[TowerTalk] yaesu rotator and aluminum mast

Robert Chudek - K0RC k0rc at citlink.net
Fri Mar 27 20:33:45 EDT 2015


FWIW...

I have the junior version G1000SDX rotator. I have a 2" diameter (1/4" 
wall) aluminum mast, 20 feet long. Ten feet is in the tower, ten feet 
sticking out. A TH-11DX is one foot above the apex (that has a thrust 
bearing), a 5-element 6m Cushcraft five feet above that, and a 17' 
Diamond 144/440 MHz vertical at the top. This is all held up on a 70' 
Universal self supporting aluminum tower (picture on QRZ - a 40m dipole 
is side mounted to the tower and does not turn with the mast).

I did not pin the mast. I was very careful to torque the U-bolts evenly 
as I tightened up the clam shell. Be aware you can easily snap those 
U-bots if you "strong arm" the tightening process. You also need to be 
careful to center the mast with the centerline of the rotator. Don't 
just "slap" these parts together!

My array has stayed in place for a decade or more. With that long mast 
(11 feet separating the rotator from the TH-11DX) and the flexibility of 
the tower, these apparently absorb the torsion that develops in the 
wind/rain  storms. At least that's my non-engineered thinking on the topic.

In the long run, I would rather the antenna slip on the mast than tear 
out the rotator drive train if something "must give" in the wind.

73 de Bob - KØRC in MN

------------------------------------------------------------------------
On 3/27/2015 7:08 PM, David Robbins wrote:
> I have never put the bolt through the mast.  I have had some big antennas
> slip in high winds but nothing has broken.
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt at arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Steve
> K7AWB
> Sent: Friday, March 27, 2015 23:47
> To: towertalk at contesting.com
> Subject: [TowerTalk] yaesu rotator and aluminum mast
>
> I have a new Yaesu rotator model  G-2800DXA   which I will put in my Rohn 25
>
> tower
> in a month or two.  The rotator comes with a pin to put through the mast (by
> drilling out a hole through the mast).  I know that would work in steel
> masts, but do you think the aluminum is too soft to use that requirement so
> should I not or  should I do it?
>
> I am looking for anyone who actually had to make that same decision and
> their consequences, if any.
>
> 73
>
> Steve Sala
> K7AWB
> DN17es
> Nine Mile Falls, WA
>
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