At 06:39 PM 1/15/01 EST, you wrote:
>In a message dated 1/15/01 3:20:50 PM Pacific Standard Time,
>baycock@HIWAAY.NET writes:>>
>> This type of base has two parts- one is a plate that is bolted to the
>> concrete. It has hinge and bolt-down features. The other part fits to the
>> normal straight section, and has the other half of the hinge, and a
part to
>> lock it into place. The J-bolts use at least two nuts each, to allow
>> adjustment to vertical.
>
> FB. Now what do you use to TILTOVER the tower? I've never seen a Rohn
>fixture for that although US Tower crank-ups can have them.
>
>Cheers, Steve K7LXC
>Tower Tech
>Champion Radio Products
>
>--
Steve, et al- I used this feature only to erect the tower, not as a regular
operation. There is no permanent mechanism for tilting the thing. The
process was:
1. Make the base concrete block, with J-bolts, per Rohn specs. Mount the
base plate in place,. Fasten the hinge bolts. mount one section in the base
plate and do a dry run. With the single section in place, adjust the nuts
on the J-bolts to make the section vertical. Tilt the single section back
down. (very light- can be done by hand.)
2. Somewhere in here, locate and put in the bases for the guys (four pairs
on the Rohn Foldovers) I used screw anchors, about twice the size of the
Rohn types. I added another anchor, at a right angle to the hinge line, to
use in erecting the unit. It was about 60 ft from the base, hidden under my
XYLs Mock Orange shrub.
3. Assemble the second section to the first. Elevate the end (20 ft from
the base hinge) on a saw-horse. Assemble the foldover hinge section. This
is a two ft section, a hinge, an eight ft section, and a beam that
bridges the hinge, and is the means used to fold the thing over, later.
Fasten this to the two sections on the base hinge. Add another section and
the top section. (this totals 48 ft) I held mine up, nearly horizontal, on
saw-horses. Note that the length above the foldover hinge is greater than
that below.
3a. I rig the ends of the guys that terminate at the hinge level, and drape
them, ready to go up.
4. I now rigged the winch and cable that will be used to control the
foldover, except that I left the cable off the winch- I am going to use the
winch and another cable to lift this thing into the air. The temp cable
runs from the winch, to the extra anchor, (with large pulley)back to the
foldover hinge point. I put a 2x4x10' board sticking upfrom the base hinge,
to hold this cable away from the tower assembly, to give elevation to the
cable, so it lifts the assembly. (This is another device called a
'gin-pole', but not like the one normally used with towers.)
5. I put the top end of the tower onto a garden cart, so it can move toward
the base, as I lift the center. This way, only half the top weight is to be
lifted. As I turn the winch, the center hinge point is lifted, and the top
rolls toward the base. As a safety, every few turns, I put braces (2x4 s)
under the hinge point. As the center lifts, the cable angle improves, and
the winch load gets less. When it reaches vertical, it is in the normal
position occupied when folded. Now- rig the guys that go to the hinge
level. Recheck the vertical .
>From here, it is standard procedure for a fold-over. I checked the loads at
all critical angles for safety, and had a new winch with safety brake.
It worked for me- so I could do it alone, although Iris was always aware of
what I was doing, and checked on me frequently. As an aside- I put the
thing so the solar noon shadow cuts the left edge of my shack window. This
is "TRUE NORTH"- and I can check the alignment of the tri-bander at any
time I can see it. (I did not plan this .)
Fun- Bill-W4BSG
-
Bill Aycock --- Persimmon Hill
Woodville, Alabama, US 35776
(in the N.E. corner of the State)
W4BSG -- Grid EM64vr
baycock@HiWAAY.net
w4bsg@arrl.net
--
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