channels switching by itself - DirecTV

Have standard receiver in bedroom. Will be watching TV and channel will switch to another (usually church or infomercials). Sometimes it will switch back by itself. Other times it has to be reset. Sometimes it works, sometimes not. Was watching ID channel, it switched to infomercial, reset it, infomercial came back on. Changed channel and nothing comes on. Reset again, now stuck on searching for signal screen. Went to 771 signal loss. Is it the box or cables? Never happens on HD/DVR in living room.