We had radio time receivers (Rugby MSF, now Anthorn MSF) for a long time in the UK. Just plug them into an RS232 hole and have a site-wide master NTP server on that box, fire up the daemon and you're done.
I think the last one we paid for was in the region of $250 as the hardware is very simple.
GPS is an interesting prospect but they are pretty HF which is a PITA if you have a unit inside a rack inside a machine room inside a building. MSF is 60KHz so is ground wave propagation so it had great coverage.
Very true, but system-wide consistency across all participants is a different problem to external reference accuracy but it starts as a reasonable basis that you can reason about.
I think the last one we paid for was in the region of $250 as the hardware is very simple.
http://www.npl.co.uk/science-technology/time-frequency/produ...
GPS is an interesting prospect but they are pretty HF which is a PITA if you have a unit inside a rack inside a machine room inside a building. MSF is 60KHz so is ground wave propagation so it had great coverage.