[UK-CONTEST] Guying Versatowers

[Clive GM3POI]

This is a subject that I have had a lot to do with. My main tower was
supplied by versatower with guys at each level it consisted of 5 sections
with the top guys being 1/2" steel!! The crank up cable was 8mm steel. I
like some have suggested changed that cable to 8mm SS after having to change
out the steel one a few times. A few years ago during January The wind speed
at the top (93ft) reached approximately 130mph, The crank up 6 month old SS
cable tore apart mid cable with a resulting bit of a mess. The thing to
remember is Horizontal wind speed is transferred into downward force on the
cables and in my case was enough to tear the cable. I have now changed the
pulleys and gone back to Galvanised cable and gone up in size to the maximum
I could run through the sections ( 11mm). By the way SS has about 20% less
breaking strength than Galvanised.
The only real answer to getting towers down under windy conditions is to
have positive pull down on the top section i.e. a cable attached to the
bottom of the top section and preferably working in sympathy with the crank
up winch in the reverse direction.
73 Clive GM3POI
----- Original Message -----
From: "Chris Tran GM3WOJ" <gm3woj at talk21.com>
To: "GW4BLE" <gw4ble at btinternet.com>; "UK CONTEST"
<uk-contest at contesting.com>
Sent: Tuesday, May 20, 2003 5:15 AM
Subject: [UK-CONTEST] Guying Versatowers


> Hello Steve et al
>
> I'm afraid I have not read the article "Installing Towers Safely" by Peter
> O'Dell
> WB2D, published in the 1989 CQ Antenna Buyer's Guide, but I would have
> to strongly disagree about guying - I don't think U.S. amateurs have much
> experience of crank-up towers, although this is changing in recent years.
>
> I think it is essential to guy any Versatower which is spending most if
its
> time at full height, for the following reasons :-
> 1. If the wind speed increases unexpectedly, a Versatower can easily 'jam'
> in the fully-extended position.  Because of the tolerances, the sections
> tilt
> slightly, and it is impossible to lower the tower just when you need to
> most.
> For this reason, you should always have at least 1 or more ropes attached
> to the top of the tower, to allow a helper to keep the tower straight
while
> you lower it.
> 2.   The argument that guys exert too much 'down-force' on the telescoping
> wires is rubbish.  Yes, there is a slight extra load on the telescoping
> wires,
> but this should not be excessive, and without guys a fully-extended
> Versatower
> is relying on the forces being transmitted down to the base.  Versatowers
> almost always bend just above the join of the sections.  I've chopped up a
> damaged Versatower section with an angle-grinder, and the steel is
> surprisingly soft - like the old 'steam pipe' stuff.
> 3.   Even guyed, a Versatower is still vulnerable if the guys are too far
> apart
> - they really should be on every section (this is more than Elliott
> Versatower
> recommend)   Guying only at the top is dangerous because side-forces can
> make these guys slacken, and once the tower moves beyond a certain point
> the guys are actually adding to the problem, and the tower can bend near
> the middle.
>
> Stainless steel ropes - somewhere in my memory I recall being warned
> against using Stainless steel for tower ropes - I think it was partly
> because
> of the bending radius as discussed, but also that they are not as strong
as
> ordinary steel wire ropes, and there were problems fitting the eyelets to
> the ends - however I may be wrong here. I agree with Doug that soaking
> the wire ropes in oil or grease before installation is essential, and I
use
> up a
> whole can of grease here on each tower's ropes every year.
>
> 73
> Chris     GM3WOJ
>
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