This is interesting. I wonder whether in the domestic apartment, the wifi signal carries most energy density (Watt/volume) or whether there are more fruitful ba

This is interesting. I wonder whether in the domestic apartment, the wifi signal carries most energy density (Watt/volume) or whether there are more fruitful bands to explore, such as - 50Hz radiating power cables (especially heavy current like for the oven or water heater) - socket transformators (the old ones, not thinking of switching power supplies as your smartphone charger has it) - cellular networks (especially the waves emitted by mobile phones in the same room) In principle, exploiting these signals is like operating solar cells but optimized for other frequencies in the electro-magnetic spectrum.