What does the screen look like when the channel goes out? It does sound like someone is broadcasting and I have seen that get in threw the back of the set. Set a DVR (at their TV) to record that channel at 5:30. If the problem shows up on the recording then its in your system. If the recording is clean then most likely it's the set.
God is great, beer is good, and people are crazy.
This is CABL.com posting #345975. Tiny Link: cabl.co/mbCap