I would like to share my experience with a tree mounted A3S yagi. I had a
tree that had been topped due to some sort of disease that had killed the
top portion of the tree. I was advised to cut the bad portion off and
maybe the tree would survive. It has for almost 20 years.
I built an angle iron frame to hold a Ham-M rotator and used all thread to
bolt it to the side of the tree. The frame has a mast bearing of sorts at
the top. I used some kind of unknown plastic made for its low friction.
The Mount has never come loose. I think thats due to the tree growth
although it has not really gotten much larger at the rotator. It has been
up there for about 15 years with no problems at all.
I assembled the antenna on the mast at the top of the tree. I assembled
the elements and marked positons, hauled them up thru the tree and put the
reflector on, moved the boom so I could put the director on and then
mounted it and put the driven element on. Easy to do with the small A3S.
One thing does happen, the tree will grow upward and requires some trimming
so the antenna will still turn.
The antenna is at about 35 ft and works pretty well. Better on 10 and 15
than 20. And it has kind of proven a point to me that a low yagi is a good
thing to have for 10 and 15. I agree with Steve K7LXC that trees are
better than metal towers under a yagi.
I will be moving soon and am going to try it again on another taller tree
which coincidentally also has upper damage from an ice storm.
The new tree will be a tougher climb as its a Spruce. Original was Cedar
which is much more friendly.
73 Jim KI7Y
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