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Re: [TowerTalk] 30 foot Rohn 25G calculations

To: Gedas <w8bya@mchsi.com>, towertalk@contesting.com
Subject: Re: [TowerTalk] 30 foot Rohn 25G calculations
From: BC <bcarling@cfl.rr.com>
Date: Fri, 13 Feb 2015 1:33:36 +0000
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Constant winds? No we only had hurricanes come through here one year in 60 years
We don't get a lot of wind actually. Still I would rather be safe than sorry!
If we get 139 mph gusts a lot more will be moving out of place - like the fancy 
copper plated tin roofs 
that peeled off a fairly new college building near us when the hirricanes did 
come and I think we had no more than 95 - 105 mph winds. I am just guessing on 
that speed but it was not pretty. Looked like crumpled aluminum foil.

We DO get a lot of sunshine and warm weather though (grin!)

Best regards - Brian Carling, AF4K


>>> Universal Towers does not even give windload data for 140 MPH on their 
>>> web site (they provide spec's at 80, 100 and 110 MPH for the light duty 
>>> towers but nothing for the heavy duty models) but given the nearly 
>>> constant winds in Seminole County, FL, I would *never* trust one of 
>>> their towers as I've seen how badly their bolted connections "egg 
>>> out" after only a few years in the much more calm areas of the Great 
>>> Lakes region. 
>>> 
>>> 73, 
>>> 
>>>    ... Joe, W4TV 




---- Gedas <w8bya@mchsi.com> wrote: 
> It's fascinating how different people have had different experiences 
> with towers like Universal.
> 
> I have one short, light-duty tower (50') that I bought used over 30 
> years ago and it still looks and functions exactly like the day I bought 
> it.  I have changed it's configuration several times over the years 
> pulling apart sections, making the tower higher or shorter and changing 
> it's loading and I have yet to see any signs of egging in any section 
> whatsoever.
> 
> My two other towers (both 70' and the ones that use the three 30" HD 
> sections have also been configured and reconfigured multiple times over 
> the years.  I have owned one for about 12 years and one for about 20 
> years.  Neither tower (or any section) has shown any signs of egging.
> 
> I have had all kinds of antennas on all of them.....X7, XM240, 402CD, 
> small az-el EME array, an 11 elem Sumner HF yagi, all kinds of long boom 
> VHF stacks, rotatable 40m dipoles, etc, etc so I know they have had 
> plenty of opportunity to flex around and play in the wind esp here in 
> Indiana where we get crazy fricken wind storms all the time.
> 
> I am positive in my mind that if Brian were to use a pair of 30" HD 
> sections and a 2.5" steel mast that the completed structure will be 
> standing straight and true though all but the worse imaginable tornadoes 
> or hurricanes.  At that point every house around him will end up in 
> Kansas anyway so who cares.  I, like Don, would not hesitate to purchase 
> another Universal tower.
> 
> 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 5:38 PM, Joe Subich, W4TV wrote:
> >
> > I saw plenty of Heights and Universal towers that were egged out
> > during my time on Ohio.  Many of them had the bolts/nuts tightened
> > to the point that the legs were somewhat flattened but that did
> > not prevent "egging out".  I know one old timer in the Columbus
> > area who replaced towers twice within 10 years - both times because
> > they were so badly egged out that nobody would climb them to repair
> > antennas.
> >
> > Again after what I saw of those towers, I would not trust one here
> > in the higher/constant winds in Florida.  If I had to use a free-
> > standing tower here, it would be the biggest sections available
> > from AN Wireless or a properly engineered commercial - Rohn SSV,
> > Pirod (if they're still around), etc. - tower with bolted flanges.
> >
> > 73,
> >
> >   ... Joe, W4TV
> >
> >
> > On 2015-02-12 5:09 PM, n8de@thepoint.net wrote:
> >> Joe,
> >>
> >> The 'egging out' is usually caused by insufficient tightness in the
> >> original erection.
> >> Have had many (over eight) Universal towers since 1975, and only once
> >> did that factor into the situation ... my error is not retightening the
> >> bolts/nuts AFTER erection.
> >>
> >> Those 'light duty' towers are TV towers in my mind, and would never use
> >> one.
> >>
> >> 73
> >> Don
> >> N8DE
> >>
> >>
> >> Quoting "Joe Subich, W4TV" <lists@subich.com>:
> >>
> >>>
> >>> On 2015-02-12 2:00 PM, n8de@thepoint.net wrote:
> >>>>
> >>>> 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.
> >>>
> >>> While that may be true in Michigan where the wind requirements are not
> >>> particularly high (70 MPH rev F, 90 MPH Rev G), that may not be true in
> >>> Seminole County, Florida where the building requirements are for 140
> >>> MPH (139) wind speed.
> >>>
> >>> Note the force due to wind is *2.5 times higher* at 140 MPH than at
> >>> 90 MPH.  Directly comparing the allowable antenna in Rohn's example
> >>> designs for 90 and 130 MPH indicates the same tower will support
> >>> less than half as much antenna 1t 130 MPH as it will support at 90
> >>> MPH.
> >>>
> >>> Universal Towers does not even give windload data for 140 MPH on their
> >>> web site (they provide spec's at 80, 100 and 110 MPH for the light duty
> >>> towers but nothing for the heavy duty models) but given the nearly
> >>> constant winds in Seminole County, FL, I would *never* trust one of
> >>> their towers as I've seen how badly their bolted connections "egg
> >>> out" after only a few years in the much more calm areas of the Great
> >>> Lakes region.
> >>>
> >>> 73,
> >>>
> >>>    ... Joe, W4TV
> >>>
> >>>
> >>> On 2015-02-12 2:00 PM, n8de@thepoint.net wrote:
> >>>> 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@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@frontiernet.net> wrote:
> >>>>>>>
> >>>>>>>
> >>>>>>>> On Feb 12, 2015, at 9:58 10AM, bcarling@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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