Maybe I don't understand, but how can you have a rotator at the base of a
crank-up tower?
k7puc
----- Original Message -----
From: "W4LDE-Ron" <w4lde@cfl.rr.com>
To: "TowerTalk" <towertalk@contesting.com>
Sent: Saturday, August 25, 2007 8:18 AM
Subject: [TowerTalk] Tower choices
I have recently written a contract on a new home, 2.5-acre lot with lots
of trees, and as part of the contract the builder gets to install the
tower base plus the pour and conduits back to the house plus clear an
area for a new tower/beam.
My plans are for a SteppIR 3 element with a wind load rating of 6.5 sq
ft plus a small 4 - element two-meter beam. The home area is rated at
70MPH wind speed.
My dilemma is what tower to use? Due to age and other conditions I will
need a tilt over crank up. I also want a neighborhood friendly tower if
that’s possible. All CCR issues have been resolved.
My first thought has been the U.S. Tower model MA-550 with the
freestanding self-supporting base model MARB-550 that allows for the
rotor at the base and the tilt over unit MAF-550.
Second tower to be considered is the Tashijan TM-358 tower with the
rotor cage at the top since I do not think they make a base rotor mount
option. The WEB site is lacking in information and I am not sure what
tilt over device is available if any.
Third and last is the Heights Tower crank up aluminum 42 ft at a wind
load of 12 sq' at 80 MPH.
My only experience is with a guyed Rohn 25G 40' tower and what I will
greatly appreciate any feed back on is!
1. With the rotor at the base, as in the U.S. tower MARB; will the
rotation torque be amplified? I assume there's a thrush bearing at or
near the base?
2. Will the sway be reduced since the rotor is not at the top? With tile
over I can still service the rotor and not need the base rotor assembly
3. How bad is the sway with the tubular type towers in general?
4. With a rotor gage at the top of either the U.S. Tower or the Tashijan
doesn't this add to the wind load ratings and how do I calculate that load?
5. It appears that the U.S. tower has a thrust bearing for the base
mounted rotor? The others will require added cost? Guess the thrust
bearing gets mounted in the rotor gage for the Tashijan or shelf on the
Heights model
6. Can I expect noise form any of the three above in the cranked up
position. What has been your experience with noise?
7. What have you experienced with delivery time and support from the
manufacturer? I will need the base assembly on site near the end of this
year.
Last and final question, if you were to buy a new tower with a desired
height of around 45 feet and be neighbor friendly what would you buy?
You thoughts and recommendations are greatly appreciated.
73 de
Ron W4LDE
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