The FCC and other government bodies (ITU) in other countries tightly control the radio spectrum to prevent interference. There are a few bands that are set asi

The FCC and other government bodies (ITU) in other countries tightly control the radio spectrum to prevent interference. There are a few bands that are set aside for general use called the ISM bands (industrial, scientific, medical). In those bands you can emit RF that might interfere with other devices. So you can run stuff like wifi, cordless phones, induction heaters, and microwaves that emit RF energy that can cause interference without a license (subject to some restrictions). https://en.wikipedia.org/wiki/ISM_band https://en.wikipedia.org/wiki/ISM_band