Audio Systems: Out of ordinary ! PLEASE HELP !, dc brushless motor, antenna cable

Question
I spend multiple hours each day inside the cab of a Kubota tractor. I have installed a Pioneer AM/FM/CD . Everything works great except the AM.  AM works reasonably well until I turn on the A/C  fan. Then the fan noise is so bad I can't make out what is being said on the radio.[By fan noise I mean noise comming through radio.]I have tried grounding the antenna. Also tried grounding radio at firewall.AM works well when fan not running but signal seems weak.  Nothing seems to help. Any suggestions ?   THANKS !!

Answer
Bruce,
Try running a seperate shielded wire directly to the battery for the stereo power. Also install some DC motor filters on the wires going into the fan. The fan motor is a DC motor that most likely uses brushes and thats where the noise is coming from. If the fan motor is a motor with brushes you may want to replace it with a DC brushless motor, plus move the antenna cable/wire as far as possible away from the fan motor.

TOM,
T&D ELECTRONICS
[email protected]