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Re: [TowerTalk] Solid center conductor LMR400 for crankup tower?

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Subject: Re: [TowerTalk] Solid center conductor LMR400 for crankup tower?
From: "Barry Merrill, W5GN" <>
Date: Thu, 27 Oct 2011 00:11:19 -0500
List-post: <">>
Don't expect the arms to keep the cable cluster from being blown
into the telescoping tower sections, if you tarry a bit and don't
start lowering the tower before the storm arrives.

Early on, I used the standard US Tower arms on my HDBX 72 to 
"stand off" the cluster of three coax and two rotator cables,
but as soon as the tower was lowered just a few feet, the 
slack in the cable cluster would be dancing all around when
the wind got to only 20 or 25 mph.

Several times, I found I had to stop lowering the tower after
Mr. North Gust had pushed that slack loop INTO the tower;
sometimes I'd have to raise the tower to tighten up the cable
and thus to pull the slack "loop" out of the tower, and then
I had to wait-for/hope-for a Mr. South Gust to come along to 
push the cable away from the tower sections, as it was stiff
enough to have some memory, and only then, could I restart
the lowering.  And then, sometimes along would come an unwanted
Mr East, pushing a lower section of cable into the tower from
a different direction.

After the last and most harrowing experience, where the wind 
was pushing 60 mph and it took a long time to get the tower
down, I gave up on using the standoffs, and simply tied three 
rope lines to the center of each section of the cable cluster.

Now, when the tower is up, the cable cluster hangs from the only 
remaining arm, at the top.  The cable cluster hangs down to 15 feet
and then has a drip loop back up to 20 feet, and then the cable
cluster goes horizontal to the shack.

Then, when I lower the tower, I can pull individual tension as
needed on each of those three rope lines that are tied to the cable
cluster at those three points, and I can thus keep the cable cluster 
out of the tower while it lowers.

I also mounted three pulleys for those rope lines at 20 feet and
ran those three lines thru those pulleys. When the tower is down, 
I can pull up those lines thru their pulleys, and keep the entire
cable cluster hanging off the ground, the weight on those three lines. 

And, I had much earlier given up on using the installed remote 
raising/lowering feature of the tower, even though it was way cool 
to flip the $1000 remote switch on, and then step out onto the porch
of the second floor radio shack, and watch the tower, about 85 feet
away, begin to lower. Kewl it was, to be remote, but only until the 
first time when it abruptly stopped lowering, with a dull bang from
the vicinity of the tower base, but I was too far away to have any idea
of the source of the noise or what happened.
  (Attempt to restart failed, no power, as the circuit breaker was the 
   bang. Reset breaker, retried at the tower base, and could hear the
   motor whine and see it stall and then heard the circuit breaker bang.

So I decided it was wise to ALWAYS be at the base and to ALWAYS manually 
control AND ALWAYS WATCH the lowering and raising of the tower, from the
base of the tower.


Barry, W5GN 


-----Original Message-----
[] On Behalf Of W0MU Mike Fatchett
Sent: Wednesday, October 26, 2011 9:12 PM
Subject: Re: [TowerTalk] Solid center conductor LMR400 for crankup tower?

I don't think using a solid conductor on crank up is a good idea.  I don't
believe the cable was designed for those types of applications.


J6/W0MU November 21 - December 1 2011 CQ WW DX CW
W0MU-1 CC Cluster

On 10/26/2011 7:58 PM, krishna kanakasapapathi wrote:
> Howdie folks,
>    I am installing the DB18 on a 75ft crankup. Have a roll of LMR400, 
> the solid center conductor type.
>    I thought i might just ask before i cut the cable from the roll. 
> Any possible issues with
>     using the LMR400 on a crankup?
>    I have arms mounted on each of the 3 sections to keep the cables 
> away from the telescoping sections.
> 73s
> krish
> w4vku
> _______________________________________________
> _______________________________________________
> TowerTalk mailing list

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