Update: Antenna Rotator

For my first nontechnical article in probably a year, I had to do some repair on the antenna rotator. I am prepping for this weekend’s favorable EME conditions - hopefully I have another nontechnical post on the contacts we make!

The Background

Weather Forecast for this Week

I noticed that my rotator’s azimuth only had about a 30 degree range of 53-79 degrees. The moon was at about an 88 degree azimuth, so I was just barely unable to reach it. After an inspection of the cable, I saw no tears or snags. This meant it was either a software or internal issue: loading the rotator software on my computer didn’t change rotation in any capacity. So our OIC and I marched up to the roof, in 8 degree windchill, to unscrew the case.

The Diagnosis

Unscrewing the case showed us the grease-laden rotator assembly. You can clearly see the issue - the entire gear is covered in ice. The limit switch (right) stops when it hits one of the screws in the center circular slots. However, the switch just clears the gear well, which is frozen solid with 2cm of ice.

The Solution

Flathead, engaged!

I had to icepick the gear for about 20 minutes to clear the ice from the well. A quick brush with my glove, and a couple blows, and the gear was as good as new. It went from 157 to 150 degrees clockwise - well within the parameters I need it to operate.

Hopefully I can update this post with some EME contacts from the upcoming weekend!