Has anyone on the list attempted to wind torque balance
a KLM KT34XA? I just went thru the numbers and my
calculations show that the KT34XA should be a great
weather vane. The factory specs show that the boom-to-mast
connection is about 20" inches behind the physical center
of the boom. Presumeably this is done to compensate for the
fact that most of weight from the elements is concentrated
towards the back-end of the antenna boom.
My calculations show that the torque balance is decent
if the wind is blowing at 45 degrees relative to the line of
the boom, since the wind induced torque from longer section
of boom forward of the mast balances pretty well with the wind
induced torque of the large element surface area that is
concentrated rearward of the mast. When the wind is
blowing perpendicular to the boom, however, there is quite a
large imbalance due to the 20" offset between the mast clamp
and the physical center of the boom. The antenna is at
a club station, so pointing it into the wind is not an option
(most of the time nobody is around).
http://www.its.caltech.edu/~w6ue/Spalding/Spalding_Stack_5a.jpg
I am planning on pinning the mast that holds this thing
to the OR-2800 rotator this weekend (I am tired of it
windmilling in the rotator mast clamp and wrapping the
coax around the mast), but I am concerned that unless I
properly wind torque balance the KT34XA, I am going to
end up finding the next weakest link in the system (rotator
parts for instance) the next time the Santa Ana winds
blow hard here.
Anyone been around the block with this thing?
Thanks and 73,
Mike, W4EF..................
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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