[time-nuts] Possibly off topic - Jitter on Ethernet overpower adapters

David J Taylor david-taylor at blueyonder.co.uk
Mon Feb 11 11:12:34 EST 2013


All,

Strangely today the jitter numbers seem to be behaving themselves! Nothing
has been done to the set up.

Thanks to everyone for their comments. I'm looking at putting a direct
Ethernet cable in here to see what the difference might make.

Attached is a picture of latest NTP Monitor readout. Bottom two devices are
the Meinberg LanTimes. The others are pool servers.

Rob
===================================

Rob,

Two comments from your screen-shot.

- NTP version 4.2.4p8 is now rather old.  You may well find better 
performance using a more recent version, and especially with the most recent 
development versions on Windows-7 and Windows-Vista.  There are some upgrade 
notes on my Web site.

  http://www.satsignal.eu/ntp/setup.html#updating

- with a local stratum-1 server, you can get better performance using a more 
frequent poll i.e. limit maxpoll.  For my PCs I typically have (with NTP 
4.2.6 or later):

_____________________________________________________
# Local stratum-1 LAN-based servers
server    192.168.0.3     iburst    minpoll 5 maxpoll 5    prefer    # Pixie
server    192.168.0.2     iburst    minpoll 5 maxpoll 5        # Feenix

# External servers from the UK pool
pool    uk.pool.ntp.org        minpoll 10
_____________________________________________________


For measurement, you may want to let the poll interval drift to 1024s, but 
for lower offsets keeping poll to 32s (maxpoll 5) gives better results.

My apologies if you were already aware of this.

Cheers,
David
-- 
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-taylor at blueyonder.co.uk 



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