What does MSF stand for? (FAQ - Time)
MSF is the three-letter call sign used to designate the UK’s 60 kHz standard-frequency and time signal. The first character can be only 2, G or M for a UK-based signal, and it appears that MSF was chosen from the available combinations so that it could be memorised as “Master Standard Frequency”. However, MSF is not intended to be an acronym.
When the service began in 1950 there were announcements every 15 minutes, "MSF MSF MSF" in Morse code followed by speech, "This is MSF, Rugby, England, transmitting ...". Similar services in other countries also have call signs, such as DCF, HBG, JJY and WWVB.