Using SDR Touch to calibrate PPM of a RTL-SDR Dongle


If you do not want to mess arround with PPM settings, buy a high quality dongle with fix PPM of 1.

  1. Start SDR Touch app and go to 162.025 MHz ( AIS Vessel Freq Chan B )#1-ppm-rtlsdr--sdrtouch-freq-setting
  2. Switch to Spectrum view and zoom in#2-ppm-rtlsdr--sdrtouch-settings
  3. PPM setting is in SDR Touch not where you expect it.
    Setting is under menu >>Gain<<
  4. Now see the result in the spectrum. So my dongle has got about 44 ppm
    # 4ppm rtlsdr sdrtouch ppm result

 Use this PPM value in the AIS Share app.

AIS Share ppm Settings

8 thoughts on “Using SDR Touch to calibrate PPM of a RTL-SDR Dongle”

  1. Hi Christian,
    this is exactly the way I did it and it works like a charm … 🙂
    For PPM fine adjustment you can use the number of packages received listed in “AIS_Share”.
    After that, I have about 25NM range with a simple VHF rod antenna !

    Christian, thanks again for the great stuff here … !!


  2. So calibrate after connected to a good antenna and not with the small antenna? Still not sure how to do this.

    1. You can calibrate with any antenna and any frequency. You just need a known frequency where somebody is transmitting , could also be a local radio station , or GSM frequency.

      1. Ok I got tuned in to a local station and then I just change the number at gain until it sounds best or should I do something else?

        1. Yeah FM Station is maybe not the best example because they are sending un such a big bandwidth. But let’s say you tune to FM Station 1 at 88.80 MHZ. In the spectrum you will see a vertical line . That’s should represent 88.80 MHZ. You also will see some mountains with the signal. So start chaning the PPM until your vertical line is equal with mountain peek / top in the waterfall spectrum.

        2. maybe such videos also help you

          This is on the PC with the free SDR# program. But the principe is the same as with SDRTouch APP

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