[TowerTalk] Advice on type of tower

[Bill Coleman AA4LR]

On 1/11/2000 23:56, thaxton@ptgroup.com at thaxton@ptgroup.com wrote:

>I would like to solicit feedback and opinions on two types I 
>am considering.  I am looking at a crankup, motorized, and a 
>foldover type tower.  What are the drawbacks and good points to 
>these two styles of towers. I believe a height of 55 to 75 ft. will be 
>sufficent for my qth.

Each tower type has a tradeoff. You didn't mention other types, but 
perhaps you should. I divide towers into three categories:

* Guyed / Bracketed. Typically made by Rohn, but there are other 
manufacturers. When you get right down to the specs, these towers can 
hold up more antennas than anything else. Disadvantage is having the 
space to put down guy anchor points. Some people don't want to have to 
deal with guy wires in their yard. Bracketing to a structure (typically 
your house) is an alternative to guys, but the usable height above the 
bracket as well as the capacity of the tower is limited. You also have to 
engineer a solid bracket attachment to the structure.

* Freestanding. Freestanding towers can have nearly the capacity of guyed 
towers. They have two disadvantages: they cost a LOT more than guyed 
towers with the same capacity and height; they require a huge monument of 
concrete in the ground to hold them up. 

* Crankup / Tiltover. A crankup is typically a variation of a 
freestanding tower that varies in height. Advantage is the ability to 
crank the system down in poor weather, or to appease neighbors. 
Disadvantages are numerous: crankups with any reasonable capacity are 
incredibly expensive -- manufacturers usually compensate by understating 
their ratings (ie ratings at 50 mph, when the minimum EIA specification 
is for 70 mph); crankups require a monument of concrete (although there 
are some types that are bracketed); crankups can NOT be climbed when 
extended or retracted (there are exceptions -- KNOW your tower -- don't 
plan on climbing a crankup unless the manufacturer says it is safe), 
installation of antennas may require tall ladders, scaffolds or a bucket 
truck. Tiltover towers are a variation. Some towers both crank up and 
tilt over. Tilting solves a lot of antenna installation problems, but 
comes at a reduction in capacity. Some tiltover designs are guyed, and 
have nearly the capacity of guyed towers -- these can only be tilted in 
very calm weather.

I was in your position a few years ago. I moved and vowed never again to 
install a roof tower, but wanted a REAL tower instead. At first, I 
dreamed of a freestanding tower. But the concrete monument deterred me. 
Next, I thought of crank ups, but found their capacities to be abysmal, 
unless I paid in excess of $6000.

Currently, I'm collecting parts for a bracketed installation of 45 feet 
of tower. Not as high as I originally thought, but I'm confident it will 
meet my needs without fear of being blown over in forseeably bad weather.



Bill Coleman, AA4LR, PP-ASEL        Mail: aa4lr@radio.org
Quote: "Boot, you transistorized tormentor! Boot!"
            -- Archibald Asparagus, VeggieTales


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