AM radio static

IIRC.

There is a capasitor IN the alternator.
One on the coil
One on the radio
One on the IVR
one in the dist.

The one in the dist is there to protect the points from burning.

I suspect the one on the IVR is for the same.

The one in the Alternator, on the coil and on the radio would be for noise suppression.