My Stratum-0 Atomic Clock

But O-1 has a flaw: it is only as good as its signal from the GPS satellites. Should the GPS transmissions, from which the one Hertz 1PPS pulse was synthesized, be unavailable, due to weather or what not, O-1 would be only as good as the standard quartz oscillator used by its Raspberry Pi 3. In time, O-1 would drift away from UTC. What good is that? What I needed was a better, more stable oscillator. What I needed for O-2 was an atomic clock. Atomic clocks are not clocks in the sense of telling.