National Physical Laboratory time signal
Encyclopedia
The Time from NPL is a radio signal broadcast from the Anthorn radio station near Anthorn
, Cumbria
which serves as the United Kingdom
's national time reference. The time signal is derived from three atomic clock
s installed at the transmitter site, and is based on time standard
s maintained by the UK's National Physical Laboratory
(NPL) in Teddington
. The service is provided by Babcock International
(with which former providers VT Communications
merged) under licence from the NPL and is funded by the Department for Innovation, Universities and Skills
.
The signal, also known as the MSF signal (and formerly the Rugby clock) is broadcast at a highly-accurate frequency of 60 kHz and can be received throughout the UK, and in much of northern and western Europe.
The signal’s carrier frequency is maintained at 60 kHz to within 2 parts in 1012, controlled by caesium atomic clocks
at the radio station.
. From 19 December 1927, it broadcast a 15.8 kHz time signal from the Royal Observatory
which could be received worldwide. It consisted of 306 pulses in the five minutes up to and including 10:00 and 18:00 GMT
, with a longer pulse at the start of each minute. Frequency-shift keying
was added in 1967, making the signal harder to use as a frequency reference. Eventually, time signals from GBR were terminated in November 1986 and it is no longer used as a frequency reference.
The MSF signals started in 1950, following the transmission pattern described below. They were originally intended to provide frequency references at 2.5, 5 and 10 MHz, originally only occasionally during the day. At first, there were announcements every fifteen minutes, beginning with the Morse code
representation of "MSF MSF MSF", followed by speech "This is MSF, Rugby, England, transmitting ...". From May 1953, the signal was broadcast 24 hours a day, but with regular five-minute stoppages to allow the reception of other signals. The 60 kHz signal finally became an uninterrupted 24-hour service in 1966, and the frequency references were discontinued in February 1988.
On 27 February 2007 the NPL started tests of the new time signal transmissions from Anthorn, latitude 54° 55' N, and longitude 3° 15' W. This station has the callsign GBZ
and is operated by VT Communications
.
The formal inauguration of the relocated facility took place on 1 April 2007, when the name of the service became "The Time from NPL" and the signal from Rugby was permanently switched off. The change in location and consequent change in signal strength can make some equipment designed to use the MSF signal fail to continue doing so. This is found more in domestic equipment not designed for optimum sensitivity and positioned haphazardly; only the few people aware of the Rugby switchoff will have made the connection between failure of MSF devices and the switchoff.
. The transmitter's original location meant that the clock was referred to as "the Rugby clock". Following its relocation, the NPL now formally calls the signal "The Time from NPL".
The Rugby transmitter's callsign was MSF, where 'M' is one of the ITU prefix
es allocated to the United Kingdom, and the letters 'SF' were allocated for no documented reason. This resulted in the common terminology "the MSF signal", which is still used by the NPL. The official history of the service says that "Rugby was given an additional commitment for the transmission of reference Modulated Standard Frequencies", but no actual explanation is given for the call sign "MSF".
of 17 kW, on a frequency of 60 kHz to within 2 parts in 1012. The signal strength is greater than 10 mV/m at 100 km; it is greater than 100 μV/m at 1000 km from the transmitter, and thus can be received at not less than this strength throughout the UK. The signal can also be received, and is widely used, in northern and western Europe
.
While at Rugby the transmitter generated 60 kW of radio frequency
power (using 70 kW of mains power
). The 180m-high T-aerial
antenna was 500m across at its top. The vertical part of the antenna radiated the signal, so that the received strength was similar in all directions (it was approximately omnidirectional
).
.
) near the beginning of each second to encode the current time and date. The rise and fall times of the 60 kHz carrier are determined by the combination of antenna and transmitter.
Each UTC second begins with 100 ms of 'off', preceded by at least 500 ms of carrier. The second marker is transmitted with an accuracy better than ±1 ms relative to Coordinated Universal Time
(UTC), which is itself always within ±1 second of Greenwich Mean (solar) Time
(GMT).
The first second of the minute, denoted second 00, begins with a period of 500 ms with the carrier off, to serve as a minute
marker. The other 59 (or, exceptionally, 60 or 58) second
s of the minute always begin with at least 100 ms 'off', followed by two data bits of 100 ms each, and end with at least 700 ms of carrier. Bit A is transmitted from 100 to 200 ms after the second, and bit B is transmitted from 200 to 300 ms. Carrier on represents a bit value of 0 and carrier off a value of 1.
If each second is considered as ten 100 ms pieces, the minute marker is transmitted as
Although two data bits are transmitted per second, the time code has the property that only one of them is variable; non-zero B bits are only transmitted when the corresponding A bit has a fixed value.
Seconds 01–16 carry information for the current minute about the difference (DUT1) between atomic and astronomical time, and the remaining seconds convey the time and date code. The time and date code information begins 43 seconds before the corresponding minute marker (second 17 of the previous minute, in the absence of leap seconds), and is always given in terms of UK civil time, which is UTC in winter and UTC+1h when Summer Time
is in effect.
Consecutive bits from 01B–08B are set to 1 to indicate positive DUT1 values from +0.1s to +0.8s. For example, bit 05B is set if DUT1 ≥ 0.5 s. Consecutive bits from 09B–16B are set to 1 to indicate negative DUT1 values from −0.1s to −0.8s. For example, bit 11B is set if DUT1 ≤ −0.3 s.
In case of a leap second, a zero bit is inserted between seconds 16 and 17. In case of a negative leap second, second 16 will be deleted. Since negative leap seconds can only occur when DUT1 is positive, bits 9B through 16B will be zero.
Bits 17A–51A encode the time of the following minute in binary-coded decimal
, most significant bit first. Beginning with bit 17A comes 4 bits of tens of years, 4 bits of years, 1 bit of tens of months, 4 bits of months, 2 bits of tens of days, 4 bits of days, 3 bits of day of week (0=Sunday), 2 bits of tens of hours, 4 bits of hours, 3 bits of tens of minutes, and 4 bits of minutes.
Bits 54B–57B provide odd parity over the time code. The 4 parity bits cover years (8 bits), months and days (11 bits), day of week (3 bits), and time of day (13 bits) respectively.
Bit 58B indicates the broadcast time is summer time. Bit 53B gives warning that the summer time bit is about to change. It is set for 61 consecutive minutes, starting 1 hour 7 seconds before the change, and ending 7 seconds before the change, 5 seconds before the first changed bit 58B, which is itself transmitted 2 seconds (1.7–1.8 seconds, to be more precise) before moment of the time change.
In addition to the 500 ms carrier-off minute marker, bits 53A–58A are all set permanently at '1', and are bracketed by bits 52A and 59A at '0'. This sequence
s which occur less than once a year on average. The only indication is a change in the number of padding bits before the time code during the minute before the leap second. Therefore, unless a leap-second announcement is manually entered into a receiver in advance, it may take some time until an autonomous MSF receiver regains synchronization with UTC after a leap second (especially if the reception is not robust at the time of the leap second).
The time signal only provides 1 hour warning of summer-time changes.
Anthorn
Anthorn is a village in Cumbria, England. It is situated on the south side of the Solway Firth, on the Wampool estuary, about thirteen miles west of Carlisle...
, Cumbria
Cumbria
Cumbria , is a non-metropolitan county in North West England. The county and Cumbria County Council, its local authority, came into existence in 1974 after the passage of the Local Government Act 1972. Cumbria's largest settlement and county town is Carlisle. It consists of six districts, and in...
which serves as the United Kingdom
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
's national time reference. The time signal is derived from three atomic clock
Atomic clock
An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...
s installed at the transmitter site, and is based on time standard
Time standard
A time standard is a specification for measuring time: either the rate at which time passes; or points in time; or both. In modern times, several time specifications have been officially recognized as standards, where formerly they were matters of custom and practice. An example of a kind of time...
s maintained by the UK's National Physical Laboratory
National Physical Laboratory, UK
The National Physical Laboratory is the national measurement standards laboratory for the United Kingdom, based at Bushy Park in Teddington, London, England. It is the largest applied physics organisation in the UK.-Description:...
(NPL) in Teddington
Teddington
Teddington is a suburban area in the London Borough of Richmond upon Thames in south west London, on the north bank of the River Thames, between Hampton Wick and Twickenham. It stretches inland from the River Thames to Bushy Park...
. The service is provided by Babcock International
Babcock International Group
Babcock International Group plc is a British-based support services company specialising in managing complex assets and infrastructure in safety-critical and mission-critical environments. Although the company has civil contracts, its main business is with public bodies, particularly the UK...
(with which former providers VT Communications
VT Communications
VT Communications was a part of VT Group plc. VT Communications was essentially the company formed from the privatisation of the BBC World Service transmitter sites. It was initially named Merlin Communications, then, after acquisition by VT, VT Merlin Communications...
merged) under licence from the NPL and is funded by the Department for Innovation, Universities and Skills
Department for Innovation, Universities and Skills
The Department for Innovation, Universities and Skills was a UK government department created on 28 June 2007 to take over some of the functions of the Department of Education and Skills and of the Department of Trade and Industry. In June 2009 it was merged into the newly formed Department for...
.
The signal, also known as the MSF signal (and formerly the Rugby clock) is broadcast at a highly-accurate frequency of 60 kHz and can be received throughout the UK, and in much of northern and western Europe.
The signal’s carrier frequency is maintained at 60 kHz to within 2 parts in 1012, controlled by caesium atomic clocks
Atomic clock
An atomic clock is a clock that uses an electronic transition frequency in the microwave, optical, or ultraviolet region of the electromagnetic spectrum of atoms as a frequency standard for its timekeeping element...
at the radio station.
History
A radio station at Rugby was first operated by the Post Office from 1926, with the call-sign GBRGBR
GBR can refer to of Great Britain and Northern Ireland**The ISO 3166-1 3-letter abbreviation for the United Kingdom**The International Olympic Committee country code for Great Britain and Northern Ireland*GBR – Walter J...
. From 19 December 1927, it broadcast a 15.8 kHz time signal from the Royal Observatory
Royal Observatory
Royal Observatory may refer to:* The Royal Observatory, Greenwich * The Royal Observatory, Edinburgh* Before 1997, Hong Kong Observatory* The Royal Observatory of Belgium, Uccle...
which could be received worldwide. It consisted of 306 pulses in the five minutes up to and including 10:00 and 18:00 GMT
Greenwich Mean Time
Greenwich Mean Time is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. It is arguably the same as Coordinated Universal Time and when this is viewed as a time zone the name Greenwich Mean Time is especially used by bodies connected with the United...
, with a longer pulse at the start of each minute. Frequency-shift keying
Frequency-shift keying
Frequency-shift keying is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier wave. The simplest FSK is binary FSK . BFSK uses a pair of discrete frequencies to transmit binary information. With this scheme, the "1" is called...
was added in 1967, making the signal harder to use as a frequency reference. Eventually, time signals from GBR were terminated in November 1986 and it is no longer used as a frequency reference.
The MSF signals started in 1950, following the transmission pattern described below. They were originally intended to provide frequency references at 2.5, 5 and 10 MHz, originally only occasionally during the day. At first, there were announcements every fifteen minutes, beginning with the Morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...
representation of "MSF MSF MSF", followed by speech "This is MSF, Rugby, England, transmitting ...". From May 1953, the signal was broadcast 24 hours a day, but with regular five-minute stoppages to allow the reception of other signals. The 60 kHz signal finally became an uninterrupted 24-hour service in 1966, and the frequency references were discontinued in February 1988.
On 27 February 2007 the NPL started tests of the new time signal transmissions from Anthorn, latitude 54° 55' N, and longitude 3° 15' W. This station has the callsign GBZ
GBZ
GBZ is the call sign of a British VLF transmitter on 19.6 kHz from Anthorn, Cumbria , which is involved with transmitting encrypted signals to submarines...
and is operated by VT Communications
VT Communications
VT Communications was a part of VT Group plc. VT Communications was essentially the company formed from the privatisation of the BBC World Service transmitter sites. It was initially named Merlin Communications, then, after acquisition by VT, VT Merlin Communications...
.
The formal inauguration of the relocated facility took place on 1 April 2007, when the name of the service became "The Time from NPL" and the signal from Rugby was permanently switched off. The change in location and consequent change in signal strength can make some equipment designed to use the MSF signal fail to continue doing so. This is found more in domestic equipment not designed for optimum sensitivity and positioned haphazardly; only the few people aware of the Rugby switchoff will have made the connection between failure of MSF devices and the switchoff.
The 'MSF signal' and the 'Rugby clock'
From the time signal's inauguration in 1950 until 1 April 2007 it was transmitted from Rugby radio station near Rugby, WarwickshireRugby, Warwickshire
Rugby is a market town in Warwickshire, England, located on the River Avon. The town has a population of 61,988 making it the second largest town in the county...
. The transmitter's original location meant that the clock was referred to as "the Rugby clock". Following its relocation, the NPL now formally calls the signal "The Time from NPL".
The Rugby transmitter's callsign was MSF, where 'M' is one of the ITU prefix
ITU prefix
The International Telecommunication Union allocates call sign prefixes for radio and television stations of all types. They also form the basis for, but do not exactly match, aircraft registration identifiers. These prefixes are agreed upon internationally, and are a form of country code...
es allocated to the United Kingdom, and the letters 'SF' were allocated for no documented reason. This resulted in the common terminology "the MSF signal", which is still used by the NPL. The official history of the service says that "Rugby was given an additional commitment for the transmission of reference Modulated Standard Frequencies", but no actual explanation is given for the call sign "MSF".
Transmission and reception
The transmitted signal has an effective radiated powerEffective radiated power
In radio telecommunications, effective radiated power or equivalent radiated power is a standardized theoretical measurement of radio frequency energy using the SI unit watts, and is determined by subtracting system losses and adding system gains...
of 17 kW, on a frequency of 60 kHz to within 2 parts in 1012. The signal strength is greater than 10 mV/m at 100 km; it is greater than 100 μV/m at 1000 km from the transmitter, and thus can be received at not less than this strength throughout the UK. The signal can also be received, and is widely used, in northern and western Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
.
While at Rugby the transmitter generated 60 kW of radio frequency
Radio frequency
Radio frequency is a rate of oscillation in the range of about 3 kHz to 300 GHz, which corresponds to the frequency of radio waves, and the alternating currents which carry radio signals...
power (using 70 kW of mains power
Mains electricity
Mains is the general-purpose alternating current electric power supply. In the US, electric power is referred to by several names including household power, household electricity, powerline, domestic power, wall power, line power, AC power, city power, street power, and grid power...
). The 180m-high T-aerial
T-aerial
A T-aerial is an antenna used for VLF, LF, MF and shortwave transmission or reception.It consists of a horizontal wire suspended between two radio masts or towers. A vertical wire is connected to the middle of the horizontal wire and hangs down close to the ground, where it is connected to the...
antenna was 500m across at its top. The vertical part of the antenna radiated the signal, so that the received strength was similar in all directions (it was approximately omnidirectional
Omnidirectional antenna
In radio communication, an omnidirectional antenna is an antenna which radiates radio wave power uniformly in all directions in one plane, with the radiated power decreasing with elevation angle above or below the plane, dropping to zero on the antenna's axis. This radiation pattern is often...
).
Uses
In addition to professional uses where accurate time is required, radio-controlled clocks with both digital and analog displays using the NPL signal are widely used (similar clocks are available in other regions with standard time transmissions). As far as users are concerned they are simply clocks with the same features and settings as others, but always display the right time, and correct themselves for summer timeSummer time
Summertime may refer to:* Summer, one of the temperate seasons* Daylight saving time , advancing the clock one hour during summer...
.
Protocol
The MSF transmitter is switched off for brief intervals (on-off keyingOn-off keying
On-off keying the simplest form of amplitude-shift keying modulation that represents digital data as the presence or absence of a carrier wave. In its simplest form, the presence of a carrier for a specific duration represents a binary one, while its absence for the same duration represents a...
) near the beginning of each second to encode the current time and date. The rise and fall times of the 60 kHz carrier are determined by the combination of antenna and transmitter.
Each UTC second begins with 100 ms of 'off', preceded by at least 500 ms of carrier. The second marker is transmitted with an accuracy better than ±1 ms relative to Coordinated Universal Time
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
(UTC), which is itself always within ±1 second of Greenwich Mean (solar) Time
Greenwich Mean Time
Greenwich Mean Time is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. It is arguably the same as Coordinated Universal Time and when this is viewed as a time zone the name Greenwich Mean Time is especially used by bodies connected with the United...
(GMT).
The first second of the minute, denoted second 00, begins with a period of 500 ms with the carrier off, to serve as a minute
Minute
A minute is a unit of measurement of time or of angle. The minute is a unit of time equal to 1/60th of an hour or 60 seconds. In the UTC time scale, a minute on rare occasions has 59 or 61 seconds; see leap second. The minute is not an SI unit; however, it is accepted for use with SI units...
marker. The other 59 (or, exceptionally, 60 or 58) second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s of the minute always begin with at least 100 ms 'off', followed by two data bits of 100 ms each, and end with at least 700 ms of carrier. Bit A is transmitted from 100 to 200 ms after the second, and bit B is transmitted from 200 to 300 ms. Carrier on represents a bit value of 0 and carrier off a value of 1.
If each second is considered as ten 100 ms pieces, the minute marker is transmitted as
1111100000, while all other seconds are transmitted as 1AB0000000.Although two data bits are transmitted per second, the time code has the property that only one of them is variable; non-zero B bits are only transmitted when the corresponding A bit has a fixed value.
Seconds 01–16 carry information for the current minute about the difference (DUT1) between atomic and astronomical time, and the remaining seconds convey the time and date code. The time and date code information begins 43 seconds before the corresponding minute marker (second 17 of the previous minute, in the absence of leap seconds), and is always given in terms of UK civil time, which is UTC in winter and UTC+1h when Summer Time
British Summer Time
Western European Summer Time is a summer daylight saving time scheme, 1 hour ahead of Coordinated Universal Time. It is used in the following places:* the Canary Islands* Portugal * Ireland...
is in effect.
| Bit | A | B | Meaning | Bit | A | B | Meaning | Bit | A | B | Meaning |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 00 | 1 | 1 | Minute mark | 20 | 10 | 0 | Year (00–99) | 40 | 10 | 0 | Hour (00–23) |
| 01 | 0 | +0.1 | DUT1 (0.1–0.8) Unary encoding, bit set if DUT1 ≥ Weight |
21 | 8 | 0 | 41 | 8 | 0 | ||
| 02 | 0 | +0.2 | 22 | 4 | 0 | 42 | 4 | 0 | |||
| 03 | 0 | +0.3 | 23 | 2 | 0 | 43 | 2 | 0 | |||
| 04 | 0 | +0.4 | 24 | 1 | 0 | 44 | 1 | 0 | |||
| 05 | 0 | +0.5 | 25 | 10 | 0 | Month (01–12) | 45 | 40 | 0 | Minute (00–59) | |
| 06 | 0 | +0.6 | 26 | 8 | 0 | 46 | 20 | 0 | |||
| 07 | 0 | +0.7 | 27 | 4 | 0 | 47 | 10 | 0 | |||
| 08 | 0 | +0.8 | 28 | 2 | 0 | 48 | 8 | 0 | |||
| 09 | 0 | −0.1 | DUT1 (−0.1–−0.8) Unary encoding, bit set if DUT1 ≤ Weight |
29 | 1 | 0 | 49 | 4 | 0 | ||
| 10 | 0 | −0.2 | 30 | 20 | 0 | Day of month (01–31) | 50 | 2 | 0 | ||
| 11 | 0 | −0.3 | 31 | 10 | 0 | 51 | 1 | 0 | |||
| 12 | 0 | −0.4 | 32 | 8 | 0 | 52 | 0 | 0 | End of minute marker 01111110 | ||
| 13 | 0 | −0.5 | 33 | 4 | 0 | 53 | 1 | STW | Summer time warning. | ||
| 14 | 0 | −0.6 | 34 | 2 | 0 | 54 | 1 | P1 | Year parity (17A–24A, odd parity) | ||
| 15 | 0 | −0.7 | 35 | 1 | 0 | 55 | 1 | P2 | Day parity (25A–35A, odd parity) | ||
| 16 | 0 | −0.8 | 36 | 4 | 0 | Day of week Sunday=0 Saturday=6 |
56 | 1 | P3 | DOW parity (36A–38A, odd parity) | |
| 17 | 80 | 0 | Year (00–99) | 37 | 2 | 0 | 57 | 1 | P4 | Time parity (39A–51A, odd parity) | |
| 18 | 40 | 0 | 38 | 1 | 0 | 58 | 1 | ST | Summer time in effect. | ||
| 19 | 20 | 0 | 39 | 20 | 0 | Hour (00–23) | 59 | 0 | 0 | Unused, always 0. |
Consecutive bits from 01B–08B are set to 1 to indicate positive DUT1 values from +0.1s to +0.8s. For example, bit 05B is set if DUT1 ≥ 0.5 s. Consecutive bits from 09B–16B are set to 1 to indicate negative DUT1 values from −0.1s to −0.8s. For example, bit 11B is set if DUT1 ≤ −0.3 s.
In case of a leap second, a zero bit is inserted between seconds 16 and 17. In case of a negative leap second, second 16 will be deleted. Since negative leap seconds can only occur when DUT1 is positive, bits 9B through 16B will be zero.
Bits 17A–51A encode the time of the following minute in binary-coded decimal
Binary-coded decimal
In computing and electronic systems, binary-coded decimal is a digital encoding method for numbers using decimal notation, with each decimal digit represented by its own binary sequence. In BCD, a numeral is usually represented by four bits which, in general, represent the decimal range 0 through 9...
, most significant bit first. Beginning with bit 17A comes 4 bits of tens of years, 4 bits of years, 1 bit of tens of months, 4 bits of months, 2 bits of tens of days, 4 bits of days, 3 bits of day of week (0=Sunday), 2 bits of tens of hours, 4 bits of hours, 3 bits of tens of minutes, and 4 bits of minutes.
Bits 54B–57B provide odd parity over the time code. The 4 parity bits cover years (8 bits), months and days (11 bits), day of week (3 bits), and time of day (13 bits) respectively.
Bit 58B indicates the broadcast time is summer time. Bit 53B gives warning that the summer time bit is about to change. It is set for 61 consecutive minutes, starting 1 hour 7 seconds before the change, and ending 7 seconds before the change, 5 seconds before the first changed bit 58B, which is itself transmitted 2 seconds (1.7–1.8 seconds, to be more precise) before moment of the time change.
In addition to the 500 ms carrier-off minute marker, bits 53A–58A are all set permanently at '1', and are bracketed by bits 52A and 59A at '0'. This sequence
01111110 never appears elsewhere in bit A, so it uniquely identifies the following second 00 minute marker.Shortcomings of the current signal format
MSF does not broadcast any explicit advance warning of upcoming leap secondLeap second
A leap second is a positive or negative one-second adjustment to the Coordinated Universal Time time scale that keeps it close to mean solar time. UTC, which is used as the basis for official time-of-day radio broadcasts for civil time, is maintained using extremely precise atomic clocks...
s which occur less than once a year on average. The only indication is a change in the number of padding bits before the time code during the minute before the leap second. Therefore, unless a leap-second announcement is manually entered into a receiver in advance, it may take some time until an autonomous MSF receiver regains synchronization with UTC after a leap second (especially if the reception is not robust at the time of the leap second).
The time signal only provides 1 hour warning of summer-time changes.
See also
- Greenwich Time SignalGreenwich Time SignalThe Greenwich Time Signal , popularly known as the pips, is a series of six short tones broadcast at one-second intervals by many BBC Radio stations to mark the precise start of each hour...
- Coordinated Universal TimeCoordinated Universal TimeCoordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
- Radio clockRadio clockA radio clock or radio-controlled clock is a clock that is synchronized by a time code bit stream transmitted by a radio transmitter connected to a time standard such as an atomic clock...
- WWVBWWVBWWVB is a NIST time signal radio station near Fort Collins, Colorado, co-located with WWV. WWVB is the station that radio-controlled clocks in most of North America use to synchronize themselves. The signal transmitted from WWVB is a continuous 60 kHz carrier wave, derived from a set of atomic...
, time signal radio station, also on 60 kHz, from Fort Collins, Colorado - DCF77DCF77DCF77 is a longwave time signal and standard-frequency radio station. Its primary and backup transmitter are located in Mainflingen, about 25 km south-east of Frankfurt am Main, Germany. It is operated by Media Broadcast GmbH , on behalf of the Physikalisch-Technische Bundesanstalt, Germany's...
, 77.5 kHz time signal radio station from Mainflingen, Germany
External links
- The Official History of Rugby Radio Station
- A History of Rugby Radio, M Johnston, 1976 History from 1910.
- "SOMETHING IN THE AIR - A GUIDE TO THE RUGBY RADIO MASTS", by Peter Chambers, out of printhttp://www.subbrit.org.uk/sb-sites/sites/r/rugby_radio/index71.shtml
- Press release about MSF relocation to Anthorn
- National Physical Laboratory – public information leaflet about relocation