Stan,
Please get on line and look at the Rohn specs for a base for a bracketed 25G
tower http://www.rohnnet.com/bracketed and then follow the recommended
guidelines from Rohn. Rohn specs call for an SB25G5 base in a 30" square or
30" round X 48" reinforced concrete pier. Also note that the Rohn specs do
not give safe maximum wind load data for a 40 foot high 25G tower with only
one (1) wall bracket.
73,
Marsh, KA5M
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Stan
Labinsky Jr.
Sent: Monday, July 29, 2013 8:52 PM
To: Tower Talk
Subject: [TowerTalk] Questions from the unwashed on a small project.
Gentlemen, ladies, I'm in the process of repairing my standalone garage
(replacing some of the Dutch Lap siding and of course, painting) to use as
the upper support (by wall bracketing) for about 40 ft of 25G.
Rohn says that 40 ft of it can stand unguyed, but probably with not too much
of an antenna.
My plans are for a TA-33 and maybe a smaller six meter beam above it. Would
stand thirty feet above the roofline.
The upper bracket would attach to the tower just below the first to second
section joint. I've drawn up a bracket made out of Unistrut, which to me,
looks to be more substantial than the factory offering for far less cost.
If curious, I can attach a jpg of it to a follow-on note, just don't know if
the reflector will pass it.
Question(s):
I have the choice of using a base plate (all this courtesy of an SK estate
sale) listed in the catalog as the BCP25G, but planning rest it on the
ground with an 8 foot ground rod set as the pier pin. I know that
galvanized on earth is not a good plan and would probably coat it with some
sort of undercoating as a protectant.
Or, I can build another wall bracket and attach the lower end of the tower
to the wall as well, set at about a 1/2 foot above ground level, the tower
legs setting on some concrete pavers.
My concern would be, using only option two, that the two point leverage
against the wall might be excessive where using just the pier pin and upper
support would put less twisting stress on the wall.
Or, I could use both at the tower bottom, but see that as over-kill...
either-or. Also, suggestions on an on-earth undercoat for the base?
Thoughts anyone?
Stan
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