This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 1 Vote(s) - 5 Average
  • 1
  • 2
  • 3
  • 4
  • 5
SDR AIS available in OpenPlotter 2
SignalK is the data server. You can look at the signalK dashboard via your browser with localhost:3000.

The available data then can be used in OpenCPN via an internal network link with the SignalK server called locaLhost. If you use the latest OpenCPN 5.2 data input can allready be done in the SignalK format.

network signalK localhost port 3000
or with an older OpenCPn version: tcp localhost port 10110

Bram, just sent you a PM
Well, was playing around with signalK, opencpn 5.0.0 and the RTL-dongle yesterday evening as well as this morning.
I still haven't managed to get the AIS working...

During calibration to get the right PPM, when searching the GSM900 it does say that the values might be too different and that the PPM might be way off.
I've done many calibration now and I keep ending up with a PPM of -2.
Then I edit the AIS line and put in the gain of 49.6 and the PPM of -2.

When I open SignalK, it does say RTL connected to localhost 10110 but no data coming up.
Settings in SignalK for RTL device are TCP client, localhost and 10110.

I must be missing something that is causing it not to work, the only question is what...


Hi Jo,

if you follow the instructions it must work. But you need to do another thing. That is to start the process. Prossesses settings. Switch on the Ais and start the server. Then it is running.

But there must some Ais objects in your area. It works here very well. On my RPI and on my Linux Mint AMD64.

Woon je in Nederland ?

Hey Bram,

Belgium, flemish part near Brugge.
The’re be must ais signals around, we’ve got some canals that are used by cargo vessels.

Do you have fb/messenger? Maybe you could assist me via messenger?


Allo Jo, I live just across the Scheldt rivers. You can send me a message in the Dutch/Flemisch language. Perhaps I can help you.

Groeten uit Zeeland,

Okay, one step further now.
Thx to Bram I managed to get the AIS service working.
I would say it's receiving data very well now, I can see ships that are moored in the dock of Zeebrugge, that's 15km away.

Not all ships are showing on the map.
When I consult, you can see that many more ships are around.

What could be the cause of this?
I live in the USA and I am not getting any stations using GM-850 or GM-900.  

I have a Glomax Splitter on my marine VHF antennae.  

I am using a Nooelec NESDR Mini USB RTL-SDR & ADS-B Receiver Set, RTL2832U & R820T Tuner.

It is recognized by OP.  Initial PPM seems to be 21.  but it never picks and 850 or 900 GSM signals.

Any Suggestions??
Good evening to all.

I followed the instructions to install AIS in latest version of openplotter with the exeption of the last point (UDP-port)
In use is a NooElec NESDR Mini 2+ connected to an Raspberry Pi 4

Short calibration manual
  • Select a device
  • Click "Initial PPM" to get an approach to your ppm value. The longer you let the program calculate the better result you will get. If you run the program for hours you will get almost the final ppm but if you do not have time just wait for the value to stabilize.
  • Close the program and put the result into the PPM field.
  • Select the GSM band for your zone and try to get the strongest channel clicking "Get Channel".
    [Image: attachment.php?aid=911]   
  • Put the strongest channel into "Channel" field and press "Get PPM". Put the result into the PPM field again rounding the value without decimals and you are done.

But where can I provide an UDP port for my RTL-device?
  • Provide a UDP port to send AIS data to (default 10110). A Signal K connection will be created for that UDP port.

In SDR VHF 2.1.1 (processes) openplotter-rtl_ais stays inactiv and "dead",
ADS-B  dump1090-fa and piaware are activ and "running"

What must/ can I do to get openplotter-rtl-ais activ and running?

Thanks to all.

Good evening.
The USB-RTL-dongle is recognized in Gqrx, but the "Play"-Button in Gqrx GUI does not effect anything.
How can I get the waterfall in Gqrx?

System is latest Openplotter on a Raspberry Pi 4.

Thanks to all

Launch OpenPlotter application and go to settings (options).
Then to "connexions", you can add a UDP connection (in your case, to localhost, port 10110, or else such as marinetraffic, etc if you want)

You can maybe re-install gqrx but kalibrate app or one used by SDR VHF should be enough. An easy way to install kalibrate is to write "kalibrate" on "add/remove software", then kal -c 900, and when you get the strongest channel, kal -s "Channel"

Some helps on youtube :
or that one (better) :

Good luck,


Forum Jump:

Users browsing this thread: 1 Guest(s)