[Boatanchors] Guy Wire Insulator Placement

Thu Jul 25 11:53:43 EDT 2013

I put up a Universal aluminum tower in 1972.  It was rated for 18 square feet wind load at 60 feet.

I had a Mosley Pro-67 (7 el on 6 bands) weighing a bit over 110 pounds at the top, 13' of 2" o.d. (1/4" wall) aluminum mast out the top (11 feet in the tower), a full-size 10 MHz dipole about 9' above that and 15 el 2m beam at 73'.

It stood up to quite a few 60+ mph winds and 2 or 3 that were around 80-90 mph in the 27 years of its life.

It did NOT hold up to a direct hit by an EF-3 tornado, but neither did my house or hundreds of other houses in the BIG twister that hit central Oklahoma in a path about 70 miles long on 3 May 1999.  That storm was the FIRST evaluated as an EF-5 and an EF-4 when it went through our neighborhood, but I was about 500 feet east of the center path.
A friend about six miles to the east has a 40 footer with SteppIR 3 el and his tower withstood a tornado that hit his neighborhood.  I have the same 40 footer up (rated at 15 sq ft at 87 mph) and will have an identical SteppIR on it in a month or two. 

I do NOT plan to push the manufacturer's stated engineering limts!

* * * * * * * * * * * 
* 73 - Mac, K2GKK/5 * 
* (Since 30 Nov 53) * 
* k2gkk at hotmail.com * 
* Oklahoma City, OK * 
* USAF & FAA (Ret.) * 
* * * * * * * * * * * 

> Date: Thu, 25 Jul 2013 07:48:48 -0700
> From: gzook at yahoo.com
> To: brianclarke01 at optusnet.com.au; ranchorobbo at gmail.com; cwopr at embarqmail.com
> CC: boatanchors at mailman.qth.net
> Subject: Re: [Boatanchors] Guy Wire Insulator Placement
> 
> What I am using is personal experience.  In each case where I know of problems with an aluminum tower, the tower was installed using the manufacturer's recommended procedures.  In each case the wind load on the tower was less than the maximum rating of the tower.  In each case, the tower "buckled" at about the half-way point.  That is, there were no problems with the base installation.
> 
> These towers were installed in north Texas (Dallas, Texas, area) where the wind speed does, on occasion, get above 70 mph.  In fact, every few years, the wind speed can go over 90 mph.  These are "straight line" winds and not tornadoes.  A tornado, of course, is a completely different matter.
> 
> Obviously, there are different manufacturers of aluminum towers and, probably, different specifications that must be met in different countries.  As such, I have no idea as to if the aluminum towers sold in Australia are the same as those that were sold in this area.  But, I do stand on my comments based on my experiences.
> 
> In my professional experience as a telecommunications consultant, I have had quite a number of towers installed from less than 100-feet to over 500-feet.  As such, I do believe that I do have at least a "little" experience with different tower types.  Those towers ranged from guyed to self-supporting and I would never recommend using an aluminum tower!
>  
> Glen, K9STH
> 
> Website: http://k9sth.com
> 
> 
> ________________________________
> From: "brianclarke01 at optusnet.com.au" <brianclarke01 at optusnet.com.au>
> To: Glen Zook <gzook at yahoo.com>; Rob Atkinson <ranchorobbo at gmail.com>; Bill Stewart <cwopr at embarqmail.com> 
> Cc: boatanchors <boatanchors at mailman.qth.net> 
> Sent: Thursday, July 25, 2013 5:08 AM
> Subject: Re: [Boatanchors] Guy Wire Insulator Placement
> 
> With all due respect, Glen,
> 
> Usually, I find you give fairly good advice.
> 
> But this diatribe you have contributed has no engineering merit whatever. You have given no statement of design for dead weight, wind loading, erection, ground support ...  I have designed towers using both aluminium and steel. Those two metals have different crush strength, sheer strength, fatigue resistance, weight, ease of fabrication, cost - I could go on.
> 
> To everyone else on this list, get an engineer to assess and certify any proposed tower you want to erect.
> 
> 73 de Brian, VK2GCE
> BEng, PhD, Fellow IEAust 