Harold Lanfear
Well Known Member
Most FM or other car stereo components are chassis grounded, even if they have a separate ground wire. If you need to isolate a FM or other radio, most hardware stores carry flanged nylon bushing and either nylon or rubber washers. I bought some that fit an 8-32 screw which fit well in a hold made with a #5 drill.
Push the bushing in, put a washer on the other side and use a razor knife to trim the bushing to length. If you need to ensure other portions of the system don't touch metal, the plastic top of a coffee can (some are clear- you just have to teach your wife to like the 'right' coffee) will make very nice washers.
You can also buy nylon screws if strength isn't important, but the method above uses standard screws with full strength. Don't forget to test isolation with an ohmeter when done.
Push the bushing in, put a washer on the other side and use a razor knife to trim the bushing to length. If you need to ensure other portions of the system don't touch metal, the plastic top of a coffee can (some are clear- you just have to teach your wife to like the 'right' coffee) will make very nice washers.
You can also buy nylon screws if strength isn't important, but the method above uses standard screws with full strength. Don't forget to test isolation with an ohmeter when done.