DVB-T dongles based on the Realtek RTL2832U can be used as a cheap SDR, since the chip allows transferring the raw I/Q samples to the host, which is officially used for DAB/DAB+/FM demodulation. The possibility of this has been discovered by Eric Fry (http://rtlsdr.org/#historyanddiscoveryofrtlsdr). For Linux users of rtl-sdr, you will likely want to link the provided udev rule into your system installation in order for the hardware to have the correct permissions:

sudo ln -s $CONDA_PREFIX/lib/udev/rules.d/rtl-sdr.rules /etc/udev/rules.d/
sudo udevadm control --reload
sudo udevadm trigger

You may have to restart for this change to take effect. Even though the Linux kernel's built-in DVB-T module that would normally claim the device should be unloaded automatically, you might also want to blacklist the DVB-T module by running:

sudo ln -s $CONDA_PREFIX/etc/modprobe.d/rtl-sdr-blacklist.conf /etc/modprobe.d/
sudo modprobe -r $(cat $CONDA_PREFIX/etc/modprobe.d/rtl-sdr-blacklist.conf | sed -n -e 's/^blacklist //p')