[time-nuts] Can anyone help?

[bg at lysator.liu.se]

My DSL-modem will buffer several hundreds of milliseconds while doing
heavy down/up-loading. Hence do NOT fill any of the pipes between you and
the ntp server. Even though you probably "control" only one hop and the
later routers are probably not buffering as much as my DSL-modem.

Here is a start for getting "local" ntp-servers.

      http://www.pool.ntp.org/zone/za

As for performance a stratum-2 server I run is right now showing offsets
between 3us and 38us for four servers, with a poll interval of 64 seconds
and distances between 0.3ms and 15.5ms. This is probably not
representative, but shows that very good performance can be seen in
favorable conditions.

Local servers can sometimes be found even though not advertized. But as
with "open" WiFi-nets -- do not abuse! 'ntpq -c pe hostname.yourisp.za'
can be used to probe various hosts. Gateways, routers, and other servers
at the ISP is probably syncing time. They might be enough opened for you
to check what servers they are using. Using routers as a server is
probably a bad idea...

Happy timing!

--

   Björn

On Sat, October 28, 2006 23:08, Didier Juges said:

> Some ISPs over here in the USA run their own ntp server, and sometimes
> those are made available to the customers. You may ask if your ISP
> offers this service, or if they know of an ntp server that's easy to get
> to from your location.
>
> Didier KO4BB
> .
>
> John Ackermann N8UR wrote:
>> Hi Paul --
>>
>> You can go down as deep a rathole with internet timing as we do with
>> atomic clocks :-), but in very gross terms if your computer is running
>> the "NTP" time daemon you can keep time to better than 100ms pretty
>> easily.  With a broadband connection and good choice of servers, a few
>> milliseconds is possible.
>>
>> Earlier versions of Windows did not have a good timekeeping system, but
>> I understand that the latest service pack of XP is much improved; I
>> don't know how it compares with the "real" NTP program though.
>>
>> John
>> ----
>>
>> ABSA Email said the following on 10/28/2006 12:32 PM:
>>
>>> Hi there,
>>> I need some advice.
>>> I'm not into the nano-second accuracy region, so this could well be
>>> considered OT.
>>>
>>> 1. I have a Gent's mechanical clock, and I check it by my computer
>>> clock. To
>>> set the computer clock, I use the built-in synchronisation to
>>> time.windows.com, or time.nist.gov.  How accurate can this be by the
>>> time
>>> that the synchronising signal reaches my computer in South Africa?  Are
>>> there any time stations nearer to me than USA? Does the time signal
>>> update
>>> itself as it travels the Internet to me?
>>>
>>> 2. This is for frequency measurement. Can anyone recommend a
>>> divide-by-ten
>>> counter to use as a pre-scaler up to 500 MHZ?
>>>
>>>
>>>
>>> Paul Galpin
>>> South Africa
>>>
>>>
>
>
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