Droitwich Signal
Droitwich 198 kHz signal is broadcast by a BBC Radio 4 transmitter with a
carrier power of 400 kW. The Droitwich station uses rubidium frequency
standards and the fractional frequency offset typically observed is less
than 10^-11 over a one day averaging period.

MSF is the radio signal which broadcasts the national time standard for the
UK. The MSF service broadcast from Rugby is the principal means of
disseminating the UK national standards of time and frequency which are
maintained by the National Physical Laboratory. Transmission is 24 hours a
day, and the carrier frequency is maintained at 60 kHz to within 2 parts in
10^12

Frequency:     162 kHz; Power:         2,000 kW
Schedule:      continuous except every Tuesday from 01:00 to 05:00 UTC
Relative Uncertainty of the Carrier Frequency:  2 parts in 10^12.

We are trying to be accurate to <1Hz in 1700kHz or <6 parts in 10^7. So the
standard frequencies are at least 50,000 times more accurate than we need
:-)

73
Steve Whitt
05.04.2005 on mwoffsets@yahoogroups.com