I get many questions about how the HamSphere system works.
How come it sounds like a real radio?
The answer is: I use real radio principles with local oscillators, balanced mixers, filters etc. The modulation is true Double Sideband Modulation with carrier suppression hence the "donald duck" sound when you swirl the knob. The receiver is a direct LO-mixer detector where I just add the carrier (Beat oscillator) to detect the audio.
Here is an attached schematic of the system.
Just email me if you have any further questions.