[TowerTalk] KLM 20M6 6 L 58' Boom

dan hearn dhearn@ix.netcom.com
Sun, 25 Nov 2001 07:15:16 -0800


Hi Jim: Tnx for the note. I used a 20M5 for many years in Dallas. It was
on a 85 ft self supporting tower. It had a low swr and good pattern
across the band. Some people have had trouble with the insulators at the
center of each element cracking. I did not. Maybe that is a function of
the local environment. The worst thing about the beam is the mechanics
of it.
1. Because of the gull wing tilt upward of the elements, it is top heavy
and when you raise it and try to attach it to the mast, it has a
ferocious desire to turn upside down. It takes 2 people to keep it
upright and I used a nylon strap wrench to hold it in place while
another guy bolted it to the mast. Possibly a tram lifting system would
help in this
2. The beam is mounted to the mast at the CG which is fine when no wind
is present. It is not balanced for wind forces and tends to put extra
torque force on the rotator. If I put it up again, I would still hang it
at the CG but would put a plate or PVC pipe extension on one end of the
boom to balance wind force. There have been articles in the journals on
how to do this.
3. I would think these problems would be exacerbated with the larger
20M6.
73, Dan 

Jim wrote:
> 
> Anyone on the list have any words of wisdom about the KLM-20M6     6 element
> 58' boom 20 meter
> monobander ?
> 
> I have one and am thinking of putting it up. It is about 15 years old and
> has only been up for 2 years. It has been stored for the rest of that time.
> Fortunately it has been stored out of the sunlight but has been outdoors all
> this time.
> 
> Aside from the usual cleanup, what else ?
> 
> Thanks and 73!
> Jim W7RY
> 
> w7ry@earthlink.net
> 
> List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
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