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Author Topic: Homemade antenna tower  (Read 7386 times)
N8CBX
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Posts: 136




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« on: March 24, 2012, 01:09:23 PM »

I need to get my 80M dipole up about 40 feet or more. I have many 12' x 1.75" (.049") 6061-T6 aluminum tubes and I was thinking about just building my own 4 or 3 legged tower. I have an idea of it's design, and I was wondering if anyone else has made their own?
Jan N8CBX
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Dayton Ohio - The Birthplace of Aviation
N4JTE
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Posts: 1154




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« Reply #1 on: March 24, 2012, 02:18:18 PM »

Yep pretty much all the time, use fiberglass on 16ft 2x4 or fiberglass flag poles.
Get to 45 feet with little problem especially for dipole center.
Bob
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NJ3U
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Posts: 122




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« Reply #2 on: March 26, 2012, 06:58:48 PM »

Take a look at the link as it captures the way I built my roof tower from 6061 alum, my was L stock not tube.  I'm pleased with how it turned out and the Mosley TA33jr on top has done wonders for my QSO's.

http://s47.photobucket.com/albums/f190/dad250/Mosley%20Beam%20Antenna%20Project/?albumview=slideshow

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K4RVN
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Posts: 758




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« Reply #3 on: March 26, 2012, 07:27:18 PM »

I took a look, great presentation and results were first class for appearances. Wish I were that neat with my projects.
Have fun with the hobby, and good luck.

Frank
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WX7G
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« Reply #4 on: March 27, 2012, 05:44:56 AM »

Your aluminum tubing tower sounds interesting. Perhaps the cross pieces can be aluminum angle stock. I'd go to a metal supply shop (all big cities have them) and get some 6061-T6 stock. The stock at hardware stores seems to be a much softer alloy.

It can all be brazed together using aluminum brazing rods available at the hardware store. MAP gas works well for this. Straight propane is not quite hot enough. It makes joints stronger than the aluminum itself.

To join the 12' tubes 1.875" aluminum tubing can be slipped over the joints.
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K4SAV
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Posts: 1825




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« Reply #5 on: March 27, 2012, 08:24:42 AM »

Take a look at the link as it captures the way I built my roof tower from 6061 alum, my was L stock not tube.  I'm pleased with how it turned out and the Mosley TA33jr on top has done wonders for my QSO's.

http://s47.photobucket.com/albums/f190/dad250/Mosley%20Beam%20Antenna%20Project/?albumview=slideshow



Good job on the tower and excellent pictures.  I enjoyed looking at all of them.
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WB6BYU
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Posts: 13029




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« Reply #6 on: March 27, 2012, 09:18:50 AM »

If you are just hoisting a dipole you don't need a very strong tower - a simple
mast may be sufficient.  3 sections joined together could be tilted up using a
"falling derrick" to keep them from bending in the process, then guyed in place.
Put a pulley and halyard on it to hoist the antenna so you don't have to lower
the mast to tune the antenna or make repairs.

If you cut the tubing into shorter sections (or have a tall ladder available)
you can stack the sections vertically rather than tilting the whole assembly up.
I use this method with the 4' military mast sections and have put up 40' by
myself.  Basically you install temporary guys attached to the top section,
add a second on the bottom, and lean it against the guy ropes while you pick
up the next one.  As you add sections you have to keep walking sideways to
keep the mast leaning against the guys so it doesn't fall over.  I'm fairly tall,
and the 4' sections are about the longest I'd want to use for this because
I have to pick up the stack with one hand while adding the next section
with the other (unless you have more than one person, of course.)  If you
can stand on a ladder (or on the roof) then you can use longer sections.


If you want something more than a single mast, consider a tapered triangular
tower with spacers - basically three masts coming together at a common point
(or with a single section of mast on the top.)


The problem with any tower is getting it upright.  I wouldn't want to climb a
tower made of such thin tubing, so it wouldn't work to stack the sections with
a gin pole in the normal manner unless you have a bucket truck available.  That
leaves the approach of tilting the whole tower upright as a unit, which puts a
lot more lateral force on the tower than keeping it vertical.  I've done that with
30' of Rohn 25G, but only because we could put a pulley at the 20' level to
pull it up into place.  The aluminum tower will be lighter, but tilting up a 40' tower
is not a trivial task without an additional support to pull from above ground level.
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N8CBX
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Posts: 136




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« Reply #7 on: March 29, 2012, 03:21:03 PM »

The tower is close to my property line, so it will need to be free standing. Also, to conceal most of the tower, its going to be located between two 60' pine trees. I will make a hinge base and it should be light enough to have two people walk it up into the vertical.
Jan
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Dayton Ohio - The Birthplace of Aviation
K9KJM
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« Reply #8 on: March 29, 2012, 10:34:26 PM »

Why not just attach to one of the 60 foot pine trees?Huh?

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N8CBX
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Posts: 136




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« Reply #9 on: March 30, 2012, 05:25:01 AM »

A 60' tree? Yes, that was my original solution, but after sizing up the situation, I don't want to be tree climbing, or acquiring a very long extension ladder, or shooting a line up to catch an upper branch and missing and instead hitting my neighbor's house and have to answer to him. I put a lot of thinking into this and building a light weight, hinged tower is a good solution to me.
Jan N8CBX
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Dayton Ohio - The Birthplace of Aviation
KG4RUL
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« Reply #10 on: March 30, 2012, 07:11:37 AM »

Engineering a 40', free standing, aluminum tower is NOT a trivial undertaking.  This is best left up to experts. 

Even if you did construct this yourself, do you have any scheme for anchoring the tower base?  Getting a base consisting of several yards of concrete between your pine trees could be a real challenge.

You have got the trees there.  Hire a tree climber to install your anchor point.  It could be a LOT cheaper in the end.
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N8CBX
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Posts: 136




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« Reply #11 on: March 30, 2012, 11:32:36 AM »

Oh, I agree, its not a trivial project. There's a lot of work and expense, but I think its worth it for me. I enjoy the planning, engineering and the scrounging of materials for my projects.
Jan N8CBX
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Dayton Ohio - The Birthplace of Aviation
KW6LA
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Posts: 91




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« Reply #12 on: March 31, 2012, 01:38:02 AM »

Jan N8CBX

I made a tower out of EMT Hot dipped galvanized  electrical tubing. First a  triangle Jig on both ends to space the 10 ft. pipes. Then cutting up smaller pipe to make the Z braces . I used
heavy duty water pipe brackets with huck rivets to secure the corners / Z braces . The Z pipe have to be flatten 1  ½”   both ends so you can bolt together. 3 sections gave me a 30 ft.
tower. Then with only cement Lag bolt in to a patio slab for the base. The trick is to install close to a garage so you can bracket it at the roof line with more pipe. Its serious business to
hold a tower at the base, but a building holding it 1/3 the way up is very strong if done correctly. The drones will think this is crazy for they are not engineers !  I had a Mosley TA-33 up
on that tower plus 4 ft. of mast for 15 years and it didn’t budge in a wind storm. Food for thought… Good Luck.
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