Help for building 300m post

[michaelelec]

Hello
For a project i have i need to build a very high post for antenna purposes.Height is must be near 300m (like Eiffel tower height).This post must be electrical isolate from the earth.It can be all plastic or metal with plastic or glass base so there is no connectivity with the earth.
I dont have the knowledge on how to build this so it can sustain the weight and the wind.
Any ideas how to proceed or informations to study would be appreciated.

Michael

 

[hokie66]

Suggest you find an 80 storey building, and convince the owner to allow you to mount your antenna on it.

 

[michaelelec]

That is a clever idea but unfortunately in my country the tallest building is 62 meters.

 

[msquared48]

Any 1000 foot hills?

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[michaelelec]

Nope.Any ideas on how i can build it? .........or i can move to Paris and use Eiffel tower instead lol ?

 

[Ussuri]

Is a guyed tower a possibility?

 

[paddingtongreen]

Economics would force a guyed tower. This is a specialized design. Hire an expert. Most codes require a lightning protection, this would force conductivity to ground.

Michael.
Timing has a lot to do with the outcome of a rain dance.

 

[dik]

It would have to be a guyed system with a minimum of three sets of cables along the length of the tower. The 'footprint' would be quite large... maybe 300 or 400m and these would have to be electrically isolated. For security reasons, the cables would have to be protected by suitable fencing or whatever. Lightning arrest may be accomplished by isolating the tower and having, yet, a slightly taller arrest system... I'm not sure... most large toweres I've been involved with are grounded... best to check with a lightning dude.

Dik

 

[rb1957]

can you build a "proper" structure, and install an isolated antenna inside it ?

i imagine the strength of electrical isolators is pretty low. it seems a bit "ass-backwards" to build a tower from "proper" structural materials only to have the most heavily loaded bits (the attachment to the ground) made from the weakest ? materials.

question ... if the tower is isolated from the ground, how will it react to a lightning strike ? i see images of a roman candle.

question ... does the tower structure need to be electrically (magnetically ?) inert ?

 

[ishvaaag]

I think the owner needs at least to specify the total conductance allowed for the mast support. Starting from that you maybe can query specialty support guys that may provide or adapt some rubber or plastic devices to the purpose. In my view the item under study is more an industrial device or part of a particular electrical machine, and its design must also be examined and maybe undersigned by some people with knowledge of the intent of the device, and means of getting the electrical isolation. Maybe specialty very resilient porcelains may add to the materials able to provide in the end what wanted. Typically, an structural engineer should mainly provide competent clamps to their isolator. If you get deeply involved with the design with others, consider the advantages of getting a patent on what innovated and maybe tested.

 

[MiketheEngineer]

Even "wet" plastic will conduct lightning. And since lightning can arc for miles - just isolating a couple feet from earth is no guarantee it will work. Not sure this is possilbe.

 

[JStephen]

It's going to be expensive. If you don't have a lot of funds available, the details won't matter.

If you do have funds available, start getting in touch with antenna companies, or with engineering companies that do antenna design (including the electrical part), and see what the options are.

If it need not be a permanent structure, consider a tethered balloon.

 

[rb1957]

i liked the idea of the 1000' hill (and building a 300m well) ...

 

[hokie66]

Electrical isolation is not my thing, but I don't like your chances. If you intend to build this thing, don't forget to warn the aviation authorities.

 

[michaelelec]

@rb1957 <<....if the tower is isolated from the ground, how will it react to a lightning strike?>>

If the lightning find the tower a better path for going to ground then it will use it.

<<... does the tower structure need to be electrically (magnetically ?) inert ?>>

No it will be used like an inductor.

@ishvaaag
The isolation it will need is huge.Around 10-20kv insulation max

@JStephen
<<consider a tethered balloon.>>
I already worked with balloons and the cost and labour efficient is not worth it.

Thanks everyone for the reply s,really informative and helped a lot.Any more ideas is welcome.
I search on the internet and found some towers that are more than 300meters but i cant find the suppliers/companies that sell the towers.Iam thinking that these companies must have engineers and designers to build what iam after.
Michael

 

[michaelelec]

I dont know how to edit my post so..
@ishvaaag this sentence is wrong,i meant to write not huge.
The isolation it will need is huge.Around 10-20kv insulation max

 

[msquared48]

Is this a HARP project for zapping UFO's?

How are you ever going to isolate the structure from the earth and yet get power to the antenna for it to function? Is this antenna a collector or distributor?

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[michaelelec]

As a Collector.

 

[Pud]

Some 213m high masts, electrically isolated from ground:

http://tx.mb21.co.uk/gallery/droitwich/droitwich-ab.php

www.tynevalleyplastics.co.uk

It's ok to soar like an eagle, but weasels don't get sucked into jet engines.

 

[Grahammachin]

I am not sure where you are based, but a quick search on google turned up these "guys"

http://www.gordtelecom.com/Contact Information.htm

(Canada with a 300m high guyed mast)

http://www.sabretowersandpoles.com/ContactUs.aspx

(US with a 1200' guyed mast)

http://www.fli.co.uk/contact-us/Contact Details/

(UK with a with a 300m guyed mast)

Hopefully at least on of these can help you. There are quite a few companies out there.