[58799] in North American Network Operators' Group
Re: Non-GPS derived timing sources (was Re: NTp sources that work in
daemon@ATHENA.MIT.EDU (Peter Lothberg)
Sun Jun 1 11:13:40 2003
Date: Sun, 1 Jun 2003 8:13:08 PDT
From: Peter Lothberg <roll@stupi.se>
To: Sean Donelan <sean@donelan.com>
Cc: nanog@merit.edu
In-Reply-To: Your message of Sun, 1 Jun 2003 08:18:45 -0400 (EDT)
Errors-To: owner-nanog-outgoing@merit.edu
> I don't expect GPS to spin out of control soon..
So GPS tracks TAI and the difference is published (2 months after the
fact..)
But it's simple to build a 'jamer' that makes GPS reception not work
in a limited area, same for Loran-C used in combination with GPS in
many Sonet/SDH S1 devices.
> but I did wonder how
> hard it is to find a another reliable clock source of similar quality to
> GPS to double check GPS.
Short for a lab part of TAI, I really don't knew. GPS
price/perfromance is fenomenal.
> US clocks account for 40% of the input to TAI.
In the month of April 2003;
NIST was 4.662%
USNO was 44.314%
(and we where 0.501%...)
-Peter
