Tower Guying Question-Rohn 25G - TowerTalk Forum at eHam.net

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Tower Guying Question-Rohn 25G	Reply
by KB9E on March 31, 2002	Mail this to a friend!
I'm in the process of putting together my first tower/antenna system and have a question regarding the guying of Rohn 25G tower. I'll be installing the tilt over base section in at least 1.5 sq yard of concrete. On top will be Force 12 C-3SS and Cushcraft 2/440 yagi. All mounted on a Hazer H-3 with an Alliance HD-73-1 rotor and 8 foot galvenized 2" mast. Total weight of just under 70lbs on top of the tower at 5.3 sq ft total wind load. My question: Do I need to guy the tower if I put up less than 40 feet of Rohn 25G? I'm not sure I have the room for guy wires so I may have to keep it under the 40' I originally wanted to go or bracket it to the side of my house, which I had hoped to avoid. Rohn doesn't provide info for guying or windload max for anything under 40'. Keeping in mind that we seldom have wind in excess of 50 mph and that I can crank the antennas down with the hazer if necessary during sustained high wind loading. Any suggestions would be appreciated. Thanks and 73' Ron KB9E

RE: Tower Guying Question-Rohn 25G	Reply
by AB8BC on March 31, 2002	Mail this to a friend!
Ron---I posted a few questions myself on a 25G and did some research in the meantime. Did you look at http://www.rohnnet.com/rohnnet2001/catalog/pdfs/25G/25gtowers.html ?? Read between the lines there. You most certainly will need some support at the highest level you can, wether it be a house bracket or guy wire. I was spared once when I erected an American Steel tower without even thinking of guy support. As soon as we winched it up to the 40 ft. position, it started rocking just a bit. We ran like hell to the hardware and made a temp. support!! Others may have some better advice, but I would say NO DOUBT...you need some support!!

RE: Tower Guying Question-Rohn 25G	Reply
by WB2WIK on April 1, 2002	Mail this to a friend!
Note re "1.5 sq yd of concrete," I assume you mean cubic yard. Note re Hazer operation: If you intend to locate the 25G close to your house, the Hazer will never lower below your roofline, since the F-12 beam will crash into your house if you attempt to lower it beyond that point. Another note re Hazer operation: The Hazer won't crank up and down through guy wires. Based on what you've provided, I'd securely bracket the 25G to the house, using the Rohn-supplied house bracket accessory, then do not guy above that point, otherwise the Hazer won't work. Install the Hazer from the roof, as well as the rotor and beams, and it will only crank up and down from the tower top until the F-12 hits the roof, and that's it. Probably not a lot of height adjustment, but better than nothing. If it were me, I'd forget the Hazer, bracket the tower, install the beams on top of the tower in the conventional manner, and then guy the tower near the top, permanently. You can run two guys to corners of your roof (house) and if there's no room for a third guy opposite those, you can guy to an outrigger that's attached to the house at the roofline, like the utility companies do with their poles when they have no place to guy in one direction. It works fine, I've done it on 100' towers made of 25G. 73 de Steve, WB2WIK/6

RE: Tower Guying Question-Rohn 25G	Reply
by K9KJM on May 7, 2002	Mail this to a friend!
If you mean 1.5 cubic YARD of concrete, that will sure be more than adequate for the base. The weak point will be your "fold-over" base. with no upper support, it will over time fail. As other posts suggest, A house bracket will do the job. You can also guy it for use with a Hazer, The guy wires go at the very top of the tower. Antenna raising and lowering needs to be done on a windless day, with the guy wires slacked in to the tower (disconnected at ground level and walked in to the tower) then pulled back out, reconnected, and retensioned. This is done so the antenna can get up past the guy wires. If you do use guy wires, Use the correct 3/16" EHS (Extra High Strength) galvanized wire, Not some hardware store junk. Rohn 25G towers were designed to be "guyed" towers, NOT free standing......... However, I have installed lots of them with one cubic yard of concrete, an antenna load like you describe, to the 50 foot level, and they are all still standing after more than 20 years! Very strong tower! (these did not use the "fold over" base...... a weak link) If free standing. Good Luck!

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