Are you saying the signals or images are weak and what does the static 'look like' on the screen? Is this a new setup or an older setup, and has your picture recently deteriorated or has it always been poor?
There could be a problem with the equipment or coaxial cable from the cable company to your home, your cable inside your walls might have a problem as might the 'jumper' cable from your wall socket to your TV set. There may be a cylindrical adapter on the back of your set called a balun, that connects the cable to two screws marked antenna: that unit may have failed or one of the screws might be loose. There could be internal problems with your old RCA.