rohn 25g

bayfire300 · Post by **bayfire300** » Fri May 26, 2006 6:11 pm

hello,
does anyone know if a rogh 25g needs to be guyed or not?
i've seen them self supporting .......whats the circumstances involved.
my senario is this :....60 ft tower in concrete base as per the instructions by rohn...also 23 feet up braced to the house via rohns house bracket.

do i need to still guy it
otto

kb0nly · Post by **kb0nly** » Fri May 26, 2006 8:06 pm

I would have to dig up or download their spec sheets. How many feet do you have unsupported above the house bracket?

If i recall correctly the specs said that you could only go a max of 30 feet unguyed above the house bracket, and it won't be that fun to climb up to the top due to movement.

440roadrunner · Post by **440roadrunner** » Fri May 26, 2006 9:27 pm

Rohn is by design a guyed tower, period. You CAN scrape by, "depending." I sure as heck wouldn't want to climb that thing. You've got some 40 ft "self supporting" assuming the house bracket is solid, and I mean solid.

Now it depends on what's on top (a two meter ground plane, maybe?) what the wind, the snow and ice load is in your area, and think about THIS

What would happen if it DID fall, could it hurt/kill anyone, fall on other peoples property?

I'd guy it , were it me, there isn't any other option, unless you want to install a free standing design.

Twenty feet of 25G, with an omni on top, maybe. anything taller........

bayfire300 · Post by **bayfire300** » Sat May 27, 2006 4:20 am

thanks guys for your input.
i really have no way of guying it w/out goin onto neighbors property so i guess i'll put up the rohn bx tower i have and buy 1 or 2 more sections for it ......i know the bx is self supporting and i still plan on bracing it to the house.

thanks
otto

Rocky Coast · Post by **Rocky Coast** » Sat May 27, 2006 5:03 am

bayfire300 wrote:thanks guys for your input.
i really have no way of guying it w/out goin onto neighbors property so i guess i'll put up the rohn bx tower i have and buy 1 or 2 more sections for it ......i know the bx is self supporting and i still plan on bracing it to the house.

thanks
otto

I had a 32 foot Rohn HBX up for 4 years in New England
with a 3 band HF quad on it, no need to brace it to the
house. What do you plan to put up for antennas?

Peter
K2XM
The Rocky Coast of Maine

bayfire300 · Post by **bayfire300** » Sat May 27, 2006 7:59 am

just 1 17 foot vertical antenna

for my repeater

otto

KI4M · Post by **KI4M** » Sun May 28, 2006 7:20 am

The answer you need is located on this page:

http://www.radiancorp.com/ROHNNET/rohnn ... index.html

Click on online catalog..then click on gt series tower.... then click on 25g... then click on bracket elevation.. You will need to know the square foot windload rating of your antenna. Does not cover partial guyed/bracketed installs but will give you an idea of what you can do.. Hope that helps a bit

bayfire300 · Post by **bayfire300** » Sun May 28, 2006 6:24 pm

ok thanks ........i appreciate all you help guys thank you

otto

kj7xe · Post by **kj7xe** » Tue May 30, 2006 3:21 pm

Here's one of the Rohn 25G tower sites slated for replacement here this summer. Yup, it's not guyed. It's been up for over 20 years in some of the nastiest weather, all that's on top is a PD220 super stationmaster. A 60-foot SSV is its replacement, I feel much more comfortable climbing one of those... heh

I'm sure glad i'm not this guy, I swear the tower is bending the direction he's leaning...

440roadrunner · Post by **440roadrunner** » Tue May 30, 2006 6:03 pm

Just because one guy gets away with it..........

I notice that it is bracketed up pretty high--which helps, but climbing, you are depending on the semi-might-just-be rotted 2x at the roof peak, not to mention whatever box nails someone might have used to hold the bracket.

I have no idea of the snow and ice, wind loads in your area.........

The area appears well shielded from direct wind by the trees.......

Just because YOU got away with it.........

kb0nly · Post by **kb0nly** » Tue May 30, 2006 8:45 pm

I don't know about ya'll, but i sure as heck wouldn't be up on non-guyed 25G that far, yikes!!

AEC · Post by **AEC** » Tue May 30, 2006 10:39 pm

I've been up 100' on GUYED Rohn 25G towrs, but NEVER on one that's not guyed, you are just looking for disaster to strike!

I would guy every two sections going up, then brace it if it's close to a solid structure, and add still more guys again every two vertical sections.

25G is NOT a solid tower, and the further UP you go, they more movement you will get at the top as each leg is secured with ONLY TWO bolts per leg, and who knows the quality of those bolts anyway?

I hope he's at least got some real base work completed with good drainage as well.

kj7xe · Post by **kj7xe** » Wed May 31, 2006 7:34 am

I believe the base is 4'x4'x3' concrete and the house bracket is thru-bolted through the eave and attached to the peak beam, which is not rotted out (yet). This site is in a valley and is subject to snow, light ice loading, and 75mph winds.

I didn't mean to imply that such a tower is 'safe' or that it's an 'acceptable' example of an unguyed tower whatsoever, but it defiantely has lasted through the years. I'm just glad none of the antennas have needed work since i've been working here

At work our safety standards have changed in the past few years and because of this and the old age of the towers, they're being replaced with the SSV self-supporting towers, which include a steel cable grab climbing system and are much safer to climb (not to mention they don't wobble around as much at the top).

AEC · Post by **AEC** » Sun Jun 04, 2006 12:18 am

(quote)4'x4'x3' concrete (/quote)

I would have hoped he had more concrete DOWN than around, as the upper sections are a far more powerful lever to pop that small section of concrete right out of the ground.

I would have gone down to at least 6' of reinforced concrete with a 5 X 5 foot base.

Any sizable tower installation requires a large foundation to remain 'solid' in high winds and ice loading, as well as a proper guying system as even light wind loads can cause the tower to move and wear the joining sections and cause metal fatigue due to excessive movement.

A ham I know in Park Falls, WI. put his own tower up (60') and it is so hastily assembled and wobbly, that by the time I made it to the second story, I was ready to be airlifted OFF tha darn thing...he used ROPE to guy it!!!

I wish I was an inspector, because my FIRST act would be to CONDEM this junk and if he wanted a tower, he would have to provide proper guying and base support......His 'base' was two feet square and three feet deep...no reinforcement, and no drainage!

The base was below ground level.

No wonder people sue when towers fall over!

kj7xe · Post by **kj7xe** » Wed Jun 07, 2006 8:38 am

I wish I was an inspector, because my FIRST act would be to CONDEM this junk and if he wanted a tower, he would have to provide proper guying and base support......His 'base' was two feet square and three feet deep...no reinforcement, and no drainage!

Exactly. The towers in the outlying areas here were installed many years ago by someone who has since retired, and probably had a different opinion on what was required for the tower base specs. None of them have fallen, but that's besides the point. Tower safety and proper engineering is top priority. May not have been then, but it definately is now.

The new 60' Rohn SSV (self-supporting) towers we're replacing them with require 11.3 cubic yards of reenforced concrete for the SB5 base, which amounts to 8'9" square by 4' deep (tower manufacturer's specs). One of our older SSV tower sites is in an area that endures 90mph winds with about 2" of rime ice each winter, it's been inspected annually for the last 15 years with no problems.

rohn 25g

rohn 25g

Rohn BX