[TowerTalk] Rohn SSV … or is it? Stump the experts.

[Patrick Greenlee]

I too acquired a (probable) Rohn tower, part of one anyway. Triangular 
configuration, 4 inch tubular legs with 1/4 inch wall thickness.  It is 20 
ft sections connected by bolting together welded-on flanges. Legs are 14 ft 
on centers at ground level.  This tower failed in service when the wind 
generator and top 60 ft of the 100 ft tower crashed to the ground due to not 
anticipating the effects of the gyroscopic forces when wind changed 
direction without slacking speed.

I'll be refurbing the bottom 40 ft and putting an observation deck on top. I 
also intent to put a crank-up tower atop the 40 ft base.

Good luck to you on all your endeavors,

Patrick AF5CK

-----Original Message----- 
From: John Todd
Sent: Tuesday, October 22, 2013 12:00 AM
To: towertalk at contesting.com
Subject: [TowerTalk] Rohn SSV … or is it? Stump the experts.

Hello!
  I'm new to the list here, and I've jumped in way over my head.  :-)  I am 
building a new shop out here in rural Oregon, and figured while I'm at it, I 
should put in a ~100' tower for various antennas and cameras I wanted to set 
up.  Unlike most of you, the cart is before the horse - I don't have my 
ticket yet, but it's a matter of time and infrastructure.  I figure I'll 
first be using my tower for some mid-range (4-14 km) microwave data in 
unlicensed spectrum,  plus a 1080P PTZ IP camera for looking at the horizon 
that I can't see due to the thick forest in most directions. I might also 
put up some ultra-bright controllable multi-color LEDs that I can have set 
themselves to various color patterns for statuses (for example, a color 
slide that shows the number of minutes since someone last drove up the 
driveway so when I get close to home and see my tower on the horizon I know 
what to expect, etc.)  The amateur radio antennas will show up as soon as I 
have my shop done and a
safe warm place in the winter to put my butt in a chair and some equipment 
near a tower.  But there are some problems along with just the big tasks of 
"making a good foundation for the tower" and "hiring a crane and actually 
assembling the tower".  See below.

The Pictures:
  http://www.loligo.com/big-tower/

THE PROBLEMS:
  I have a free-standing tower that I got secondhand.  It was being used as 
a windmill tower, and was disassembled and stored in a backyard for 8+ years 
until I bought it and moved it to my place (possibly the most un-safe move 
I've ever done - long story, but moving big stuff off the top of an 
un-maintained mountain home clearing is a challenge.)  I know _nothing_ 
about the tower, though I strongly suspect it's a Rohn.  But I don't know 
how to identify the sections and there are no obvious maker marks - only 
assembly ID numbers.  There are 5 20' sections of decreasing diameter with 
height, all of which except for the topmost section (shown in pictures) were 
partially disassembled for loading onto my trailer.

Problem 1: Identify the tower.  Is this actually a Rohn?

Problem 2: Determine foundation structure.  I live on clay/shale that is 
incredibly difficult to dig through.  It took a special drill rig to go 5' 
down for my pole barn footings.  What's the best method to use in soil like 
this?  Where do I find diagrams that have some math behind them that is 
understandable?

Problem 3: What are the hints?  I found this: 
http://www.do-it-yourself-tower.com/  which was great, but 75 yards of 
concrete I think is more than I'll need here.  Are there other quick hints 
on how to get the footings aligned and poured?

Problem 4: What are the limits?  The tower had a HUGE amount of rusty 
homebrew insanity on it that I have since removed (shown in the pictures, 
but now sitting in a pile in the driveway.)  There must have been 400 pounds 
of steel at the top of that thing, and I have no idea how much the windmill 
weighed.  I don't think I'll ever have anything even remotely approaching 
that kind of weight or cross-section, but it would be useful to know what 
the weight and/or square footage wind ratings are.  If I _could_ use it 
safely as a windmill base, that might be interesting for some point in the 
distant future.  It held up previously, obviously, but I don't know what 
kind of swept surface area was on the turbine previously on top.

Problem 5: I am missing the bolts to hold the sections together, and 
probably also missing some bolts, nuts, and locknuts for the struts since I 
didn't take them apart and the disassembly was a bit "roughshod".  Where can 
I get that kind of thing, in the appropriate galvanized format?

Problem 6: I now have a 120' Rohn 45G (with hinge, two top sections, guy 
connectors) that I was ready to set up but now seems redundant to my needs. 
(and a Tri-Ex H-354 crank-up, which came with it)  Anyone in the PNW want to 
buy either for a reasonable price?


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