[TowerTalk] Crankup tower safety question... (Crankup Danger!)

Fri Aug 2 00:42:36 EDT 2013

This is why I like motorized towers like LM-470 with a positive pull down
system.  I experienced your problem first hand and managed to catch it in
time, that sudden jerk on the cable probably exceeded the cable rating by
ten times which is why it snapped.

Mike/K6BR

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of Larry
Sent: Thursday, August 01, 2013 7:03 PM
To: TowerTalk at contesting.com
Subject: Re: [TowerTalk] Crankup tower safety question... (Crankup Danger!)

I had one collapse vertically during a storm while I was at the base and it
is scary. I just sensed it was collapsing and took off across the backyard
covering the distance in not too many steps and not much time.

So what happened? It was a 75 foot(+/-) EZ-Way tower which had 3 sections. I
was trying to lower the tower. The top section became slightly cocked and
hung up. I realized that and as I tried to crank it back up to put tension
on the cable again but the wind pushed the top section enough for it to drop
with the cable slightly loose. It snapped the cable for the top section and
the middle section. I forget exactly what happened to the tower but it was
bent a bit at the bottom and a welder was able to fix it. The KT34XA 3 inch
boom was bent on one side at 45 degrees and one element was bent.

73, Larry  W6NWS
-----Original Message-----
From: Mike
Sent: Thursday, August 01, 2013 9:10 PM
To: 'EZ Rhino' ; 'Mickey Baker'
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Crankup tower safety question... (Crankup Danger!)

I have been around a long time and had a few crank up towers, I have never
had one come down or known anyone to have one collapse.  There is a huge
safety factor built in with the cables.  If it is looked after and inspected
on a regular basis why would the cable snap?

The trouble with a locking mechanism as you suggest would be also prone to
failure and maybe in a more dramatic way, I am sure you would be pretty
unhappy if a 100mph wind blew up and the solenoids controlling the locking
mechanism failed because of a power failure or other reasons and your tower
blew over on someone's house!  I have seen plenty of solenoid systems fail
from weather etc. because they were locked in place and never exercised.

The more simple you keep a winching system the easier it will be to maintain
and less to go wrong.

When you erected a crank up tower you also inherit a responsibility to
maintain it which includes inspecting and lubricating the cables, maybe you
do know of crank up towers cables that have failed, but I bet it was due to
deferred maintenance and not because the cable just snapped.

Mike/K6BR

-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces at contesting.com] On Behalf Of EZ
Rhino
Sent: Thursday, August 01, 2013 5:21 PM
To: Mickey Baker
Cc: towertalk at contesting.com
Subject: Re: [TowerTalk] Crankup tower safety question... (Crankup Danger!)

There was a discussion on this topic a couple weeks ago, check the archives.
I think it comes down to the bean-counters.  Of course something *could* be
done.   If hams want to pay for it is another discussion!

Chris
KF7P

On Aug 1, 2013, at 18:13 , Mickey Baker wrote:

Patrick, AF5CK's thread on his tower raised an issue that I really don't
understand...

Why isn't there a "lock" mechanism on crank up towers?

We spend lots of money on these things, and, basically, they hang there
suspended by a single cable. We all have either known someone or have had
our own tower's cable (or winch) fail and the tower crashes, with great
damage to tower and antennas.

I could thing of a number of gadgets that could be made to work:

  - A solenoid locking bolt
  - A brake mechanism (Electronically controlled?)
  - Stops every few feet requiring a raise then lower like a safety ladder.

But here I am, about to step off into yet another $10k tower project with
another tower hanging by a cable. (I feel like Homer Simpson - Doh!)

I realize that the market is small and price sensitive for these towers, but
certainly this has been recognized as a problem.

Isn't there a better way? If there is, and I can implement it, I'd do so,
simply for the purpose of making the tower safer for me and my antennas.

Thoughts?

--
Mickey Baker, N4MB
Fort Lauderdale, FL
*"Tell me, and I will listen. Show me, and I will understand. Involve me,
and I will learn." *Teton Lakota, American Indian Saying.
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