How do I mount a 4" C dish mount to a 3" poll?

[ken2400]

I have an 8' C band dish I that needs a 4" poll BUT only have a 3" roof mount thing. Looks like a pallet so I don't have to put holes in the roof.
It is on the mount that sits on the ground now BUT need a better way to convert it?

Thanks

 

[gabshere]

Ken pictures would be nice sounds like you have a non-pen (penetrating) mount that has a 3 inch pole

a 8 ft dish would need a large non-pen mount usually these are 8X8 the smaller mounts are for smaller dishes

but most weld shops should be able to fab up an adapter if thats the route you want to take

 

[Titanium]

This is the size of NPM base and approximate concrete block ballast for a 8' dish. I might consider making a full height sleeve if the base and ballast were appropriate, but topping with a 4" adapter is pushing fate. Tremendous wind load on this large reflector. Also advised to install safety lines.

 

[Magic Static]

And use concrete block, Cinder blocks are not heavy enough.

 

[Titanium]

Corrected! I use CONCRETE blocks. 48 blocks approx. 1800lbs.

 

[Cham]

Hope you have a good strong roof there Brian!!

For a big reflector, I would go with at least a 4" post.

Mine uses a 6" diameter post and it has too much give when it is windy, should have an 8" but the mount has a 6" locking collar. If I was to get a newer dish I think I would re-design the whole mount and use an 8" dia post and a foot or so longer to keep the dish farther away from the snow (for winter). I would likely weld the top foot of the existing pole to a larger pole so the collar works, most of the stess moment is closer to the bottom of the pole or where braces attach anyway. This is for a 10' fiberglass dish though.

 

[Titanium]

Yep! The building engineer confirmed the load before I hired the crane. We do have an occasional snow up here in the Sierra foothills, so the roofs are engineered better than down in the central valley.

 

[ken2400]

The pictures you guys wanted

 

[FaT Air]

Think that NPRM is meant for a max of a 1.2 meter offset dish. Way too small to reliably hold a BUD in the air.
I'd want it, at least, doubled in area. Take a look at a cement NPRM

and further details (down the page) here : http://www.wisegise.net/BUD/3469/
8 ft wide and 5 deep by 8 inches thick. Has stood up to 60 plus MPH winds.
weight = 1 ton

 

[Lone Gunman]

Here ya go. I made this one back a year or so ago and I'm still using it on that temp trailer mount.

http://www.satelliteguys.us/xen/threads/4-dish-mount-on-a-3-pipe.341744/#post-3524080

 

[RimaNTSS]

I've just recently made adapter out of 125mm (inner diameter) x 8mm wall thickness pipe. Drilled 9 x 20mm holes and welded 9 x 20mm nuts to it. So, pipe is connected to concreted infrastructure in the ground. I can put inside of this adapter any pipe up to 125mm and also make it plumb. I also have ground stand with 100mm pipe on which I had 1,8m Prodelin mounted. Right now I have installed 1,4m plastic dish on my test-bench.

 

[RimaNTSS]

To install bigger antenna on the same ground stand I just replaced inner pipe. Now there is 89mm pipe and 1,8m plastic motorized dish on top of it.

 

[ken2400]

I have an 8' C band dish I that needs a 4" poll BUT only have a 3" roof mount thing. Looks like a pallet so I don't have to put holes in the roof.
It is on the mount that sits on the ground now BUT need a better way to convert it?

Thanks

Lets back the boot up a min.
It was a 3.5' post I need and i think the mount was 2.5" or 3" I get back to you on that.
Well it kinda of a pain so I put a 3.5" inch X 6' pipe in
2.5' hole
80 lb of cement with 3/8" X 12" rod to keep it from turning
It is setting up now

 

[armadillo_115]

I think I would add more cement...much more.IMHO.

 

[Titanium]

I agree. Even in the hardest packed soil, it will not be adequate for a 8 foot dish. I typically use at least 4 - 80lb bags for a 90cm (36") dish.

 

[armadillo_115]

Something else I didn't notice early this morning : Is 30" below frost line for Central NY State?
I believe I would pull it up with a front-end loader once the concrete has set,dig out some more,and re-set it in more 'crete. (Wash the previous concrete of good first.I THINK the 2 concretes would bond ok then)Only 80 lbs of concrete should pop out easily.

Not news you want to hear,I'm sure,but easier to fix now than later.

 

[Comptech]

I agree. Even in the hardest packed soil, it will not be adequate for a 8 foot dish. I typically use at least 4 - 80lb bags for a 90cm (36")y 12 foo

My 12 foot unimesh has only only four bags of concrete because of my soil. Once I cot down about 3 feet I could not go farther because of the hard clay and granite and the diameter was only about two foot. So what I did since I had no blasting caps was to dig sideways as far as I could at the bottom to make a inverted mushroom shape. Dish has not moved form ice, snow or some 80mph gusts in six years.

 

[ken2400]

Where did the time go?

On my next poll I will go a bit lower, add a bag, and see how a 5' poll works.
This one feels good so far BUT it has not go though winter or stood the test of time.
That reminds me I need to put a date on the poll

I mounted the 8' dish on it today.
For the sake of science I plan on keeping you all posted.
Feel free to PM me if I forget or just want an update whenever.

Thanks for the help and ideas.

Lets back the boot up a min.
It was a 3.5' post I need and i think the mount was 2.5" or 3" I get back to you on that.
Well it kinda of a pain so I put a 3.5" inch X 6' pipe in
2.5' hole
80 lb of cement with 3/8" X 12" rod to keep it from turning
It is setting up now

Something else I didn't notice early this morning : Is 30" below frost line for Central NY State?
I believe I would pull it up with a front-end loader once the concrete has set,dig out some more,and re-set it in more 'crete. (Wash the previous concrete of good first.I THINK the 2 concretes would bond ok then)Only 80 lbs of concrete should pop out easily.

Not news you want to hear,I'm sure,but easier to fix now than later.