Installing OTA antenna

[JimMac]

What would be the best way to install an OTA antenna in the ground, on a telescoping pole ? It currently is bolted to the side of a 4x4 post on our deck, but it will need to be moved. It is about 15' above ground.

I am thinking of setting a metal pole in concrete, then bolting or clamping the telescopic pole to it. Is there a better way to do it ?

I'm unsure of how deep and what size diameter hole to use, whether to use sonotube or something else , etc. ?

Thanks for any advice.

 

[harshness]

A quality pole will come with installation instructions as well as data on what kinds of loads it will support given your local winds.

I do NOT recommend mashing two poles together as there's likely to be some issues with electrolysis.

Without knowing what the height of the finished mast, there's no safe way to advise on the hole diameter and depth.

 

[primestar31]

Chain link fence TOP rail fence poles work well as antenna masts. They come in various lengths, BUT, if you buy two 10' lengths (carried at Lowes or Home Depot), the poles are swaged to fit together. You'd want to put them together so that the OUTER sleve of the top pole is over the bottom pole. That way rain running down the pole sheds off, instead of wicking inside. Put a eves bracket on the house to bolt it against, and every 10' above the roof you should use at least 3 guy wires, in a tripod type formation. Turnbuckles in each guy line, can be used to equally tension the wires. I've done this in the past and gone up 40'. Never had any issues, IF you do the guy wires properly.

 

[JimMac]

Thanks guys. The antenna height will be about 15' above ground. Electrolysis would only happen if the 2 poles were made of different metals correct ? I think my telescopic pole is galvanized.

The bottom of my current pole is 2' above the ground.

 

[JimMac]

With the antenna only 15' above ground, I didn't think I'd need to attach to house or use guy wires. I don't currently, and it's been up at least 15 years. The bottom half of the pole is screwed to the 4x4, but the top 8' is not secured to anything.

I'm just trying to duplicate that scenario, but have it in the ground.

 

[harshness]

I can't say I've ever seen a telescopic pole that was galvanized (most are aluminum for weight and dimensional tolerance reasons) but since it is relatively short, I suppose the weight isn't a huge burden.

With standard winds, the rule of thumb is you need 20% of the overall length in the ground. This could be a perfect application for the fence rail that Mike spoke of as you could bury 4' of a tube and put the second tube on top to get 16' above grade.

Whatever you bury, make sure you poke something crosswise through the tubing (like a big spike) so that the tubing can't turn in the concrete. Some favor flattening bottom of the pole.

 

[primestar31]

I have an old 50' telescopic pole from the late '80's, and it is galvanized. I used it at our first house.

I would NEVER consider not using a bracket at the eves for mounting it. Swinging around in the wind is not good for reception, and can weaken the pole eventually. It's the bare minimum thing to do, if you aren't going to guy-wire it.

 

[harshness]

I would NEVER consider not using a bracket at the eves for mounting it. Swinging around in the wind is not good for reception, and can weaken the pole eventually. It's the bare minimum thing to do, if you aren't going to guy-wire it.

I had a vision that the antenna may be installed on a corner of a deck that is away from the house rather than near the house where a brace could be employed ( surely because I have such a deck on my house).

Whether the mast needs help depends largely on wind loading and I don't think we know what kind of antenna it is. An 8-bay bowtie with a reflector grid is like a windmill blade but a Yagi or an electronic antenna is an entirely different load.

 

[JimMac]

It's a big Winegard antenna. It looks similar to the HD8200U. I wasn't going to install it close enough to the house to secure it to the fascia board, but I can.

Primestar31, are you talking about installing 2 fence rail poles in the ground, then mounting my telescopic pole to that? Or use 2 fence rails instead of my telescopic pole ?

Thanks.

 

[Bobby]

The 8200u weighs 17 pounds. You put that on top of a 15’ steel pole and it would seem likely that the pole would bend without some kind of support.

 

[primestar31]

Primestar31, are you talking about installing 2 fence rail poles in the ground, then mounting my telescopic pole to that? Or use 2 fence rails instead of my telescopic pole ?

Thanks.

Either way works well. If you already have a telescoping pole, by all means, use that.

Threads get read in the future also, and telescoping poles are usually a lot more expensive than chain link fence top rail posts, which make fantastic antenna mounts for an average person. Bonus is that they are available at Home Depot, Lowes, and the like.

 

[harshness]

It's a big Winegard antenna. It looks similar to the HD8200U.

A "deep fringe" Yagi such as that generates a substantial wind load so care should be taken. Winegard makes much of how the design reduces wind loading but let's be real -- it is a behemoth.

Even if your antenna just "looks like" an HD8200U, the installation instructions for the HD8200U are illuminating in that they speak specifically to using a telescoping mast:

https://d38mfwkkxtsm2m.cloudfront.net/documents/1450089.pdf

Of course it is in Winegard's best interest that the antenna be mounted in such a way that it isn't wagging in the wind so I'm sure they're being somewhat conservative. All the documentation I've seen says at least one set (three or four, equally spaced) of guy wires for every ten feet of mast as Mike noted in post #3. If you're somehow sheltered from Winter windstorms coming off of the Great Lakes, it may not matter but if you're not, there's nothing like your antenna crashing to the ground to ruin your day.

 

[JimMac]

Thanks guys. I didn't want to sink my telescopic pole in the ground because I would lose at least 3 feet of height. It currently is bolted to a 4x4 post on my deck, and the bottom of pole is about 1 foot above the ground. Add to that the 2-3 feet I'd lose underground, and I'd be losing 3-4 feet of height.

I was hoping I could sink another pole in concrete, then somehow mount my telescopic pole to that, keeping it above the ground. Any ideas ?

 

[harshness]

What is the inside diameter of the lower section of your telescoping pole? Masts work best when there's a very close fit between sections.

Is there a situation where you might use the telescoping feature of the mast? A single 21' fence top rail (or two 10.5' rails) would put you a higher than the elevation you're at now.

 

[primestar31]

I was hoping I could sink another pole in concrete, then somehow mount my telescopic pole to that, keeping it above the ground. Any ideas ?

Sure, do just exactly THAT. You find a pole slightly smaller in diameter than your extendable mast bottom pipe section. Put that pole 3-4' underground, with a 1' stub above ground. Once the concrete is hardened (make sure you round the top, so water sheds off it) (4-5 days) put up your mast, over the top of that ground pipe.

Drill two holes at 90 degree angles through both of them, and stick galvanized bolts through it. Stainless is not a good idea, they'll fuse, and twist off. Screw on the nuts, and put up an eve bracket, clamp the mast to it. Stand on the roof, install the antenna and coax, and guy wires and whatever, then start lifting the sections UP one at a time.

 

[JimMac]

What is the inside diameter of the lower section of your telescoping pole? Masts work best when there's a very close fit between sections.

Is there a situation where you might use the telescoping feature of the mast? A single 21' fence top rail (or two 10.5' rails) would put you a higher than the elevation you're at now.

1) I don't know the inside diameter, but the O.D. is 1-7/16".

2) Yes. I was hoping to use the telescopic pole as it is, and just move it to an inground location on the side of the house.

Thanks.

 

[harshness]

1) I don't know the inside diameter, but the O.D. is 1-7/16".

The ID is what we need to match up with. As it turns out 1-7/16" is not something that is easy to match up with in terms of finding something that will slip fit around it. 1-1/4" schedule 10 pipe has an ID that is close but that may be too wimpy a wall thickness to support the un-guyed wind load of a 16' high mast. According to Winegard, the HD8200U has a wind profile (sail area) of 5.5 square feet and at 50mph that translates to about 34.4lbs of force. Multiply that by 14' and you get around 480foot-pounds of force trying to snap off the mast at the joint. At 70mph, the wind load goes up to 66lbs or 924foot-pounds (approximately the torque of a Chevrolet V8 diesel pickup engine) cranking on the joint. The numbers are higher for where the pipe goes into the concrete.

2) Yes. I was hoping to use the telescopic pole as it is, and just move it to an inground location on the side of the house.

You made it clear what you were hoping to do but it sounds like it won't be tall enough nor as well supported (being attached to the deck post) as it is now. It is important that water doesn't collect inside the tubing as it may cause a rupture when it freezes and the best way to avoid that, as Mike pointed out, is to slip the pole over the pole beneath it.

 

[JimMac]

Sure, do just exactly THAT. You find a pole slightly smaller in diameter than your extendable mast bottom pipe section. Put that pole 3-4' underground, with a 1' stub above ground. Once the concrete is hardened (make sure you round the top, so water sheds off it) (4-5 days) put up your mast, over the top of that ground pipe.

Drill two holes at 90 degree angles through both of them, and stick galvanized bolts through it. Stainless is not a good idea, they'll fuse, and twist off. Screw on the nuts, and put up an eve bracket, clamp the mast to it. Stand on the roof, install the antenna and coax, and guy wires and whatever, then start lifting the sections UP one at a time.

So drill holes and run 2 bolts at 90 degree angles to each other. What size bolts ? Because 1" of pipe sticking up doesn't give me much room to have 2 bolts clear each other.

Thanks.

 

[JimMac]

Thanks again. I won't know the I.D. until I take the antenna down. I need to give this more thought.

 

[waylew]

1" of pipe sticking up

Look again,he wrote 1',that's foot.