Nasa AIS and Garmin 128 GPS - help urgently needed

[tomdmx]

Hi there,
I've an old but workign Garmin 128 gps and bought a new nasa ais..hooked up for the gps signal (as reading it needed nmea 0183 signal) but nothing worked...I re read and it stated RMC sentencing required for the AIS...

The 128 gps does not have this sentencing, so is there any way to make it work?
On a similar note, I have a new cobra radio with a +ve and -ve gps input..hooked up the blue gps cable (nmea out) to +ve but again gps position does not display on the radio...so do I need to buy a new gps?
Thanks in advance for your help

 

[Keith-i]

I doubt your Garmin can accept the fast data rate that AIS sends out on NMEA, so it probably won't work. Check the Garmin website though to see if it will take high speed NMEA then make sure the receive mode on the plotter is set to this.

As for the radio, you need three connections normally. GPS plus is probably the transmit wire from the plotter. GPS minus is probably the receive wire from the radio and then the ground/earth wires of both need to be connected. Again, makes ure the plotter is set to NMEA on the communication seeeting and not to Garmin proprietary.

 

[crossbones]

Nasa ais and garmin 128

I have used a garmin 128 with my nasa AIS for many years without any problems. You need to have both units on the same power supply. (The negative supply is the nmea reference) You need to conect the garmin blue wire to the nasa blue wire then set the garmin to "nmea to nmea" and bob's your uncle.

 

[Martin_J]

Tomdmx

The RMC sentence looks like this...

$GPRMC,081836,A,3751.65,S,14507.36,E,000.0,360.0,130998,011.3,E*62

Page 59 of the GPS128 owners manual states that this sentence is sent (in both NMEA1.5 and 2.0) by the GPS 128.

The NASA AIS unit should therefore quite happily receive this information.

Page 59 of the Garmin manual also suggests NMEA out is blue and common is black. Try using these two colour wires for the input to the AIS.

Don't worry about speed - that is the high speed AIS output 'from' an AIS unit to a plotter for display of AIS targets on a modern chart plotter.

Same two wires should also input to your radio for position input (to the radio).

 

[prv]

I doubt your Garmin can accept the fast data rate that AIS sends out on NMEA

I'm certain it won't, but what would a GPS128 do with AIS info anyway? It's a classic old GPS (I love 'em) that just gives you a lat and long and handles waypoints.

Fortunately, the OP wants to send the position data from the GPS into the AIS, not the other way round.

Pete

 

[Keith-i]

Misunderstood the direction of data required

 

[ostell]

If your Garmin GPS is anything like the ones I have had then the NMEA output minus signal is connected internally to the battery negative connector. If you radio has leads for -ve and +ve NMEA input then the -ve needs to be connected to battery negative (and hence the GPS NMEA -ve) to complete the circuit.