Mac-
I had a 40' tall Rohn 25 supporting my 2-element cubical quad for many years.
No guy wires. Survived 75 mph gusts. It had a house bracket under the eaves.
If your soil is a problem you might be able to put in a "mat foundation" which
spreads the weight horizontally instead of going down into the earth. That
would depend on how much room you have next to the house foundation for the mat.
73,
Steve
N6SJ
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
WT4BT-Barclay Thomas
Sent: Tuesday, September 13, 2016 1:09 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Bracketed but Unguyed Monopole
My aim: Vertical support for a Hexbeam at about 30-35 feet.
Space for guys is severely limited by property lines, trees and other
structures I cannot use a lattice type tower for several reasons.
Ground here is clay over ledge/bedrock and only 18 - 24 inches deep so anchors
may be marginal without rock drilling.
I am in a 70 mph wind zone (90 mph @ 30 sec. gust zone) here on the Cumberland
Plateau in So. Central TN.
What I am thinking of:
Mast system like the Penninger Radio “Tipper” 35 foot using 2” x 0.25” (rather
than the stock 0.125") wall tubing (8’,10’ or 12’ sections) which would be
bracketed to the shack building (separate from the main house) at about the
10-12 foot level.
Yaesu G-450, or similar, rotator at top of mast turning a Hexbeam with maybe a
6 meter short-boom yagi (3-5 elements).
There would be 1 or 2 pulleys below the rotator for inverted V or L antennas
and “experimental wires” as the mood strikes.
Base of mast would be in concrete (TC-24 concrete base mount) but the amount
poured might be sub-optimal (can go somewhat wide but not deep).
As noted above, guying will be a compromise situation.
Due to roof overhang on main house bracketing to it, or trying to mount a
shorter mast off the face of a dormer is not a strong option. Roof mount a la
Glenn Martin is possible but the roof pitch is greater than 12 in 12 so getting
up there to do any work is not an option for me.
Questions:
Can I get away with the top 25 or so feet of mast being unsupported (unguyed)?
Are there any other suggestions or thoughts for doing what I want?
Different mast or tubing suppliers?
Mac / WT4BT
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