Releasing version 0.4.12 of xpsa, the rtl_sdr dongle based Linux spectrum analyzer:
There is quite bit of work that went into this. You can set FFT size, sample rate, zoom factor, harmonic selection, and audio commands to run it as radio all from the GUI. Display speed varies depending of type of processor you have, from about 25 fps on a Sempron to > 50 fps on an i5 for the smallest FFT (2048 points). And from about 8 fps to > 25 fps for the largest FFT When using the largest FFT (131072 points) you can zoom in to a factor 64, and look at a few Hz precision at several hundred MHz. Heterodyne function is provided, you can set a local oscillator frequency. Tested with 4000 tuners and 820 tuner based sticks.
I have added stdin to stdout piping, so you can even run 2 or more in series via the internet when using 'netcat', easily save streams etc etc. That is the power of Unix, teh ability to use pipes. So it will work remote too. There are some simple examples in the README. No manual, it assumes you have the clue somewhere at hand.