[time-nuts] Meinberg or T/Bolt for PC time?

Chris Albertson albertson.chris at gmail.com
Mon Aug 11 15:57:29 EDT 2014


On Mon, Aug 11, 2014 at 10:29 AM, Chris Wilson <chris at chriswilson.tv> wrote:
>
>
>   11/08/2014 18:26
>
> I have 4 windows based PC's on my home network, for years i have used
> Meinberg or an equivalent to set the PC time.

The best way the keep the PC clocks in sync would be to run NTP on all
the PCs.

You say "Meinburg" I think that just one place redistributing NTP
which is free.  I always download from ntp.org  the reference NTP
implementation and build it myself but Meinberg save you the effort of
building from source.  Either way you seem to already have NTP running
on the PCs.

What you need next is a better reference clock connected at least on
of the PCs.  Currently, I bet they are using some other NTP server out
on the Internet as a reference clock.  You would do much better
(almost three orders of magnitude better) if you used the Thunderbolt
as the reference clock.    Ignore Lady Heather for now.  It is not
needed for this.

Pick one of the PCs, the one you are going to leave running 24x7 and
connect that one to theTB using a serial cable.  Yes a real RS232
serial cable.   It is MUCH better to use a serial port then a serial
to USB dingle.     When you guid the serial cable make sure the PPS
from the TB is on the DCD line and get the polarity correct.

After this is done all that remains is to edit an NTP configuration
file on each of the PCs.    To keep this short, ask about this later
if you decide to got this route.

The is an NTP email list you can find on ntp.org and that is a much
better place to ask about NTP then here.

One more thing.  Perhaps you don't have a PC with a real RS232 port
you want to run 24x7.   In that case you get a tiny  ARM based PC like
the Raspberry Pi of Beagle board for about $50."  You run Linux and
NTP on that and connect the Thunderbolt there.   This will pay for
itself from saving on the electric bill in under a year.

-- 

Chris Albertson
Redondo Beach, California



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