[TowerTalk] 30 foot Rohn 25G calculations

[n8de at thepoint.net]

Unless he is intending to put up a stack of huge monobanders and/or  
SteppIR yagis, he doesn't need the 30" sections.

A free-standing Universal aluminum tower composed of 26" tapered, 22"  
tapered, and 18" topper will support ANY common tribander/vertical/VHF  
combo presently being used in ham radio.

Do the research ... I have 3 Universal towers up now ... and plan to  
put up 4 more soon.

73
Don
N8DE


Quoting Gedas <w8bya at mchsi.com>:

> Brian, I would not rule out a free standing tower esp since you need to
> stay under 30'.
>
> I have several self-supporting Universal towers here, each of which
> uses as their first 3 sections, their 30" HD series sections.  When
> assembling the towers and after getting those first 3 sections up in
> the air, you realize how strong that structure is.
>
> In your case, since you mentioned 24', I would use two 30" HD sections.
>  See if you can get the top section modified either by Universal or by
> a local welding/fab place to make it a topper with a collar where you
> can then use a 2" or 2.5" mast.  My gut tells me that two 30" HD
> sections with a 4'-5' mast will still be standing long after your home
> is leveled from some severe wind storm.
>
> Gedas, W8BYA
>
> Gallery at http://w8bya.com
> Light travels faster than sound....
> This is why some people appear bright until you hear them speak.
>
> On 2/12/2015 1:03 PM, Brian Carling wrote:
>> Many thanks Bud.
>>
>> I will need to review which version they are using. Yes I had   
>> someone pointing me in the direction of a freestanding tower but I   
>> think I may go to using guys.
>>
>> It's either that or trade my tower sections in on a stronger better  
>>  built freestanding tower designed for that purpose. I only need   
>> about 24 to 28 feet in height. Maximum.
>>
>> Best regards - Brian Carling
>> AF4K Crystals Co.
>> 117 Sterling Pine St.
>> Sanford, FL 32773
>>
>> Tel: +USA 321-262-5471
>>
>>
>>
>>
>>> On Feb 12, 2015, at 12:27 PM, W2RU - Bud Hippisley   
>>> <W2RU at frontiernet.net> wrote:
>>>
>>>
>>>> On Feb 12, 2015, at 9:58 10AM, bcarling at cfl.rr.com wrote:
>>>> I am putting together a permit application with my city which   
>>>> requires certfication for 139 mph
>>>> for three second gusts as in TI-222 spec. Also steady 100 or 110   
>>>> mph I think.
>>>> We are making a 30 foot Rohn 25G tower according to the Rohn   
>>>> specification with  4 foot
>>>> cube base of concrete with no guys.
>>> I?m not sure I understand what you?re hoping to find.
>>>
>>> My 4-year old Rohn catalog makes it VERY clear that 30 feet of   
>>> Rohn 25 can hold only 1.7 sq. ft. of added antenna when the   
>>> environment is 90 mph (ANSI/EIA-222 Rev. E) and NO ICE.  (For   
>>> areas that experience icing, Rohn 25 is specified by the   
>>> manufacturer at ZERO sq. ft. of additional antenna load!)  From   
>>> your e-mail address and the wind speeds you mention, I?m going to   
>>> guess you?re in Central Florida, and I daresay a 90-mph Rohn   
>>> EIA-222 Rev. E specification is not going to be adequate for your   
>>> city.
>>>
>>> Nowhere in your posting do you mention what total antenna,   
>>> rotator, feedline, etc. wind surface area or wind load you   
>>> anticipate putting on this tower.  But my guess is that NO   
>>> freestanding 30? Rohn 25 tower is going to make the grade.
>>>
>>> Also, you fail to mention which version of TIA/EIA-222 your city   
>>> is using.  The latest I?m aware of is Rev. G ? a substantial   
>>> revision from previous methods of specifying wind loading.
>>>
>>> Bud, W2RU
>>>
>>>
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