The power button does power button things. The small knob changes volume, the large knob changes the tuning.
Existing Signals: 249.5: Test Signals - Random sounds to test if this even works. 572.9: TrooMusic - All of my shared music on Scratch! You can add your own radio signal by duplicating an existing one and changing the "p_signal" variable. Then you can add whatever sounds you want to it! I might even add it to the original project!