Thanks for the ideas, but this is a new subdivision (no trees), and the dish is mounted securely to my deck (no wobble).

I have a 510 and a 301 receiver connected to a Superdish. I had local channels added about a year ago and they've worked perfectly since then up until about a month ago. A situation developed where the 510 would lose signal when we changed channels. I called Dish and they determined the 510 was...