Concrete Pad - 8' Dish

[PopcornNMore]

I have a 4 day Memorial Day weekend. Since the weather is going to be beautiful i'm thinking about pouring a concrete pad (45" x 45") to support the 8' dish I got as a Christmas gift from my wife who purchased it from WS International.

I was thinking about laying out a 2x4 frame and simply filling it with rebar and concrete. A guy at work recommends I dig at least 3' to give it a solid foundation, so the dish doesn't pull the pad up during strong winds.

How deep should the pad be and does anyone have any advice? Or are there other options for installing this dish?

 

[Lak7]

If you are using a Post........
Get below the frost line!
Shape the hole like a Bell, wider at the bottom.
Drill a hole thru the post, about a Foot from the bottom, and slide a piece of ReBar in. That will keep it from breaking loose and twisting in the wind.

As for a Pad, the more Volume the Better, but may move over time, freeze / thaw cycles.

 

[brentb636]

Might be possible to dig in 4x4 posts at the corners of the pad to help tie the whole thing down . That would be my inclination , in addition to Tim's fine suggestions.

 

[Lak7]

4x4 posts at the corners of the pad

Or sink a few SonoTubes, down below the frost line, and put anchor bolts in the top.

Do you have a Pic of the Post?

Something like this maybe.....
http://www.geo-orbit.org/sizepgs/grndpole.html#anchor28895

 

[B.J.]

I have a 4 day Memorial Day weekend. Since the weather is going to be beautiful i'm thinking about pouring a concrete pad (45" x 45") to support the 8' dish I got as a Christmas gift from my wife who purchased it from WS International.

I was thinking about laying out a 2x4 frame and simply filling it with rebar and concrete. A guy at work recommends I dig at least 3' to give it a solid foundation, so the dish doesn't pull the pad up during strong winds.

How deep should the pad be and does anyone have any advice? Or are there other options for installing this dish?

I don't think the "pad" thing is a good idea. Like discussed above, you really need to go below the frost line, and unless you go down the whole 3' or so under the entire pad, it will probably be messed up or cracked by freezing in the winter.

I think you are better off just going down to the 3' level, with a smaller concrete footer or whatever you call it. Up here, I just dig about a 1' diameter hole down below the frost line. Like mentioned above, I usually try to have it flare out wider at the bottom if possible, but that's not always easy. How wide, and how deep depends a lot on your ground. Up here, it's pretty rocky, with BIG rocks, so once I get the hole down into the big rocks, I usually figure it's solid enough. I used to live in Ingomar, near Gibsonia, and I seem to remember there was a lot of shale rock, which I'd think would also be OK if you got down into that, but if you're in a valley with only soil, maybe you'd have to go wider and deeper. But I really think 1' diameter by 3' deep should be enough.
But I sure wouldn't want it wider at the top, which a pad implies, because that would mean a lot of upward force from the frost.
Re the rebar through the pipe, I usually just put a 3/8" bolt through, so it sticks out a bit. In concrete, that will never twist in the wind.
If you still want a pad, perhaps to make it look nicer, or perhaps to make a base for ladders, I think I'd almost not have it connected to the actual support for the dish. Ie maybe pour the 1' by 3' deep support sith the pole first, then pour a decorative pad around it. But I really think a wide pad would be less stable in the winter frost than a smaller deeper concrete footer.

 

[FaT Air]

My 10 footer is on a concrete pad on top of the ground. Pole is welded to a triangle base which allows the pole to be plumbed. It needed re-plumbing about a year after installation. Since then, 1986, very little re-adjustment has been necessary. The pad is 6in thick and 4ft by 6ft. In the day, we'd assemble complete dish and pick it up with a custom built trailer, and deliver it. I'd include a picture or two, but it's raining pretty good.

 

[Corrado]

My thoughts are about the pole itself. How is it to be attached to the pad? Most pad mounted dishes I've seen had legs coming out from the post which were all lag bolted in place for support. Not just a pole sticking through the concrete.

Another temporary solution I have is using a NPRM on top of the ground. I have 2 Prodelins setup that way behind the barn. They were both free and setup quick. They can also be moved if need be.

 

[FaT Air]

PAD mounted 10 Footer

Here's pics. The bolts coming up out of the concrete have a 4 to 6 in. piece of rebar welded to their head, forming a "T" and are wired to the rebar in the pad. Can't remember bolt size, but probably 5/8 or 3/4.
Pad is 6ft 10in x 4ft 7in x 6in

 

[B.J.]

Here's pics. The bolts coming up out of the concrete have a 4 to 6 in. piece of rebar welded to their head, forming a "T" and are wired to the rebar in the pad. Can't remember bolt size, but probably 5/8 or 3/4.

Neat. That's a nice setup. That something similar to what's used to mount a ham tower. I'm amazed that being as far north as you apparently are (I think your location said 48N), that that doesn't move around a lot with the frost in winter/spring. Around here the frost will lift BIG rocks out of the ground. But the proof is in the pudding I guess, if it works.
I'm curious though, what kind of soil is under there? Ie is it all topsoil, sand, clay, or a mixture of rocks, etc. I'm also wondering about the drainage, water table. Ie around here the water table is not too deep, and it's usually the water in the ground freezing that lifts everything up. Particularly in the spring, when the ground is still frozen deep, and it starts to melt on the surface (some years, with heavy snow cover, it thaws from the bottom up, but if there isn't much snow, it freezes deeper, and thaws from the top down, and if it melts on the surface, the water doesn't drain, so that a subsequent freeze will lift up everything. Our roads around town often get these frost heaves in them, creating BIG bumps, where the pavement has lifted up several inches.
Anyway, I'm curious what the conditions are there, that you don't seem to get frost heaves?

 

[N0QBH]

Back in the day (when BUDs were all over the place) those cement pads with plumb adjustment were real popular up here in MN.

 

[PopcornNMore]

Thank you guys for the suggestions. I won't be using a pole or polar mount. The dish attaches to a (sit 'n spin) stand as shown on the link below:

2.4m Prime Focus Dish | 240cmts Prime Focus C band Dish | 2.4mts C band Dish

The dish will remain stationary pointed at one satellite.

 

[FaT Air]

I'm curious though, what kind of soil is under there?

Black river bottom dirt. That's about all we have around here. unless you go 10 or so east or west. The first winter/ spring cycle, it settled, to one side, about a full bubble on the level. Since then, I don't remember it being off by more than 1/4 bubble. I don't think the frost moves it much 'cause it's above the frost. Kinda like the buildings around here, that are on a slab, they usually move and crack the slab early in life, then they just stay put. No sand or other material was put down under it. Heavy frost or no frost years, like this past winter, don't seem to effect it any more or less .

 

[B.J.]

Back in the day (when BUDs were all over the place) those cement pads with plumb adjustment were real popular up here in MN.

My first dish had a plumb adjustment, but it was up at the TOP of the pole, not at the bottom. The adjustments would be finer up at the top, however I guess it's more accurate measuring plumb to get it perfect if the adjustment is at the bottom, so I guess it's 6 of 1 half dozen of the other.

 

[Blindowl1234]

Well If I'm thinking of the 8' dish similar to the Fortec 8' I have, you should be able to do it. My 8 footer is mounted using the pole mount that Sadoun sells. Mine is mounted to a roughly 36" concrete patio table top, which is round. It's about 2" thick. I used lead anchors and 3/8" leg screws. So far it has moved at all in the six to eight months since I put it in. So far it's withstood 50 mph winds. I figure I can always lay concrete blocks or sand bags on it if a tornado comes thru lol...I can take a pic and post it if you need it. Blind

Oops I saw where you are using the other mount and not the pole mount. I had a six foot Fortec mounted on the same exact concrete pad. I left the bolts just loose enough at the base so I could turn it on the pad. Same concrete pad though. Seemed to stay put.