Anyone know how to build a 30m/100ft tall mast/pole?

reply to post by RFBurns

You can get a telescoping mast complete with guy wire rings and the guy wire for about 180 bucks at rat shack (Radio Shack) or find one at a ham fest, or run on down to the hardware store and get two 15 foot long poles, one at 2 inches ID and one at 1 3/4 ID. Mount 4 bolts on the 1 3/4 pole about 2 feet from its bottom, insert into the 2 inch ID pole, mount guy wire points at the top, and middle section of the entire pole and there you go.

i wish it was that simple... i am looking at 30m not 30ft... I checked it anyway in case you meant what i need but i couldn t get anything...
However

Or go fancy and get you a Rohn self supporting tower for about 1,200 bucks.

When checking the Rohn products out i was impressed. Especially if this is the price for what i need. It comes a bit expensive but i would go for it if i can get it shiped to Greece.
In fact i made an inquiry about it on ww.antennasystems.com/rohn .

Anyway since i doubt i will manage to get that solution for under 1500 € (about 2000 $- this is really expensive for the case but i might get by) i will propably have to go on with my current endeavour. In any case i am awaiting on their offer.

Have you considered "topping" your mast with a really long fishing pole?

Light weight and strong too.

Telescopic and put-together poles are available and come in a variety of lengths...up to about 20 (ish) meters I think.

Would keep the weight down and make erecting it easier.

If the tip makes it too flexible just remove the top section or two, each section is usually around 1.2 - 1.5 meters long, maybe more for a longer pole.

That would leave you needing to construct a mast only 10, maybe 15 metres...much less bother eh.

Just an idea.....nerb

Originally posted by GEORGETHEGREEK

Unfortunately all these dimensions are just guesses as to fulfilling my design requirements since i dont know about load criteria to the specific design.

No offense meant, but from what you have stated it is apparent that this task is not within your capabilities to complete.

A mast 100 feet or 30 meters tall, lifted from the ground by tractors as you suggest, would have to be able to support it's entire weight at the center part of the pole as you are raising it. If it is not strong enough to handle its own weight it will snap in half as you raise it.

100 foot tall flagpoles generally come in 3 or 4 sections and are erected by cranes. Flagpoles of this size cost well over $10,000 (USD) just for the pole. I have no idead what delivery or installation costs would be. These flagpoles weigh well over 1000 pounds.

Also, I don't know if Greece has the equivilent of our FAA (Federal Aviation Administration), but here in the states there are specific requirements regarding the brightness of the illumination of masts. The amount of LED lights needed to meet the illumination requirements (here in the USA) would require a huge amount of LEDs, and subsequently a large, expensive battery array to hold the solar charge. Come to think of it, the solar panels and the battery array you would need to power your webcam and wind sensing devices would be a tremendous expense.

reply to post by craig732



Hmmm... might be true that statement of yours:

No offense meant, but from what you have stated it is apparent that this task is not within your capabilities to complete.

However i am doing the best i can to ensure everything will go smoothly, whatever the case. (maybe in the end of the day i find a specialist...)

More to your points if a @ inch pipe is not sufficient a three inch one might.
Moreover its wall thickness can be 3 or 4 mm. I think that this order of size may be sufficient. If the mast can balance horizontaly on its centre poin without significant deflection, then it should be able to be erected by the method i proposed.
LED wise, i have ordered through e-bay a led aray that is to be used on 260ft windturbines, its light, consumes little energy and fullfills the FAA requirements.
Although the local authorities have alloved me to go ahead and that i would not need an FAA licence, i shall go pay a visit to our FAA offices to make necessary arangements.

Don t worry about the power, both devices, webcam and sensing equipment have minimal requirements. The LEDs take up some more signifficant amount of juice, but that is tollerable too.

Come to think of it, the solar panels and the battery array you would need to power your webcam and wind sensing devices would be a tremendous expense.

Yeah, but tremendous is relative... the one aspect is that i have to balance costs within different materials required by the project. This is what forces me using the least amount (but not less) possible on the mast.
Good thing is that the people i have undertaken this project for have sponsoring on th ephotovoltaics and the batteries and the inverter!
Its just that new thing that came up that i am a bit worried about and i certainly have not resolved yet...LIGHTNING...!!!

Be well and don t worry everyword helps!
Be well.

Don't forget also, that you are actually constructiong one, big, lightening conductor!

Hope your equipment doesn't get fried.

Originally posted by GEORGETHEGREEK
If the mast can balance horizontaly on its centre poin without significant deflection, then it should be able to be erected by the method i proposed.

Not true.

You have to calculate the extra stresses being put on the mast by movement and tension from the cables being used to raise it.

Originally posted by nerbot
Don't forget also, that you are actually constructiong one, big, lightening conductor!

Hope your equipment doesn't get fried.

you took the words outta my mouth on that one my friend. The guy said the area has very little in the way of trees etc. One strike and he's out!

reply to post by GEORGETHEGREEK


Hi, I’ve built a few Guyed Masts in my time (Radio and Aerial Engineer), there not that difficult assuming you know what your doing and have the tools and parts for the job.

The Mast is built in stages using shortened Scaffold Tubes or Gas Pipe tubes and slotted together using couplers and O rings and guy wire (wire rope). The Mast is built and climbed (Harness and Pole ladders required) building each section at a time. No welding required just a few Stainless Steel Bolts.

My only concern is your height, 100ft, although I’ve done 125ft in the past, these days with H & S concerns I would probably only build to 60ft.

I would not recommend you don't even think about doing anything without proper training, good engineering skills, and no lone working.

Get qualified Riggers to do the job for you, or on a weekend for some Beer Tokens.

wow - you are ` aiming high `

i looked at this and thought ` thats so freaking easy ` - but having read the eintire thread - i am struggling to avoid ` how i would do it ` crap that might be out of the OPs league - and suggest SENSIBLE plans


now 2 ` solutions ` spring to mind

1 - build or have built for you a single ` lattice ` mast in 3 to 5 sections

a micro vesion of this design :



with 2 banks of 3 guy wires , the main drawback is that this design ` swallows steel ` - and needs to be proffesionally fabricated and errected by crane - as it will warp if you try to lift it from flat

it will look cool - and do the job - but the budget might go out of hand

2 - the simple solution - a tripod design

the advantages are - ` relativly easy ` self build - and POSSIBLY self errection

the disavantages - a massive ` footprint ` and relativly unsightly

but here goes with the basic outline

construction is of fairly cheep 50mm scaffold pole - joined by internal welded ferrules

step one - get everything you need :

basaically - 18 * 6 m scaffold poles [ for the tripod ] another 10 for ` other uses ` various brackets , strengthening fillets and other misceleny , enough concrete to make 3 ` base pads ` a ` yoke ` to top the tripod and a platform for your ` payload ` , a lightening conductor ,

step 2 ground work - you will need your 3 base pads to be rock solid - so you will need to dig a trench / hole - fill it with concrete - and set your base bracket into it

step 3 - build 2 legs of your tripod + the yoke - flat on the ground - so you have a ` vee ` with the ground ends secured to the bases by loose clevis pins

step 4 - attatch your payload - and all elecrics etc - and lightening conductor - and test EVERYTING - remember you will need IP 67 connections al the way down - and fix everything to be wind resisatant - inservice maintainance will be trickey

step 5 - errection - this is the " fun " part - that is easier said than done - there are so many ways it can go wrong - it is not funny

basically you are going to raise the 2 ` fixed ` legs incrementally – and attach the 3rd leg in sections from the top down

it sounds easy – but doing it without warping is harder than it sounds

here are a few illustrations – nothing to scale just a demonstration of concept

get your vee of 2 legs attached to two of your bases – and attacht everything at the top end



Heres how it looks ` from the side `



Now to raise it



Use a simple a frame [ shown in red ] supplemented by supports [ green ] to raise the top end with block and tackle – and simply fit the 3rd leg [ blue ] from the top down

PS – having a ` hinge ` at this joint will make life a lot easier – and less stressfull – for both you and the errection

And up she goes – once you reach the limit of you’re a frame – simly move it back beyond the ground pivot – and pull it up



Also – once you have sections of the 3rd leg on – you can “ push “ the leg up too using intermediate brackets – and a single spar

Lastly – up – secure the bottom of the 3rd leg to the last base – and its built



" just like that " - it sounds oh so simple - but actually raising it without warping - requires know how or blindingly good luck

it is possible though -

but like i say - there is a lot of prep and groundwork required to do this right and if one thing fails then over 300kg of steelwork is going to come crashing down