anyone running GPS clocks in Southeastern Georgia?

Fri Jan 21 21:53:08 UTC 2011

On Jan 21, 2011, at 4:45 PM, Gary Buhrmaster wrote:

>> NTP isn't going to be the only "ripple".
> 
> Most of the "brand name" GPS NTP solutions have a clock
> with is more than stable enough to survive without GPS
> lock for 45 minutes(*).  Some of the more expensive units with
> temperature controlled oscillators have hold times in the
> many weeks.  My guess is that the NTP ripples will be
> limited to those NTP servers just (or recently) booted
> which have not yet achieved a stable clock state.
> 
> Gary
> 
> (*) This presumes that this test results in loss of signal
>    lock, and not intentionally injected false information.
> 
Even if there actually was an "NTP ripple", a properly designed NTP solution should rely on at least three geographically diverse sources. Given the ubiquity of the internet this is not difficult to achieve, barring extreme circumstances.

James R. Cutler
james.cutler at consultant.com