsopb@gloryroad.net>
To: Richard Spindler <spindoc@digital.net>
Sent: Wednesday, October 20, 1999 8:23 AM
Subject: Re: [TowerTalk] Crankup Aluminum Tower
> Richard,
>
> Can't comment on most of this. However, you may
> not be able to accurately tension the phylistrand
> to the appropriate tension because of the lack of
> instruments to do so!
>
> I have t1200 on one tower. It's supposed to be
> tensioned to 120 pounds.
> First, all devices I have found assume steel
> cable. Second they don't measure to such a low
> tension.
>
> On the second tower I have half phylistrand
> (T4000) and half EHS. It's supposed to be
> tensioned to 400#. I can measure this on the EHS
> sections with a LOOS tension gauge.
>
> Keep in mind if you are guying a telescoping tower
> (where guys are not part of the original design)
> you are exerting a considerable downward force on
> the sections. For example, if the guys are
> tensioned to 400# and at a 45 degree angle, each
> guy exerts a 200# downward force. Multiply this
> by 3, 6 or 9 guys and you can see how quickly the
> downward forces add up.
>
> The alternate approach in guying telescoping
> towers is too settle for "limiting the sway in the
> winds" approach. The guys there are just barely
> tensioned and serve only to be a constraint on the
> maximum horizontal motion. These type of guys
> don't add much downward force.
>
> 73 de Brian/K3KO
>
> Richard Spindler wrote:
> >
> > I am in the process of erecting a nice AlumaTower crank-up 75
footer.
> >
> > This reflector has been a help in several respects, but some of the
most
> > important issues discussed reveal that I am tower-savvy-impaired
despite
> > reading what I can get my hands on.
> >
> > First, the issue of lightning protection. It looks to me as if the
> > three sections of the tower are essentially insulated from each
other
> > with plastic pads which prevent them from rubbing against each other
> > when the tower is cranked up. So it seems to me as if, even though
I
> > ground the legs to kingdom come with radials and multiple rods, the
> > major lightning path is going to be right down the old coax. I'll
have
> > PolyPhasers at the tower base and again at the entrance to the
house,
> > but that whole ground-at-the-tower-base issue seems moot. Am I
missing
> > something here? Is there a custom of bonding the sections
electrically
> > somehow? Looks like a real problem to me.
> >
> > Secondly, the issue of guy tension. I have read several treatises
on
> > properly installing and tensioning guys. It seems to me that if I
try
> > to tension my (PhillyStrand) guys to 10% of breaking strength, I am
> > going to have a tough time cranking the tower up all the way in the
> > first place, and have a pretty good chance of breaking the cable
which
> > cranks the tower up in the second place. I plan to guy each
section,
> > since we have a 100mph wind speed figure here in this county
(Highlands,
> > Florida), so I would have nine guys tensioned. I don't see any
> > information on this issue in the stuff I got from the manufacturer,
but
> > I have written for it.
> >
> > There must be fellows (I hesitate to say "guys") here who have faced
> > these issues. Any advice?
> >
> > Doc Spindler, N9AM
> > Sebring, FL
> >
> > --
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http://www.contesting.com/towertalkfaq.html
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>
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