I went up the tower yesterday to take down the Christmas
lights and noticed something disturbing. I happed to notice
that the boom to mast plate (stock 1/4" aluminum plate) on
my KLM 40M4 had stress cracks radiating out from the points
where the four clamps attach the plate to the mast. The
wind blows a lot here in the Mojave Desert and clearly the
stress of the large yagi has taken it's toll on the plate.
Fortunately I had planned to take down the beam soon anyway,
hopefully within the next few weeks. It should last a while
longer but it could have come down the hard way and perhaps
taken out the guys on the way down. There were no signs of
problems from the ground level and it was easy to overlook
even standing 2' underneath the beam on the tower.
Next time you're up the tower, take a careful and close look
at your boom to mast plates to make sure stress cracks
aren't developing. This was a first for me.
73, Bob K6ZZ
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