Adafruit has released a tutorial showing how to build a portable TFT screen based Raspberry Pi RTL-SDR spectrum analyzer that was inspired by the HackRF portapack. Construction of the project is very simple and the “FreqShow” python software is provided as a simple download that is ready to run once the RTL-SDR is installed on the Raspberry Pi.
The FreqShow software appears to be fully featured with the ability to change the center frequency, sample rate, and gain. It can show on the TFT screen the real time RF spectrum of the currently tuned area or it can be switched to show a waterfall of the spectrum as well. Below is a video of the finished project that shows the software in action.