[TowerTalk] Free Standing Tower

[K7LXC@aol.com]

In a message dated 06/12/2000 12:00:55 PM Pacific Daylight Time, 
david.b.curtis@intel.com writes:

> Hmm... I spend a considerable amount of the weekend looking at the SSV
>  section of the Rohn catalog, because I have been considering going with a
>  free-standing 70 footer. The Rohn catalog shows a rotor shelf for SSV.  It
>  also states that a tapered top (with mast tube) is delivered with several 
of
>  the flavors of top termination.

     There are several flavors of SSV. The usual SSV is for commercial 
installations and comes in many different configurations depending on local 
windspeed and ice conditions and design load. For any section there may be 
more than a dozen designs that vary in leg thickness, number and size of 
diagonals and other construction/design parameters.

     The ham SSV is called RTP (rotator/top plate) and comes in less custom 
configurations since it's an -off-the-shelf' design. 
>  
>  The thing I'm wondering about on SSV is how hard these puppies are to
>  assemble.  Most of the sections seem to weigh in around 500 lbs.  

     They're easy to assemble on the ground and they are heavy.

> That'll stress test the ol' gin pole.  I'm sure the big boys use a crane. 

     That's correct. If all the sections are assembled on the ground, it 
takes less than 90 minutes to stack a 100-footer one section at a time. 

     If you attempt assembly with a ginpole, you'll need an industrial 
strength version. Since the sections are 20-feet long, you'll need special 
skills, tools and techniques to do it by hand. 

> The catalog says to bolt the sections together on the ground and square 
them up.
>  How difficult is it to assemble the pieces in place?  I'm sure it's time
>  consuming....

      Figure 2-4 hours per section. 
>  
>  And, while we're at it, how does cost compare to say, 45G?  45G will have 4
>  slugs of concrete, 4 holes to excavate, guy wire, turnbuckles, etc.  SSV
>  will have one big mamma concrete block (16 yards for a fairly stout 70'
>  tower).  Has anyone worked out the $numbers?

     Well, just on the weight/cost of the steel itself they are completely 
different. A quick cost estimator is to look at the total weight of the 
towers - the heavier one will cost more. SSV/RTP is MUCH heavier than 45G.

    Yes, going to a guyed tower is much cheaper but not everyone has the room 
or spousal permission for guys and anchors. 

     Champion Radio Products handles the Trylon Titan self-supporting tower. 
The Titan is a communications-grade tower for a very reasonable price. 
Current price for 100 feet of SSV/RTP is in the $5-6000 range; price for 
96-feet of Trylon Titan is $1974.00 and it'll handle 15 sq.ft. @ 70 MPH. A 
T500-72 will handle 45 sq.ft. @ 70 MPH (22 sq.ft. @ 85 MPH) and costs 
$1825.00. 

     A comparison of cost and capacity appeared in my "Up The Tower" column 
in the April 1998 issue. If you'd like a copy of it, send an SASE to Box 572, 
Woodinville, WA, 98072. More information, construction photos and 
downloadable drawings are available at http://www.championradio.com. 

      I've worked on hundreds of commercial and amateur tower installations 
and there is no better price/performance ratio in self-supporting towers than 
the Trylon Titan.

Cheers,   Steve    K7LXC
Champion Radio Products

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