ais problem

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gwizz

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I've bought a NASA AIS plotter but it cant seem to receive the necessary signal from my GPS so is not a lot of good at the moment. The NMEA output is from my Raytheon RC320 gps and this feeds my Raymarine 215E dsc radio fine, the gps has nmea +ve and -ve output wires. The Nasa seems to have three output wire;s red, black and blue. Red and black are for an external buzzer and only the blue is supposed to be for the nmea input. I've tried the other two wires thinking they may be common -ves but still no signal is being received. anybody got any ideas? the manual is useless (or I am)
 
I rewired mine this w/e.

Blue wire takes the NMEA signal from the GPS (4800 baud).
I seem to remember that the black acts as a common ground whilst the red is the NMEA 38400 out (to the PC / Plotter etc)

I think - when I first did it - I had to connect the GPS NMEA -ve to the common ground (i.e. black wire) to work

Also - how are you testing it ? Are you sure the application is setup to use the GPS - perhaps should check this first ! e.g. ship plotter optionally uses a GPS feed - it can be set to come as part of the AIS data or from a separate feed - i.e. another coms port on the PC.

You could always use the built in Windows tool - hyper terminal - make sure you set coms port correctly and baud rate to 38400 - you should then see NMEA strings containing AIS data - but also NMEA LatLong strings

HTH
James
 
Sounds as though this is a plotter rather than an engine, then it takes NMEA from the GPS at 4800 baud.

Don't get confused with an AIS engine which will output NMEA AIS sentences at 3800 baud to a plotter.

Have a search around on how to connect NMEA. It must be commonest question on this forum.
 
Try and connect to the AIS engine with your PC and Hyperterminal and see if anything arrives.... and set the comport to 38400 as this is the NMEA AIS speed.
 
I have the same problem at the moment. Fixed up my AIS engine yesterday, then wired it exactly the same as the one i saw on demo, which is straight forward.
So far i can see nothing that tells me it's working. Got bored with pushing buttons today, so try again tomorrow.
 
This is a NASA plotter with (i assume) a built in engine. I don't see how i can connect it to a PC as there is no serial or usb output, just these three damned wires? - let me know how you get on Mick and I''l get on to NASA helpdesk.
 
Got mine up and running OK today. Had to reset the plotter.

Mine is the stand alone AIS, linked into a Standard Horizon.

What three wires are giving you the problem?
 
I have just installed a NASA GPS repeater which also requires a GPS output and has the same three wires. I assume the connection will be the same:

Red: +ve power supply
Black: -ve common supply AND -ve NMEA output
Blue: +ve NMEA output

This worked first time for me - hope it helps

Jonny
 
The one i have just fitted is the Nasa AIS Engine for connecting to my plotter or PC. Handy piece of kit.
 
Hello

Just fitted the same unit. I had to connect all three red black and blue to the gps nmea cable before it worked. Also the com output has to be set up for nmea sentence and on my garmin 276 I also had to turn off the additional functionality.

It took me all day to work it out!!

Cheers

Lee
 
Thanks all - I phoned NASA who were helpful, unlike their manual, and they affirmed Johnny -H's method, I'll try it at the weekend and report back.
 
I got a new problem today. Having just fitted my new Horizon GPS plotter and coupled it to my AIS engine, got it all working fine.
Today i fitted my radio, connected all the NMEA wires as per the book. Switched everything on and there was no info being transmitted from the GPS back to the radio.
AIS was OK. Sat down and re-read the books, everything was wired correct...scratched head?? OK, i disconnected the AIS leads, Hey presto! the radio was now accepting all the GPS info.

As far as i got today, it seems that i can't run the AIS and the radio together, either it's the AIS or the radio but not both??

Now all i have to do is find out why/what NMEA wires i need to swap around, as i am sure that i should be able to run all three units together + more if required.
The book only shows wiring up one item, nothing about adding other units. /forums/images/graemlins/confused.gif /forums/images/graemlins/confused.gif
 
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