[ntp:questions] Re: Best way to harness multiple stratum 1 servers

Darryl Otzen "darryl otzen at acterna com" at ntp.isc.org
Thu Apr 6 10:37:38 UTC 2006


John Ackermann N8UR wrote:
> Hal Murray said the following on 04/05/2006 03:08 PM:
> 
> 
>>As a practcal matter, the best is probably the one that's that most
>>reliable.  Or the one that's most convenient.  Or the one with the
>>fastest CPU or best network connection.
>>
>>The last few nano/micro seconds won't make much difference
>>after a network hop.
> 
> 
> You're probably right, but my problem (if you can call having too many
> time sources a problem!) is that it's not intuitively clear which one of
> the servers is the best, other than that the WWVB server is
> significantly worse than the GPS and Cs ones.  But the GPS and Cs ones
> have very similar performance.  To the outside world it doesn't matter
> because the internet and even my firewall performance will mask
> differences at this level, but as an academic exercise, and on the local
> wire, I'd like to see if I can wring the best possible performance out
> of the system.
> 
> I'm probably asking NTP to perform at a level it's not really designed
> for, and that perhaps the OS/hardware can't even support (in terms of
> system clock stability and time resolution -- though a longer term goal
> is to replace the mobo clock with a source derived from the Cs to solve
> at least one problem).
> 
> John
> 
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If your Cs and GPS all have a common freqency output signal (2048kHz, 10MHz), you can use a phase meter to track any difference between them.
This will only be of benefit if you have three or more sources.
I have done this with Cs references to keep track the performance of old units.

dotzen.




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