[ntp:questions] Re: Good GPS for attic?

John Pettitt jpp at cloudview.com
Sun Feb 13 00:02:31 UTC 2005


Chris Malcolm wrote:
> While GPRRs have to keep time internally to within several
> nanoseconds, few of them bother trying to report it to the user with
> that degree of precision. For a start it's impossible over an RS232
> serial link. Up to a second out is not uncommon. You'd get more a more
> accurate time fix with a program that listened to radio time pips over
> a microphone!
>

and that is why most a good ntp implementation using a GPS use the pulse 
per second (PPS) output found on some GPS units (like the Garmin GPS18 
LVC) which is accurate to around a microsecond.

John



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