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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