Hop on one foot, light candles.. and pull the smart card out and re-insert it.
Try another reciever (if you have one in the house). If the other one has the same problem.. it's the dish. If not, it's either the reciever or the line to it. If your other reciever is working, swap them out and see if the same reciever is having trouble. If the problem is in the same room, it's either the dish or the line, if the problem goes to the other room, it's the reciever.
Check the dish to see if it's loose anywhere, the mast isn't level.. something to knock it out of alignment. Check the line, rusted connectors, burnt stingers, and kind of corrosion at all. If you have a switch, bypass it and see if that fixes it.
If you're at all uncomfortable with fixing this yourself, call Dish and tell the CSR's you found what your problem is and send someone out. You can usually get an appt within 2-3 days max.