Cat5 cable for NMEA 0183?

[SY Cushla]

Is a LAN cable with the connectors cut off ok for connecting NMEA0183 signals over a 5m run? Is the wire thick enough?

[smac999]

it's very small and will be hard to connect. it's normally solid core too so easy to break.

I would find some ~20awg cable.

[thomm225]

Is the end point connection wire to wire or wire to USB?

My NMEA connects to a USB adapter at the VHF then USB cable to my computer.

If yours happened to be going to USB, you could get a 15' USB extension cable.

[GordMay]

Greetings and welcome aboard the CF, S/Y Cushia.

NMEA 0183 INSTALLATION AND OPERATING GUIDELINES
“8.2.2.2 Cable Type:
Interface cables, regardless of length, shall be composed of multi-conductor tinned shielded cable with a minimum 95 percent shielding. A twisted pair employing 22 AWG stranded wire shall be used for the NMEA 0183 data signals. NMEA 0183-HS requires a third conductor, which is used to ensure that the common mode ground potential is the same at all drivers and receivers.”
➥ https://www.navcen.uscg.gov/pdf/gmds...rce/nmea_7.pdf

[j.g.evans]

I replaced Reymarine instruments leaving the SeaTalk cables unused. They are great for NMEA 183. SeaTalk cables have red+yellow+shield wires that work well for transmit and receive NMEA 183. You need shield plus one wire for NMEA receive such as a GPS. Power has to be provided separately for NMEA doesn't have power. I have used the red wire for +5V to a GPS.

[duckpond49]

Raymarine has a 5m cable that should work for you. They use CAT5 cable with RJ45 connectors on the ends of their Radar Antenna to MFD displays.
They only use 4 of the 8 pins and also have a really fierce weatherproof coupler: Raymarine R32142 Waterproof Coupler.

Not as cheap as generic CAT5 stuff but definitely a seaworthy approach.

[Calaban-Alleria]

Originally Posted by SY Cushla

Is a LAN cable with the connectors cut off ok for connecting NMEA0183 signals over a 5m run? Is the wire thick enough?

CAT6 patch cords are available in different lengths and are stranded and shielded wire.

[Lake-Effect]

Originally Posted by SY Cushla

Is a LAN cable with the connectors cut off ok for connecting NMEA0183 signals over a 5m run? Is the wire thick enough?

NMEA0183 isn't very fussy about cable. And it certainly doesn't require 8 conductors (4 pairs).


Cat5 could work, but I would probably grab some shielded twisted pair, tinned & stranded, AWG20 to 24 gauge. Mainly because I have tons of it left over from my audio days.

[svfinlandia]

Originally Posted by Lake-Effect

NMEA0183 isn't very fussy about cable. And it certainly doesn't require 8 conductors (4 pairs).

Cat5 could work, but I would probably grab some shielded twisted pair, tinned & stranded, AWG20 to 24 gauge. Mainly because I have tons of it left over from my audio days.

+1
What ever engineer or standard motor never thought that cat5 cable would be good to use in a marine environment should have his head examined!

I have a cat5 cable in my system that I have to replace about every two years because it breaks due to bending and vibration. Solid wire of any type should not be used on a boat.

Al, S/V Finlandia

[andypag]

In terms of voltage drop over thin wire with nmea, it took me a day to diagnose this: the ais signal from the vhf split to 2 plotters, one at the end of signal wire that was too thin, combined to create an nmea signal that was less than 1v. Too low for one of the chart plotters to read. I ended up using a cheap multiplexer as a signal booster.

Not sure if the voltage drop came from the wire, the other chart plotter internal resistance, or a weak output from the vhf.

[Reefmagnet]

Cat 5 is fine. I'm running higher speed AIS NMEA0183 data through about 10 metres of the stuff back to my chartplotter at the helm via the bilge. I didn't even cut the RJ45 connectors off so it would be easy to replace in the future. I just grabbed a couple of double adapters (one a cheapo bog basic and one nearest the helm an actual waterproof outdoor style) used for inline cable joining and crimped RJ45's onto the ends of the NEMA leads to suit. I would suggest using stranded cable, which is what you will get if you buy a "patch lead" (aka Ethernet cable off the shelf). If you are doing the TX/RX thing, make sure you run each TX and RX down it's own twisted pair (share the common if a 3 wire with each pair). I did also "cheat" and liberally coated each rj45 connection with silicon grease to keep the moisture out. Works great!