The reason why we do not recommend routers that do not create a 5 GHz Wi-Fi is very simple.
There are twelve channels in the 2.4 GHz frequency range, which means that theoretically a maximum of twelve such Wi-Fis can co-exist. In practice, a maximum of four 2.4 GHz Wi-Fis will work side by side without interfering with each other excessively.
2.4 GHz penetrates walls very well, but can transfer data less fast.
For dorm rooms a 2.4 GHz Wi-Fi is therefore very likely to suffer from interference and dropouts if you have more than four neighbors within a distance of 30 meters around you (even above and below you!).
A bad Wi-Fi okay for WhatsApp and surfing, but not for videoconferences.
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