also , when he pushed the bar that supposedly switched from am to fm on his car radio , a station on a particular frequency groaned out indefinite muzak-type music , but this noise being transmitted to his car was filtered out , unscrambled , by the microphone-transmitter within his radio , so that whatever was said by those in his car at the time was picked up by his equipment and broadcast to the authorities ; but this one funky station playing away , no matter how loud , was not received by them and did not interfere at all ; the grid eliminated it .