I used to tune my shortwave radio to various frequencies emitted by my ZX Spectrum +2A. It had terrible shielding!
You could hear the noise/tone change with various different types of computation, and for some frequencies listen to the framebuffer scanout (I think) where the sound appeared to match the display changes. Definitely not in the UHF range of the actual signal though.
You could hear the noise/tone change with various different types of computation, and for some frequencies listen to the framebuffer scanout (I think) where the sound appeared to match the display changes. Definitely not in the UHF range of the actual signal though.