During the last month, we have experienced complete signal loss to varying degrees. We had a tech come out who blamed it on trees. The trees are over 40 years old and the dish has been there for over 3. There have been days with no issues, but for the last week or so we are back to having recordings and certain channels lose signal...120, 154, and 162 are particulary problematic...switching channels sometimes causes it, but then it lets go as long as I stay away from those 3 channels. Does anyone have an idea what could be causing this?