[TowerTalk] Rohn 25G or 45G?

[Stan Griffiths]

Hi Robert,

With all due respect, you make it sound like there is only one "proper way"
to guy a Rohn tower and that is the way pictured in the Rohn Catalog.  Rohn
suggests ONE way that they have calculated to be safe for a particular load
and wind speed.  I am sure there are dozens of other ways that may even be
safer and will hold much more antenna load than Rohn says you can put on any
particular height of tower they have shown in thier catalog.  For example,
what kind of load could you put on a 25G, 120 feet high, guyed every 20 feet
with six sets of guys?  I certainly don't know, but I'll bet its a lot more
than Rohn says you can put on 120 feet of 25G with the guying plans they
show in the catalog.  You would need a PE to help figure it out (at least, I
would.)  Don't try this at home without some REAL GOOD help.

Stan  w7ni@teleport.com

PS   I agree that the side arms also make a difference . . .


>Stan,  thanks! but no.  That's not it.  It's the 8 Square Feet of arms on
>the 45G as noted in the foot notes of the 45G print.  The 25G has them not.
> Both heights are properly guyed for each tower as per the Rohn prints.
>
>73  Robert W5AJ
>
>----------
>From: Stan Griffiths <w7ni@teleport.com>
>To: Robert W5AJ <w5robert@blkbox.com>
>Cc: towertalk@contesting.com
>Subject: Re: [TowerTalk] Rohn 25G or 45G?
>Date: Monday, July 13, 1998 3:17 AM
>
>
>>
>>On subject of 45G being more than 25G.
>>
>>ROHN BOOK:
>>80 FOOT TALL
>>25G   70MPH-15.7 SQ.FT.
>>45G   70MPH-15.3 SQ.FT.  
>>OR
>>100 FOOT TALL
>>25G   70MPH-15.0 SQ.FT.
>>45G   70MPH-14.2 SQ.FT.
>>
>>Interesting that at 70MPH ratings the 25G has higher SQ.FT. ratings.  Go
>to
>>90MPH & 45G is better as we expect.  But there's no question the 45G wider
>>leg spacing adds stability when you climb'um.  
>>
>>73  Robert W5AJ
>>
>>PS:  if you don't have your ROHN book, call Steve & get one!
>
>Hi Robert,
>
>There are a few important details you did not mention regarding you 25 vs
>45
>comparison above.  Both 25G towers have 3 sets of guys while both 45G
>towers
>have only 2 sets.  Both 25G towers have the top set of guys attached only 5
>feet below the top of the tower while both 45G towers have the tops set 15
>feet below the top of the tower.  If you just used the same guying on the
>45G towers that is shown on the 25G towers, it would make a huge
>difference.
>So it was not a simple case of 25 vs 45 but also a comparison of 2 sets of
>guys vs 3 sets.
>
>You have to realize that the configurations shown in the Rohn book are only
>a few of the hundreds of possible configurations you might use.  As soon as
>you deviate from the Rohn examples, though, it is time to get a PE involved
>to make sure the changes you propose are safe.
>
>Stan  w7ni@teleport.com


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