A Stratum 1 NTP Server provides an accurate timing reference to computer networks. Precise time is obtained from external reference clocks to synchronise the NTP servers clock. The most popular reference clocks for stratum 1 NTP servers are GPS and radio time and frequency broadcasts.
In the UK, the MSF radio time and frequency broadcast has been transmitted from Rugby for over 80 years. The transmission provided a reliable accurate source of time throughout the British Isles. The However, as of 1 April 2007, the transmitter was relocated to Anthorn in Cumbria. Since the relocation, much of the south of England and South Wales has suffered signal reception problems. Hence, in many areas of the British Isles GPS is the better option for time reception.
GPS has the advantage that provided the GPS antenna is shown a good view of the sky, a good signal lock is virtually guaranteed. However, this being the case, the ideal location for a GPS antenna is on a rooftop with a full 360 degree view of the sky. Therefore, initial installation costs can be greater for GPS installations as opposed to radio ones. The guaranteed signal lock of GPS reference clock systems however, generally makes the extra expense worth-while.