Radio time signal stations of the world

Radio-controlled watches and clocks set themselves from a handful of long-wave transmitters, each run by a national time institute with atomic clocks. Here are the six that watches use, followed by the other time signal stations still on the air.

The six stations radio-controlled watches use

Multi-band watches, such as Casio’s Multi Band 6 models, can receive all six. Most watches receive one or two, depending on the region they were made for.

DCF77

77.5 kHz

Germany

Transmitter: Mainflingen, near Frankfurt am Main
Time source: PTB (Physikalisch-Technische Bundesanstalt)
Power: 50 kW
Range: about 1,000 km for watches, up to 2,000 km
On air: Continuous

The main signal for watches and clocks in continental Europe. German legal time, from PTB’s caesium clocks.

Out of range? Sync your watch with our DCF77 signal

MSF

60 kHz

United Kingdom

Transmitter: Anthorn, Cumbria
Time source: NPL (National Physical Laboratory)
Power: 17 kW
Range: about 500 km for watches, up to 1,500 km
On air: Continuous, apart from scheduled maintenance

UK time. Moved from Rugby to Anthorn in 2007.

Out of range? Sync your watch with our MSF signal

WWVB

60 kHz

United States

Transmitter: Near Fort Collins, Colorado
Time source: NIST (National Institute of Standards and Technology)
Power: 70 kW
Range: about 1,500–3,000 km; most of the mainland US
On air: Continuous

Transmits UTC; watches add the US time zone. Also carries a phase-modulated code used by newer receivers.

JJY 40

40 kHz

Japan

Transmitter: Mount Otakadoya, Fukushima
Time source: NICT (National Institute of Information and Communications Technology)
Power: 50 kW
Range: about 1,000 km
On air: Continuous, apart from maintenance and thunderstorms

Eastern Japan. One of two JJY stations with the same time code.

JJY 60

60 kHz

Japan

Transmitter: Mount Hagane, Kyushu
Time source: NICT (National Institute of Information and Communications Technology)
Power: 50 kW
Range: about 1,000 km
On air: Continuous, apart from maintenance and thunderstorms

Western Japan. Sometimes received in South-East Asia and Oceania at night.

BPC

68.5 kHz

China

Transmitter: Shangqiu, Henan
Time source: NTSC (National Time Service Center, Chinese Academy of Sciences)
Power: 90 kW
Range: about 1,500 km
On air: 21 hours a day; off 21:00–24:00 UTC (05:00–08:00 Beijing time)

China Standard Time. Watches usually try to receive it at night, before the daily break.

Other long-wave time stations

These stations carry time information but are not received by consumer watches. Most use phase modulation, which needs a specialised receiver.

Station	Country	Frequency	Location	Operator	Power	Notes
ALS162	France	162 kHz	Allouis	ANFR	800 kW	Phase-modulated time code on a former broadcast transmitter, encoded similarly to DCF77. Range up to 3,500 km. Used by professional and public clocks in France.
RBU	Russia	66.66 kHz	Taldom, Moscow region	VNIIFTRI	50 kW	Phase-modulated time code.
RTZ	Russia	50 kHz	Irkutsk	VNIIFTRI	10 kW	Phase-modulated time code.
Beta (RJH63, RJH69, RJH77, RJH86, RJH90, RAB99)	Russia, Belarus, Kyrgyzstan	around 25 kHz	Krasnodar, Vileyka, Arkhangelsk, Bishkek, Nizhny Novgorod, Khabarovsk	VNIIFTRI	300 kW each	Very-low-frequency stations, each transmitting time signals in a short daily slot of 20–25 minutes.
BPL	China	100 kHz	Pucheng, Shaanxi	NTSC	800 kW	Loran-C type signal, 05:30–13:30 UTC, range up to 3,000 km.
RNS-E and RNS-V	Russia	100 kHz	Karachev (Bryansk) and Alexandrovsk-Sakhalinsky	VNIIFTRI	800 kW / 400 kW	Chayka navigation signals with time information, on fixed daily schedules.
BBC Radio 4 long wave	United Kingdom	198 kHz	Droitwich	BBC / NPL	500 kW	Broadcast transmitter with a phase-modulated data signal that includes time, used for radio teleswitching.
Polskie Radio long wave	Poland	225 kHz	Solec Kujawski	Polskie Radio / GUM	1,000 kW	Broadcast transmitter carrying a phase-modulated time signal from Poland’s official time (e-Czas Radio).
DCF49, DCF39, HGA22	Germany, Hungary	129.1, 139 and 135.6 kHz	Mainflingen, Burg bei Magdeburg, Lakihegy	EFR / PTB time	50–100 kW	Radio teleswitch signals for utilities; they carry time but no reference frequency.

Short-wave time stations

Heard on short-wave radio receivers, often across whole continents. Many announce the time by voice.

Station	Country	Frequencies	Location	Operator	Notes
WWV	United States	2.5, 5, 10, 15, 20 and 25 MHz	Near Fort Collins, Colorado	NIST	Voice announcements and a time code; heard worldwide on short-wave radios.
WWVH	United States	2.5, 5, 10 and 15 MHz	Kekaha, Hawaii	NIST	Sister station of WWV for the Pacific region.
BPM	China	2.5, 5, 10 and 15 MHz	Pucheng, Shaanxi	NTSC	Time code on a sub-carrier; schedules vary by frequency.
RWM	Russia	4.996, 9.996 and 14.996 MHz	Taldom, Moscow region	VNIIFTRI	Carrier pulses once and ten times per second.
HLA	South Korea	5 MHz	Daejeon	KRISS	Time and frequency signal.
YVTO	Venezuela	5 MHz	Caracas	Venezuelan Navy	Time signal with voice announcements.
LOL	Argentina	10 MHz	Buenos Aires	Naval Hydrographic Service	Time signal from the Naval Observatory.
PPE	Brazil	10 MHz	Rio de Janeiro	Observatório Nacional	Time signal from Brazil’s national observatory.

Closed stations

Station	Country	Frequency	Location	Operator	What happened
CHU	Canada	3.33, 7.85 and 14.67 MHz	Ottawa	NRC	Short-wave time signal with voice announcements and a digital time code. Discontinued on 22 June 2026.
HBG	Switzerland	75 kHz	Prangins	METAS	Swiss long-wave time signal. Switched off on 1 January 2012, as DCF77 covers Switzerland well; the masts were demolished later that year.
MIKES	Finland	25 MHz	Espoo	VTT MIKES	Local short-wave time signal for the Helsinki area. Discontinued in 2017.
MSF at Rugby	United Kingdom	60 kHz	Rugby, Warwickshire	NPL	Original MSF site. Moved to Anthorn on 1 April 2007.

Good to know

Range depends on conditions. Long-wave signals travel further at night, so most watches try to sync in the early morning hours. Steel and concrete buildings, electrical equipment and mountains weaken the signal. A window facing the transmitter often helps.

The signal arrives slightly late. Radio waves need about 1 millisecond for every 300 km, so a watch 1,500 km from the transmitter receives the time about 5 ms late. That is far below what a watch can display.

Same frequency, different codes. MSF, WWVB and JJY 60 all use 60 kHz but with different time codes. A watch made only for WWVB cannot decode MSF, and the other way round.

Sources: the station operators (PTB, NPL, NIST, NICT, NTSC) and published station lists. Typical watch reception ranges are those quoted in watch makers’ manuals. Checked October 2026.