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Old 01-17-2017, 3:55 PM
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Default raising the rohn 25

Hello All !

New old guy here, about to raise a 70' (a little shorter) rohn 25 up against my house. House peak attachment point is 25'. Tower is 70' rohn 25 as mentioned and I ran green house framing 1 1/4-1/2 they entire length and extended 3' above the top. I used 21 clamps , 3 to each leg of the tower every 10' to tie the tower and tube together. The upper 20' has an additional 1" greenhouse frame inside of the bigger tube. Al this stiffens things up.

I put the tower up at 50' and am taking it down to add 2 more sections. I have a small tv antenna on top, and a 12" dish for internet as well. (interent is reason it has to go up higher.)

Real question is about raising the taller assembly. I have 2 pullys attached tot eh peak of house @ 25 foot. I have another pulley that can hook to tower to give me a luff tackle or jigger set up. What is the best places to attach for this lift??
I drew 2 options but there are more. I could attach everything at 25' like i did for the first tower, or everythign at 50'.

we will assist lift with tractor under the tower, as well as a line at 50' that will go over the house.


I am also debating on guys for this install. The tower is wind protected up to 45', attached to house at 25 ' adn i live in the country there is nothig for it to fall on but the house and even then gutters are only thing easily damaged, no porches etc and the house has a higher peak runing the opposite direction.
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Old 01-17-2017, 5:22 PM
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I'm seeing some problems here. Using the existing tower as part of your lifting apparatus is going to put a lot of load on the existing tower (and probably your house) that it was meant to handle. Probably much more than it's wind load capacity. Furthermore, the rigging positions you have in drawing "A" for the aqua (maybe light blue) colored lines won't allow you to pull the tower up completely. At some point, the new tower will stop going up and all your lifting force will be directed toward destroying the towers. The blocks need to be positioned at equal distances from the pivot point so that they can eventually touch as the new tower reaches vertical.
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Old 01-17-2017, 6:29 PM
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For Rohn 25, 45 and similar towers, I've always installed the first section into its permanent position and built the tower up vertically using a gin pole. With the smaller 25 series I can pull a 10ft section up and lift it into place by hand while strapped into the top of the tower.

These towers are designed to be guyed and I would not try tilting up 70ft of it, unless you have several lifting points along the tower that spread the pull perfectly all the way up, otherwise the tower might tweak and bend under its own weight.
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Old 01-17-2017, 6:50 PM
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Quick and easy way, rent a bucket truck. Do this fairly regularly for Rohn 25 and Rohn 45. Assemble 100 feet on the ground and pick it up.

Rohn 25 is only rated to 30 feet between between support points…so for 70 feet or would have to be guyed.


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Old 01-17-2017, 6:53 PM
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Glad to see someone with experience weigh in on this. I don't erect towers but I've done my fair share of rigging and moving over the years. The tower sections just don't look strong enough to lift the way the OP has planned. If he isn't going to, or have someone to climb, A crane seems the safest option.
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Old 01-17-2017, 11:48 PM
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Appreciate the insights.

I am considering that the aqua section will reach a point where it is no longer lifting. Doing scale drawings it looks like it should be ok because once the tower reaches the point that the line attached at 50' is no longer assisting the tower will be near enough to vertical that it will require little force at that point. I am taking the existing tower down by cutting it off 1' above the concrete leaving two tabs as hinges for the lowering, will remove 5-6' of the cut section and add 2 full 10' sections. I have a good base built at the peak of the house that can handle the pull.

I raised the 50' all alone with a similar rig, minus the higher attachment point, and mnus a pivoting base. During the first install I assembled on teh ground put the base next to my pit and lifted tilted it into place. Hardest part was not having a soldi pivot on the bottom. That will be fixed for this go around. I am also going up a rope size and switching from nylon to poly to eliminate the stretch.
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Old 01-18-2017, 12:03 AM
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I will do a scale mock up tomorrow and when I go up with it I will film it. I will have a 75' bucket truck on hand to assit with lifting (though i want to attempt lifting without to see how much it wants to bend for future reference) and

I have a guy plan I just really dont want to use it but am sure i will. just happen to have a long piece of 7/16 wire rope that is long enough to V from 50' down to attachment points with several clamp and a few turn buckles that takes car of two. Think I have enough smaller wire rope to do the third leg. I will do this for certain if the internet folks will not give me the dish and wire to preinstall before teh lift, because then they will have to climb to the top to install as that is thier way. I plan to hook to one guy with a long section of rope and assit the lift as well.
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Old 01-18-2017, 6:26 AM
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posted wrong pic here is the tower mod if you will. Thank for the input I appreciate it. You guys would be amazed at some of the Tv/CB antenna up around here LOL 100' of this greenhouse tubing freestanding, our local 911 dispatcher has a rohn 25 that has to be at least 80' no guys bracketed at 25' with several antennas hanging off it.

So I modified my lift idea i will post again after I get it drawn up
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Old 01-18-2017, 6:33 PM
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Better?
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Old 01-18-2017, 8:18 PM
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Default Gin Pole

Out of the suggestions so far, my most recommended is using a gin pole. Like prcguy said, put your first section in the ground, let the cement get set, and raise the other sections up with the gin pole. Do some 'net research on what that is, safety involved, fall protection and proper procedure.
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Old 01-18-2017, 8:33 PM
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i spent 600 on renting on for the 50' and it would not lift it. I used a similiar pully and rope method.
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Old 01-19-2017, 5:00 AM
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Don't cut your existing section that's in the ground. 70 feet of tower not in concrete and not "properly" guyed is a disaster waiting to happen. You only need to add two sections to top of existing tower. A bucket truck or a local tower climber(Ham radio guy) with a gin pole is the way to go, after properly guying the 50 section.

FRank
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Old 01-19-2017, 7:11 AM
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I also see a ELECTRIC METER DANGER DANGER DANGER. I stood 25g for years using a factory Rohn GIN POLE. Just because one person is lucky I would never push my luck.
From the ROHN TOWER MANUAL 25G for new UNMODIFIED TOWER
#1 Base section hole 3 foot by 3 foot by 3 foot in CONCRETE (1 CUBIC YARD)
#2 House Bracket
#3 GUY WIRES every 30 Feet above Brace point.
#4 More than the height of the tower from POWER LINES.
In the last 10 years 60 miles from me 3 have died putting up towers and got into POWER LINES.
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Old 01-19-2017, 7:58 AM
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Remember: GRAVITY KILLS!
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Old 01-19-2017, 5:29 PM
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That is why Rohn made and published a spec and installation manual for all towers. There are still towers I put up over 40 years ago by the book and they are still standing. I had several ask to short cut the manual and I had one rule my way or do it yourself.
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Old 01-30-2017, 11:46 AM
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Quote:
Originally Posted by FKimble View Post
Don't cut your existing section that's in the ground. 70 feet of tower not in concrete and not "properly" guyed is a disaster waiting to happen. You only need to add two sections to top of existing tower. A bucket truck or a local tower climber(Ham radio guy) with a gin pole is the way to go, after properly guying the 50 section.

FRank

Yes for sure!
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