In Western Europe, there are the so-called DCF77 - long-wave transmitter.
This post on 77KHz the exact time and date information.
I know I'm probably just looking in the wrong place but I spent some time just now trying unsuccessfully to find the Propeller Manual on the Parallax
Can it be done? Seems like it could.
MS-DOS source code is available. There are some other DOS versions out there too...
While browsing various Electronics Apps for my Phone/Tablet I came across quite possibly the absolute most useful App of all. "Electrodroid".