[UK-CONTEST] Guying a "lugless" Versatower

[Clive GM3POI]

It is amazing the difference in Strumech tower specs.
	 When I was thinking about a tower for here, I
approached Strumech with a specification of headload 23 sqft at
125mph. That is the specification built and it has not changed
dramatically since, with the exception of Paraphill 16mm dia top
guys and Phillystran on the next set down. And a half tonne
worm drive power crank up winch.
	The third section up from the base is the bottom section
of a 60ft HD versatower. So big crankup tower were made and I
still have the engineering calculations supplied for the tower.
73 Clive GM3POI

On 29 Aug 2011 at 9:16, Don Beattie wrote:

> May I add to this ?
>
> We live here on top of a hill, with a 30 mile view to the SW
> (whence,
> generally, cometh the wind). Both towers here have been up for ten
> years, and
> the HD 80ft one is always guyed and normally up about 65ft. I raise
> it (in
> non-storm weather) to full height. It carries a ten-element 10-40m
> yagi. The
> guys work at both heights through use of strong commercial-grade
> galvanised
> lifting chain for the bottom 15ft or so, which allows the right link
> to be
> selected after raising or lowering. It is (touch wood) unmoved by
> the large
> gales we get here. Guying is Phillistran at three levels.  The 60ft
> standard
> tower sits at about 45-50 ft unguyed all the time, with a 3 ele
> SteppIR. I
> generally keep it with the bottom of the top section sitting in line
> with the
> top of the bottom section, meaning there is a good degree of
> overlap.
>
> Based on my experience, out of caution I would not leave the 80ft HD
> tower guyed
> at full height in the worst gales, but it has survived some really
> big blows at
> 65ft. The key thing for me is to turn the yagi to offer least wind
> resistance
> during a gale. And I agree with Chris - I would never try to adjust
> it when it's
> blowing, nor would I consider leaving it at 65ft unguyed in strong
> gales. When
> it's up at 80ft, I keep a regular eye on Wind Map (
> http://www.xcweather.co.uk/ ) which I find really helpful. But even
> at 80ft,
> when a big contest is afoot, I would take a risk and leave it there,
> even in
> a gale. It's just my natural caution that makes me lower it at other
> times.
>
> The spec says tha an 80ft Versatower can be left at full height with
> 5.2 sq ft
> of top load at 85 mph unguyed. Not my idea of fun but...a guyed
> tower can take
> 17 sq ft at 100 mph.
>
> Just my 4d-worth.
>
> Don, G3BJ
>
>  
>
>
>
> ________________________________
> From: Chris Tran GM3WOJ <zl1ct1 at gm7v.com>
> To: Regwoolley at aol.com; uk-contest at contesting.com
> Sent: Monday, 29 August, 2011 7:46:27
> Subject: Re: [UK-CONTEST] Guying a "lugless" Versatower
>
> >
> > I must add anyone that would want to leave a tower fully up in
> high winds
> > is barking mad. I would much prefer to get the thing down the slow
> way
> > than seeing it crash the fast way!
> >
> > Reg G8VHI
> >
>
> Hello all
>
> Sorry to disagree Reg but the worst thing you can do is to try to
> lower a
> guyed crank-up tower in a high wind.
>
> Let's be clear - I am talking about a tower guyed in the correct
> places,
> with properly tensioned wire rope guys and antennas which do not
> exceed the
> recommended head loading for the tower.
>
> As soon as you start to crank the tower down, the effect of the
> guying
> disappears immediately and the tower is very vulnerable to the wind
> forces.
>
> So the best advice is to do the guying job properly and sleep easily
> through
> every storm (OK maybe with one eye open watching the tower!)
>
> 73
> Chris
> GM3WOJ / ZL1CT
>
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