The Rohn Catalog that I received on Mar 15, 1968 says that a 40' 25G tower
calls for a 2' x 2' x 4' deep reinforced concrete base that contains 4 #6
vertical bars and 4 #3 horizontal lateral ties (each tie bar is bent into a
square that surrounds the 4 vertical bars), all bars contained withing the
concrete, guyed in three directions at the 20' and 40' level and tied to
concrete anchors 3' x 3' x 1', reinforced on the top and near sides with
1/2" rebar maximum 12" on center with the bottom of the anchor 3' below the
surface of the ground and 35' from the base of the tower.
Then the catalog shows an SDB25G single drive-in base that has one spike out
the bottom that appears to be maybe 24" long that is driven into the
ground - no concrete, and a note that says "towers mounted on these bases
must be bracketed or guyed at all times, etc". Further there is a note that
"The extra strength of the No. 25G allows it to be self-supporting provided
a house bracket is used and can go 35 feet above this bracket under normal
conditions, etc"
That said, I presently have 45 feet of 25G planted in a 3' x 3' x 3'
concrete block, no guy wires, and a large TV antenna on top (this has
survived an 85mph microburst). At a previous location I had 45 feet of 25G
in a 2' x 2' x 5' concrete block guyed three ways (3" dia screw-in anchors,
no concrete) at the 40 foot level that supported a Hygain 204BA. And I
climbed both towers and felt secure.
I would be very comfortable installing an h.f. antenna on my 45 foot TV
tower - AFTER I installed guy wires at the 40 foot level.
An ounce of guy wire is worth a ton of concrete in my book.
de Paul, W8AEF
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ZF2TA FO8DX FO0PLA 8Q7AA XZ0A
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----- Original Message -----
From: "David Cook" <wa0ttn@netdave.com>
To: <towertalk@contesting.com>
Sent: Tuesday, June 24, 2003 12:12 AM
Subject: [TowerTalk] Rohn 25G installation basics
> Hi, I'm a newcomer to this group and am looking for some basic information
> on putting up a Rohn 25G tower that I inherited from a retiring ham. I've
> looked on Rohn's Web site and it doesn't appear that they provide much in
> the way of customer support for these little towers. I've searched the
> TowerTalk archives, and haven't found a specific answer yet, so I thought
> I'd go ahead and just ask.
>
> I have a 10 foot section and a 9 foot top section. I bought a replacement
> SBH25G hinged base section and am thinking about adding another 10 foot
> section to the whole assembly. The fellow who owned this had the SBH25G in
> what appears to be about a 1 1/2 foot by 2 foot footing and the tower was
> free-standing. Unfortunately, he didn't have any original specifications
> from Rohn as to the requirements for his configuration or, of course, what
I
> would like to put up with the extra section.
>
> So, I'm wondering a) does Rohn make this information available anymore, or
> b) recommendations from the group on how big the footing should be. If the
> additional 10 foot section might mean that guys are required (antenna is a
> Hy-Gain TH3-Mk3), I can live with that.
>
> Thanks in advance for any guidance.
>
> -- Dave, WA0TTN
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