Help With Securing Pole For New Internet Connection

[alannm37]

Hi All,

We are installing new internet within the next 2 days and we are looking to secure a 25ft pile to a concrete fence post and then mounting the wireless dish for the network on the top of it. I was wondering for the dish to be as safe as possible, what would be the best bracket to use to secure to pole to the concrete fence post? The pole is only 3/4inch.

Any input appreciated.

Thanks,
Alan.

 

[kanewolf]

What diameter is the fence post? Epoxy in place threaded anchors with bolts will be strongest. At 25ft, you will probably require guy-wires to prevent movement. You should also put in a ground rod and #4 or larger copper for grounding. You should probably read a good tutorial on antenna mast installation if you have never done it. Here is a good reference on grounding http://www.reeve.com/Documents/Articles%20Papers/AntennaSystemGroundingRequirements_Reeve.pdf

 

[Ralston18]

Alan:

No disagreement or debate intended with respect to Kanewolf's response.

Just a question: are there any zoning requirements or other regulatory approvals needed with respect to to proposed 25 ft. pole installation? Hopefully such matters have been addressed but you do not want to go all that expense and then have some neighbor, competitor, or regulatory agency file a complaint.

 

[kanewolf]

Alan:

No disagreement or debate intended with respect to Kanewolf's response.

Just a question: are there any zoning requirements or other regulatory approvals needed with respect to to proposed 25 ft. pole installation? Hopefully such matters have been addressed but you do not want to go all that expense and then have some neighbor, competitor, or regulatory agency file a complaint.

Good points. Homeowner associations can be vengeful ...

 

[alannm37]

Alan:

No disagreement or debate intended with respect to Kanewolf's response.

Just a question: are there any zoning requirements or other regulatory approvals needed with respect to to proposed 25 ft. pole installation? Hopefully such matters have been addressed but you do not want to go all that expense and then have some neighbor, competitor, or regulatory agency file a complaint.

Thankfully I live in a rural area, should have pointed that out. There won't be any problems like that, just simply wanting to secure a pole to the concrete fence post and the concrete post is a good few inches in diameter, don't know exactly but will find out now after posting this. The dish at the top of the pole will then just run a cable to our garage a few feet away.

 

[kanewolf]

Alan:

No disagreement or debate intended with respect to Kanewolf's response.

Just a question: are there any zoning requirements or other regulatory approvals needed with respect to to proposed 25 ft. pole installation? Hopefully such matters have been addressed but you do not want to go all that expense and then have some neighbor, competitor, or regulatory agency file a complaint.

Thankfully I live in a rural area, should have pointed that out. There won't be any problems like that, just simply wanting to secure a pole to the concrete fence post and the concrete post is a good few inches in diameter, don't know exactly but will find out now after posting this. The dish at the top of the pole will then just run a cable to our garage a few feet away.

Since you mention a garage, you might have more stability using the roofline of the garage as a support. That would give you an anchor at 10 - 15 ft. You might not need guy-wires if you use a wall standoff.
Is your mast actually purpose made to be antenna mast or is it some other type pipe/tube ?

 

[bill001g]

You are likely to have a issue with a thin pole like that. Even a big flag pole 3-4 inches around without the flag will move around enough you can see it when the wind is blowing.

A dish....especially solid ones.... will catch a lot of wind and put a huge strain on the pole. It might actually bend and fail in high wind.

There are all kinds of calculations on tower design and wind loads. You will find that even towers 6-8inches square use wires to secure them.

I have a free standing 30ft aluminum tower and it is made of 3 1 inch tubes in a triangle 18inch across. Although it does not move much you can feel the vibrations in it when the wind is blowing.

You best be is likely a telephone pole or a very large diameter thick wall steel pipe.

 

[alannm37]

You are likely to have a issue with a thin pole like that. Even a big flag pole 3-4 inches around without the flag will move around enough you can see it when the wind is blowing.

A dish....especially solid ones.... will catch a lot of wind and put a huge strain on the pole. It might actually bend and fail in high wind.

There are all kinds of calculations on tower design and wind loads. You will find that even towers 6-8inches square use wires to secure them.

I have a free standing 30ft aluminum tower and it is made of 3 1 inch tubes in a triangle 18inch across. Although it does not move much you can feel the vibrations in it when the wind is blowing.

You best be is likely a telephone pole or a very large diameter thick wall steel pipe.

What we are planning to go ahead and do is dig a 2 foot deep hole, fill it with concrete and let it set while the pole is set in it, that would reduce a lot of the sway then. The pole doesn't really sway much anyway and considering that there is a lot of trees around it it shouldn't get hit by the wind too badly.

 

[Alabalcho]

What we are planning to go ahead and do is dig a 2 foot deep hole, fill it with concrete and let it set while the pole is set in it, that would reduce a lot of the sway then. The pole doesn't really sway much anyway and considering that there is a lot of trees around it it shouldn't get hit by the wind too badly.

I am not a building engineer, but my guts tell me 2ft of concrete will do nothing to stabilize 25' pole with 10lbs dish on top of it. You will probably have to dog deeper (with pole extending all the way down) in order to compensate for the momentum caused by the dish.

 

[kanewolf]

What we are planning to go ahead and do is dig a 2 foot deep hole, fill it with concrete and let it set while the pole is set in it, that would reduce a lot of the sway then. The pole doesn't really sway much anyway and considering that there is a lot of trees around it it shouldn't get hit by the wind too badly.

I am not a building engineer, but my guts tell me 2ft of concrete will do nothing to stabilize 25' pole with 10lbs dish on top of it. You will probably have to dog deeper (with pole extending all the way down) in order to compensate for the momentum caused by the dish.

I concur. I would think a minimum of 36 inches plus 2 to 4 inches of gravel at the bottom for drainage. Do you have a link to the equipment that will be at the top of the pole? The group is conjecturing on what the estimated wind load would be. A picture and some specs would help with the speculation.

I also believe you should plan on one set of guy-wires. You may find that that with a set of guy-wires at the top, the middle of the pole wants to flex and you will have to add a second set.

 

[bill001g]

I have over 3000 lbs of concrete holding my tower up.

So I ran the number though some of the antenna calculators. A 3/4 stee pipe designed for antenna...ie not water pipe.... will fail at a wind speed of 15mph with a small dish on the top at 25ft. Even 2inch steel pipe with 1/8 walls will fail at 50mph. Now this is total failure from a wind gust not that it just sway around and makes it unusable. That will happen at a much lower speed.

 

[kanewolf]

I have over 3000 lbs of concrete holding my tower up.

So I ran the number though some of the antenna calculators. A 3/4 stee pipe designed for antenna...ie not water pipe.... will fail at a wind speed of 15mph with a small dish on the top at 25ft. Even 2inch steel pipe with 1/8 walls will fail at 50mph. Now this is total failure from a wind gust not that it just sway around and makes it unusable. That will happen at a much lower speed.

I assume your calculators assume no guy-wires. I worked for a TV repair shop in the 80s and we put up plenty of antennas. Since we were 60 miles from the transmitters these were large VHF antennas. Two sets of properly installed guys would handle them with 20 ft masts. I know some antennas are still up after 30 years.

One thing you will want to do is put some bolts sticking out a couple inches through the mast where it is buried in the concrete. That will keep the post from twisting. Guy-wires can keep it from falling over, but aren't very good at keeping it from twisting. If you have multiple sections of mast you need to ensure they are locked in unison and that the there are some "fins" of some kind that stick into the concrete base. That will ensure that it won't twist.

 

[bill001g]

Yup assumed someone who thinks they can just put a pole up and it works. They are asking all the wrong questions if they planned to guy it.

 

[kanewolf]

Yup assumed someone who thinks they can just put a pole up and it works. They are asking all the wrong questions if they planned to guy it.

My recommendation has been to guy it from the first post ...

 

[alannm37]

Alright, just to be even more clear, this is a wireless broadband installation.

To see how the system works here is their page on "how it works" - http://www.ivertecbroadband.ie/howitworks.html

All I need to do is put that at the back of my garden so the thing that they put at the top of the pole has a line of sight with their mast, holding in mind the thing at the top of the pole is extremely light and will have no affect of the weight of the pole.

 

[bill001g]

This is pretty much what I suspected you were doing and is also what I use the tower I have for at one of my houses.

If you go say 10ft above the roof you your house it might work on the antenna tubing you get from radio shack or where ever would work. That is thin wall steal tubing that is 1.5in around. When you try to go 25ft you are going to have to use guy wires. It is not the weight that matters it is the area that catches the wind. Just the pipe alone catches enough wind to cause it to oscillate.

Your problem is not how you secure it to the ground it is how you prevent the pipe from flexing. Have someone hold one end flat on say a table and then go gently pull up and down on the far end. On a thin pipe like you are talking the end will swing up and down like it is made out of rubber. No antenna will stay aligned when the pipe moves around.

The only way to avoid this is to run guy wires to the top and likely a mid point. When you use guy wires then the diameter of the pipe doesn't matter as much since all the force in now vertical and it is very strong that way.