[UK-CONTEST] Steel versus poly rope guys?
G3RIR
g3rir at yahoo.com
Sun Jan 27 07:15:10 EST 2008
Alex,
I suggest never using polyprop for guy ropes as it is unstable in daylight
(uv). Polyester is very much better and there are even better ropes
available at a cost. Try a chandlery website such as Jimmy Green (Beer,
Devon) who has a wide range of guying materials.
I suspect that stainless steel wires are the way to go so that the guys are
resistant to the weather. You may even get salt in the air where you are
which could really give grief. You would probably have to break up the
lengths of the guys to avoid unwanted resonances. Cost is certainly an issue
as 12mm stainless is £10 per metre! You probably don't need such thick wire
and of course the thinner ones are cheaper.
In my many years of dinghy racing I always used stainless steel standing
rigging for the mast.
Neil, G3RIR
-----Original Message-----
From: uk-contest-bounces at contesting.com
[mailto:uk-contest-bounces at contesting.com] On Behalf Of Martin Snow
Sent: 27 January 2008 10:23
To: Alex GM3ZBE; uk-contest at contesting.com
Subject: Re: [UK-CONTEST] Steel versus poly rope guys?
GM3ZBE de GW3PRL
Alex,
Just noticed your request for info regarding rigging of
masts.
I come from a sailing/fishing background where safety is
paramount. Having said that there is a fair amount of overkill in the boat
insurance market, when it comes to rigging.
The following comments are based on the assumption that your
mast is up to perhaps 60/70 feet.
Polypropylene is usually the cheapest type of rope
available. The main problem with this material is that it is not UV
stabilised. This means it has very low
resistance to UV radiation from the sun and ‘rots’ very quickly, if left out
in
all seasons.
There are two main types of rigging: Standing and
Running.
Standing rigging is the rigging that holds the mast up all the
year round, It is usually fixed and not moved at all. (though not
necessarily motionless,
due to it vibrating in the wind) This can be stiff or flexible and need to
be
non-elastic or pre-stretched.
Running rigging consists of the halyards you use to haul up
the end of the antenna. This is used (moved)
fairly often and is required to be flexible around pulley blocks, and waggle
about in the wind with the antenna. This requires to be flexible.
The main advantage of using Galvanised or Stainless Steel
wire for your standing rigging is that it stands a lot of chafing before it
losses any of its strength. So, if it has to pass from the mast through
trees
and bushes on its way down to the strong point where its fixed permanently,
you’re
best using a steel wire (better still trim the trees/bushes back, remember,
these
blow about in the wind!)
Of course, from the radio point of view you must break up
the lengths of the guy wires, as shown in the Handbooks, to avoid resonances
and RF absorption.
If you can guarantee
that the guys will not suffer any chaffing whatsoever, or being chewed by
farm
animals! You could then use a UV stabilised fibre rope i.e. Terylene/Dacron
etc
from the sailing industry, also look in to the ropes used in the fishing
industry, they use some synthetic fibre ropes, some of which are Black,
which
is better.
Of course, Galvanised wire will be significantly cheaper
than Stainless. But will have a shorter
life. Take care not to remove the thin coat of zinc galvanising or it will
rust.
Again you have two choices of material for your running
rigging; steel or fibre, but for amateur radio use steel is a bit over the
top,
except for the wires used in telescopic masts where fibre should never be
used.
Since you live in Scotland,
I suggest you look in Yellow Pages for fishing supplies or chandlers, or ask
a
friendly fisherman if you live near a harbour.
Fibre rope comes in three main types plaited, and three or
four strand. The stranded ropes are very easy to splice.
Steel wires come in various specs. and some are classed as
flexible: -
1/19 = 19 single thick strands, is stiff and only used for standing rigging.
Requires
machine splicing. (Talurit)
7/7 = 7strands each of 7 medium wires, is only used for standing rigging.
Can
be hand spliced with difficulty
.if you’re keen!
7/19 = 7 strand of 19 fine wires, can be used for standing
rigging, but is intended to be flexible
enough for running rigging.
Fairly
easy to hand splice
. if you’re keen.
ALWAYS used a thimble in any eye splice, particularly in
wire standing rigging.
If you are near a firm doing yacht rigging, or a local scrap-yard,
ask for their scrap wires. You will find these perfectly good for the
average
amateur mast, very cheap, and in short lengths.
Hope this is of some help.
73 de Martin, gw3prl.
> From: alex at gm3zbe.plus.com
> To: uk-contest at contesting.com
> Date: Sat, 26 Jan 2008 20:35:30 +0000
> Subject: [UK-CONTEST] Steel versus poly rope guys?
>
> Hi
>
> I've never used steel guy wires on any of my (modest) masts having always
> used polypropylene or similar.
>
> Since I now live on the top of a 600ft hill in East Scotland I am thinking
> of replacing the present guys with steel cable.
>
> Exactly what type of cable is normally used, is it galvanised wire or
what?
>
> How do you specify it and who would stock that sort of stuff?
>
> Alex
>
>
>
> Alex, GM3ZBE ~~~~Kingdom of Fife~~~~~~~~~~~~~~~~~~~~~~~
> Member of:
> De Montfort University ARS,
> Kingdom Amateur Radio Society (KARS)
> GMDX Group, CDXC, G-qrp club (10455).
> Previous callsigns G3ZBE, GM8BYG,
> holder of GM4BRN club call.
>
> Remember..............It's only a hobby!
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
>
>
> _______________________________________________
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> UK-Contest at contesting.com
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