[TowerTalk] Vertical/Crank up questions

[Larry Esau]

> Hi Larry,
>
> That is _very_ good information.  And it is applicable to a
> number of lead dress for crank-ups threads that have appeared on
> towertalk over the last few years.  May I post your response to
> the reflector?  Many reflectees will probably be interested in
> your solution.


Sure.  Here are a couple more details:

My tower is a Triex LM-354.  The cable loop pulled from the base
is about 17 feet long when the tower is fully retracted.  Thus a
simple 1-pulley system works well on a 54-foot tower because the
height of the base section is 20 feet, and the pulley raising
cable moves up the side less than that distance and at the right
speed.

The 18-inch pulley I use is a plastic wheel rim from a small
bicycle.  It is smooth between the flanges and gentle on the
cable bundle.  I use a light-duty spring between the pulley
slider and the pulley raising cable as a safety device in case
the bundle snags or the pulley takes up the bundle at a slightly
different rate than the movement of the raising cable.

On a 71-foot tower the cable loop will be about 25 feet long
which is difficult to handle since it exceeds the height of the
base section.  Towers taller than 54 feet require multiple
pulleys to take up the longer loops of cable.

It works out that 54-55 foot and 89-foot towers (those with an
odd number of sections) make the best candidates for this system
because the retracted loop lengths are even multiples of the
movement of a single tower section.  The pulley raising cable
speed will be correct for a 1-pulley system on a 54-footer or a
3-pulley system on an 89-footer.

Taking the cable loop up vertically along the outside of the base
section makes for a compact system that can be enclosed with the
tower inside a protective fence or screen to protect people or
animals from the moving parts.

Best regards,

Larry AD6W.


			 --------------

I hope someone gest some useful ideas from Larry's solution to
this fairly common problem.

73, Eric  N7CL

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