Aftermarket Antenna for Raymarine Chartplotter??
It depends. I'm not familiar with your plotter, but typically, GPS antennas are active requiring power to an amplifier inside the antenna. It's usually 5vdc and can be measured across the center pin & shield of the coax connector. If you have multiple wires instead of coax antenna cable, yours will probably encompass the GPS antenna and receiver. The GPS data is sent to the plotter in this case in some format, possibly NMEA. Again, I'm not familiar with what you have.