More of the world DOESN'T have access to time signals than does. Europe, Japan and North America at present are it. Clocks, watches and such won't sync to shortwave,the stations are all longwave. So even where a shortwave time signal exists (China, for example), no longwave devices are possible. Also, unless a device is specifically designed to do so, it won't work outside it's 'home' territory as frequencies and methods of broadcast differ.