GPS satellites broadcast time signals; you don’t need Internet access to receive them. But if you don’t want to be dependent even on GPS, you can apparently bu

GPS satellites broadcast time signals; you don’t need Internet access to receive them. But if you don’t want to be dependent even on GPS, you can apparently buy a small atomic clock for $1500, well within reach of many tech enthusiasts: https://physicsworld.com/a/atomic-clock-is-smallest-on-the-market/ https://physicsworld.com/a/atomic-clock-is-smallest-on-the-m...