My System (receiver )has been freezing up alot in the past 2 weeks.I have to reset receiver at least once every few days(today it happenned twice).What could be the causes,there are no obstructions with my dish.Today it just froze on History International channel and last night on Biography channel.Should I call dish and have them come check out dish and receiver.I have DHPP so that not a problem ,but what is best way to describe issue