Searching For Satellite (771)

For the last two nights, I have been unable to view channels 202 or 265 due to Searching For Satellite.  Those were the ONLY channels affected (Yes, I scrolled through all of them.)  A restart took care of the problem each time, but natually the DVR records what it sees.

Why would only 2 channels be affected and how can I prevent it in the future?  There have been no storms or wind or children playing with the cables.