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[TowerTalk] Rohn 45 Foldover

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Subject: [TowerTalk] Rohn 45 Foldover
From: (Bowen, Arlan)
Date: Wed, 5 Nov 1997 15:18:39 -0500
At 10:28 AM 11/5/97 -0600, you wrote:
>I need some opinions and experiences... I'm thinking of replacing my
present 60 foot 
>Rohn 25 with a 64 foot foldover Rohn 45 next spring.  My VHF-UHF stack
(single yagis 
>for 50MHz thru 1296MHz) meets the windload specs and is slightly less than
the max 
>weight rating of 135 pounds (including rotator, mast etc.) at the apex.
I'm thinking 
>of this change mostly because I do not like to climb, maintanance and
repair on the 
>yagis at the top of my mast is very difficult since they are out of reach
from the top 
>of the tower and some home renovation is to be done next spring and the
timing is good 
>for base, guy anchor and trench digging while the equipment is on the
property.  My 
>questions; how easy/difficult is it to un-tension and detach the top set of
guys prior 
>to folding over - can it be a single person job?  What type and how often does 
>maintanance need to be done on the winch, cable, foldover section etc.  Are
there any 
>reports of disasters/failures during the foldover process?  How does the
Rohn foldover 
>concept compare with crank-ups?
>Any info and experiences on the topic will be appreciated.

I have two of the above, installed and guyed pretty much per specifications
in the Rohn catalog/specification sheets. I moved the guying points out by
about 3 feet, just because I thought it would provide a little better guying
angle for the top set.

There is no problem at all, taking the tension off the guys using the
turnbuckles provided with the standard guying kit. Take off the tension and
then remove the pinning bolt in the jaw of the turnbuckle. 

I did have a problem in that the opening in the jaw was a force fit over the
ground anchor eye. The solution to that was to make or buy the equalizer
plates. I made mine because the parts did not come with the guying kit and
the supplier wanted an outrageous price for them. I had some 3/8" thick
steel parts and simply welded them in a tee configuration. The parts already
had holes at the ends (sometimes pays to be a saver of stuff). Bolted the
tee to the eye of the anchor with 1/2" galvanized steel bolts and a large

There is no particular problem with tilting the tower. I found that I had to
attach a rope to the lower end of the boom to put tension on it which in
turn puts tension on the winch. The clutch mechanism in the winch needs a
fair amount of tension until the top portion tilts enough to create that
tension. Naturally, the bigger the load out at the end (top), the more
"grunt" that will be require to raise the assembly back up. Best to do these
activities when the wind velocity is low. Under windy conditions, the
assembly tries to twist somewhat.

Depending on the weight of the antennas at the top and the length of the
longest boom, you may wish to construct an X shaped frame to steady the
tower/mast while tilted. I made mine from 2 X 4 lumber with the cross bolt
located about 18" from the top. I also put a brace across the bottom. I
splice 2 of the 8 ft 2 X 4s to give a total length of about 14 ft for each
piece. My antenna had a half boom length of 12 ft. You can move the frame
back or forward to fit as required. Some assistance is required.

Assembly of the tower is straightforward, but note that the tilt section is
extremely heavy. It took 2 people in good condition to get the thing in the
air using the conventional gin pole. Everyone was exhausted when that
portion was completed. For the second one, I used my tractor and a very
sturdy pulley at the base. That was a lot easier, although communication
required a middle man because of the noise from the tractor. The tractor
operator needs to be experienced because some really fine tuning is required
to get the thing lowered in place just right. The tractor was operated in
reverse so that activities were in full view. If you as the tractor
operator, use bad language, be aware that the others will hear you quite
well. My wife commented on that once when she was helping me on another project.

You should inspect all hardware periodically. I see the guy hardware every
time I cut the grass. The winch will develop rust spots now and then, but
that can be fixed with a number of compounds. Oil or grease the moving winch
parts before use. If you use the wire clips (little U bolts) for clamping
the guy wire, the nuts should be inspected every 6 months or so. Especially
after a couple of seasons of "temperature cycling". I put a drop of paint on
the threads which seems to be holding the nuts in place quite well. It does
not appear that the hinge joint requires any maintenance. I am not aware of
any accidents with this tower type, but accidents are waiting if you do not
pay attention to inspection of the working parts in advance of anticipated
tower work.

I also own a crank up/down tilt over tower. It used a worm gear winch to
raise and lower the sections. It took somewhere around 1200 turns to lower
and raise the thing. Family and friends used to disappear when I did tower
work so I finally learned how to couple a variable speed, 1/2" drill motor
to that shaft. Made life a lot easier. I have not had any problems raising
and lowering the tower, except for ropes and coax that become tangled in
either process. When you note that the drill motor is laboring, you need to
stop because it is probably already too late. Something is about to bend or
break. The pre-stretched coax is usually useful as ground braid or radial wire.

I did have a serious problem with the tilting process for this tower. It
uses a second winch. The winch is locked in place while all the bolts are
removed from the bottom. The tower is now supported by just 2 heavy bolts at
about the 7 ft level, on which the tower pivots over to a horizontal
position. You unlock the winch and carefully begin to lower the tower to the
horizontal. In this case, the detachable handle came off in my hands, and
the tower went into free fall via the gearing in the winch. In this case it
bent the mast when the boom of a TA33 hit the ground. TA33 survived. I later
pinned the handle so that it would not come off. Moral: Know how you winch
operates and try to anticipate any failure modes. I do not think this system
is being used by any of the current manufacturers. Newer models of crankup
towers appear to use a gin pole arrangement for tilting. They are very hard
to climb in the nested position and should never be climbed while erected.

Both, I feel, are reasonably safe as long as you and your helpers are
extremely careful and the manufacturer's safety procedures are observed. It
would be a good practice to develop and use a check list before operating
any of these devices.


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