Ditto on the battery. Note that the Raystar is not an antenna, it is a self-contained GPS receiver. Much older Raymarine gear used an external antenna, pretty much obsolete now. If the battery option doesn't pan out, you can use a Digital Yacht 160. It is NMEA so some changes will be necessary. You can still connect it to the SeaTalk via a converter, but it will be more money. Another option is to connect it to your MFD's NMEA IN port, and configure the DY160 to the correct baud rate, and make sure your MFD NMEA IN port is enabled. Your baud rate will be dictated by the MFD's NMEA IN configuration. If you have other SeaTalk connected devices, the MFD you connect the GPS to should handle the conversion of the NMEA data to ST and propagate it to the ST buss/network. Caveat that the MFD must be powered up to get the data to the ST buss. If you have multiple devices that use the GPS data via ST, a converter may be a better choice, it all depends on how your ST network is configured. It's not likely going to be plug n play, so be prepared to do some manual study. On the upside, the new technology is more accurate, faster position acquisition and updating. If you change the electronics in the future, the DY160 will still be compatible with any device that uses NMEA.