Muttnik, Thanks but way beyond my abilities or interests but could be an interesting project
Hakan, the GPS is no problem, I have a USB GPS puck
which works fine. My understanding is that a GPS feed is not required for the radar only display and that a compass is only required for a radar image overlay on charts, hence my question about using a null background (or the world map as you suggest) in order to have a simple radar display backup (with GPS disconnected?).
The way the Simrad documentation
for the chartplotter is written, one can view the radar OR chart display individually, but a radar overlay on the charts requires a compass/sensor.
So the GS25 would work directly with the Simrad NSS display to provide radar overlay on charts on the plotter but without the NMEA 2000
to NMEA 0183/USB converter this overlay would not work on a laptop running OCPN.
In a backup scenario:
- with a dead chartplotter I would use OCPN.
- with a dead compass/sensor I would switch between these two views on the plotter or the OCPN laptop (no overlay).
- with a dead GPS antenna
on the plotter I would use the GPS puck
on OCPN for charts and the plotter screen
- with a dead radar unit I would use either the chartplotter or OCPN for location and my foghorn!
Anyway, it would be interesting to confirm my assumptions about how all the pieces work together for various functionality. Except for the compass/sensor the components of the OCPN based backup are likely to already exist for most users for everything except radar overlay on charts (assuming a stand alone radar display is possible) so maybe that is good enough. A Chart/Radar split screen or switching display might be an interesting enhancement. US electronic charts are free but Canadian electronic charts are now at 600$CAN for a regional chartbook so the OCPN backup can get expensive for sailing Canadian waters.
Of course there is always the Navionics
charts (US and Canada) on a tablet for 17$ per year and paper charts as the ultimate backups but no radar.
What do you think ?