[ntp:questions] Trying to use Dimension 4 time keeper

W. eWatson wolftracks at invalid.com
Sat Sep 14 20:39:17 UTC 2013

On 9/14/2013 2:45 AM, David Taylor wrote:
> On 14/09/2013 05:48, W. eWatson wrote:
>> What have I gained?  What does the data mean from ntpq -n -clpe -clas?
> Please see:
>    http://www.satsignal.eu/ntp/setup.html#check
> for a brief guide to checking that NTP is working.
> The command "ntpq -p" or "ntpq -pn" will show the delay between the
> servers and your PC (in milliseconds, expect 20-30 ms for network-locale
> servers 100+ ms for servers on an inappropriate continent), and the
> offset column shows how well NTP is doing, the lower the offset the
> nearer to UTC is your PC running.  The offset value will be highly
> dependant on the OS (i.e. Windows of Linux/FreeBSD), the servers you are
> using (i.e. Internet or local), and whether or not you have a PPS (pulse
> per second) feed to your PC.
> In general, you will see offsets in the tens of milliseconds range for a
> purely Internet-synced Windows PC (but may be better with some versions
> of Windows), and sub-millisecond for FreeBSD/Linux PCs.  For best
> performance, you may want a local Linux PC synced to the Internet (or
> with a GPS/PPS source), and sync the Windows PCs to that server (but
> sync them more tightly than you would to the Internet).  I don't think
> you're at that stage yet, but it's worth bearing in mind.  The Linux box
> could be as simple as the Raspberry Pi card PC, and even adding a GPS to
> that only adds ~US $35 to the cost.

A little bit of data from the two XP PCs:
Older and more troublesome PC
  Jitter high 300-650
  Offset around 685
  Delay about 100.xxx
  Reach 80  jumped to 377 an hour later
  One * for the single pool

Newer XP
  Jitter low, 11-8
  Reach 377
  * + - + - on five servers
  Delay 100-150

Those are fairly rough, as seen in a five minute span. To really make 
any progress I would think a monitor of the data would be more helpful.

I noticed Broken Clock in the documentation mentioned above. It looks 
tricky to evaluate.

In my situation, I would be happy if one of the important parameters 
would sound an alarm in my den when one went out of bounds. Fat chance 
of that.

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