Users of the National Physical Laboratory’s (NPL) MSF time and frequency signal are probably aware that the signal is occasionally taken off-air for scheduled maintenance.
NPL have published there scheduled maintenance for 2010 where the signal will be temporarily taken off-air. Usually the scheduled downtimes lasts for less than four hours but users need to be aware that while NPL and VT Communications, who service the antenna, make every effort to ensure the transmitter is off for a brief amount of time as possible, there can be delays.
And while NPL like to ensure all users of the MSF signal have advanced warning of possible outages, emergency repairs and other issues may lead to unscheduled outages. Any user receiving problems receiving the MSF signal should check the NPL website in case of unscheduled maintenance before contacting your time server vendor.
The dates and times of the scheduled maintenance periods for 2010 are as follows:
* 11 March 2010 from 10:00 UTC to 14:00 UTC
* 10 June 2010 from 10:00 BST to 14:00 BST (UTC + 1 hr)
* 9 September 2010 from 10:00 BST to 14:00 BST (UTC + 1 hr)
* 9 December 2010 from 10:00 UTC to 14:00 UTC
As these scheduled outages should take no longer than four hours, users of MSF referenced time servers should not notice any drop off in accuracy of their network as their shouldn’t be enough time for any device to drift.
GPS time servers receive the time from the orbiting navigational satellites. As these are available anywhere on the globe and the signals are never down for outages they can provide a constant accurate time signal (GPS time is not the same as UTC but is easily converted by NTP as it is exactly 17 seconds behind due to leap seconds being added to UTC and not GPS).