I have my 60ft aluminum tower titled over, primarily to refurbish the Ham
II rotor on it. That completed, I started examining all else on the tower.
I have a 1/4 wave sloper (coax shield grounded to the tower) for 80m near
the top with a bunch of ferrites to choke off the outside of the coax for
RF. I noticed that two of the ferrite sleeves lt looks like they have
chunks melted out of them. Not cracked off, but about 1/2 inch deep. Looks
like melted. I first thought it might me from running power, but the most I
can put into the sloper is 1kw. So do I toss out the whole string of
ferrites thinking they have been overheated - probably by lightning? Or
does it really matter?
I also noticed that my mast to boom bracket (a cast aluminum hygain) had a
small chink that may have been burned off. Looks like an arc from the mast
to the antenna through the bracket. The top of the bracket looks like it
had a blow torch put to it. The 2 inch aluminum mast also hast a bunch of
odd looking indentations in it.
Apparently my ground is adequate, because the antenna SWR was fine (2
element homebrew yagii with homebrew hairpin match). Each tower leg is
connected to a ground rod.
Also - assuming lightning did al this, I am glad I am religious about
disconnecting the coax in the shack every day. I have not inspected the
1/sloper coax for damage yet. I guess I'll just check it with my analyzer.
I am surprised the rotor control box was not damaged, sine I never
disconnect it.
I never would have noticed all of this if the rotor had not quit working
(mechanical)
Lucky, Doug N4IJ (Oklahoma)
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