[TowerTalk] Rohn 45 top weak point

[Michael Wetzel]

Hi Rich,  

I think I which holes you are talking about-they are vent holes, so that if
water does get inside any leg it has a chance to get air to it and dry out,
just like there are holes at the bottom of the tower base in each leg to let
water out.

On my 45 tower with a stock top section and with guys just slightly above
the rotor (with a halfway big load on the mast) the winds here broke two top
sections for me.  The leg actually pulled away from the top plate after a
big windstorm!  It happened twice to me even after I moved the guys up a
little, so on the third time I bought a stock top section and had a plate
from the stock top section welded to it along with the z braces welded to
the top plate and it has held.  I think the stock tops also didn't have any
z braces in the last portion of the tower for some reason.

On the guying, it's a toss up- as you want the very top of the tower guyed
(biggest overturning moment) but you also want to have your torgue guys
close to the rotator to take the twist out of the tower (biggest twist at
the rotator)-I split the difference and put top guys about in the middle!

By the way I have over 30 sq. ft. on the top of my 140' tower that broke the
stock top sections.  Also this tower has the aluminum mast that I spoke of
earlier (sked 80 with 2" insert) tower broke, aluminum mast didn't take a set!

And I don't think a bolt would really do you any good through those holes.

73-Mike W9RE

At 06:13 PM 5/3/97 +0000, you wrote:
>
>I have two Rohn 45s up and notice that on the flat top section, just 
>below the top plate, there is a hole (bolt size) through each of the 
>three legs.  This certainly weakens the tower legs at that point.  In 
>fact, I have some serious metal fatigue on one of the three on one of the 
>towers.
>
>Like many people's installations, mine are guyed some feet down from the 
>very top.
>
>I'm wondering if a bolt through this hole or something else would improve 
>the situation.  That is, a bolt though each of the three holes.  ?
>
>73 - Rich Boyd, KE3Q


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