More layers mean a larger arm from the axis of the drum. The more
layers, the more force it take on the input for the same pull on the cable.
As for supporting coax on any tower, not just crank-ups you want to
avoid sharp bends. Sharp bends mean the dielectric ends up supporting a
major portion of the weight leading to center conductor migration off
center even with solid dielectrics although they are much more
resistant. Devices as shown through links work well. I prefer an arc
or sweep made of EMT conduit. I'm partial to permanently adhering the
coax through the whole arc with epoxy, It makes the shield and jacket
support more of the load.
Depending on the coax and tower height, there should be "support turns"
every so often along the height. Crank up towers make this approach a
bit problematic although it can be done. Like many "fixes", Where there
is a will there is a way!
73
Roger (K8RI)
On 6/4/2015 10:51 PM, Don W7WLL wrote:
Fulton, as I recollect, advised me that a minimum of 5 to 8 wraps on
the drum (not a full layer) is recommended to remain at full cable pay
out. I was also advised to NOT have more cable on the winch drum than
needed to accomplish the job. More layers add more needed pulling
power. Ask Fulton, they are very responsive. I have K1550's on both of
my 70 and 51 foot crankups and the 70 foot tiltover fixture. I use a
K1250 on the 51 foot tiltover fixture. But, one may feel more
comfortable with more cable and bigger winches.
There was also some earlier discussion on this reflector about how to
support hanging coax. Those of you who had an interest should read
K2STN's paper on a great rope trick using the old whipping technique.
I use this method for supporting wire antenna coax's and when I was
using a G5RV as a portable antenna I used it between the ladderline
and coax to take the load off the xmfr. Simple, cheap and works great.
Don W7WLL
-----Original Message----- From: Tony
Sent: Thursday, June 04, 2015 12:07 PM
To: towertalk@contesting.com
Subject: [TowerTalk] Fulton K1550 / K2550 Swap: Cable Question
All:
I recently replaced the Fulton K1550 winch on my U.S. Tower rasing
fixture with a Fulton K2550. It was a direct swap so I didn't have to
modify mounting plate.
My only concern is that the wider spool of the K2550 has 2 layers of
cable on it so it will be down to last layer when the tower is tilted
over.
Although most of the last layer will still be on the spool, I need to be
sure that it provides enough grip to safely lower and raise the tower.
The K1550 had 3 1/2 layers to work with.
So should I leave it as is or buy a longer cable?
Tony
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73
Roger (K8RI)
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