Jim Gettys wrote: > Radio clock receivers often don't work where these devices are deployed > (like in my basement). Not enough view of the sky (and multiple layers of > floors). Radios are "nice to have", but can't be guaranteed to work. No, the problem of radio clock is not its availability but that they can easily be faked, which means it is no better than relying on some NTP service, such as time.nist.gov, which is as (un)trustworthy as USG. Masataka Ohta