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Bisugo
| | Posted on Thursday, November 21, 2002 - 3:24 am: | 
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Where can I find specs/dimensions drawings of concrete base for antenna tower? I have two twenty foot sections. Also, do you have guide wire suggestions like how many sets and at what height intervals is best. Can you suggest optimum depth and diameter of concrete base for the anchors of the guide wires? What length of mast should I use to elevate my Maco Comet antenna from the heighest point of the tower. Appreciate any information you folks can provide. |
Taz
| | Posted on Thursday, November 21, 2002 - 8:58 pm: |
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for my 40 foot tower I used 4 commercial wheelbarrows full of 600psi concrete. No guy wires at all. But iw I was to, they make large screw anchors for down guys. I would elevate it high enough so none of the elements are hanging infront of the tower.
an 8 foot mast would do just fine |
Buck
| | Posted on Friday, November 22, 2002 - 7:52 am: |
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I would use no less than a yard of concrete for every 40' of tower |
Scrapiron63
| | Posted on Friday, November 22, 2002 - 10:55 am: |
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Below is a link to Rohn Tower, it gives specs for concrete and guys for their different grades. Most of the Rohn tower that CB's or Hams use is 25g or 45g. They are meant to be guyed, even 40 feet. A free standing tower would be large at the bottow, and taper toward the top. Lots of people go overboard on the concrete base, the strength of the tower is in the guy wires. If a tower is fastened to another structure like a house, it would need less guying.
http://www.rohnnet.com/rohnnet2001/catalog/html/gtowers.html
Tech 833 adds:
In the back of my Rohn catalog, they have various wind load ratings for 25, 45, 55 and 65 towers in free standing configuration. You CAN put up Rohn tower free standing if you use solid bases (not pinned bases).
Based on a 70 MPH windspeed and other factors, you can have up to 30 feet of Rohn 25 or 45 feet of Rohn 45 free standing. I would highly suggest a phone call to Rohn to discuss possible installations. The engineers at Rohn are very friendly and helpful.
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Stepchild
| | Posted on Friday, November 22, 2002 - 3:21 pm: |
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Tech 833,When you say "pinned"are you talking about a hinge plate? |
Tech833
| | Posted on Saturday, November 23, 2002 - 1:22 am: |
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A pinned base is one that is allowed to rotate. |
Poullutionpete
| | Posted on Sunday, January 05, 2003 - 2:03 am: |
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AS to say how much concrete to use for a base we had a rohn HDBX tower 48' and we used 9yds. of concrete of 6000 psi type or what the concrete pople called 47-b type mix and the hole that dug was 6'x6'x6' and used two mats of steel rebar and
we had acceass to a concrete vribrater to settle the mix and to get the air pockets out. and we used plywood to form up the hole to put the mix in to and the tower stud for 15years until we moved and took it down. |
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