I recently noticed that my '87 Spoiler was picking up radio interference when the volume knob was above 3/4.  You can hear either local radio or tv in the background.  I have tried several amp and cord combinations to no avail. Thus I assume it is the bass.  Any thoughts, suggestions, etc.

Mmmmm ...I am a technical moron but I know defenitely that this issue has been discussed before. We have a tall wise greyhaired wizzard around here with Gandalf looks -we call him  Moder Dave- and he can dig up anything you want from the dark grey area's way back from the beginning of this club. It has to do with placing a kind of tube-shaped thing into you electronics department -well ...that of your bass of course- and ...oh well ...you'll see ...he'll be here quich enough!
 
Paul the bad one

Hi Lee;
 
As Paul suggested, it sounds like your bass does not have the ferrite bead.  There is a FAQ here.