Newbie NMEA0183 help, please

[SkyeMarine]

Originally Posted by Lake-Effect

Here's one source for the FTDI USB-to-serial boards I mentioned. Very useful if you like to mess with serial interfaces.

And there are also complete encapsulated USB-to-serial interfaces with built-in adapters for RS232 or RS422 serial.

Great, thank you! We'll get some better hardware and see if we can come up with a good debug tool. In parallel, we'll see if we can re-wire things, as I just mentioned.

[tidefalling]

Try inverting the input. I had to do this for a serial gps that was doing the same thing.


SoftwareSerial mySerial(rxPin,txPin,1);

The 1 as the third parameter inverts the logic.

[OldGreyB]

Good input from Lake-Effect, Muttnik and others already
Here is additional input i have found that may help you:


Raymarine G Series
As per the Raymarine G - Series User manual, you need a separate GPS- it is not internal.

21.4 GPS setup
The GPS setup options enable you to configure a connected GPS receiver.

The Global Positioning System (GPS) isused to position your vessel ont he chart.You can set up your GPS receiver and check its status from the GPS Status option in the Setup Menu.

I note the diagram you posted shows the GMP 400 has both Seatalk NG ( NMEA 2000) and NMEA 0813 connections.


ICOM IC-M604
The ICOM IC-M604 needs a separate GPS Signal . See connection diagram ( with PIN outs) here:
https://www.icomamerica.com/en/downl...x?Category=220




Roberson AP300X Autopilot

Apparently there is an optional NEMA interface box with this unit - have you located that? From the AP300X manual:

1.4 Optional components NI300X NMEA Interface Unit This unit has 4 NMEA I/O ports for communication to other systems, and a selectable heading output for radars (Anritzu or Furuno). Includes two ROBNET connectors for connection to the AP300X system.

Arduino
If you still want to go down the Arduino path since you have the card, then Arduino to NMEA 0183 threads- may be of interest:

https://kingtidesailing.blogspot.com...device-to.html

https://shah253kt.github.io/arduino-nmea-parser-v2/



0813 Network Tutorial
Boat-Project.Com - A tutorial on making a basic NMEA-0183 connection between a Chartplotter and VHF Radio.

[OldGreyB]

Folks,

Typo in my previous post. The 0813 written twice should ofcourse be 0183.

I was outside the edit time when I noticed.

[ranger58sb]

Originally Posted by muttnik

Interesting. By "Antenna" do you mean a simple antenna connecting to an internal GPS or a small external gps unit which feeds the radio NMEA-0183 sentences?

It was a small external antenna that came with the radio, IIRC looked like a little hockey puck (but I'm a little hazy on that).

Don't know where sentence formulation began, whether at that antenna or inside the M604... but the radio in turn could feed GPS sentences to other devices via the 0183 OUT line.

-Chris

[muttnik]

Originally Posted by ranger42c

It was a small external antenna that came with the radio, IIRC looked like a little hockey puck (but I'm a little hazy on that).

Don't know where sentence formulation began, whether at that antenna or inside the M604... but the radio in turn could feed GPS sentences to other devices via the 0183 OUT line.

I took a look at the documentation for the connections on the 604 and they look similar to the 603: There's no apparent connection for a GPS antenna so I'm guessing your "puck" is a complete GPS receiver which hooks up to the NMEA in. Is it something like this BU 355 which is often recommended on forums as a cheap standalone GPS for VHF units?



Really interesting that the 604 repeats GPS to the output. It's an odd choice in that many people (including me) have NMEA in and out connected to the same plotter, so it would be echoing back the plotter's GPS with a slight delay which is not ideal. However it gives the OP a choice of how to hook up a GPS. Connecting the GPS to the VHF and then the VHF to the plotter would be the better topography for people who like to sail with the VHF always on but the plotter only on when needed.

Thanks for this info: It may be specific to certain firmware revs but I need to check if my 603 also repeats its NMEA inputs to its outputs.

[SkyeMarine]

Originally Posted by tidefalling

Try inverting the input. I had to do this for a serial gps that was doing the same thing.

SoftwareSerial mySerial(rxPin,txPin,1);

The 1 as the third parameter inverts the logic.

BINGO!!! Getting nice sentences printing out now on the serial monitor.

Thank you!!!!!!

Progress....

[SkyeMarine]

Okay, some good progress today, thank you all for the great information!! With a valid GPS source hooked up to the VHF, it's now correctly displaying position.

However, the date shows "OCT 22" while the time appears to be correct (though I think it's GMT). I can't see anywhere to input the date (either to the GPS or the radio), and it seems like that should come along with the time information from the GPS?? Any ideas on why the date is off?

Thank you again,
Erin and Jon

[muttnik]

Originally Posted by SkyeMarine

However, the date shows "OCT 22" while the time appears to be correct (though I think it's GMT). I can't see anywhere to input the date (either to the GPS or the radio), and it seems like that should come along with the time information from the GPS?? Any ideas on why the date is off?

https://en.wikipedia.org/wiki/GPS_week_number_rollover

Your GPS is old, didn't correctly deal with the GPS rollover in 2019, and thinks it's 1024 weeks before today (October 22 2001). You can check with the GPS manufacturer to see if they have a firmware update you can install, but if there's no way of updating it you can either live with the wrong date or buy a new GPS.

[ranger58sb]

Originally Posted by muttnik

I took a look at the documentation for the connections on the 604 and they look similar to the 603: There's no apparent connection for a GPS antenna so I'm guessing your "puck" is a complete GPS receiver which hooks up to the NMEA in. Is it something like this BU 355 which is often recommended on forums as a cheap standalone GPS for VHF units?

Really interesting that the 604 repeats GPS to the output. It's an odd choice in that many people (including me) have NMEA in and out connected to the same plotter, so it would be echoing back the plotter's GPS with a slight delay which is not ideal. However it gives the OP a choice of how to hook up a GPS. Connecting the GPS to the VHF and then the VHF to the plotter would be the better topography for people who like to sail with the VHF always on but the plotter only on when needed.

Thanks for this info: It may be specific to certain firmware revs but I need to check if my 603 also repeats its NMEA inputs to its outputs.

Erp... sorry... belay that... I've mis-spoken. Memory like a steel sieve.

I meant M605. not 604. (Our original replacement VHFs were ICOMs M604s... but then later we replaced those with M605s... and the latter are the ones with the optional GPS antenna.) UX-241 is the GNSS Antenna part number.

Yes, it sorta looks like your example, only rectangular.

FWIW, your example also looks like the external GPS antenna we use with our ship's laptop, only our connector is USB. Works pretty well, actually.

Anyway, sorry for misleading info...

-Chris

[muttnik]

Originally Posted by ranger42c

I meant M605. not 604.

That explains it and makes much more sense than the 604 repeating its input :-). Thanks for the update.

[SkyeMarine]

Originally Posted by muttnik

Your GPS is old, didn't correctly deal with the GPS rollover in 2019, and thinks it's 1024 weeks before today (October 22 2001). You can check with the GPS manufacturer to see if they have a firmware update you can install, but if there's no way of updating it you can either live with the wrong date or buy a new GPS.

Ah, makes sense now, thank you!! So much to learn!