A number of the Oregon Scientific instruments have a dual band radio-controlled clock and calendar.  This allows them to receive accurate time and date from Anthorn, England or Frankfurt, Germany.  The MSF clock at Anthorn has a 30KW output giving a range of 1200km ( 745 miles). The DCF clock at Frankfurt has a 40kw output giving a range of 1500km ( 932 miles).  The signal strength will be dependant on the distance and terrain between you and the signal source.