I've been using this setup for several years now (and probably post about it during each holidays), but I'm still amazed how well the combination of an RPi3 as Wifi access point with an old Android phone as LTE modem over USB tethering works. It needs setup once after booting (enabling tethering on the phone) and then runs for weeks. All the other portable access points I've used before were a disaster in comparison, even when the hardware was supported by OpenWrt.
@lioh I could (and did for some time), but there was some reason that I can't remember right now why it turned out not working too well. Also with the RPi in between I get to run Pi-Hole and also have some visibility into the client traffic patterns (mobile data is expensive in Germany).
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