Al...I replied to another email earlier tonight with an explanation of what
happened at my QTH when one of the winch cables broke. I hope I was clear,
if not let me know what blanks to fill in.
I am not defending the tower, or attacking/defedning anyone else's topics,
just describing what happened here, and trying to understand the
strengths/weaknesses of this series of tower.
73
Dan
K0DAN
----- Original Message -----
From: "Al Williams" <alwilliams@olywa.net>
To: <towertalk@contesting.com>
Sent: Monday, October 03, 2005 9:13 AM
Subject: Re: [TowerTalk] Lift cable, Galv Steel, vs Stainless
> I agree with w4hy. One of the reasons that I selected the LM470 was that
> Joel of First Call claimed that there were two cables so that the tower
> would not collapse if one broke. This tower was built by the short lived
> Paragon company and unless other manufacturers versions are rigged
> differently they too will collapse if the main pull up cable breaks.
>
> I would appreciate very much if k0dan would explain exactly which cable
> broke etc.
>
> k7puc
>
> PS This was not the only claim by Joel that wasn't true!
>
> ----- Original Message -----
> From: "Julio Peralta" <jperalta@tampabay.rr.com>
> To: <towertalk@contesting.com>
> Sent: Monday, October 03, 2005 3:46 AM
> Subject: Re: [TowerTalk] Lift cable, Galv Steel, vs Stainless
>
>
> > Pat I don't think this is entirely correct. If the main pull up cable
> > were to break the 2nd section would fall bring the 3rd and 4th inner
> > sections with it. The pull down cable runs from the base of the tower to
> > the bottom of the 4th or top section and serves to help the tower
> > retract in conditions where the wind is blowing and may bind the
> > sections. The pull down cable will not support the weight of the tower.
> > Not because it's not strong enough but because it's not rigged to do so.
> >
> > I think I'm right about this can someone else confirm my comments?
> >
> > Julio, W4HY
> >
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com] On Behalf Of k0dan
> > Sent: Sunday, October 02, 2005 10:55 PM
> > To: Pat Barthelow; towertalk@contesting.com
> > Subject: Re: [TowerTalk] Lift cable, Galv Steel, vs Stainless
> >
> > Pat:
> >
> > I can't address the M.E. issues you bring up, but is the engineer in
> > question aware that the Tri-Ex LM series uses redundant cables?
> >
> > That is, there is a pull-up and a pull-down cable, but if one were to
> > break,
> > the other one still does hold up the structure, and will raise/lower it
> > for
> > emergency purposes? (I know, I have had one cable fail...came off pulley
> > and
> > got pinched/broke, and I was still able to safely control the tower.)
> >
> > Based on my experiences here (west-central Missouri) I would definitely
> > try
> > for the S.S. cable, as corrosion and contamination are definitely issues
> > with galvanized, especially over time.
> >
> > I have restrung the cables on my LM470D, and while it can be done, it is
> > a
> > rather lengthy and tiring process. Anything which will keep the tower
> > safe,
> > while extending its maintenance periods, is worth the investment.
> >
> > GL & 73
> >
> > Dan
> > K0DAN
> >
> > ----- Original Message -----
> > From: "Pat Barthelow" <aa6eg@hotmail.com>
> > To: <towertalk@contesting.com>
> > Sent: Sunday, October 02, 2005 4:03 PM
> > Subject: [TowerTalk] Lift cable, Galv Steel, vs Stainless
> >
> >
> >>
> >> I am reviewing the engineering calculations for a Triex LM 354 tower,
> > a
> >> paper copy of which is signed and sealed by a Civll Engineer. The 19
> > page
> >> doc, gives the uninitiated a small, insight into the calculations,
> > including
> >> the mathematical equations used, for all aspects of mechanical
> > engineering
> >> of that particular tower. One calcualation, that of loads on, and
> > thus
> >> tensile strength requirements of, the lift cable, I am examining for
> > insight
> >> to viability of stainless steel lift cable substitute for galvanized
> > steel
> >> iin hopes of eliminating worries of deterioration due to corrosion.
> >> The LIFT CABLE STRESS Calcs:
> >> (Quote)
> >> 1/4 x 7 x 19 galv aircraft cable
> >> Maximum Breaking Strenght = 7000 lbs
> >> Factor of Safety = 7000/540 = 13.0 >3.0
> >> (Unquote)
> >>
> >> (where 540 is a calculated value of tension on the bottom run of the
> > cable.)
> >>
> >> If I interpret this line correctly, is it saying:
> >>
> >> Factor of Safety is 13.0 which is much greater than a minimum factor
> > of
> >> safety of 3, therefore easily passes.
> >>
> >> Is this an good interpretation of what the Engineer writes?
> >> If so, then stainless steel lift cable, which according to most wire
> > tables,
> >> has only slightly less tensile stregth than similar galvanized steel
> > cable,
> >> should also easily meet requirements for lift cable for ham towers..
> >> Or am I, as an unprofessional observer missing or assuming too much?
> >> Tnx...
> >> 73, DX, de Pat Barthelow AA6EG aa6eg@hotmail.com
> >>
> >>
> >> _______________________________________________
> >>
> >> See: http://www.mscomputer.com for "Self Supporting Towers",
> > "Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> > any
> > questions and ask for Sherman, W2FLA.
> >>
> >> _______________________________________________
> >> TowerTalk mailing list
> >> TowerTalk@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/towertalk
> >>
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> > any questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
> >
> > _______________________________________________
> >
> > See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
> > Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
> > any questions and ask for Sherman, W2FLA.
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
> >
>
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any
questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
>
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
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