Losing picture & sound on Locals - DirecTV DVR

For Losing picture & sound on Locals, relating to DirecTV DVRs and receivers. I have the H20 reciever & 5LNB dish. Started having problems first day & night with locals. Picture scrambles partially and sound goes out for a few seconds. Called customer no-service and got the usual answer "That happens sometimes" so I went on roof and checked dish. Out of approximately 10 bolts holding dish in place, 70% of bolts were finger tight and half of those were not even finger tight. Dish post could easily be moved in one direction about 2 inches. Bubble in mast was more outside the circle than inside. I moved mast and retightened so bubble was in circle. Most transponders went from 70-80 to 45-55 so I readjusted ele. and az. slightly to regain 70-80 signal but still have same problem on locals. When I check website for dish settings for my zip they are 10-12 degrees off from the actual dish setting. My thoughts are that the dish is not aimed correctly but I'm 63 yrs. old and don't need to go back on that roof again. Could someone give me some suggestions?