The manual for my Sirius docking station at home said to aim my antenna toward the sky over Minnesota. At certain times of the evening, it would start cutting out, so I tried to figure out why. There was some confusing information in online forums speculating why, then I found this image which illustrated my problem.
It's not one bird, it's three, and they're in a nifty elliptical orbit with a nice pivot over Canada. I aimed the antenna a little more directly north, and that fixed the problem.