I have experienced radio interference from what I later learned was "sun spots" over the years. I do not now recall whether it was AM or FM or satellite radio or all three. As far as I know, none of that involved an EMP that hit earth.
In an EMP event, either nuclear or solar, how long before, during and after will it interfere with or completely knock out AM, FM and Satellite radio communications (assuming, perhaps falsely, that there will still be electric power). How about other radio signals - such as shortwave? Citizens Band? Walkie talkies? Police bands?