There have been four people that have had honour of providing the permanent voice to the speaking clock over the last 70. And over 70 million calls are made to the speaking clock making it an important from of accurate time but have you ever wondered how accurate it is and where the time comes from and how accurate it is?

The speaking clock is controlled by a major British telecoms company who took over the General Post Office (GPO) and the time was originally supplied by the National Physical Laboratory (NPL) who also provide the MSF signal that NTP time servers use as a source of atomic clock synchronisation.

NPL no longer help with the speaking clock but the time is still controlled by NTP servers, either GPS or MSF, which ensures that the time you hear on the end of the telephone is accurate.

NTP servers are also commonly used by computer networks to ensure that IT systems, from traffic light signals to the office PC are all running an accurate form of time.

NTP time servers can either receive the MSF radio signal broadcast by NPL or, more commonly now, GPS signals beamed directly from space.

Often network administrators opt to use online NTP servers that send time signals over the internet but these are not as accurate and cause security problems so it is far better to have a dedicated NTP time server to control the time if you wish to have a computer network that is running accurately.

The Accuracy of the Speaking Clock is a post from: Galleon Systems

Accuracy, when it comes to time synchronization, means only one thing – atomic clocks. No other method of keeping time is as accurate or reliable as an atomic clock. In comparison to an electronic clock, such as a digital watch, which will lose up to a second a day – an atomic clock will remain accurate to a second over 100,000 years.

Atomic clocks are not something that can be housed in an average server room though; atomic clocks are very expensive, fragile and require full time technicians to control so are usually only found in large scale physics laboratories such as the ones run by NIST (National Institute of Standards and Time – USA) and NPL (National Physical Laboratory – UK).

Getting a source of accurate time from an atomic clock is relatively easy. For a secure and reliable source of atomic clock time there are only two options (the internet can neither be described as secure nor reliable as a source of time):

• GPS time
• UTC time broadcast on long-wave

GPS time, from the USA’s Global Positioning System, is a time stamp generated onboard the atomic clocks on the satellites. There is one distinct advantage about using GPS as a source of time: it is available anywhere on the planet.

All that is required to receive and utilise GPS time is a GPS time sever and antenna; a good clear view of the sky is also needed for an assured signal. Whilst not strictly UTC time (Coordinated Universal Time) being broadcast by GPS (UTC has had 17 leap seconds added to it since the satellites were launched) the timestamp included the information needed for NTP to convert it to the universal time standard.

UTC, however, is broadcast directly from physics laboratories and is available by using a radio referenced NTP server. These signals are not available everywhere but in the USA (the signal is known as WWVB) and most of Europe (MSF and DCF) are covered. These too are highly accurate atomic clock generated time sources and as both methods come from a secure source the computer network will remain secure.

NTP Servers Which Signal is Best Radio or GPS? is a post from: Galleon Systems

The need for accurate time is therefore essential if you wish to prevent time sensitive applications on your network failing or to avoid debugging problems – not too mention keeping your system secure.

NTP time servers (Network Time Protocol) are common devices that many computer networks use to provide a source of accurate time as NTP is able to ensure entire networks are synchronised to just a few milliseconds to the time reference.

The time reference that NTP servers use can come from several locations:

• The internet
• GPS satellite
• And National Physical Laboratories

In the UK, the National Physical Laboratory (NPL) produce a time signal that can be received by radio referenced NTP time servers. This used to be broadcast from rugby in central England but in recent years the transmission has been moved to Cumbria.

The Cumbrian signal, known as MSF, is broadcast from Anthorn with a signal strength of 100 microvolts per metre at a distance of 1000 km. This should mean that the signal is available everywhere in the UK; however, this is not strictly the case as many MSF clocks and time servers can run into trouble when first trying to receive this atomic clock generated signal.

However, a simple checklist should ensure that no matter what your location you should be able to receive a signal to your MSF clock or NTP time server:

• Check the power. Perhaps the most common problem ensure the battery is inserted and if the clock uses both mains power and a battery, remember to switch the mains power on. It can take quite a few minutes for the clock to pick up the MSF signal, so be patient.
• Try rotating the clock or time server. As the MSF signal is long wave the antenna needs to be perpendicular to the signal for best reception.
• If all else fails move the clock or time server to a different location. The signal can be blocked by local interference from electrical and mechanical devices.

* Note the MSF signal is down for scheduled maintenence on Tuesday 9 September 2010 from 10:00 BST to 14:00 BST

The Time According to Cumbria Using the UKs MSF Time and Frequency Signal is a post from: Galleon Systems

There is no single master clock used for the world’s timing but there are a constellation of clocks that are used as a basis for a universal timing system known as UTC (Coordinated Universal Time).

UTC enables all the world’s computer networks and other technology to talk to each other in perfect synchronicity which is vital in the modern world of internet trading and global communication.

But as mentioned controlling UTC is not down to one master clock, instead, a serious of highly precise atomic clocks based in different countries all work together to produce a timing source that is based on the time told by them all.

These UTC timekeepers include such notable organisations as the USA’s National Institute of Standards and Time (NIST) and the UK’s National Physical Laboratory (NPL) amongst others.

These organisations don’t just help ensure UTC is as accurate as possible but they also provide a source of UTC time available to the world’s computer networks and technologies.

To receive the time from these organisations, a NTP time server (Network Time Server) is required. These devices receive the broadcasts from places like NIST and NPL via long wave radio transmissions. The NTP server then distributes the timing signal across a network, adjusting individual system clocks to ensure that they are as accurate to UTC as possible.

A single dedicated NTP server can synchronize a computer network of hundreds and even thousands of machines and the accuracy of a network relying in UTC time from the broadcasts by NIST and NPL will also be highly precise.

The NIST timing signal is known as WWVB and is broadcast from Boulder Colorado in the heart of the USA whilst the UK’s NPL signal is broadcast in Cumbria in the North of England and is known as MSF – other countries have similar systems including the DSF signal broadcast out of Frankfurt, Germany.

The Worlds Atomic Clock Timekeepers is a post from: Galleon Systems