Mounting a TV antenna pole/mast in the ground

18017 Views 12 Replies 5 Participants Last post by GrayHair, Apr 1, 2016

Jim McC

Discussion Starter · Mar 31, 2016

I currently have a telescopic TV antenna mast bolted to a 4X4 corner post of out deck/pergola. When we build a new deck or porch, I need to move it, and I want to put it on the side of the house, in the ground.

What do you suggest I use to do this? Set a galvanized pole in the ground in concrete, then mount the telescopic pole to that? That would last longer than setting a wood post in concrete, correct? What size hole and depth would you suggest?

Thanks.

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Windows on Wash

· #2 · Mar 31, 2016

The steel should outlast the wood in this case.

I would dig the hole at least 12" below the frost line in this case and make it bell shaped at the bottom. No need to go crazy on the width as 8" wide should be more than enough. Its not carrying any real weight in this application.

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GrayHair

· #3 · Mar 31, 2016

Hate to disagree with WoW, but I would never pour a telescoping mast (AKA: push-up) in place; virtually no up-lift from a mast. Take a look at these 20-50' masts for ideas. Rohn has been around for over 50 years and is back in the US now. Guying kits are here and a 20' mast needs to be guyed or secured with brackets. I have gone 15' AGL with a single bracket at the peak, but the extended antenna barely cleared the roof. With the antenna so near the bracket, there was little transfer of moment.

The mounting plate shown is much easier and also moveable. No gripples when I was installing, I used turnbuckles, not the hardware store variety. Guy anchors have to be in-line with guy unless they are heavy duty. I did use I-beams and lots of concrete once to elevate anchor points, but that was a 90' tower with big truck traffic near the anchors.

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Windows on Wash

· #4 · Mar 31, 2016

No need to hate disagreeing. I am always open to ideas and love the open forum.

That is some cool set ups there. I am not sure how high the pole needs to be for this application.

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Jim McC

Discussion Starter · #5 · Mar 31, 2016

Thanks guys. Currently it's extended to about 16'. The bottom half is secured to the 4X4, and the top half floats. It's been up about 12 years with no problems. I'd like to have it similar when I move it.

If I set a galv. pole in concrete, with at least 8' above ground, I can secure my mast to the pole somehow. Does that sound good?

1) What diameter pole should I use?

2) What is the best way to secure the mast to the galv. pole in the ground?

Thanks.

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GrayHair

· #6 · Mar 31, 2016

If you're going to put a pole in the ground, it looks like your frost line looks to be 32-48" and the end of the pole needs to be below that. Dig another 12-18", add gravel and compact for a 6" lift. Set and plumb your pole making absolutely sure the inside is clear, add more gravel and compact for another 6" lift ensuring the pole stays plumb. Now you're ready to pour the concrete.

Why? To allow moisture that will condense in the pole to get out. I had to drop several improperly set towers because the above wasn't done, the legs filled with water and split when the water inside froze. With no house brackets or guys, all the stress will be at the base of the pole.

As for pole diameter and securing a mast to the pole, I have no idea.

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SeniorSitizen

· #7 · Mar 31, 2016

If it's still daylight when I get finished with this poker game I'll post some pics how I built mine back 30 some years ago when I was younger and could dig big holes, mix concrete by hand and weld.

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SeniorSitizen

· #8 · Apr 1, 2016

Ok Jim McC, here are pics as promised albeit disappointing. Disregard the clutter, there is a solar light mounted there.

The post on the left is about 7' tall, in concrete about 3 ft. deep and 2 ft. diameter hole. The mast is around 30 ft. tall with the half inch plates welded to it and pivots on the 1/2" bolt that's through the post while yours telescopes.

Keep in mind this is some heavy duty stuff with 4" schedule 40 pipe reducing to 3", reducing to 2" and finally to 1" so yours this won't be like this and this is only an example to give you an idea. The U bolt and double saddle would hold your mast to your post and yours would need 2 sets of those rather than a bolt to pivot on.

BTW, I won the on line poker game. Thanks for your patients.

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Msradell

· #9 · Apr 1, 2016

SS, I was going to suggest something very similar to how yours is mounted but I don't have any pictures available. As an excellent set up they will hold up very well over time. Having the ability to swing it down to make adjustments or replace parts is certainly a major advantage and they are much stronger than the telescoping type masts.

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Jim McC

Discussion Starter · #10 · Apr 1, 2016

Thanks guys.

GrayHair, are you saying the galv. pole could split if the bottom is not below the frost line? Is there something better than a galv. pole for the part in the ground?

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GrayHair

· #11 · Apr 1, 2016

Ice freezing solid inside a tube will eventually split it. The ones I saw were probably 18 gague (wall thickness about 0.05") but a thicker wall will resist the force better. The 1st thing is to keep water out of the tube (cap it) and the second is to provide a drain point (tube bottom set in gravel). If the drain point isn't below the frost line, ice can plug the tube.

My recommendation would be a ground mount at the pole base and a pole bracket as high as you can get it on the house. I did this at my house and it was still in good shape when I moved 7-8 years later. This seems much easier, to me. Of course my frost line was only 12".

I'm only familiar with the quality of Rohn products (and that was nearly 50 years ago) but here are links to some other things you might consider.

Rohn wall mount catalog page

Summit Mounting Hardware page

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Jim McC

Discussion Starter · #12 · Apr 1, 2016

Thanks GrayHair. What type of ground mount are you referring to? Is the mount set into the wet concrete?

I have a 2' overhang on my soffit, but maybe I can use a bracket to secure the pole to the fascia board?

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GrayHair

· #13 · Apr 1, 2016

There is one shown at the bottom of the page on the Summit website. Basically a plate with a piece of angle iron through it. The long part of the angle is driven into the ground until the plate sits on the ground. Then the mast is placed over the protruding angle iron. Set your bracket and drop a line to locate the ground mount.

This site sells single brackets in offsets from 6 to 24 inches, but I'm guessing you have a hip roof, so Rohn's WM4 may be a better choice. I always tried to get at least one bracket mounting bolt into structure, like a rafter tail.

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Mounting a TV antenna pole/mast in the ground

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