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[TowerTalk] Re: Crankup tower limits

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Subject: [TowerTalk] Re: Crankup tower limits
From: zl1aih@ihug.co.nz (zl1aih@ihug.co.nz)
Date: Sun, 11 Nov 2001 21:22:00 +1300
Hi Barrie
I bought a 3rd-hand Triex H354 2 years ago.
Apart from routine maintenance - new raising cable, sheaves, 
re-galvanise base and rotator plates etc. all OK.   Antenna is 
Force 12 C3, rotator Ham M IV, mast 20', 10' inside, 10' 
above.
I fitted a heavy duty thrust bearing above the rotator for 
insurance - the sleeve at the top of the tower was a sloppy fit, 
and the Ham M IV was 30 years old - of course, I overhauled it 
before installation.
The tower has an electric winch - this has been added to the 
original manual winch - a good idea for the operator's safety, 
in that the operator can raise and lower the tower outside the 
radius of any falling debris from antennas if the raising cable 
fails for any reason.   Nothing special - just extend the power 
cable from the winch to a safe position - this lets you observe 
the situation, especially the slack guys as the tower is being 
raised.   
N.B.   I would not operate an electric winch while standing at 
the base of the tower.   If the raising cable fails, you'll have only 
your safety helmet to protect you.      A manual winch will at 
least let the operator know when there is a problem.   
When your tower is vertical but "nested", and accessible by 
ladder (I use light chain to secure the base of the ladder to the 
tower, and rope to lash the top of the ladder) you can attach 
the guys if it is a guyed tower.   I wear a safety belt at the top of 
the ladder - 20 feet is a long drop if you land on your head.

Having raised and lowered your tower for a test, you will no 
doubt have determined the overlap for each section of tower 
when fully raised.   My Tri-ex has safety stops, which must be 
placed in position from the ladder as each section is raised.
It is MOST important that the bottom section of tower is plumb.
      
tWhen raising, the top section comes out first - when just 
above final setting, the safety stops are placed in position. 
DO NOT REACH THROUGH THE TOWER TO PLACE 
THESE STOPS IN POSITION, OR FOR ANY OTHER 
REASON.   If you cant reach around the tower, climb down the 
ladder and set it on the other side.   A cable failure turns the 
tower into a guillotine - Steve LXC has warned us all many 
times about these hazards.
Assuming your tower has three sections, raise the first section 
to just above the point where you can insert the safety stops.
Then repeat for the second section and insert the safety stops. 
  Then, lower the tower until the raising cable slackens slightly.  
 If all is correct, each section of the tower should be resting on 
the safety stops, which is where it should be.    To the best of 
my knowledge, no crank-up tower should be held in position by 
the raising cable in tension.
If your tower does not have safety stops, seek help from a 
professional.
I am not a professional  - just 66 years old, and taught to be 
cautious.   If I'm careful with towers and lucky with genes, I'll 
enjoy a few more CW contests yet. HI

Good luck, and please take care,
73   Ken ZL1AIH          


 
From: "Barrie Smith" <barrie@centric.net>
Subject: [TowerTalk] Crank-up tower limits

I have a Telex Hy-gain HG-70HD crank-up tower installed with 
four
6M 7 element yagis on an H-Frame.  I have an electric winch
attached for raising and lowering.  The tower has been raised 
and
lowered from fully retracted to about 20 feet up, and then back
down.

Everything seems to run very smoothly, with no 
odd noises,
shudders, grinds or bumps.

I'd like to be able to raise the tower to it's full 
height, but I
don't know exactly what to look for as it approaches 
maximum
travel.

Does it just "stop"?  Could it bind at full extension?  
Anyone
have clues for the clueless?

TNX, Barrie, W7ALW


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