I'm installing my new Raymarine C-80 system and the instructions say, "it is important that an effective RF ground is connected to the system. You can ground the DSM300 by connecting the drain wire of the power input cable to the boat's RF ground."<br />I assume RF stands for "radio frequency" but I have no idea where the RF ground is located. Any help would be appreciated.<br />Thanks,<br />Backlash