In a message dated 3/29/2001 04:38:25 Eastern Standard Time, email@example.com
> WE HAVE LOST during last 20 years more than 40 tips on 10m. We have had
> various designs, stepping, material... We have used plain elements, closed
> tips, end of tips with some weight- screw... open tips, ropes inside, even
> Copper stranded conductor in PVC (better experience compared to rope inside
> since it is less susceptible to ice and is heavier than the ROPE).
...and others mentioned 10m element problems.
If the tips are being lost, this would indicate that tip is vibrating, the
last piece of tubing would vibrate from the mounting point on, last clamp to
the tip. (Rest of the element can contribute to "tuning" of the tips too.)
The maximum amplitude would be at the end (tip) of the tip, this is where
dampening will be most effective.
I would try to put some sand (granules or similar consistence material)
inside of tubing towards the tip, maybe one-third from the end, seal it with
plugs and make sure that there is a room for sand to "jump" inside, I would
say no more sand than about one-third of space (volume).
something like this:
(last third of the tip)
| . . . . . . . . . . . |
| : : : : : : : : : : : : : : : : |
plug sand plug
The other alternative might to use type of little "flag" made out of tape,
rope or soft wire attached to the tips. Flag's flapping in the wind would
counteract the vibration of the element tip (different resonant frequency).
They just have to be made to last.
Variation of this is to add little extra wind loads, something like ping-pong
balls, this would add some extra wind load when windy, that would dampend the
It is always easier (cheaper) to bring the antenna down and try to get rid of
vibration (while it is still intact) as soon as they are observed, rather
than after elements fall off. They eventually will, it is a matter of time
(number of cycles) I CAN GUARANTEE that. :-(
I have not tried the above (my antennas behave :-) but my logic tells me that
it should work (no software used :-). Also liquid would work, just make sure
it doesn't freeze (use antifreeze like Slivovica, Becherovka, Vodka, etc.:-)
It is important to remember that we need to have a mass present at the
critical point that has different resonant frequency than the offender or is
completely "wild" and will "jump" at a different beat than the offender and
break his rhythm when he (she, it) wants to vibrate.