Comment by wolrah

> Huh? Is this true? It doesn’t make intuitive sense to me—if the device doesn’t have a 5ghz radio I would expect it to be physically impossible for the 5ghz network to interfere.

It's not an issue with the device itself, it's an issue with the device setup process.

For whatever reason, I assume it's easier in some common device platform, a lot of IoT devices do not use the SSID for discovering WiFi APs. Instead they connect directly to the BSSID (read: WiFi MAC) of the specific radio on the AP. These devices always rely on a phone app for setup, and the phone app has you select the WiFi network by the SSID name, but passes the BSSID to the device over Bluetooth.

When your phone is connected to the 5 GHz (or now 6 GHz) radio as would be normal for a modern device in a combined network, the BSSID it sees is invisible to the 2.4-only IoT device and thus it doesn't work unless you force your phone to only see the 2.4 GHz radio.

The problem also comes up if you have a larger network with multiple access points, set up a device, and then move it (or if your phone just happens to be hanging on to a more distant AP that the IoT device's puny antenna can't see).

It's been a stupid problem from the beginning, it'd be trivial to solve permanently in software if these device vendors would get their heads out of their collective asses, and yet the "you have to disable 5GHz" nonsense persists for the same reason as software vendors still insist on admin privileges for everything, any/any firewall rules, etc.