On any tower of any description a yearly maintenance check is a must, no
matter which system is being used. Towers that fail have been left with out
----- Original Message -----
From: "Jim Thomson" <email@example.com>
Sent: Tuesday, August 30, 2011 6:36 AM
Subject: [TowerTalk] Preforms
> Date: Mon, 29 Aug 2011 18:41:52 -0400
> From: "Dick Green WC1M" <firstname.lastname@example.org>
> Subject: Re: [TowerTalk] Preforms
> To: "'Gregg Seidl'" <email@example.com>, <TowerTalk@contesting.com>
> Message-ID: <002501cc669c$d9f11ad0$8dd35070$@com>
> Content-Type: text/plain; charset="us-ascii"
> Preforms are an industry-standard product that doesn't loosen up over time
> if correctly sized and installed. You must have had the wrong size,
> defective grips, or they weren't installed correctly. I've got a friend
> preforms on his tower and they haven't loosened up in 20 years. Mine show
> sign of loosening up, either. Personally, I think grips are far superior
> cable clamps, which can deform the cable, can be installed incorrectly and
> the screws can loosen up over time.
> 73, Dick WC1M
> -----Original Message-----
> From: Gregg Seidl [mailto:firstname.lastname@example.org]
> Sent: Monday, August 29, 2011 10:44 AM
> To: TowerTalk@contesting.com
> Subject: [TowerTalk] Preforms
> I personally don't like the preforms. I have tried some and I feel they do
> loosen up after time. I took them all off and now only use cable clamps.
> Cable clamps are cheaper and can be reused or retightend. Just my
> Gregg K9KL
> ## I worked for the local telco for 34 years..and never even heard of one
> loosening up. I saw one instance where a
> D-9 cat hit the pole and snapped the ehs cable in the middle...and didn't
> put a dent in the preforms. The preforms are
> usually 4 x strands..and formed into a 'U'. You effectively end up with
> 8 x strands, 4 in and 4 out...which is one more strand than the
> 7 x stand ehs guy wire you have the preform attached to. Where the
> pre-form loops around the egg, turnbuckle etc, is actually stronger than
> the ehs cable.
> The more tension you put on it, the tighter it grips, just like those
> chinese finger devices. Now they are only supposed to be used once.
> They have to be installed correctly, and no gunk, grease, debris, etc, on
> the ehs cable. The ehs cable has to stick out the end of the
> preform a bit...so it doesn't quite touch the egg insulator, etc.
> ## the real old style cable clamps the power co's used consisted of a 2
> x piece steel double trough clamp assy..with 2-3 bolts compressing the 2
> x halves
> together. I know of one KL7 ham that used those things, the bolts
> loosened up on him, and the ehs cable slipped out, and he lost a 100'
> tower. We still
> have a lot of them in use around town, but they are rare these days.
> Telco's and power co's will use preforms at BOTH ends of the ehs cable..
> and no turnbuckles used
> anywhere. They use a different technique to get the slack out of the
> cable [ they actually grab and bend the wooden pole over a bit in the
> process] , then attach the lower
> preform. Of 100's of thousands of preforms in use, they are the most
> reliable thing going.
> ## If you do insist on using U style cable clamps, typ 4 x are used, and
> they have to be spaced correctly, with the U bolt bearing down on the
> dead end of the cable [ short pig tail portion].
> The saddle of course, bears down on the live end of the cable [ long
> portion]. "you can't saddle a dead horse" Every time I see a ham
> tower using cable clamps, I have yet to see one
> that's actually done correctly. They either don't have enough clamps, or
> ham will alternate the clamps 180 degs..or have em spaced too far apart,
> too much slack between clamps,
> bolts not lubricated, nuts not tight enough, too tight, etc. Don't get
> me started on guy anchors, esp elevated ones. Samll diam steel tubes,
> with thin walls, sticking out of
> the concrete by 5'-8' are semi useless at best. Then they don't typ
> construct the concrete base correctly either. If you do use a steel tube,
> at least fill it with concrete, or it will
> fill with water, freeze, and then split, or rust from the inside inside
> later... Jim VE7RF
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