SailNet Community banner
  • SailNet is a forum community dedicated to Sailing enthusiasts. Come join the discussion about sailing, modifications, classifieds, troubleshooting, repairs, reviews, maintenance, and more!

Does AIS require GPS input?

4K views 11 replies 4 participants last post by  night0wl 
#1 ·
Hi all,

I've recently picked up one of these ICOM MXA5000 receive only AIS units. Under $200 for a name brand like ICOM made me bite the bullet.

I'm not sitting here trying to wire everything up. I've got a the radio cabling handled...but now wondering what is the best way to wire to the Raymarine C80 plotter.

Would I simply take the Data Out (NMEA 0183 @ 38400 baud) to the plotter at the helm? Or do I also need to give the AIS a GPS data feed for it work properly (so from NMEA/Seatalk junction box, 1 nmea data feed to the AIS box input, then 1 output wire from AIS box to plotter).

My GPS is directly wired via seatalk to the plotter already, and is repeating down to the NMEA/Seatalk junction box I've got down below for the purposes of sending data to the laptop.
 
#2 ·
Quickly. For AIS you need to get GPS data to the AIS. Most transmit/receive units have a dedicated GPS as that is required by law. For your application a NMEA talker feed on your Chart Plotter goes to the AIS to give it GPS data presuming it did not come with a dedicated GPS. The output of the AIS goes to a high speed NMEA input on your chart plotter. Since you don't transmit you don't have the last feed, the heading data from the gyro-compass. This is not a required feed for a class B AIS.
 
#3 ·
Thats what I needed to hear. Also, since the AIS is connected to the radio, do I need to have a separate set of wires to the VHF for emergency/distress DSC button?

Last question, I purchased a length of 28gauge wire (6 in the bundle)...so is it possible to plug in 2 wires each to the NMEA out of the seatalk/nmea junction box...2 for the AIS, 2 for the VHF for emergency distress/DSC? Meaning can I plug multiple "listeners" to the NMEA out of the seatalk/nmea box.
 
#5 ·
Ok...progress. I dont have enough wire to finish the project tonight.

But I *think* I followed the instructions you gave. From my NMEA out on the Seatalk/Nmea box, I plugged in 2 wires in each the + and the - ports (So, 2 + and 2 -). Back at the nav station below, I took 1+ and 1- wire and hooked it into the ICOM M422 radio. *VERY* weird setup Icom has, with 1 single wire handling both nmea polarity wires. The wire in the core was for the + and the shielding was for the -. It took me hours to figure this out. Nevertheless, the result as follows:



I took the other + and other - and put them into the ICOM AIS unit. As I mentioned before, I dont have enough 28 gauge wire to run from the output of the AIS to the NMEA input (38400/high speed) on the plotter. Need to make a run to Boat Owners Warehouse or West Marine tomorrow to finish the job.

So, today's lesson was to *FINALLY* hook up my VHF for DSC distress which will broadcast my GPS location. Woo hoo...? :D
 
#8 ·
Hey,

You are correct that your AIS receiver does not need GPS data. Since you are not broadcasting AIS information, it doesn't need GPS. It will SEND the AIS data, which includes location information on a vessel (LAT/LONG, as well as COG, SOG), to another device, like a chart plotter. That plotter needs to have GPS information it can calculate CPA and other information.

Your ICOM DSC VHF radio SHOULD receive GPS data so that you can broadcast DSC alerts.

Barry
 
#10 ·
Well, its hooked up to get GPS and multiplex it back to the plotter. I guess there are now two routes for this data back to the plotter.

Got everything dry-fit today for AIS data to helm. Pretty neat, Beneteau or my dealer even included the NMEA cable to plotter (which I had bought an extra one of, not knowing it was prewired). That saved me $40 and having to fish wires down the pedestal. So, only now have to butt-splice/shrink tube the wiring connections and fish the wires to make it all clean.



 
#12 ·
So, the last part of this project had eluded me for some time....AIS at the nav station at my Laptop (Macbook running Parallels running Windows 7 running OpenCPN).

I was really enjoying the pre-work. Made my own serial cable about of components from Radio Shack until the Serial/USB converter cable arrived. Seemed straightforward enough. Pin 2 and Pin 5 to the female serial and then the USB/Serial to the Mac...and Win7 should take it from there.

After wiring everything up and playing in COM Port *HELL* for 4 hours...no love :(

At 12:40 AM...an epiphany. Female DB9 and DB25 pins are read *BACKWARDS*...right to left. I wont comment on the symbolism of that...but regardless. 2 pin swaps and *YES*!!!!

We have AIS at the nav station :)



I cannot *WAIT* to test this out in the Gulfstream.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top