Thanks to all who provided input on this question!
Living in an area that gets a lot of ice and sticky snow, I am not a fan
of spiral wrapping anything around elements. I have observed that even
small hardware items such as a screw head on an element creates an area
that does not shed ice or snow nearly as well as a smooth element. I can
only imagine what would happen with a spiral wrap of material along the
whole element.
This is the only antenna I have had which seemed to have a vibration
problem. It was doing it on the other tower for years but seemed to be
only on rare occasions. After moving to a different tower at the same
height it was much worse. There must be something different about the
air flow or mechanical properties of the particular tower involved. I'm
going to get some cheap nylon or poly rope to put inside the elements
and see what happens.
Paul N1BUG
On 8/29/22 07:25, Paul N1BUG wrote:
I'm trying to get a better sense of how the rope in elements to stop
vibration thing works. I've read that it works because as the element
swings in one direction, the rope slams against the opposite side,
providing a counter-force. What confuses me is that I don't understand
how the rope is free to move around. Nylon or polypropylene seem to be
recommended but those ropes come coiled or folded and they have a memory
effect, so they don't lay flat. When put inside an element, they are
going to be pressing against it in multiple places and directions. It
seems like that would limit the rope's ability to move to do its job.
What am I missing? I have seen braided rope with extremely fine strands
that is soft and doesn't have the memory effect. Is that what I should
be using?
My 6 meter yagi was having a problem. The element tips were oscillating
at about a ~200 Hz rate, and the tips were moving at least two inches!
It took four trips up the tower to rig and get it down. It will take
another four climbs to put it back up, and more if it still has a
problem and needs to come down again. I'd like to try to get this right
on the first try to avoid all that extra climbing. The four foot center
section of each element is .750" OD, with .625" tips. Any practical tips
or experiences with similar elements would be appreciated.
Paul N1BUG
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