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How to calibrate RTL-SDR AIS properly http://navigatrix.net/viewtopic.php?f=10&t=813 |
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Author: | sailoog [ 25 Jun 2015, 12:03 ] |
Post subject: | How to calibrate RTL-SDR AIS properly |
Fine calibration using GSM network. - IMPORTANT. Once connected, let it warm up for some minutes (10-20 minutes approx.) to reach its steady state operating temperature. - Open terminal window and type rtl_test -p - Write down the maximum supported gain value. In my case 49.6. - Wait for the cumulative ppm value to stabilize and write down it too. In my case 69. - Close terminal window - Open a new terminal and type kal -s GSM900 -g 49.6 -e 69. Replace values in red by yours (GSM850: North America and Western South America. GSM900: Rest of the world). - Wait for the system to check the band and write down the strongest channel (power). In my case channel 8. - Now type kal -c 8 -g 49.6 -e 69. - Wait for the system to check the channel and write down the average absolute error. In my case 63.247. This is my final ppm value! - On opencpn plugin rtl-sdr, fill in the Error Correction field with your rounded ppm value. In my case 63. Activate and start receiving AIS signal. |
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