Also see the original Pieter Noordhuis's guide
Note: I created this fork since I had some issues with the Pi 4 and Raspbian not talking properly to a RTL-SDR dongle due to some known incompatibilities and I needed more processing power than the Pi b+ that I had on hand. I noticed this by starting goesrecv and seeing the first 5 packets coming in around 400 vit and then it would jump to 1500 and start dropping packets, more on this later in the article. Also the lastest version of raspbian pulls an incompatible version of opencv from its repo.
You need: