I had a recent bad experience with the Cushcraft XM-240. The present
manufacturer had changed the U channel design from the original when it was
made by the NH company. The original design ( according to the guy that
actually designed it) used a heat treated aluminum channel but the "new"
design uses a thinner channel formed from sheet in a brake ( not heat
treated).
Mine was of the newer design and the wind ( 40-50MPH gusts from the remnants
of Bob) tore the 1/4" hex head cap screw heads right through the U channel
on one side and left the element dangling. I called the manufacturer in MS
who said they had never heard of that failure but they sent me a new U
channel for free. I put large stainless fender washers under the heads of
the 1/4" cap screws this time to spread the stress out more and so far so
good. If I was to do it over I would replace the less rugged U channel with
something more like the original design.
If you want to see the pics email me directly aa1qd@arrl.net
Also if you plan on 1.5KW AM I would not use the stock balun as it is like
to fail with that much heating from what I've heard from other hams.
Dale
AA1QD
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