Junghans

Max Bill radio controlled wall clock

Radio controlled watches and clocks are timepieces that are able to receive a radio transmitted time signal and set themselves to it. They are what you and me can use to benefit from these incredibly exact atomic clocks out there. There are many different time signals, most countries have their own, so lets get technical: There is the MSF signal, also known as “Rugby Clock”, which broadcasts at a frequency of 60 kHz from the Anthorn radio station in Cumbria at a signal strength of 17 kW. The effective range is approx. 1000 km, so it will be received throughout the UK and western Europe. There are three atomic clocks on site, operated by the National Physical Laboratory. The information in the signal includes the UTC (former GMT) year, month, day of month, day of week, hour, minute, British Summer Time. The other commonly used radio time signal broadcast in Europe is the DCF77. This is broadcast from Mainflingen, near Frankfurt/Germany. So it is placed pretty centrally in Europe. It is transmitted at 77.5 kHz with a relatively high power of 50 kW, which means it has an effective range of 2000+ km. The signal contains pretty much the same information that the UK MSF signal does, but in UTC+1 (or CET). It is widely used in Europe because of its strength and centrally located broadcasting station. It is also quite popular in the UK, as almost all radio controlled watches can be set to a different time zone. This means they will still receive the DCF77 signal, but then add or subtract the amount of hours according to which time zone they have been set to.
There are multi-frequency watches available. These watches will be able to receive different time signals on different frequencies. Apart from the UK’s MSF and the European DCF77, the most common ones are the US WWVB (60 kHz) and the Japanese JJY (40 kHz and 60 kHz).
It is very important to know that the radio signal and the reception thereof is subject to various conditions. Apart from the fact that the signal does not mix that well with thick concrete and steel buildings, the time of day and the weather play a huge role. Rain will lower the range, but the signal will bounce off clouds, amplifying it a bit. The signal can travel further at nights and even the time of year and the position of the moon can have a slight impact. It has happened, that radio controlled clocks in eastern Canada set themselves regularly to the German DFC77 signal. It can also happen that you will have problems receiving the signal in the middle of England. Most commonly it is a too weak battery, but you could live in a valley or behind a mountain or just a massive building. If you are having problems receiving a radio signal, place it on the windowsill over night, preferably in the direction of the broadcasting station which signal you are trying to receive. If this does not work, turning the watch by 45° might do the trick. Sounds like a lot of witchcraft? Well, radio controlled watches are a lot more technical and tricky than normal ones. A perfect every-day reception is by no way guaranteed by the manufacturers. And it is not really required as the watches only use the signal to set their highly accurate quartz movements. Unless you calculate time in milliseconds, a couple of days without a signal will pass unnoticed.

Radio controlled watches and clocks are timepieces that are able to receive a radio transmitted time signal and set themselves to it. They are what you and me can use to benefit from these incredibly exact atomic clocks out there. There are many different time signals, most countries have their own, so lets get technical: There is the MSF signal, also known as “Rugby Clock”, which broadcasts at a frequency of 60 kHz from the Anthorn radio station in Cumbria at a signal strength of 17 kW. The effective range is approx. 1000 km, so it will be received throughout the UK and western Europe. There are three atomic clocks on site, operated by the National Physical Laboratory. The information in the signal includes the UTC (former GMT) year, month, day of month, day of week, hour, minute, British Summer Time. The other commonly used radio time signal broadcast in Europe is the DCF77. This is broadcast from Mainflingen, near Frankfurt/Germany. So it is placed pretty centrally in Europe. It is transmitted at 77.5 kHz with a relatively high power of 50 kW, which means it has an effective range of 2000+ km. The signal contains pretty much the same information that the UK MSF signal does, but in UTC+1 (or CET). It is widely used in Europe because of its strength and centrally located broadcasting station. It is also quite popular in the UK, as almost all radio controlled watches can be set to a different time zone. This means they will still receive the DCF77 signal, but then add or subtract the amount of hours according to which time zone they have been set to.
There are multi-frequency watches available. These watches will be able to receive different time signals on different frequencies. Apart from the UK’s MSF and the European DCF77, the most common ones are the US WWVB (60 kHz) and the Japanese JJY (40 kHz and 60 kHz).
It is very important to know that the radio signal and the reception thereof is subject to various conditions. Apart from the fact that the signal does not mix that well with thick concrete and steel buildings, the time of day and the weather play a huge role. Rain will lower the range, but the signal will bounce off clouds, amplifying it a bit. The signal can travel further at nights and even the time of year and the position of the moon can have a slight impact. It has happened, that radio controlled clocks in eastern Canada set themselves regularly to the German DFC77 signal. It can also happen that you will have problems receiving the signal in the middle of England. Most commonly it is a too weak battery, but you could live in a valley or behind a mountain or just a massive building. If you are having problems receiving a radio signal, place it on the windowsill over night, preferably in the direction of the broadcasting station which signal you are trying to receive. If this does not work, turning the watch by 45° might do the trick. Sounds like a lot of witchcraft? Well, radio controlled watches are a lot more technical and tricky than normal ones. A perfect every-day reception is by no way guaranteed by the manufacturers. And it is not really required as the watches only use the signal to set their highly accurate quartz movements. Unless you calculate time in milliseconds, a couple of days without a signal will pass unnoticed.