Sorry for the lack of response, but it looks like you have the job done well. For the benefit of others, the cable that is used with our GPS antennas is a Japanese metric spec (RG10) which is not available in the US. You can use RG58 (50 ohm) cable to extend to a max length of 30 meters (~100 feet). It is not the exact size of the RG10, but it'll work if you use the TNC & barrel connectors that are available in the US. The important part is to ensure continuity with the cable shielding (see picture below). Also, waterproofing at the connection points is a good idea to help ensure the cable integrity. Furuno USA does sell the Japanese spec TNC connector, barrel connector and extension for a GPS antenna. The extension is 15 meters (part number 001-173-110-10) which has a TNC connector on both ends. One end connects directly to the GPS processor and the other end will need a barrel connector to connect to the existing GPS antenna cable's TNC connector (part number TNC-FML-FML). If the connector on your GPS antenna cable is bad, it can be replaced with a new TNC connector (part number 000-133-186).