Dish changed their broadcast frequency and that rendered most of the older Dish dome style antennas inoperable. You can call Winegard and ask them if your antenna is no longer usable with Dish. It is not a Winegard issue, it is an issue with ALL older dome style antennas and Dish Network. As you mentioned, DirecTV did not change there signal and your dome would still work with DirecTV (SD only, but no HD). You might be able to sell it to a DirecTV customer and get yourself one of the newer dome antennas that will work with the new Dish Network technology.
What I post is my 2 cents and nothing more. Please don't read anything into my post that's not there. If you disagree, that's OK.
Can't we all just get along?