I learned the hard way that when they say that a HAM-IV type bell
housing rotor should never be anything but right-side-up, they aren't
kidding. I'd just had one rebuilt by Norms Rotor Repair in preparation
for putting up my new SteppIR. I folded my Rohn tiltover down and went
ahead and mounted the "new" rotor. This means the rotor would be
upside-down which I knew wasn't recommended, so I covered it with a
couple of plastic bags for a few days. My tower helper and I both had
to be out of town the next weekend, but I didn't give it a thought since
I figured there was no way anything could happen. Wrong! When I did
a final test of the rotor before mounting the antenna I had no direction
indication. One side of the feedback position pot showed open circuit.
Worse, when I removed the rotor and turned it over, water ran out -
evidently my precautions were insufficient. In the inverted position
water will gather inside the "bell", resulting in an ohmic path to the
feedback pot. I don't know how the water got inside, but I have proof
it doesn't take much, or much time, for corrosion to ruin the wirewound pot.
Moral of my story - Never NEVER invert a bell housing rotor for any
period of time! This is one of those deals where you can only kick
yourself so many times! I do have to put in a plug and Thank You to
RotorNorm, who is going out of his way to help me get this squared-away.
73, Bob W9RAN
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