thought my tv was going out

i am having problems with one of my recievers, its not the reciever itself cause i tried another one out of the house and still had the problem....thought it was the cable from the tv to the cable box so i replaced that but still having the problem...the pic will be fine for one minute but anything to make a movement in the house and the pic will flicker.....what could this be could it be my wires in the attic that is the only thing i didnt check.....