Pete,
My 402CD survived estimated 80-90 MPH winds from a small tornado.
I reinforced (double walled) the first section of each half element. I
also
put 6 inch wooden dowels in each end and a 12 inch dowel in the middle.
For your environment, it's probably worthwhile to double wall the middle
half of the boom with at least 0.58 wall and possibly even greater.
The XM240 uses a 2.5 inch boom that is much sturdier and is tripple
walled at the center. I'm not sure how long those pieces are. If the
middle piece is short, I would replace it with a piece that goes out to
the next joint.
The CC X7 seems to be a well built tribander. N4AR has an X9
at 90 ft at his cabin near the shore of Lake Superior on the northern
shore of the Upper Peninsula of Michigan, not far from where the
Edmond Fitzgerald went down. That has to be a TOUGH environment.
You may want to also consider a HD version of the C31XR or the
Bencher tribander.
I would add a second tribander at 40 ft, preferably rotatable from
EU to SA, or at least fixed at 60 degrees.
A pair of CC D3W WARC dipoles at 90 degrees to each other
at 60 ft would be a nice way to cover those 3 bands. You could
add non-conductive truss lines and perhaps double the inner piece
of tubing on each side.
Non-conductive guy lines would be a plus (such as fiberglass or
Philystran, with EHS for the bottom 10-20 ft. Otherwise, place
insulators as close to the tower as possible with additional
insulators every 10-12 ft for 2 or 3 short sections before going
to longer spaces. Any conductor over 12 ft long is NOT invisible
to HF, even if "non-resonant" in the bands of interest. The old
standards of 27 and 40 ft have resonances on 12 and 17M.
Tom N4KG
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