Hak5 1526 – Building Software Radios With A Little Bit Of Python

Software Defined Radio – Shannon demonstrates GNURadio Companion on Pentoo for RTL-SDR fun. Plus, Darren Interviews Russ about the CTF Competition’s SDR Challenges at Shmoocon 2014. All that and more, this time on Hak5!

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GNURadio Companion

As we’ve mentioned these DVB-T dongles are great because they’re cheap software defined radios, but why? Well, similar to popular WiFi hacking radios, because they have a certain desirable chipset.

In this case it’s the Realtek RTL2832U. The special thing about this chipset is that it transfers raw samples to the computer, and that means it can be used with a host of open source SDR software, which we’ll be getting into today.

rtl-sdr is a package specifically for this inexpensive dongle that contains a few useful utilities for the dongle. We can use rtl_test to find out what tuner is in our dongle and what gain values it’ll support. rtl_sdr is a basic IQ modulation recorder – we’ll get more into specific modulations later – and rtl_fm is a simple FM tuner, the modulation you’re probably most familiar with from radio stations.



gnuradio_companion &

Drag in [ Sources ] -> RTL-SDR Source.

Double click variable samp_rate and set to “2e6” for 2 million

Double click RTL-SDR Source set 96.3e6 for 96.3 MHz

Drag in [Instrumentation ] -> [WX] -> WX GUI FFT Sink

Connect output of RTL-SDR Source to input of WX GUI FFT Sink

Build -> Execute


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