Big dish base

[Jee34]

Hi, i am new to this forum.
I bought a brand new 3.7 meters dish.
What i need to know, is what size of concrete base do you suggest ?
The thing looks heavy.

 

[FTA4PA]

Hi, i am new to this forum.
I bought a brand new 3.7 meters dish.
What i need to know, is what size of concrete base do you suggest ?
The thing looks heavy.

Welcome to Satellite Guys! Obviously, with a dish that size it is going to be a lot. I do know you are going to have to pour your concrete to down below the frost line which is going to be at least four feet down per this:

Arctic Cold And The Frost Line -

Understanding what occurs within it and below our soil, even during winter, is important in getting a more complete picture of Adirondack nature.

www.adirondackalmanack.com

You want to bell out the bottom of your hole (wider at bottom than top) to keep it from pulling out of the ground and you should also add something to the mounting pole to keep it from rotating in the ground as wind loads will be a big factor. Not sure if your dish is mesh or solid but with that size it is going to be significant either way. I've only done a ten footer here in PA. Hopefully someone here who has installed these large dishes in conditions like yours will come along to give further advice on the amount to use. Again, welcome!

 

[Houston Rockets]

Question do you plan to set this 12 foot dish up yourself? Have you ever installed a Big Dish before? Have you done a sight test yet?

 

[Jee34]

Thank you very much for a fast answer.
Really apreciated. Dish is mesh. I hope someone here has already done it and could tell me about the do's and dont's.

 

[Jee34]

To Houston Rockets, i have a 2.3m dish already, no problem for installation. But this time with a 3.7m i want to be sure i am doing the concrete base correctly.

 

[JFOK]

Jee34,

I’ve always put my satellite pole on a tripod to allow for ground shifting.
Dig the hole as FTA4PA described then after pouring the cement and before it dries, insert three (or four depending on your base) 7 in.J-bolts up to where the threads begin. This method has worked for me with all 3 dishes I’ve installed and had never failed. Only had to make one minor adjustment in 32 years.

John

 

[FTA4PA]

Thank you very much for a fast answer.
Really apreciated. Dish is mesh. I hope someone here has already done it and could tell me about the do's and dont's.

You're welcome! I agree with John. If you are able to add some form of adjustment plate to your dish pole then do so. It will make things easier down the line. If you can't then just make absolutely sure the pole is plumb. In either case if you are mixing quikrete yourself by the bag then here is a concrete calculator with both flat work and cylinder calculation. Results are in cubic yards.

Concrete cubic yard calculator - Calculate concrete accurately

Concrete cubic yard calculator for cylinders, sono-tubes, walls, sidewalks, slabs and floors

www.everything-about-concrete.com

The yield of a bag of quikrete is measured in cubic feet so use this to convert:

40lb bag = .3 cubic feet = .01111 cubic yards
60lb bag -.45 cubic feet = .01666 cubic yards
80lb bag = .6 cubic feet = .02222 cubic yards

Example 1: If you poured a cylinder for a pole and went to 4 feet depth and your hole was 2 feet across then you would need .47 cubic yards (from the calculator). The pole itself takes up some of that space so I always use the extra to fill up the inside of the pole to make it stronger. That would equate to:

(42) 40lb bags or (28) 60lb bags or (21) 80lb bags

Example 2: If your poured a square base with rods to mount an adjustable plate. At four feet depth and two feet across you would need .59 cubic yards.

(53) 40lb bags or (35) 60lb bags or (27) 80 lb bags

Of course how much you will need in your situation still needs to be determined. If mixing it yourself I hope you have a machine.

 

[RimaNTSS]

6 years ago I made the basement for my 4.6m Andrew according (ish) what was recommended by manufacturer. Namely, 3.5x3.5x0.35m cement block. During those years nothing bad has happened.
I think that for 3.7m mesh, the cement block can be ~ 2x2x0.3m

 

[Cham]

I've used three 14" concrete piles for one of my dishes, they are more than 10' deep to get below the frost line here, some rebar, and 5/8" X 3ft threaded rod (bent at the bottom) in the piles. Like JFOK above it allows for adjustment and/or easy removal of the antenna support structure if ever required.
I'm wondering if anyone has used those big deck screws for supporting a dish? I'm thinking of using one for a 1.2m Ku dish just to see how it would work.

 

[Jee34]

Thank you all. I will read all of your answers tonight, and reply again.

 

[Jee34]

6 years ago I made the basement for my 4.6m Andrew according (ish) what was recommended by manufacturer. Namely, 3.5x3.5x0.35m cement block. During those years nothing bad has happened. View attachment 158060
I think that for 3.7m mesh, the cement block can be ~ 2x2x0.3m

0.35m means no cement poured into ground i guess. Just a "box" on ground, no hole. ?

 

[Comptech]

Yes left me wondering also, guessing stacking them, then pour with concrete.

 

[FTA4PA]

0.35m means no cement poured into ground i guess. Just a "box" on ground, no hole. ?

Yes left me wondering also, guessing stacking them, then pour with concrete.

Well, if I'm reading and seeing it right this is clearly a poured slab. If it is 3.5m x 3.5m that is about 11.5 feet x 11.5 feet and .35 meters thick is 13.7795 inches thick. That equates to about 152 cubic feet of concrete and this calculator says that weighs about 22,800 lbs so a pretty significant slab. I wouldn't want to lift it.

 

[Comptech]

You are correct, not used to metric on this side of the pond, Made it sound like cinder bolcks in that dimension.

 

[RimaNTSS]

0.35m means no cement poured into ground i guess. Just a "box" on ground, no hole. ?

Unfortunately, there was some digging involved. And also metal rebars needed.

 

[Jee34]

Unfortunately, there was some digging involved. And also metal rebars needed. View attachment 158073

Ok i see, it changes everything. And if i use for example 0.5m x0.5mx 1.5 deep would i still need all this iron ?

 

[RimaNTSS]

would i still need all this iron ?

It is better to have some metal rebars. At least you will feel safer during stormy days.

 

[Jee34]

It is better to have some metal rebars. At least you will feel safer during stormy days.

Ok i see, thank you. Another question then, why some people use concrete deep into soil, and others like you do not ?

 

[RimaNTSS]

why some people use concrete deep into soil, and others like you do not ?

Perhaps cuz for a relatively small base, it is better to have it deeper than local frost depth, so during winter the base will not move. In my case, the base is big and heavy and it was recommended by manufacturer.

 

[FTA4PA]

Ok i see, thank you. Another question then, why some people use concrete deep into soil, and others like you do not ?

Perhaps cuz for a relatively small base, it is better to have it deeper than local frost depth, so during winter the base will not move. In my case, the base is big and heavy and it was recommended by manufacturer.

RimaNTSS hit it on the head. The frost line in our area of PA can range from about 6" to 18". Not sure how they get such a big difference for our area but they do so...

The first c band dish I installed was mounted using concrete anchors on an existing huge slab previously occupied by a shed - that one definitely wasn't going anywhere. When I planted my first pole in the ground I dug down to 24" to be past the frost line. The top of hole was a bit under 2ft and the bottom a bit over 2ft (bell shaped). Not exactly even all the way around because our ground is full of large and small rocks. I had to dig some out but left others jutting out to give the concrete something to bite into. I used (16) 40lb bags of 1101 Quikrete and rounded the top off with a dome to let the water run away. That pole has been up since late 2015. It has held the 8ft dish and now my 10ft Sami and it is still solid and plumb.