[TowerTalk] [Bulk] Rohn 25G tower permitting

[Roger (K8RI) on TT]

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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