> there are at least some use-cases where the use-case preceded the formation of any multilateral body to coordinate usage The ITU-R was founded in 1927 (it wa

> there are at least some use-cases where the use-case preceded the formation of any multilateral body to coordinate usage The ITU-R was founded in 1927 (it was known as the CCIR back then). At that point, we were mostly worried about telegraph operators using spark gap transmitters, which have been effectively illegal since 1934. There's not much to grandfather in. > I presume that, despite the ITU making no ruling on such, the band centered around 2.45GHz has ended up being "commercial use" in pretty much every country? In the case of 2.45 GHz (the ISM bands), that's done under Part 15 rules (in the US, similar rules elsewhere) that allows for low-power, unlicensed transmitters. Your WiFi signal is intentionally run at extremely low power so that it won't travel more than a few hundred feet before it's attenuated by the environment, and in that frequency range there's no risk of it bouncing off the ionosphere. Meanwhile, your microwave oven is shielded to keep any signal leakage to a minimum. This falls under the "non-interference" provision I mentioned earlier - the signal is unlikely to leave your neighborhood, let alone leave your country, so the ITU doesn't care. They're more concerned with signals that travel hundreds or thousands of miles. If you check the ITU allocation, 2.45 GHz is allocated to radioloation (radar), licensed mobile radios, and fixed broadcast users. Plus a slice for amateur radio just below it. ISM use isn't even mentioned at this level. WiFi and microwave ovens are effectively secondary users here. They get to share any spectrum left over provided they don't interfere with the primary users - and can't complain if they receive interference from the primary users. (In other words: If the government complains that your microwave oven is interfering with their radar station, your microwave oven will lose. Guarenteed.)