Securing 31 ft. mast, Guy wire setup and anchoring?

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Cruiseomatic

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How and what do I need to secure this thing down? It is three 10.5 sections of top rail with two 4 ft. sections of electrical conduit as an outer sleeve where the top rail meets. Ground to tip is 31 ft. then the antenna adds 24 ft. to a total of 55 ft. Also going to put a television antenna on and planning to add a ST-2 later on. What guy wires do I need and where can I get everything I need? I have a 250' roll from home depot that is 1/8th inch with a working load of 340 lbs. For $5 more, I could of got 800+ lbs. load but that was a bit overkill. I can still take it back and thinking of doing that.
 

LtDoc

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Well, make it 87 people who've looked at your question, and I can't give you a definitive answer. Lots of variables there, where are you going to put it, what's it going to be sitting on/in, what kind of area do you have for those guys, and more. Off hand, if you aren't subject to a lot of wind, I'd guess that the guy wire you have will probably be 'good enough'.
The guys coming off at a 45 degree angle is nice. A little difference each way probably won't make a huge difference. At least one set of guys at the top end could be sufficient. Two levels of guying would be nicer. And then, how are you going to attach the bottom end of those guys, and to what? There will be more stress on them than you might think, so good sized guy anchors would be nice too.
Do you see how that's going? I can't answer any of those questions so won't try to tell you how to do it.
- 'Doc

(Over-doing is much better than re-doing!)

(Oops, I think I was #95.)
 

Cruiseomatic

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Well, make it 87 people who've looked at your question, and I can't give you a definitive answer. Lots of variables there, where are you going to put it, what's it going to be sitting on/in, what kind of area do you have for those guys, and more. Off hand, if you aren't subject to a lot of wind, I'd guess that the guy wire you have will probably be 'good enough'.
The guys coming off at a 45 degree angle is nice. A little difference each way probably won't make a huge difference. At least one set of guys at the top end could be sufficient. Two levels of guying would be nicer. And then, how are you going to attach the bottom end of those guys, and to what? There will be more stress on them than you might think, so good sized guy anchors would be nice too.
Do you see how that's going? I can't answer any of those questions so won't try to tell you how to do it.
- 'Doc

(Over-doing is much better than re-doing!)

(Oops, I think I was #95.)

I'll try to answer all those in order,

The bottom 15ft. are being bolted to a new 6X6 wooden post that is at least 2 ft. underground with cement.

Sitting on the ground.

What exactly do you mean?

And This is Houston and we USED to get a hurricane at least once a year so I'll say we get a good amount of wind.

Don't want "Good Enough." I want "That is what you'll need for it to be safe and secure."

I have a OLD book from the 70's about guying. States that at 30' the bottom of the wire should be 20ft. away from the base, 20ft. should be 10, Etc... Don't know if that information is still true or not.

I could do 2 levels. I have enough on hand. If there will be more stress that I "might think" then I will take back what I have now and get the roll that is rated for 800+ lbs. working load.

Whatever is a good way.

BTW, It is being attached to a carport used to cover a travel trailer so the area is fairly large. The mast and metal roof will make no contact at all.

Hope this helps some.
 

Confuzzled

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I don't have any measurements regarding height to distance from base.

Mine is 40'; two 20' lengths of fence top rail, doubled (two masts side by side, connected). TV antenna and rotor are about 5' above that. It's at the back of the garage and anchored at the peak which is about 15'. Using basically the same galvanized wire you mentioned, I tied to 5 points, 2 at the front of the garage, 1 to the house, 1 to a shed behind the garage and 1 to an old, unused utility pole in the yard. Vertically, they all come together about 30-35' up the mast.

I didn't want any of them coming to the ground where I would have to move around or under them to mow grass.

We don't usually get hurricane force winds, but we do get remnants and Ike was still pretty strong here and did quite a bit of damage. This mast was not in place then, so I don't know what might have happened. Typically our highest winds might top out in the 40MPH range.
 
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wyomingmedic

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I'm a little confused, but what I think I'm hearing is,

31 feet of fence rail

Attached to a post stuck 2 feet into concrete.

And you want to put a 24 foot antenna, TV and another antenna?

If this is the usual 1.5 inch ish top rail I am thinking of, I predict this thing will fall over with the slightest provocation. I have built many antenna supports using fence rail and I have bent a number of pieces over. Usually I have less than 1 square feet of windload on them. You are going to be really exceeding that.

I tend to build to an overkill because we get frequent wind gusts to 100mph, so I tend to err on the side of caution. I would be VERY careful with what you are doing.

WM
 

Cruiseomatic

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You're hearing right. Although, I asked if I could use a scantenna st-2 as a television antenna also to reduce load on it. I am guying this thing down. It's just finding the parts and the best places to secure it down to. The guy wire I got has a working load of 840 lbs. Should be enough. What I did have was 240 and decided to strengthen it some.
 

wyomingmedic

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840 pound test stuff should be fine. Just be sure it is something that wont fracture from the wind vibration or anything.

I would personally guy it in 3 places.

15 feet up, Right at the point below where the vertical attaches, and non conductive guys at the top of the antenna.

Doing a quick calculation, taking a 24 foot eccentric load of several feet windload and figuring the effective moment right where the 2 meet, it is something in the ballpark of 1500 pounds in 10mph winds. Bringing the winds up to 40mph takes it to a scary number. Something the fence rail will not hold. Certainly need to take the bending force out of the vertical.

The other thing my physics brain comes up with is the idea of a TV antenna. I'm not sure of the version you speak, but I am envisioning something that will hang off the side in some way. Even at the top, it will present some rotational force on the mast. That brings an entirely different mathematical equation into the fray. The number 1 reason towers and masts fall is because of rotation. I battle it in my tower every day. Just today I was tightening and checking after our latest windstorm.

If you guy it correctly, all of the force will be trying to push the mast down into the ground. In this fashion, the fence rail can take a lot of force. Tons and tons. You just need to make sure you have it guyed vertically and eliminate eccentric bending force.

Good luck and let us know. I think it can be made to work if you get it right the first time.

WM
 
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