And longwave service

The 1960s saw the inauguration of time services using kilometric (long) waves. These waves overcome the drawbacks of short waves as longwave broadcasting is stable and readily penetrates buildings, thus simplifying the problem of aerials. Permanent transmitters of time signals in the longwave range exist in both America and Europe: WWVB, 60 kHz (USA), MSF 60 kHz (GB), HBG, 75 kHz (CH) and DCF 77.5 kHz (FRG). Their high degree of reliability and good reception mean that long waves lend themselves to automated applications, especially automatic clock synchronisation. Clocks of every kind nowadays are controlled by transmitters up to distances of several thousands of kilometres. These clocks no longer need monitoring as they maintain absolutely accurate time and are even synchronised to change in countries that adopt daylight saving time. The transmitters are accurate to within 1/10,000th of a second.