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Proper Connection Technique for NMEA 0183 Wires

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I have a AIS enabled VHF that I want to connect to a Raymarine E7 MFD. The MFD comes with combined Power/Video/NMEA 0183 cable. The AIS signal comes out of the VHF on NMEA 0183.

I currently have the NMEA cables attached to a NMEA 0183 to USB adapter (http://www.nolandeng.com/catalog/product_info.php?products_id=42) so that I can get the AIS on OpenCPN on my computer. I connected the NMEA 0183 cable coming out of the VHF to the adapter using the gel filled snap connectors (Klein Tools VDV826-604 Splice Connector - IDC UY - https://smile.amazon.com/gp/product/B008EAK2L0/ref=oh_aui_detailpage_o01_s02?ie=UTF8&psc=1). These were easy to use and appear to have done a good job. However, I'd like to keep the USB connection available and run the AIS to my new chartplotter as well, so I'll need to split the NMEA 0183 wiring, as well as extend the wiring from the VHF down below to the helm (about a 25ft run).

My question is three fold.

1) What is the best way to connect these very small NMEA 0183 wires? Do normal type ring and fork terminals work (assuming I get the right size - 24 to 26 AWG?)? Should I add solder to the crimped terminal?

2) What is the NMEA 0183 wire - (Data Cable? Comms Cable? just regular wire?). Should it always be twisted and shielded?

3) Related to question 2. It appear the cable marked as NMEA 0183 is pretty expensive. For the long run from VHF to Helm, can I just get generic 24 AWG? Or is there a cheaper version of "NMEA 0183" cable that is appropriate for data transfer, but doesn't carry the marketed for marine electronics premium out there?

Thank you very much!

3 Replies

  • "Best way" is always a bit of a loaded definition, but a gas tight joint is essential, crimp can do that, crimp and solder is better, Heat shrink over the crimp is more better still.

    NMEA 0183 is relatively low speed (less than 1MHz) data rate and thus not requiring particularly high standard cables, but as always better is better. NMEA 2000 and Ethernet on board are higher speed, lower signal levels and more susceptible to interference. You can break any/all of these out on a terminal strip, doing so in a shielded, sealed environment is preferred to minimize interference and corrosion issues.

    All marine cable should be twisted and tinned, that's part of what you are paying for is the vibration and corrosion resistance.

    Having said that, you can use CAT-5. Just realize that the reliability is less. You pays your money and takes your choice.

  • Here are some official guidelines for NMEA 0183 cabling published by the USCG (and probably derived from NMEA install standards):

    http://www.navcen.uscg.gov/pdf/gmdss/taskforce/nmea_7.pdf

    Soldering is frowned upon, I believe, and most pros seem to use crimped ring connectors with built-in shrink sealing:

    http://www.pbase.com/mainecruising/wire_termination

    Protecting it all with a plastic box seems to be good practice and cable strain relief is a must given those skinny wires:

    http://www.thehulltruth.com/marine-electronics-forum/117086-making-nmea-wire-connections.html#b

    All that said, I still like 3M ScotchLok connectors for skinny wires and they have held up fine in the install I described here:

    https://www.panbo.com/archives/2013/12/3m_scotchloks_is_my_love_so_wrong.html

  • Thank you both for your responses. I looked at the data cable in the pigtail supplied by Raymarine, and it actually looks like it's either not stranded or has be "solder-tinned" (I didnt' cut it to see if the solid wire characteristic continued under the wire jacket).

    Thanks for the link to Compass Marine How-to. He has great stuff and I should have known to look there as well. In fact he did a whole write up on exactly my question - terminating small wires http://www.pbase.com/mainecruising/terminating_small_wires&page=1

    He provides make and model numbers for the tools and ring terminals he uses and explains (as he always does) very clearly what he deems the appropriate method for doing a good job.

    Ben, what is the contents page for the USCG guidelines. The NMEA section make reference to using barrier strips as outlined in section 2 on AC/DC wiring, but was having a hard time finding the actual page to access the other sections of the guidelines.

    I agree with you that the 3M Scotchlocks were simple and effective.]

    Thanks again!