AIS and GPS Connections to OCPN

[PNWBoater]

Apologies if this question has been addressed elsewhere.

Currently using GPS output to OpenCPN and would like to add AIS output from a AIS capable VHF. The GPS will only output at 4800 baud and the AIS at 38400 baud. Would it be possible to use a AIS and 2 Port FTDI USB to Serial RS232 Adapter Cable and create two comm connections in OpenCPN? One port running at 4800 baud for the GPS and one port running at 38400 for the AIS or is there a better solution?

Thanks in advance.

Dan

[bcn]

- Two USB-Serial converters are fore sure an option.

- VHF radios with AIS reception have often a GPS input and a combined AIS/GPS output at 38400bd. Would make things a bit easier.

OpenCPN will live with either solution.

Hubert

[RhythmDoctor]

Originally Posted by bcn

- Two USB-Serial converters are fore sure an option.

- VHF radios with AIS reception have often a GPS input and a combined AIS/GPS output at 38400bd. Would make things a bit easier.

OpenCPN will live with either solution.

Hubert

I am not sure which VHF radios that you are referring to, but the very popular Standard Horizon GX2150 will NOT do this. It will take in GPS from an external source, but it will not repeat it back out again on the AIS wire (or any other wire). So you would need two serial/USB conversions going to the computer running OpenCPN - one for AIS, and a separate one for GPS.

The GX2150 is capable of sending out AIS and DSC sentences on a single port at 38400. Perhaps that is what you were thinking of.

The newer GX2200 has a built-in GPS, but its instruction manual's wiring schematics show no capability of outputting the GPS sentences. So if you want GPS to go into OpenCPN, you would need a GPS talker that is separate from the GX2200 radio.

[CarCode]

The RO4800 VHF does however send AIS and GPS data at his output. You will need to activate GPS output in the settings of the RO4800 to receive the combined data stream with 38400 baud.

Gerhard

[PNWBoater]

The SH GX2150 is what got me thinking about adding AIS to OCPN based on the wiring diagram shown under the heading GX2150 (MATRIX AIS+) in this document:

http://www.standardhorizon.com/downl...pplication/pdf

The GX2150 will output AIS and DSC at 38400 and also input GPS data to the VHF. Adding a 2 port Serial to USB and two OpenCPN comm ports should work just fine.

Dan

[CaptMarc]

I have a similar issue:
OPencpn with BU 353 GPS: works fine

Standard Hor GX2150 receiving gps signal from Magellan Meridian Marine: 4800 baud


I switch the GX2150 to 38400 baud to send AIS to Opencpn,via Milltech USB; it works for awhile but then I loose gps signal from Magellan to GX2150 .

The magellan does not have 38400 baud, it has: 1200,4800,9600,19200,57600,115200

it also has NMEA settings: off, V1.5 APA, V1.5 XTE, V2.1 GSA
I know this is an old gps but works great for 10 years!!

any suggestions?

Marc

[RhythmDoctor]

Originally Posted by CaptMarc

I have a similar issue:
OPencpn with BU 353 GPS: works fine

Standard Hor GX2150 receiving gps signal from Magellan Meridian Marine: 4800 baud


I switch the GX2150 to 38400 baud to send AIS to Opencpn,via Milltech USB; it works for awhile but then I loose gps signal from Magellan to GX2150 .

The magellan does not have 38400 baud, it has: 1200,4800,9600,19200,57600,115200

it also has NMEA settings: off, V1.5 APA, V1.5 XTE, V2.1 GSA
I know this is an old gps but works great for 10 years!!

any suggestions?

Marc

If you read the GX2150 manual carefully, I think that you will see that you are making a couple of mistakes.

The GX2150 will not pass-through the GPS signal that it gets from the Magellan. To use the Magallan's GPS signal in OpenCPN, you would need to split the wire and connect it to a separate COM port on your computer at 4800 bps. I suggest that you just keep using the GPS from your BU353.

Also, your statement "switch the GX2150 to 38400 baud to send AIS" is confusing. AIS always goes out from the GX2150 at 38400 bps. I suspect that what you are "switching" is the way GX2150 sends out the DSC sentences. The GX2150 offers the option of sending both AIS and DSC through the same wire at 38400 bps. However, when you select that option, the GX2150 requires that it receive the GPS at 38400 bps. Since your Magellan can't send at 38400, you cannot select that option. But regardless of whether you could or not, the GX2150 would not send the GPS signal to OpenCPN anyway.

You need to read the GX2150 manual. These things are explained there.

When you say "it works for awhile," you are probably seeing the ownship icon stay red for a minute or so until it times out and turns grey. But the fact is that OpenCPN is not getting a GPS signal from the GX2150 at all. As soon as you disconnect your BU353, the GPS signal stops, even if the ownship stays red for a few seconds.

Looks like I already said this earlier in the thread:

Originally Posted by RhythmDoctor

I am not sure which VHF radios that you are referring to, but the very popular Standard Horizon GX2150 will NOT do this. It will take in GPS from an external source, but it will not repeat it back out again on the AIS wire (or any other wire). So you would need two serial/USB conversions going to the computer running OpenCPN - one for AIS, and a separate one for GPS.

The GX2150 is capable of sending out AIS and DSC sentences on a single port at 38400. Perhaps that is what you were thinking of...

[CaptMarc]

Doc,
thanks for your reply, I need to explain my issue better...
I understand use of the BU354 for GPS signal to the PC, and the magellan just for the GX2150.(each on a different usb) I have no problem with OPencpn and BU354 connection

When the GX2150 is set at 38400, to send AIS info to the PC, it eventually looses the signal from the Magellan gps. The GX2150 can only be set to 4800 or 38400 baud

[RhythmDoctor]

Originally Posted by CaptMarc

....When the GX2150 is set at 38400, to send AIS info to the PC, it eventually looses the signal from the Magellan gps. The GX2150 can only be set to 4800 or 38400 baud

What I said was that there is no adjustable setting for AIS -- the GX2150 always sends AIS at 38400, no matter what settings you select.

You need to use the configuration shown in section 6.6.1 of the manual. GPS comes in the blue wire at 4800, AIS goes out the brown wire at 38400. If your plotter supports DSC display and has an available input, you can connect the gray wire at 4800.

You are not capable of using the configuration shown in section 6.6.2, because that requires GPS input at 38400, which your chartplotter does not support.

Section 10.10 describes the setup options for this. NMEA data refers to GPS in and DSC out. These must be set for 4800, because your Magellan does not support 38400 for the GPS.