Soon be installing AIS
and a multiplexor, connecting to a chartplotter
Have a few questions regarding the shield wire on the NMEA cables
1) From various bits of research
, the shield wire should only be grounded at the talker end of the circuit, this is to avoid ground loops (there will be a question on ground loops later)
2) Will it be OK to connect all the shield wires to a common connection point, say a bus bar, or a copper strip?
3) If item (2) is OK, where do I connect the common ground point to. Is it OK to ground to the engine
block, or can it be connected to the battery
return cable at the switch panel
4) The multiplexor, this will be a listener and a talker. The NMEA plug
on the chart plotter contains both input and output NMEA pairs, plus a shield wire. I assume that the shield wire in the plug
somehow is grounded through the plotter. The multiplexor will receive NMEA from the chartplotter
at a baud rate of 38,400, then converts that to 4800 baud rate so I can get NMEA data to DSC
. Should I ground the shield wire of the cable from the multiplexors 4800 output port?
5) What problems do ground loops cause, I donít want to make a ground loop, just interested in what havoc it can cause.
I want to keep the present system for the time being, so please, no suggestions to bin it, or sell it, and fit a N2K system or similar, thanks