Thankyou very much. very quick a clear reply. You've saved me alot of pain already.
BTW, there is no such thing as an NMEA 0183 network. NMEA 0183 is a purely serial data feed, and the specification allows one talker device, like a GPS to be connected to FOUR listener devices.
No wonder NMEA 2000 had to be developed with there being so many electronics. Fortunately, you say NMEA 0183 GPS can be connected to max 4 listener devices. Perfect for my set up but why isn't it possible to connect to more than 4?
Without knowing what GPS Antenna (new) you have, it is hard to say what you can do with it.
Just 2 dumb GPS antennas I guess as they have only coaxial cables.
The actual GPS circuitry is in the unit connected to the antenna--probably the Comar AIS transponder.
I guess that means that if the transponder has an NMEA 0183 output possibility I could connect it to the device that splits it into 4? If not then I guess I will need a GPS like the garmin you mention because its only the GPS receiver that produces the NMEA 0183 output?
My plan with questions.
1) 2) Buy a GPS that has an NMEA 0183 output.
You mention garmin. I saw a secondhand furuno GP 30 & 31 . I'll have a read and see if they also product NMEA 0183 output.
2) Current transponder set up is ok . I'll ponder buying a 2nd VHF antenna for the rail but I think I will opt for the splitter simply for the greater range of a mast-top antenna (having said that the splitter is not cheap at all so not sure).
3) Regarding the device that splits NMEA 0183 GPS into 4, what is the device called ? the 4 listeners being my radar, VHF, navtex and autpilot.
4) I need to buy the plugs so that these things fit neatly together - output from GPS, input from my devices? It must better than soldering connections NMEA 0183 together. Again, any links to a good supplier with lots of these NMEA 0183 plug/box/wiring/options (just to set me on the right track - or again am I missing something here)?
The Icom M411, the Simrad TP-32, and probably the Furuno 1623 will have NMEA 0183 ports.
yes, lots of extra coloured wires.
Once again many thanks for advice and tips.