Aluminum tower summary.

[Gene Smith]

Here are the results of my inquiry of opinions on
aluminum towers.  Thanks to everybody that responded!


Original question:

Does anybody own or have an opinion on aluminum towers such as those 
sold by Universal Towers or some other manufacturer?  
I'm looking for any drawbacks as to using aluminum instead of steel.  
If I go by the manufacturer specifications does it really matter if 
it's steel or aluminum? 

Gene
WD8OZL

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Responses:

I bought an aluminum tower from Heights, 64 feet, rated for a 25 sq. ft. load. 
Sections are 8 feet long, straight or tapered. Heights will fabricate whatever 
you need. Stainless hardware is first rate. Prices are competetive with 
Universal, but Heights offers heavier tubes. I only got to put up 48 feet 
because of FAA restrictions (I'm near an airport). My two extra sections are 
for sale. If you decide to go with Heights, let me know and I'll give you the 
sizes and price. I'm pleased with mine, just wish it was higher.
 
KU0A

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I have lots of negatives, as I had a Universal.  E mail if you want to hear
the specifics. Greg.
 
73 and good DX from Greg, wa0bnx.

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Hi Gene,
 
Did you read the post about the 100 mile per hour winds in Phoenix and the
tower damage that occurred?  The one tower that fell flat on its face with a
Heights aluminum tower.  At least I think it was aluminum because I don't
think Heights makes any other kind.
 
Bottom line:  I think aluminum is the WRONG material to make towers out of.
Ok for beams and verticals but towers should be made out of STEEL.  W7LXR
has had a very interesting experience with an aluminum tower . . . if you
could get him to talk about it.
 
Aluminum is either too soft or too brittle.  Cracks form.  They scare me.
 
Stan  w7ni@teleport.com

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Hello Gene:
I owned a Universal model 14-60 for 15 years and sold it to
Al Cresswell in Salem in 1989. It had a 26 inch base, two 22 inch, two 18 inch,
and a 14 inch top. It had a huge base of concrete nearly four yards (4.5 X 4.5
X 5 feet deep). We had winds of 93 MPH one winter which blew for hours and I
could see the tower sway. There was a 3el 15 hygain at 70' and 4el 20 hygain
at 60'. The tower performed well and was very easy to climb. I moved to a city
lot and didnt want to spend the fortune it would cost to buy new base rods and
pour the 4 yards, plus I hit solid rock when I go down 18" at this qth. I would 
have had to blast with dynamite to get a hole 5x5x5. I sold the tower and got
Rohn 25g and had a devil of a time just getting through the rock to put in the
short base!. The Universal tower was very light and I assembled it on the
ground and raised it up with four people raising the tower and a rope tied
to the front bumper of a pickup truck which slowly backed up. I had the tower 
up and down four or five times over the years to change/repair antennas. All 
said, the tower was very good.
good luck and 73
Rod AG7J
 
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Gene, my friend in Michigan has been using aluminum towers for 20 years. I
helped him replace 3 of them. None were overloaded and all were 60 or 70
feet. The last time we put guys on it, gee it's been up for 4 years now. A
miracle of sorts.   Bill

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Gene,
 
I have a Universal 40' aluminum tower that has been up for 
almost two years now.  The tower was used when I got it, and I do not 
know how long the previous owner had it.  It was/is in great shape and 
has served me well.  I had to purchase a new base and put it in 2 yards 
of crete, a bit more than recommended by the mfg.  It is free standing 
here in Lakeland, Fl. and has only been subjected to, at most, 50 mph 
winds.  As in Aug 95, when we had Hurruicane Erin come through, I lower 
it for safety sake.
 
Gary  KJ4WH
 
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Hi Gene-
 
I have had an aluminum tower for 3 years.  It uses a combination of
sections from Heights and Universal.  My tower also folds over
using a hinge made by Heights.  That's real nice.  I bought
my tower used so I got a very affordable package.  I have had
no trouble with my tower over that time, and it's weathered some
decent summer and winter storms.
 
Don't blindly follow the manufacturer's wind loading information.
The stuff I got from Heights derived windloads for 50mph winds -- that
is much too low for most areas in the USA.  I did my own analysis
for my county's basic wind speed of 75mph, with and without ice loading.
In the end I found that I had to scale back the total wind loading 
of my antennas, but I sleep well at night.  :)
 
I had to do a lot of assembly work on my own, and the aluminum tower
sections are much easier to move around than their steel counterparts.
If you go with an aluminum tower, use lots of "No-Ox" grease at
the section joints and be sure to use stainless steel hardware everywhere.
If you don't use stainless you'll get galvanic reactions at every bolt.
 
I have been collecting opinions about aluminum towers from various
postings I've seen on the net.  The major criticisms of aluminum are
that it has a much lower fatigue strength than does steel and that
aluminum loses its strength as it ages.  One must significantly 
over-engineer an aluminum tower to avoid fatigue problems.  Since 
aluminum towers cost more than steel to begin with, this further 
drives up the cost.
 
I hope this is helpful to you.  I'd be interested in a summary of
other opinions that you get.
 
73!
 
Ron (wb8ruq).