I too have some kind of GPS-disciplined high accuracy clock (I don’t recall the exact tech but I think rubidium sounds right). From what I recall, precision tim

I too have some kind of GPS-disciplined high accuracy clock (I don’t recall the exact tech but I think rubidium sounds right). From what I recall, precision timing is quite critical on the infrastructure side of things so that the user device can sync to it and accurately transmit and receive in the correct TDD windows. One of the niftiest things was using the 10MHz reference clock as the clock source for my SDR, and tuning the receiver to the centre carrier of a nearby cell tower. I got a ~0.25Hz beat frequency out of it, which means this cheap eBay clock is accurate to about 1/3.2e9 Hz (cell tower was around 800MHz). Neat!