I've had a T2X in an HDBX 48 for 30 y. It turns a 2" diameter, 1/16"
wall chrome-moly mast. There are 8' of mast above the thrust bearing
holding (from top to bottom) a 40-CD2, a WD3, and KL-KT34A (a bit over
12 sq ft). Yes, the 40 CD2 should be at the top, but... The T2X manual
says the rotator will hold up to a 2 1/16" mast. To use a 2" mast
requires a single 1/32" shim in the V of the mast mount on the rotator.
I use 1/32" aluminum sheet from the hobby shop. I've have ALWAYS pinned
the mast in the rotator and have never had an issue with it. My system
has survived gusts up to a measured 86 MPH (I have an anemometer on the
tower). That's not to say I'll *never* have a problem, simply that I
haven't yet.
But, I'll also assure you that with as short a distance from the rotator
to the thrust bearing as I have, that 1/32" shim makes the difference
between a very long rotator life and a service life of about 2 y. I know
from experience! If, however, a thrust bearing isn't used and, instead,
a tube through which the mast slips (instead of a thrust bearing), no
shim is necessary.
Kim N5OP
On 12/30/2018 9:41 AM, john@kk9a.com wrote:
I never understood the popularity of 2" masts. Going smaller that 2" gives
even less strength and less surface grip. I do not own a Hy-Gain rotator but
the way I remember them is they have a metal plate the pushed the mast into
the casting V. To center his mast he would need a 3/32 thick shim. What
material is the shim and does it cover the entire clamping area? Can the
metal clamp plate bend and not allow sufficient tightening? Perhaps
something like Tennadyne slip-nott http://www.tennadyne.com/slipp_nott.htm
could be manufactured for his 1 7/8 mast. Perhaps there is a Stauff clamp
that size. There is also the pinning option but that brings a lot of
controversy - FWIW, I pinned my P40A Ø2 1/2 aluminum masts in to my Yaesu
G-2800 DXA rotators per the manufacturer's instructions and never had an
issue in that windy environment.
73,
John KK9A
Richard Smith n6kt wrote:
A buddy of mine is using a T2X rotor with a 1 7/8" OD chromoly mast. He has
about 13.5 sq ft of antenna surface area attached to the mast, which is well
below the rating of 20 sq ft. The T2X is 10' below a thrust bearing.
The mast has been slipping from time to time (windy conditions), and he was
wondering if something can be done to stop the slippage. I have been using
the K7NV clamp on my Orion 2800's that are clamped to 2" chromoly masts, but
I don't see anything on Kurt's website for a T2X.
Has anyone here on the Reflector had a similar experience and come up with a
good solution?
Thanks, 73, Rich, N6KT
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--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
/"In theory there is no difference between theory and practice. But, in
practice, there is." //– Attributed to many people; it’s so true that it
doesn’t matter who said it./
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