[TowerTalk] Tramming help sought

[David Robbins K1TTT]

Well, either put something smooth on the edge of the top plate to let the
rope slide easier, or pull back toward the back stay anchor point.


David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://www.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://dxc.k1ttt.net
 

> -----Original Message-----
> From: Al, N6TA [mailto:n6ta at yahoo.com]
> Sent: Sunday, November 23, 2008 04:54
> To: towertalk at contesting.com
> Subject: [TowerTalk] Tramming help sought
> 
> I won't bore the readers with the usual retread questions.  Already did
> the reading etc. and lowered the old beam a month ago.  This is one on how
> to rig the haul line to pull up the 110 lb SteppIr yagi.
> 
> The tram line is to be rigged about 3 feet above the top on the Rohn 45
> tower which has a flat top plate.  The boom will be mounted right above
> the top plate.  The tram line is continuous in that it goes thru a pulley
> and down to a 'back stay point'.  Trying to allow the tram line some
> ability to move but direct most of the force down the mast to the rotor.
> 
> The beam will be hung from a sling that connects a pulley to the tram
> line.  The boom will hang about 18 inches below the tram line.  A
> tiller/torque arm will be attached 'behind' the boom, keeping the boom
> from rotating in two axes.
> The haul line is half inch polyester double braid and will be tied to the
> boom close to the CG point.  The bracket that holds the tram line above
> the tower top has a place for a pulley to be mounted for the haul line,
> probably attached with a snap link or shackle.  The question I have is how
> to rig the haul line's pulley such that I can  pull straight down and not
> have interference with the tower's top plate.  The bracket for the pulley
> is about 3 inches out from the mast and the tower needs about 9 inches
> clearance from the mast to go straight down without rubbing on the edge of
> the top plate.  I fear way too much friction if I allow this.  I lowered
> the prior beam this way and used the friction to advantage but do not want
> such issues when pulling up the new beam.
> If I rig the haul line pulley ( a CMI 2.375 inch 95% eff. rescue type)
> such that it is hanging out far enough to clear the top plate, I end up
> pulling sideways on the mast.
> 
> There must be a standard practice here but I have not yet read any
> postings about this detail.  I usually just 'go for it' and keep the
> fingers crossed.  I have way too many PhDs in the School of Hard Knocks
> and prefer to not get another....
> 
> If I can pull the beam up as far as it can get, to the haul line pulley, I
> plan to relax the tram line and let it settle the boom down where it will
> rest on the top plate until I can use other means to raise it the 6 inches
> to the boom to mast plate.
> Willing to call to talk about it.
> 
> Tnx in advance.
> Al
> N6TA
> 
> Yeah, I'm missing the CW test due to delay in getting this up.
> 
> 
> 
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