Storm #2 over ON

This time the beast has been given a name: Andrea. She even makes watefalls run uphill. Last night was bad. Overnight the wind picked up speed. But this morning around 10.40 local time the sky turned black and there was a roaring noise. I went upstairs into the shack to look through the window and check the tower and antennas. My stomach turned upside down. Hail, rain, thunder and hurricaine-ish winds. The mast had turned another 90° and while noticing this, there was a strong gust that swang the yagi and dipole another 90° live as I was watching. Total offset from from the rotor’s controller position is now 270°.

Clearly the Create (type RC5-B3, the heavy duty model) rotator’s mounting flanges got somewhat loose so they lost grip on the 50 mm aluminum tube (10 mm wall thickness). I climbed the tower yesterday afternoon when storm #1 was gone. You can see the ‘skid marks’ of the mast’s tube wrubbing the clamps. Still the clamps have enough grip to rotate the antennas even in the wind. I’m kinda lucky the mast slipped in the rotator. If not the motor’s gears might have been destroyed. The problem is that to tighten the flanges again, the inner section of the tower needs to be cranked up. You cannot put a wrench on the bolts when the inner section is nested into the two outer sections.

As per OptiBeam’s directions, I have always turned the antenna’s elements into the wind so it’s the yagi’s boom that takes the wind load. This has never been a problem in the past. Until now. I draw two conclusions. First: this is one helluva storm with the strongest winds I have ever witnessed since moving in here in 2003. Second thought: once or twice a year when the tower is tilted over, I check and tighten all the bolts. But since installing the tower and antennas in October 2004, I have never touched the rotator clamp’s bolts (because they’re hard to reach, as mentioned above). So these bolts will now also be tightened when I do a checkup. I might as well buy a tube wrench for this.

ON7RU said that sometimes people put a bolt through the mast and the clamps to join them. This way the two can’t move relative to each other and the tube can’t slip on the rotator. I wonder if this is a good idea since the torque on the rotator might become very high.

Another thing that crossed my mind is that it would be handy if the rotator’s controller had an offset adjustment. That way I could readjust the bearing and calibrate north regardless of the potmeter’s position. The Green Heron controller has this function. But it’s an expensive piece of hardware while the original Create controller is working fine. And it doesn’t tighten the bolts either.

If 80-100 km/h wind gusts can do this (and other damage all over Belgium), I do not want to see what a real hurricaine or a tornado would do to our house and the antennas… The horror!

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