[TowerTalk] Plumbing a tower with a plumb bob
Jim Hoge
knowkode at verizon.net
Fri Jul 30 07:45:45 PDT 2010
The purpose of the water filled bucket is to dampen the movement of the plumb
bob. This does nothing for the effect of wind upon the plumb line. Given the
length of the line, the weight of the plumb bob, the drag of the line, and the
windspeed, there may be some effect on an accurate reading. I use a fishing line
such as Firewire for my plumbline. The Spectra line has almost no stretch and
the tensile strength is amazing for its diameter, reducing its wind
profile/drag. One cautionary note when working with this stuff, be very carefull
with it. Special knots are required and you do NOT want to tighten this stuff
with your hands and fingers. It will cut right through them.
As for the best method to plumb a tower, it employs the use of a pair of
theodolites, set 90* apart from each other, relative to the base of the tower.
73 and be safe,
Jim W5QM
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