Thanks for all the advice. Let me fill in some more details. The radio
is OEM in a 95 Jeep Grand Cherokee Limited. It has some sort of
amplified output and an electric antenna. The problem has been more
progressive than sudden. Only affects reception when the car is 'on'
(running or key in the on position). The antenna is original, and the
connection to the radio appears good. Something else not grounded and
giving off static is a possibility...would have to be something that
powers up just with the 'on' switch, not just when running (may
eliminate alternator). If it is a 'ground leak,' might that explain how
sometimes fiddling with an electric switch seems to reduce the static?
Maybe the other switch grounds some of the static causing emission? Not
really knowledgeable about electronics.