On 7/20/19 6:46 PM, john@kk9a.com wrote:
I used to have a 20m Hy-Gain beam in addition to my stack of homebrew
Yagi's. I used no rope and it shed element tips constantly. I am not a
mechanical engineer but I believe the tips break because they are made
from very thin walled tubing and are attached to a much stiffer swedged
aluminium tube instead of using a more gradual element taper.
Or it just happens to be a bad choice of relative mechanical resonant
frequencies - imagine if your dominant aeolian shaking is at 1 Hz, and
the tip happens to be resonant at 1 Hz. the main element might only be
moving a few tenths of an inch, but the high Q of the tip means it's
moving 10 inches.
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