He's saying ubuntu 16.04, so I downloaded Ubuntu MATE 16.04.2 LTS for Raspberry Pi 2 and 3 systems.
https://ubuntu-mate.org/raspberry-pi/ https://ubuntu-mate.org/raspberry-pi/
The build-gnuradio is bombing out at "Fetching Gnu Radio via GIT" for me right now. Looks like there might be an expired security certificate at git.gnuradio.org