I star guy my Rohn 55g and Rohn 65g towers. Before adding the torque
assembly my Rohn 65 it did noticeably twist when rotating my 60' boom
antenna (this was prior to owning Green Heron controllers with a ramp) and
also twisted somewhat in the wind. It did not twist a damaging amount
however there is no harm to having a star guy. I also thought about what
happens with rotating towers. Certainly a 200 Rohn 45 or 55g must twist
considerably. I remember when K4JA's rotating AB105 tower started twisting
back and forth in heavy wind before breaking apart. I would assume that a
star guyed tower is less susceptible to destructive harmonic oscillation.
John KK9A
To: <towertalk@contesting.com>
Subject: [TowerTalk] Datasheet for Rohn TA-55
From: "Jim Thomson" <jim.thom@telus.net>
Date: Fri, 6 Jan 2017 09:32:18 -0800
## heres the part that I dont get. The 6 point guy system will reduce on
the
tower
where the..cue rack is installed... almost down to nothing. Is torque even
an
issue ?
## these rotating towers all use rings..and the typ 3 guy wires per
ring..are
attached to the
ring.... not to the tower. IE: There is nothing to stop the tower from
torquing at all !
The guy wires on the rotating towers just hold up and support the tower,
they
dont provide
any torque redux at all. Then folks install 188-220 ft tall rotating
tower
assys... with the
usual myriad of large HF yagis on them, typ with a 80m yagi at the very
top.
## meanwhile the rotor is at the very bottom, like on the K0XG setups.
The
tower appears
to me to be one big.... mother of all torque wrenches. The myriad of yagis
are
all bolted to
the same tower face too. How much to these rotating towers actually twist
in
high winds ???
## If twist is a non issue on a rotating tower, then why even mess with the
...cue-rack..aka
rohn TA55 assy at all ?? What am I missing here ?
Jim VE7RF
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