I used the HyGain supplied polypro rope in 2x TH7DX which survived
several New England hurricanes. It's pretty difficult to estimate what
wind conditions will excite a vibration and the mutual mechanical
coupling of elements is very complicated. A vertical of 3" irrigation
pipe which I guyed at 50% and 100% was a perfect mechanical resonator
(my bad) and failed at the 50% point from fatigue. So if your antenna
is "singing" it is only time until fatigue wins. There is no lower
limit of stress in aluminum which eliminates fatigue. In steel there is.
SteppIR uses a clever end cap scheme for the elements. The caps are
notched to let water out and a small piece of open cell foam is inside
to keep the bugs out. It is a PITA to find hornets in the boom while on
the tower. My A4S had solid caps on the boom and I was quite surprised
by the boom weight and slosh from it being filled with water when trying
to put it on the tram - not good!
Grant KZ1W
On 6/21/2017 7:22 AM, David Aslin G3WGN wrote:
Mindful of Steve's 'Prime Directive' which suggests I absolutely should use the
dampening rope in my recently acquired used 155CA, what is the experience of
the TowerTalkian brains trust of the need for the rope in a 155BA/CA at a
relatively exposed site?
73, David G3WGN M6O
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