I have a Dish Network satellite system with 3 tv’s on it. Why is it that 2 of the tv’s work fine but the 3rd set has an error screen and is always scannig for a satelite. I have a Dish 500. This satelite system was eyed in as far as the aiming of the dish as opposed to having it done with a meter. All 3 sets go out when its raining. TY for your response.