Eric..
If you've OCPN, some installed
charts, a
compass heading into the system and the BR24Radar_pi
plugin you can use either of Navico's scanners; BR24, 3G and 4G. (Lowrance and
Simrad are also
trade names for the same gadget.
There's also a OCPN plugin for the
Garmin 18(I think it's called that)
Good luck/Håkan (Using a BR24)