If the unit is no longer under warranty, I would take the plastic dome off to make sure that the dish is moving properly on both axis and to be certain that the coax to the LNB has not come loose. Otherwise, do you know somebody that you can borrow a portable dish and receiver from so that you can determine which component is causing the problem. Swapping out one component at a time can narrow down the problem. Be sure to check your coax as well. A kink in the coax can reduce the signal to the point that the receiver can't see it.