If FM broadcasts are interfering with your TV signal, an FM Trap may be the answer.  This filter is designed to attenuate the entire FM band.

In-Line FM TrapIn-line notch filter provides significant reduction in interference in cable television systems caused by strong FM radio stations. Simply connect in line between the source and television set or cable box. Bi-directional filter can be connected in either direction. Input and output connections are both "F" type female.