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SDR AIS available in OpenPlotter 2
maximum gain is not always the best for AIS reception. It is ok for calibration but you should find your best gain. In next versions leaving the gain empty you will apply an auto gain.
(2020-04-21, 11:51 AM)Sailoog Wrote: Please forgive a beginners question. Where do i select this device? In OpenCPN under the connections tab? I am just getting started with the OpenPlotter Basic distribution.

To get AIS data you only need to select a device and set the PPM and the UDP port values. All options in "calibration" section are just to find out the PPM of your device.

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".

  • 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.
  • Provide a UDP port to send AIS data to (default 10110). A Signal K connection will be created for that UDP port.

PPM values have a tolerance of +/-7.
PPM value can be negative.
If you do not find the correct PPM you will not get AIS data.
The PPM value will change with temperature so let the device work for 30 minutes before calibrating.
Some devices are already calibrated (PPM near 0) even with different temperatures.
This is an openplotter app, SDR VHF, not an openCPN plugin or feature. Manual under construction:
I have a realtek dvb-t rtl2832u and it was working fine in openplotter 1.
Now i am unable to calibrate. After choosing device and clicking "inital ppm" it stops at "Allocatin 15 zero-copy buffers" and nothing more happens.
I have left all fields blank. PPM is set to 13 manually (just a random number)

Found 1 device(s):
0: Realtek, RTL2838UHIDIR, SN: 00000001

Using device 0: Generic RTL2832U OEM
Detached kernel driver
Found Rafael Micro R820T tuner
Supported gain values (29): 0.0 0.9 1.4 2.7 3.7 7.7 8.7 12.5 14.4 15.7 16.6 19.7 20.7 22.9 25.4 28.0 29.7 32.8 33.8 36.4 37.2 38.6 40.2 42.1 43.4 43.9 44.5 48.0 49.6
[R82XX] PLL not locked!
Sampling at 2048000 S/s.
Reporting PPM error measurement every 10 seconds...
Press ^C after a few minutes.
Reading samples in async mode...
Allocating 15 zero-copy buffers
remove that random number and left ppm blank. use 49.6 as gain.
It seems like once i've entered a number i am unable to leave it blank. I can change, but not remove the PPM. Altso tried to set it to 0 and to uninstall/reinstall "SDR VHF" from settings.
PPM: 0
Gain: 49.6
Still same result
Hi everyone!

I have RTL-SDR usb stick with self made "flower pot" antenna.
I have calibrated the stick, found best ppm and AIS working like a charm, the OpenCPN screen is full of detected ships, but every vessel is class "A", but no class "B" ships at all Sad
I asked my marina neigbours to turn on their class "B" AIS transponders , but they are not detected despite nearest vessel in 10 meters away of me.
Class "A" ships detecting more than 10 miles away...
Could you please give me advice what else i able to try to detect "B" class ships
Hi Guys,

Purchased a SDR-RTL dongle V3 (a couple of days ago), installed the SDR VHF 2.1.1, calibrated and edited/entered values in AIS line.
The AIS service shows active and running.
In openplotter, I added UDP connection ( and 10110) but no AIS info showing on the chart!
I've been reading/surfing/consulting the web like crazy, can't find an answer?

What am I missing?
Do I need additional add-ons / plug-in to run the AIS service beside SDR VHF 2.1.1?

Looking forward to you answers.


(2020-08-02, 11:30 PM)Bikertje77 Wrote: In openplotter, I added UDP connection ( and 10110) but no AIS info showing on the chart!

I do not understand this, where have you added this connection? you do not need to add any connection anywhere, openplotter-sdr-vhf will do all the job
My bad Sailoog, I entered that info in opencpn (connections) not openplotter.
The gps connection is also present there.
Is SignalK needed to receive the ais data?
Or just sdr-vhf?

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