[The Mike Stuff] has an interesting proposition. He asserts that ancient people like the Greeks could have built a form of radio that was purely mechanical. We aren’t sure we agree, but even if it were possible, we are sure it would have sounded awful. You can see the details in the video below.
The idea is that you can compress air with a waterwheel, blow it through a rotating disk with slots in it, and a valve to amplitude modulate the airflow through the disk. Horns like an old gramophone speaker would amplify the signal at both ends. The demodulation is straightforward and doesn’t even require power, like compressed air.
