See intersperced comments and observations below
regarding Aluminum Towers de Tom N4KG
On Wed, 07 Oct 1998 20:35:00 -0500 "d.dimitry" <d.dimitry@mci2000.com>
writes:
>
>
>Dear Mr. Hider and friends,
>
>I beg to differ with the opinion you expressed. It is not uncommon
>for my
>office to hear from many hams (yes, customers) who have had their
>aluminum
>towers up for well over 20 years, some even approaching 40 years.
>Crank-ups have an especially high survival rate, even in hurricanes,
etc.
>It's not surprising to hear these testimonials anymore; that's how the
towers
>were designed.
>
>Needless to say, most of these guys have aluminum masts with the
>towers. I think it is true that some aluminum masts are on the light
side.
>However, several years ago we started offering HAMS heavier walled
material.
>No doubt, many chrome-moly masts would still have a greater yield
>strength.
>The question is: Is it necessary, and are you willing to pay the
>extra change? Consider also, that you may be paying more for a nearly
>invincible mast, only to have your antenna torn to shreds in serious
winds.
>
Are you suggesting it is better to use an inferior mast
that will fold over in lighter winds? It is a lot easier to
remove a damaged antenna from an intact straight
mast than to remove intact antennas from a bent mast.
de N4KG
>Aluminum towers in general have stood the test of time.
One of the locals installed a KT34XA on an 80 ft
self-supporting 80 ft. ALUMINUM tower, against
the advice of experienced locals.
Three weeks later, it was laying in the street following
a summer storm. One of the inward tapering legs at
the top of either the bottom or next higher section, folded
inward, bringing the whole tower down.
I have never understood why the ALUMINUM tower
manufacturers do NOT use a horizontal brace at the
top of their tower sections, especially on tapered sections
where the weight of the upper sections is pushing downward
AND inward on the bent upper leg. In my humble opinion,
this seems like an accident waiting to happen. de N4KG
>In addition to their strength, they offer the corrosion resistance and
>light-weight, that some owners both want and need.
My father's 40 ft ALUMINUM tower exhibited some leg
joints which would not separate during removal. A car
jack was used to facilitate separation and two leg ends
broke off, leaving the unbolted junction intact. Would
penetrox have prevented this problem? de N4KG
I have never understood why some ALUMINUM tower
manufacturers place the upper leg INSIDE the top of
the next lower section, allowing rain water to run down
the tower leg into the junction. All of the STEEL towers
I have seen put the top of the legs INSIDE the bottom of the
next section, forming a protective hood over the junction.
de Tom N4KG
No one can
>reasonably argue that they fill
>a niche, but even that is a large understatement. One last comment:
>like in
>anything else, compare apples to apples. There are different
>manufacturers
>of aluminum towers, just as there are different car manufacturers,
>everything from Chevies to Cadillacs. Do your homework.
>
>I would be happy to provide thorough calculations to any interested
>HAMs
>about contemporary designs that meet strict up-to-date engineering
>codes.
>
>Drake Dimitry
>DDimitry@HeightsTowers.com
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