Pole/hole overkill

[cracklincrotch]

I'm researching what I need to do to get my 12' bud in the air and I want it done right. I've been studying info over at geo-orbit.org and it seems like I may very well be over-building things following the information there.

For LOS I need the mount 10' to 12' in the air. Geo-orbit suggests the pole be not less than 1/3 below grade, for 60" - 70" down. The hole should be not less than four times the diameter of the pole, for 16". The pole should not be less than schedule 80 due to the dish size. They also suggest that guys tied on at 30 degree angles will reduce or eliminate wind oscillation.

Due to the height and weight of this dish (200lbs give or take) I don't want to take the thing down should the worst happen and some Cat3 200kph storm hit, because it's nearly happened in the past.

Following that advice would I be under, about right, or over built?

 

[FaT Air]

I's think you're about right on. As long as the bottom of the pole is below you frost line by a fair margin. 1/3 of 12 is only 4. Here in N. Mn. that IS the average frost line. Locally, footings are normally put 6 to 8 down. Shallower can expect movement. Cement around pole at the bottom (footing) backfill with dirt (packed in tight) then a pad around pole at surface. Works like a champ here. During heavy winds, retract actuator as far as possible, Add extra cables to help stabilize dish if you think it's necessary, and hope for the best.

 

[cracklincrotch]

I've been thinking about this for a couple of weeks. I want this 12 foot BUD as high as possible to get line of sight over my house. I found a 4" pole 16 feet long that will do the job. I thought what I could do is put a base on the pole and bolt it to a 16" concrete form that would be 5 feet deep. But a 16 foot high free standing dish on the side of a hill is going to be exceptionally hard to work on by myself.

A buddy of mine was talking to his brother about my plans on having the dish 16 feet in the air. His brother has a 12 foot dish himself and highly recommends having the dish near the ground because it's much easier and safer to work on and I agree. But if the dish is at ground level it can't see over the house to get the arc.

So rather than bolt a pole to a pad 16 feet up my buddy suggested that maybe I could put a pole inside another slightly larger pole so that I could raise and lower the dish as necessary. This would have the dish at the ground to work on it or in case a storm comes, and jack it up otherwise.

This drawing has a 4.5 inch pipe in the concrete 8 feet down and five feet out of the ground. This way when the 4" pole is out 16 feet at the top, 30 percent of the total pole from top to bottom is still in the ground.

With 5 feet of the 4.5" pipe outside of the ground, the smaller 4" pole is out 11 feet above the 4.5" but there is still 5 feet in the larger pole to satisfy the need to have 30 percent of the 4" smaller pole to be supported. I'd have 3/4 inch holes drilled every 12" to slip bolts through the full assembly as locks as well as to jack the pole up or down.

This would allow me to get the dish up the 16 feet as well as bring it down to 7 or 8' to work on with a step ladder on the ground.

Does this sound reasonable? Drawing is attached. (The pole in the concrete is missing a spur but I realize it needs one)

 

[phlatwound]

Wow, that's an interesting idea. A question or 3:

1.) How would you raise and lower it, with some sort of jack? That 16' of pipe and a 12' dish asssembly is going to weigh a few hundred pounds, I'm guessing.

2.) Will 4" pipe actually fit inside of 4.5" pipe? I guess the Schedule (40, 80?) would come into play there?

3.) Where did you come up with "the need to have 30 percent of the 4" smaller pole to be supported"?

 

[cracklincrotch]

Wow, that's an interesting idea. A question or 3:

1.) How would you raise and lower it, with some sort of jack? That 16' of pipe and a 12' dish asssembly is going to weigh a few hundred pounds, I'm guessing.

2.) Will 4" pipe actually fit inside of 4.5" pipe? I guess the Schedule (40, 80?) would come into play there?

3.) Where did you come up with "the need to have 30 percent of the 4" smaller pole to be supported"?

1.) Just figured I'd use a scissor jack or hydraulic jack to send it up and bring it back down. My buddy thinks I could probably set up a counter weight system or even a couple of pulleys once it was all set up.

2.) NPS 4 (4.5" OD) schedule 40 is supposed to be 4.026" on the inside. It would definitely need to be oiled. I'll be trying this at the recyclers before I buy anything. Maybe it's just a pipe dream?

3.) Over at geo-orbit.org it suggests 30% of a pole be in a form. A couple of friends are also linesmen and they recommended this independently.

 

[phlatwound]

1.) Just figured I'd use a scissor jack or hydraulic jack to send it up and bring it back down. My buddy thinks I could probably set up a counter weight system or even a couple of pulleys once it was all set up.

2.) NPS 4 (4.5" OD) schedule 40 is supposed to be 4.026" on the inside. It would definitely need to be oiled. I'll be trying this at the recyclers before I buy anything. Maybe it's just a pipe dream?

3.) Over at geo-orbit.org it suggests 30% of a pole be in a form. A couple of friends are also linesmen and they recommended this independently.

1.) I guess that is the reason for your multiple holes (12" O.C).....jack it up a foot, stab a bolt, move jack, repeat? Not sure how you'd do it but a electric winch/pulley/cable system would be slick.

2.) Good idea to get a couple of pieces and try it out. I found that the thinwall tubing for the Birdview H-H mounts is a perfect slip fit into 6" Sch 40 steel pipe when I added about 10' to the one for my BV solid.

3.) Ah so, wondered where you got that.

No matter what you are going to have to be able to tweak your dish and get it tracking in the fully extended position, of course, but it would be nice to be able to bring it down for maintenance and high winds.

I'm not enough of an engineer to be able to tell you if what you have drawn is stout enough to carry a 12 footer but I have seen 8' & 10' BUDs up in the air that high around here for years. Good luck, will be interested to see what you come up with.

 

[cracklincrotch]

I rescued this bud from a 20 foot 4" free standing pole. I figure this should be fine being 16'.

As for getting it tracking the arc, it will track between 40 and 119 at the 8 foot height because that's where my 7.5 footer is now. Once I got that much on the 12 I should be fine once jacked up. I'll get over to 139 then.

 

[phlatwound]

.....As for getting it tracking the arc, it will track between 40 and 119 at the 8 foot height because that's where my 7.5 footer is now....

Didn't realize that, that should make things much easier.

I just read your OP in this thread, wouldn't be surprised if you did need some guys on that monster if you have much wind.

 

[woodheat/nooil]

I have mine high but I would like it much better lower to the ground. The pipe rest clamps help lift the dish and hold it to turn side to side for adjustments, (otherwise pipe would drop down). One clamp is welded to pipe to hold when using hydraulic jack on the other clamp that I can move up and down on the pipe when raising or lowering the dish. The hole for the 10 foot dish was hand dug as deep as I could go and two number 10 rebar driven deep into the dirt. Has not moved, but when I put the pipe in the hole I was slightly off plumb.

I made the difference up with a bathtub wedge on the top of the deck it works well. The three bolts on one side lock it all together. Lower is always less of a fall to the ground when working on the dish.

 

[turbosat]

Would it really have to go that much higher to clear the house? How far from your house is it? If you build it higher, maybe you could scavenge some scaffolding, and just put it up by the dish when you need to work on it, though that might be difficult to do if its on a hillside. The jack idea is smart, but may not be practical due to the weight. Curious to see how your plan plays out though.

 

[cracklincrotch]

Ground level to the peak of the house is about 24 feet. The dish will be about 30' back. The dish is on a hill about three to four feet high. So, on a 16 foot pole, three feet high hill, with a 12' dish should put the top rim of the dish at 25 - 26 feet, with AMC 8 at 1.6 degree elevation and no more than 2 feet of the dish showing over the peak of the house.... That's some close.

 

[brex2001]

I've been thinking about this for a couple of weeks. I want this 12 foot BUD as high as possible to get line of sight over my house. I found a 4" pole 16 feet long that will do the job. I thought what I could do is put a base on the pole and bolt it to a 16" concrete form that would be 5 feet deep. But a 16 foot high free standing dish on the side of a hill is going to be exceptionally hard to work on by myself.

A buddy of mine was talking to his brother about my plans on having the dish 16 feet in the air. His brother has a 12 foot dish himself and highly recommends having the dish near the ground because it's much easier and safer to work on and I agree. But if the dish is at ground level it can't see over the house to get the arc.

So rather than bolt a pole to a pad 16 feet up my buddy suggested that maybe I could put a pole inside another slightly larger pole so that I could raise and lower the dish as necessary. This would have the dish at the ground to work on it or in case a storm comes, and jack it up otherwise.

This drawing has a 4.5 inch pipe in the concrete 8 feet down and five feet out of the ground. This way when the 4" pole is out 16 feet at the top, 30 percent of the total pole from top to bottom is still in the ground.

With 5 feet of the 4.5" pipe outside of the ground, the smaller 4" pole is out 11 feet above the 4.5" but there is still 5 feet in the larger pole to satisfy the need to have 30 percent of the 4" smaller pole to be supported. I'd have 3/4 inch holes drilled every 12" to slip bolts through the full assembly as locks as well as to jack the pole up or down.

This would allow me to get the dish up the 16 feet as well as bring it down to 7 or 8' to work on with a step ladder on the ground.

Does this sound reasonable? Drawing is attached. (The pole in the concrete is missing a spur but I realize it needs one)

A cable winch attached to the 3 1/2" pipe in the concrete with 3/16" steel cable ought be adequate to lift the center pole & dish. Get a winch with a worm reduction drive so its self-braking. A narrow pulley of 4" diameter with the groove even with the center-line of the pole attached to outside of the pole with 2 angle brackets. Cut a slot for the pulley about a foot below the mount & tap 2 holes to mount the pulley brackets. Just below the pulley cut hole to reach in to fish the cable end & fasten it with a bolt thru the pole. A piece of the 4" pipe would fit nice for a bolt-on cover there. Use a cable eye end to reduce the strain at the end.
14-15ft of square tubing fitting inside 13 ft of larger square tube welded to the outside of your 4" with small angle brackets in 3 places would act as your spur in the concrete & act as a guide for the pole so it doesn't twist while raising/lowering. Attach the smaller square tube to the inner pole with bolts & brackets so you can detach it then turn the dish for a windstorm if you need to.
A hole thru the inner pole for a lever to "fine tune" the azimuth.

It could work!

 

[brex2001]

I re-read my reply. Sorry but this will not work the way I described it.

A cable & pulley setup would still have to have the upper pulley(s) rigidly mounted higher than the top attachment point of the cable to the pole.

This would mean another free-standing pole! Nah!