Radio Controlled Technology Explained

One interesting feature of these clocks is their ability to check the radio signal against the accurate MSF signal transmitted from Cumbria, which is precise to within 1000ths of a second per year. The clock regularly compares the two signals and corrects itself as needed, automatically adjusting for daylight savings time changes in spring and autumn.

Although some manufacturers refer to their radio controlled clocks as “atomic clocks,” this isn’t entirely accurate. An atomic clock operates using a cesium or rubidium oscillator, while a radio controlled clock receives a radio signal transmitted from an atomic clock.

In the UK, the MSF signal is transmitted from Anthorn Radio Station in Cumbria by VT Communications, under contract to the National Physics Laboratory (NPL). This signal provides a reliable and accurate time signal that can be received omnidirectionally across the whole country, and even in Northern Europe. The signal can be decoded by the receiver found in radio controlled clocks and converted into a display of the time and date, including year, month, day of the month, day of the week, hour, minute, British Summer Time status, and DUT1.