It sounds to me like this WR-300 is fried or has the notorious "death screech" that the version 4 and 5 WR-100s, and WR-300s share. Basically it's a problem where some sort of radio receiver within the radio dies and renders the radio completely useless for warning purposes. The antenna should still be able to be easily removed from the radio by unscrewing the outside shell and removing whatever screw holds the antenna assembly down, as that can be used on another radio, and I'd harvest any other parts from the old thing you can. But as for repairing it it's not economical or possible I dont think, you would be better off buying a WR-400 if you want a "deluxe" radio like the WR-300.