I think the real problem here is that Douglas is in Cuba. There is no
meaningful free enterprise - the government either owns or controls all non
black market commerce. Mean salary is equivalent to $22 USD a month. There are
two peso currencies - a convertible (to foreign money) the CUC and the national
CUP. Unless you are a tourist or have certain privileges, your access to money
is mostly the CUP. I don't know firsthand if there is a functioning retail
scrap metal industry in Cuba. I surmise that there is not given that the
country imports much of the metal it uses and mostly lacks the facilities to
process recycled material.
He's trying to build a tower with the limited resources available to him and is
probably going to have to make significant compromises.
Al
AB2ZY
________________________________________
From: TowerTalk <towertalk-bounces@contesting.com> on behalf of Grant Saviers
<grants2@pacbell.net>
Sent: Sunday, June 28, 2015 3:56 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] [Bulk] Re: Homebrew tower...
Doug, water pipe is ungraded steel and with usually poor seam welds, so
risky to use as a structural member. From the responses and IMO you
would be better off getting the scrap value for the pipe and building a
tower from 90 degree angles (square base) or easiest would be a tubular
tower with a derrick to hoist it.
Tube can be square and provides the restraint against the rotator torque
and usually comes in 20' lengths, sometimes longer. Square tube is A36
steel. Something like 3.5" square x 1/8 wall bottom with a 3" square
1/8" wall top would get you to 38' and probably needs a guy on the
bottom section, but that is my backyard engineering. A tribander and
VHF antenna would be the limit. A mast of the size above will weight
about 300# so a derrick is the best way to raise/lower it. Check out
the various catalogs for similar masts.
A BS in ME should be able to do the necessary calcs so why don't you
visit a nearby University and check with the ME department or give a
starving undergraduate Senior a few bucks. It's only a couple hours
worth of work or so for a mast design.
Grant KZ1W
From the
On 6/28/2015 8:39 AM, Patrick Greenlee wrote:
> Galvanized water pipe is NOT very good as a strength member. If you
> use it you will have to make allowances to get the overall tower
> strength you need. Braces (lattice elements) will have to be closer
> together than with other stronger material. This means you can not
> safely copy a commercially made tower since your materials are not as
> strong as theirs. You will need more and closer lattice elements.
>
> It has been my experience when flattening the end of a galvanized
> water pipe by hammering it on an anvil or using a 20 ton hydraulic
> press that you can get it to crack or split. Heating it first and
> flattening while hot works. There are DIY You Tube videos on making
> your own forge out of a scrap car or truck brake drum
>
> I wish you the best of luck with your project. I too have a very non
> standard tower project in process. For a little info on that take a
> look at QRZ.com NJ5G and scroll down to the pictures.
>
> Again good luck with your project.
>
> Patrick NJ5G
>
> On 6/27/2015 11:45 AM, Douglas Ruz wrote:
>> Hello everybody !!!.
>>
>> Thank you very much for all ideas !!!...it is amazing...i am learning
>> a lot.
>>
>> Let me try give more information to all of you.
>>
>> FIRST, Bryan, WA7PRC, you are absolutely RIGHT..."Reinvent the wheel"
>> is a trouble but i have not other choice...
>>
>> Gerald, K5GW, yes i can get guy wires from electric power
>> company...so, guy wires are not a problem.
>>
>> Jim Lux, sorry, i have not a lot of pipes and ground space, so, self
>> supporting is not possible. Guyed tower is my choice.
>>
>> Rick, N6RK, yes, i am talking about 3/4 inch galvanized water pipe.
>>
>> I am not the welder...I have been talking with the welder and he
>> knows it is dangerous welding galvanized parts but he work in OPEN
>> SPACE with a FAN to remove all gases.
>> He is also thinking use a CONTACT SOLDERING MACHINE and not a classic
>> ELECTRIC SOLDERING MACHINE...less gases.
>>
>> To join sections i found that using a piece of 1 inch water pipe,
>> after "cleaning" the inside with a drill work perfect. Using bolts in
>> both sides to join each section.
>>
>> I am WORRY about TWO THINGS:
>>
>> TOWER STRENGHT: Is strong enought the 3/4 inch water pipe and 5/16
>> bars for braces to replicate a Rohn 25G ??
>>
>> CORROSION: Heat during welding destroy galvanized protection...i can
>> not galvanized after welding...maybe some cold galvanizing is
>> possible...I am worry about corrosion...maybe painting inmediately
>> after soldering minimize corrosion.
>>
>> I am listening (READING).
>>
>> Thanks,
>>
>> 73...Doug, CO8DM
>> "No creo que haya alguna emoción más intensa para un inventor que ver
>> alguna de sus creaciones funcionando. Esa emoción hace que uno se
>> olvide de comer, de dormir, de todo." - Nikola Tesla
>> ----- Original Message -----
>> From: Bryan Swadener
>> To: co8dm@frcuba.co.cu
>> Sent: Saturday, June 27, 2015 2:14 AM
>> Subject: Re: [TowerTalk] Homebrew tower...
>>
>>
>> Hi Douglas,
>>
>>
>> IMO, it's too much trouble to "reinvent the wheel". You need to be
>> not only the fabricator but also, structural engineer. Then, after
>> you've designed and fabricated the parts, you'll want to hot-dip
>> galvanize the parts so they'll last a long time. Just save your
>> money to buy what you want. I did exactly that.
>>
>>
>> vy 73 es gl,
>> Bryan WA7PRC
>> http://www.tinyurl.com/wa7prc-tower
>>
>>
>>
>> Date: Fri, 26 Jun 2015 11:50:40 -0400
>> From: "Douglas Ruz" <co8dm@frcuba.co.cu>
>> To: <towertalk@contesting.com>
>> Subject: [TowerTalk] Homebrew tower...
>>
>> Hello,
>>
>> I would like a tower in my property but i can not buy a Rohn or
>> any other tower, so, I WILL BUILD ONE...or will try build one.
>>
>> I have many galvanized tubes, 7 ft long, 1 1/32 inch diameter
>> and 1/8 inch wall.
>>
>> I have been reading dimensions of Rohn 25G and 45G...i like 25G.
>>
>> My goals are:
>> -Reach about 50 ft high.
>> -Install a rotator.
>> -Install a lightweight tribander yagi (maybe an spiderbeam), a
>> 6m yagi (5 elem) and maybe 2 elem moxon for 40m...I know 50ft is not
>> OK for a 40m antenna but my anchor points are to close, so, i can not
>> install a higher tower.
>>
>> I have another important questions...it is about GUY
>> LINES...what is the cheapest guy line solution ???
>>
>> 73....Douglas, CO8DM
>> _______________________________________________
>>
>>
>>
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