[TowerTalk] Latteral load capability of T2X in mast mounted

Jeff AC0C keepwalking188 at ac0c.com
Sat Jul 22 22:41:03 EDT 2017

Sorry for the confusion.  Not contesting at all.  This is just a temporary 
set up to let me check pattern & SWR before mounting it up on a separate 
permanent tower mount.  The rotor would be on some sort of little stub stuck 
to the top of the crank-up tower, and the mast above the top of the rotor 
extends about a foot or so to accommodate the entire boom/mast mount. 
Minimal distances in both above/below rotor cases.


-----Original Message----- 
From: john at kk9a.com
Sent: Sunday, July 23, 2017 4:50 AM
To: towertalk at contesting.com
Subject: Re: [TowerTalk] Latteral load capability of T2X in mast mounted

By testing purposes maybe he means conTESTING purposes where a rotator would
be very useful:)

I agree that is a lot of bending moment on the rotator lifting it up,
especially if the mast is long. With any crank-up I have always installed
the antenna after the tower was vertical but cranked down.  Being low and
with no obstructions below it is really quite easy to do.

John KK9A

To: <towertalk at contesting.com>, "Jeff Blaine" <jeff at ac0c.com>,
"Jeff Blaine" <Jeff.Blaine at epak.com>
Subject: [TowerTalk] Latteral load capability of T2X in mast mounted
From: "Jim Thomson" <jim.thom at telus.net>
Date: Sat, 22 Jul 2017 01:20:14 -0700

###  With 200 lbs much above the T2x, the bending moment on the rotor assy
will be massive.   Think of it as a big TQ wrench.  2 ft X 200 lbs = 400 ft
labs.  Do you really require the rotor  for the testing application ?   What

might work easier,
is to just use 1-2 bearings in the top of the tower,  with a short piece of
mast above the tower.    Then the mast is free to rotate 360 degs.   Mount
yagi onto the mast, as close to the top of the tower as you can.  Then with
some rope onto
the boom, say at the end of the boom, or towards the  end of the boom.
in the upright position, you will be able to orient the yagi in whatever
direction you want.  Then raise the tower to desired height, and increase
on rope of course.
We did just this at several past field day events, on both crank up, and
guyed towers.   Walk with rope in hand to desired yagi azimuth heading, then

tie down the rope.    No need for a rotor  for a temp set up.

##  The real trick will be.... with the tower in horz position, mounting the

yagi onto the mast.   The eles of the yagi cant be 90 degs to the mast,  or
tips will be embedded into the dirt.  Eles will have to be inline with the
tower.   If the els are really long, like a 30M yagi, then you also have to
worry about the nested height of the tower  vs  one half of the 30M ele
  Once tower is moved to the vert position, somebody is gonna have to go up
there, then rotate the boom clamp assy, by 90 degs so the eles are parallel
the dirt.

Jim   VE7RF


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