The maximum extension that can be used for a GXM 51 or GXM 52 audio cable

The audio cable that is included with the GXM 51 or GXM 52 is 6.1 meters (20 feet) in length. One side of this cable connects directly into the GXM antenna. The other side of this cable contains two male RCA connections designed to be connected in to an audio input on a boat's stereo system.

Garmin sells a 10-meter extension for vessels that need more distance to connect the GXM antenna properly. These extensions can be connected together if even more distance is needed. There is not a limit to how many extensions can be used for installation.