In this video I show how to install and use Kalibrate-RTL in Kali Linux, which is useful for finding out the exact frequency for GSM downlinks. (For cheaper software defined radios such as the RTL-SDR, it may in some cases be important to look at the offset, and use the calculated frequency instead of the ARFCN when decoding GSM downlinks. In my case, using either the frequency or ARFCN works.)

If you trust the output from Kalibrate-RTL, you can calculate the exact frequency in the console as follows:
echo $((951400000-23687))
This will output: 951376313 (~951.37MHz)

Topics covered:
– Installation and Basic Usage of Kalibrate-RTL
– Confirming Kalibrate-RTL Output in GQRX

– kalibrate-rtl
– gqrx
– apt (apt-get & apt-cache)

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