[TowerTalk] [Bulk] Rohn 25G tower permitting

[Bill Aycock]

Roger--
It is, indeed a sad story, but do you know if the tower was installed with 
the proper base for Unguyed use?
If not, why should we be surprised?
Bill--W4BSG

-----Original Message----- 
From: Roger (K8RI) on TT
Sent: Friday, January 30, 2015 8:14 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] [Bulk] Rohn 25G tower permitting


As to unguyed 25G at 30 feet plus.  I have a friend who was taking a 25G
down.  He was down to the last 30 feet with the last set of guys removed
when it broke.  It went over with him fastened to it.  After months in
the hospital and multiple surgeries he will never be the same.

I don't think anyone knows for sure why it broke, but when he hit, he
was on the bottom with the tower on top.

73

Roger (K8RI)


On 1/30/2015 1:56 AM, Jack Brindle wrote:
> Rohn has a section in their catalog for unguided towers which includes 
> Rohn 25. They call for something like 2.5’ x 2.5’ x 4’ of concrete for the 
> base. I’m not sure I really want to be up 35 feet on that, but it has been 
> in their literature for as long as I can remember. I am sure many folks 
> have built one of these, and would love to hear opinions on ways to make 
> it safe. I suspect this is what the original poster was referring to. Not 
> all of us can have tall towers - sometimes 35 feet will have to do, and 
> extensive guy systems can be problematic on small city lots. So, the 
> question really is how do we put this stuff up and make it safe? Is this 
> where you were heading, bcarling?
>
> 73,
>
> Jack B, W6FB
>
>
>> On Jan 29, 2015, at 8:19 PM, Roger (K8RI) on TT 
>> <K8RI-on-TowerTalk at tm.net> wrote:
>>
>> On 1/29/2015 6:57 PM, Grant Saviers wrote:
>>> My 140' Rohn 65 base is 4x4x2 ft. PE engineered.  So 3' of concrete is a 
>>> bit much, check the Rohn catalog.  The most important thing with a base 
>>> in concrete is the legs go through it and into some gravel for drainage. 
>>> I've seen many legs split by water freezing in them.
>> Or use a pier pin base with solid lefs. Easy to make and not expensive.
>>
>> 73
>>
>> Roger (K8RI)
>>
>>> I wouldn't go as far as "3/4 ply and broomsticks" but the loads from 30' 
>>> won't need much of a base for 2000psi soils.  It's all in the catalog.
>>>
>>> Grant KZ1W
>>>
>>>
>>> On 1/29/2015 10:10 AM, Wilson wrote:
>>>> I think you are being led around by the short hairs.
>>>> How did you decide a 27’ tower needed to be in 3’ of concrete?
>>>> For practical purposes there is no bending and no horizontal load at 
>>>> the base of this tower, assuming it is guyed, of course, which –25 must 
>>>> be.
>>>> You could stand 30’ of 25 on a piece of 3/4” plywood and three 
>>>> broomsticks and have a fine installation!
>>>> The guywire and anchors are your real design hotspots, so a reasonable 
>>>> estimate of overturning moment is necessary.
>>>> With it, you figure the worst guyline load and that gives you an anchor 
>>>> capacity requirement.
>>>> You may have the perfect place for some screw in anchors, or an ideal 
>>>> place to display some heavy yard art!
>>>> Yes, you’ll have a little horizontal load due to drag on the tower 
>>>> itself, if it’s in the clear, so maybe use rebar or pipe instead of the 
>>>> broomsticks.
>>>> I have a 2’ square pad and a tilt plate for mine (40’) and it’s 
>>>> overkill.  The tilt plate is great for antenna maintenance.
>>>>
>>>> And are you required to tell them all about the antennae to be 
>>>> installed?
>>>> The less you tell them, the better, since you’ll be changing eventually 
>>>> anyway.
>>>>
>>>> WL
>>>> _______________________________________________
>>>>
>>>>
>>>>
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>> -- 
>>
>> 73
>>
>> Roger (K8RI)
>>
>>
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-- 

73

Roger (K8RI)


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