Two points. First, NOWHERE was it stated that a hole should not be
drilled in the pole.
Second, the website stated that "These are extremely strong poles, with
a much greater wall thickness (up to 2mm!) than the usual "fishing rod"
types. A special reinforcing winding technique - several layers of
fiberglass are wound in alternating direction (criss/cross winding) -
provides greatly increased lateral and linear strength."
Glen, W6GJB, is a mechanical and aeronautical engineer recently retired
from the space program, and is an expert in the strength of materials,
how those materials are formulated, and how they are used. Glen is the
inventor of the Air Beam Tents used by the VK0EK DXpedition. They are
rapid deployment tents, and were designed for use by the military.
Another area of Glen's expertise is parachutes -- he's one of the guys
who knows how to catch stuff returning from space. Glen carefully
studied the pole after it broke and found that it was NOT constructed as
described above, that there were not "criss/cross windings." If there
had been, the pole would not have broken because the hole would not have
weakened it. He measured the pole thickness as 1.75 mm.
As to the poles on DXpeditions -- within the last year, I attended a
presentation by a major DXpedition who had used these poles, and saw
photographs that clearly showed that the poles had broken in the wind.
73, Jim K9YC
On Sun,11/6/2016 1:06 AM, rick@dj0ip.de wrote:
Jim broke the cardinal rule when he erected the antenna:
He drilled a hole near the bottom of the pole and it broke at the hole.
NEVER DRILL A HOLE in these poles.
_______________________________________________
TenTec mailing list
TenTec@contesting.com
http://lists.contesting.com/mailman/listinfo/tentec
|