Visiting the most important time signal station in South America PPE Observatório Nacional
Research by: Martin Butera
Photographs and Videos by: Mark Melzi
Support Camera by: Ligia Katze
We invite you to a tour of the service division of the official time signal station of the National Observatory of Rio de Janeiro, Brazil PPE BRA OBSERVATORIO NACIONAL.
Let us take you to a place for which all the readers should enjoy: the famous 10 MHz short wave transmitter of the Hour Service Division (DSHO), of the national observatory of Rio de Janeiro, Brazil.
We were invited by the engineer Mr. Ozenildo de Farias Dantas, in charge of the maintenance and flawless operation of the transmitter, to take a look at the famous transmitter.
The Hour Service Division (DSHO) broadcasts Brazil’s Official shortwave time signal on the frequency of 10 MHz.
The transmitter is located in the park, outside the main building, in a small, climate-controlled house specially designed to accommodat it.
Here are some of the transmitter’s technical notes:
Manufacturer: Redifon Telecommunications Limited, London SW.18, England
Model: HF TRANSMITTER REDIFON G453
Power: 1 kW
QRG: 10 MHz
Type of modulation: A3H
Type of antenna: horizontal dipole – ½ wavelength
Here are the geocentric coordinates of the site( WGS84):
X = 4283641.45 m Length = 43 13 27.5 W
Y = – 4026026.11 m Latitude = 22 53 44.6 S
Z = – 2466098.27 m Height = 37 m
The content of the transmission: the transmission consists of the official time of Brazil (= UTC – 3 hours) announced by a female voice that begins in Portuguese with the following phrase “National Observatory” followed by the current time (hh: mm: ss) every 10 s and with a short beep every second with a modulation of 1 kHz for 5 ms and a long beep with a modulation of 1 kHz for 200 ms at 58 °, 59 ° and 60 ° seconds.
The Hour Service Division (DSHO) also broadcasts Brazil’s official time with 2 local VHF broadcasts for the city of Rio de Janeiro on the 166.53 MHz and 171.13 MHz frequencies.
The transmission of the time signal of 10 MHz by the DSHO began in November 2008, over all these years, this signal was already picked up by radio listeners in different parts of the world, and the reports are confirmed by QSLs. Dr. Ricardo Carvalho head of that division.
It is a simple but robust dipole, perfectly cut and calibrated by engineer Ozenildo de Farias Dantas for the frequency of 10 MHz, which has given excellent results to this day.
One of the sections of the dipole is supported by the historic imperial tower of the observatory. This tower is famous because many years ago a balloon was inflated at the precise moment that it was 12 noon and was launched so that this was observed in the port of Rio de Janeiro that was called the famous “half astronomical day”.
Listening to the time signal frequency stations is an interesting aspect of the DXing. Many may not know that these stations are in operation in different parts of the world, and have been since the early days of the radio to the present twenties.
The purpose of these stations is to cover various branches of science, such as seismology, meteorology, astronomy, geodesy, etc.
Between the different stations a constant effort is made to coordinate their time internationally so that in the future they can all maintain and supply a world time standard without the slightest difference.
Brazil has the most important time station on the South American continent, I am very happy to present this report for all of you.
This was the first time a group of DXers has be welcomed by the Service Division of the Hour (DSHO), from the National Observatory of Rio de Janeiro.
I was especially welcomed by Mr. Ricardo Carvalho, Head of the division, who kindly guided us on an extensive tour, showing all the facilities. I was also able to film a pleasant interview (in Portuguese).
Surely all of you who are now reading this report know that listening to the short wave, can become the most instructive hobby that exists.
To know about a country, its customs, its culture, its gastronomy, its geography, to follow the national or international current affairs, are the interests that define the various aspects of the hobby of radio listening.
The main purpose of listening to international short wave radio stations is to know the world better, to open up to other cultures, to other ideologies, to demystify the unknown, to have access to the many facets that make up the world.
In short, the listening to international short wave radio stations of the whole world is traveling around the globe without leaving home or even getting up from the couch.
National Observatory of Rio de Janeriro 1827 – 2019
Now, I shall try to summarize 192 years of history, a mission that is not at all simple. To remain as a scientific institution of recognized competence for 192 years is an almost impossible mission in Latin America.
The National Observatory (ON), established in Rio de Janeiro, is an example of determination since its foundation on October 15, 1827 by Emperor Dom Pedro I.
Since then, much has changed at the National Observatory, where the creation of the Brazilian Official Time Division with its acronym (DSHO), established by law in 1913, stands out. Nowadays, the service is generated from a set of twelve atomic clocks that also contribute to the official world time scale.
The need for an Astronomical Observatory in Brazil began in the colonial period, its creation was necessary due to the increase in commercial activities and the rapid growth of ships arriving and departing from the ports of Rio de Janeiro since the beginning of the 19th century, and this demand became more evident.
For the sake of safer sea travel, it was essential to obtain accurate knowledge of the magnetic declination, the average time and information about the length so that commanders could regulate the timers.
That is why the installation of an observatory in a fixed location could offer ships more accurate information than those obtained at sea.
The first records date from the inception to establish an observatory in the Hill of the Castle in 1730 on the initiative of the Jesuits, in the same place was established in 1780 an observatory of Portuguese astronomers where they made the first observations of astronomy and meteorology.
But only in October 1827, by decree of D. Pedro I (first emperor of Brazil), the headquarters of the Imperial Observatory of Rio de Janeiro was established, this was the first institution of this genre built in Brazil.
Initially, this astronomical observatory was established in the tower of the Military School, in charge of Pedro de Alcántara Bellegarde (military, educator, astronomer and Brazilian engineer), who played a fundamental role in the area of important scientific institutions throughout the 19th century.
However, until at least the 1870s, the activities of the institution were almost exclusively related to the instruction of military school students.
Only in 1871 were its functions redefined, when it came out of the military administration, the Observatory could dedicate itself mainly to research and service activities in meteorology, astronomy, geophysics, measurement of time.
Such redefining of its sphere of activity was driven by the Administrative Commission of the Imperial Observatory, which in this period began the process to choose the new site, in a place that is considered more appropriate, where it would be transferred later.
The conclusion of several studies culminated with his transfer to the hill of “San Januário”, at the beginning of the 20th century, where it still operates today.
These fundamental changes, that took place after 1871, happened during the administration of Emmanuel Liais (he was a politician, botanist, astronomer and French explorer who stayed in Brazil for many years), who was responsible for the process of remodeling the observatory, during the two terms for which he was the director (from January to July of 1871 and again between 1874 and 1881).
The increase in the activities of the Imperial Observatory led to the publication of the first volume of the Observatory Yearbook in 1885, which gave continuity to the Astronomical Ephemerides, published between 1853 and 1870.
The aim of the Yearbook was to disseminate information obtained from astronomical and meteorological observations, constituting until today an important bibliographical reference on the annual scientific production of the institution.
In 1886, the Observatory Magazine, the country’s first scientific journal, was published in 1886 with the aim of disseminating scientific productions, which lasted for only a short time and were stopped in 1891.
With the new political winds blowing from 1889, triggered by the proclamation of the Republic, also changed the orientation of the institution, subordinating itself to the Ministry of War and receiving the name of Observatory of Rio de Janeiro.
Only in 1909 it was renamed as OBSERVATORIO NACIONAL (ON): the Ministry of Agriculture and the Directorate of Meteorology and Astronomy was created, and the Observatory was made subordinate to this.
From then on, the institution began to provide the weather forecasts for different purposes.
During that time, the activities of meteorology and astronomy walked together and the calculation of time was made by astronomical methods.
These two functions, however, were separated in 1917, when the National Observatory only covered studies on astronomy, geophysics, and time and frequency. With this redefinition of functions, the scientific trajectory adopted by the institution throughout the 20th century was marked.
The beginning of the 20th century also gave rise to ideas that would lead to scientific moods.
The accelerated process of urban reforms and the redefinition of the state function as a promoter of national scientific activity represented a new apparatus for the diffusion of sciences, accompanied by the notions of civilisation, modernity, reason and progress that drove all actions in the scientific field.
The institutional framework of the National Observatory, in relation to these intense transformations in the Brazilian social, political and scientific plan of the beginning of the century, was evidenced in the management of Henrique Morize (considered the great introducer of experimental physics in Brazil), having assumed the post of the Director of the Observatory in 1908, was responsible for several important modifications of the institution
during this period, in which Rio de Janeiro also underwent intense urban reforms.
During the twentieth century, several reforms in the political-administrative spheres changed the jurisdiction of administration to which the institution was linked; however, they changed their attributions. In this sense, In 1930, the Observatory was brought under jurisdiction of the newly created Ministry of Education and Culture; in 1976, it was transferred to the control of the National Council for Scientific and Technological Development (CNPq). In 1999, such transfer of jurisdiction took place to the Ministry of Science and Technology which is maintained till today.
Einstein’s theory of relativity
The National Observatory of Rio de Janeiro, has always been present on the world stage with many scientific contributions which were internationally recognized.
Perhaps one of the most “famous” such contribution was in the year 1919, when the National Observatory coordinated the English expedition that observed the total eclipse of the Sun, in the Brazilian city of Sobral, in the state of Ceará.
The phenomenon was also observed parallelly in the Prince Island. Such observation contributed to the confirmation of Einstein’s theory of relativity, when the deviation suffered by the light of the stars in the background of the sky caused by the gravitational field was verified due to the mass of the Sun.
Importance of creating a specific division of time in Brazil
To understand the importance of creating a specific division of time (DSHO), within the National Observatory of Rio de Janeiro, we list below the very relevant fact about Brazil.
Brazil has a territory of continental dimensions with an area of 8,547,403 square kilometers. The extension of the territory, we can analyse it in the following way from north to south and from east to west, in the first case, from Monte Caburaí (Roraima) to Arroio Chuí (Rio Grande do Sul) 4,395 kilometers are recorded, in the Serra da Contamana (Acre) to Ponta do Seixas (Paraíba) results in 4,320 kilometers. As you can see in the following graphic:
It is the largest country in Latin America and the fifth largest in the world. If we put all the countries of Europe ( except the Russian – European part) and there would still be space left over in Brazil.
I took the trouble to scan an old Brazilian geography book since I found the following image and it seemed very interesting, this image leads to a good reflection on the dimension of Brazil:
In case it is not clear to the valued readers, the size of Brazil and its continental dimensions, the whole United Kingdom alone, fits within the state of São Paulo.
That is why, because of the enormous size of Brazil, it has landmass in three different hemispheres at the same time: the majority in the southern hemisphere, a small part in the northern hemisphere and all its territory in the western hemisphere.
In the North It is cut by the Line of Equator and in the South by the Tropic of Capricorn, thus getting 92% of its area in the tropical zone.
Another aspect of the geographical position of Brazil is its latitudes and longitudes, that is, its geographic coordinates, which are generally measured from the equator (latitudes) and from the Greenwich meridian (longitudes). Thus, in latitudinal terms, the Brazilian territory extends from something close to 5º North to approximately 33º South. In longitudinal terms, the extension extends from 35º West to a little less than 75º West. But if we ignore some of the oceanic islands in the Atlantic, they are placed in somewhat smaller lengths.
Due to its great east-west extension, Brazil presents a great variation of time zones, totaling four different regions that we can observe in the following map:
The first time zone is two hours behind the Greenwich Meridian (-2GMT, therefore) and covers only the islands in the Atlantic Ocean, (Yellow color on the map).
The second and most important portion (-3GMT) covers most of the Brazilian states, including the Federal District and the capital, Brasilia, making it the official time of the country, (orange).
The third area (-4GMT) covers some states to the west, namely: Mato Grosso, Mato Grosso do Sul, Rondônia, Roraima and most of the Amazon, (green).
The fourth and last time zone (-5GMT) covers a small western part of the Amazon and the state of Acre, (pink).
And if you still do not understand the complexity of the Brazilian time system, we can mention this curious fact: the first day of the year never reaches all the people of the world at the same time. In Brazil it is not different, because Brazilians can celebrate the New Year four times! This is due to the four time zones that we mentioned earlier.
Brief summary of the History of the Official Time Service Division (DSHO)
The beginning of the activities of the National Observatory precedes its creation date in 1827. Since 1730, regular observations of astronomy, meteorology and terrestrial magnetism have already been carried out in Morro del Castillo, in the city of Rio de Janeiro.
With the arrival of the royal family to Brazil in 1808, the heritage with the research of the time was transferred to the Royal Military Academy. Nineteen years later, Pedro I determined the creation of the entity that would inherit his patrimony.
Since then, National Observatory has accumulated a precious history that covers the areas of Astronomy, Geophysics and Metrology in Time and Frequency.
The time and frequency metrology is the responsibility of the Services Division of the Official Time, which for more than a century and a half has been legally responsible for generating, maintaining and disseminating the Official Time of Brazil and also plays the role of Time Laboratory and Primary Frequency, denominated in its initials as (LPTF).
The Official Time Service Division inaugurated its new facilities in 2004.
The modern building is named after Carlos Lacombe, in honor of the engineer who directed that division in the period from 1963 to 1977 and participated, along with Henrique Morize and Roquete Pinto, in the creation of the first radio station in Brazil, called (Rádio Sociedade do Rio de Janeiro).
Enter the building of the official Brazilian time, it is simply fascinating, it is very large and has the most modern technologies.
To understand better how it is inside, I decided arrange the tour in the following order: Museum, Generation room, Conservation and Dissemination of time, Laboratory and we will leave the Short Wave Transmitter for the last.
Come with me !!
When entering the modern building of the Service of the hour (DSHO), of the national observatory, the first thing we can observe is a small but very interesting museum of the first clocks and measuring instruments, kindly Mr. Ricardo José Carvalho (head of the division ), he was detailing us one by one.
Among the pieces stand out different models of chronographs used in the mid-1950s, from the manufacturer Édouard Belin.
Édouard Belin, was an inventor and photographer born in France in the year 1876. Chronographs were an instrument that measured time and maintained unity. In most analog models it was up to hundredths of a second, a chronometer at that time was a high precision certificate of a watch.
Room of Generation, Conservation and Dissemination of the time
Leaving behind the small museum, we continue with our tour with Ricardo José Carvalho (Head of the Division) and we are about to enter the room where the Generation, Conservation and Dissemination time racks are located.
Before, we progress further it is necessary to understand briefly what is meant by generation, conservation and dissemination of time.
What is meant by generation?
The generation of time and frequency, that is, the second atomic, is done in the Official Time Division of Brazil, by means of Cesium commercial clocks and hydrogen maser clocks. The atomic time by the International System of Units (SI) in 1967 is defined as: “The second is the duration of 9,192,631,770 periods corresponding to the transition between two hyperfine levels of the ground state of the cesium 133 atom radiation.”
What is meant by conservation?
The conservation of the “greatness of time and frequency”, is realised through the uninterrupted operation of the atomic clocks and their evaluation of stability by means of the measurements of time and frequency difference between the clocks.
What is meant by Dissemination?
The dissemination of the “greatness of time and frequency” is carried out by the calibration of atomic clocks, frequency counters, chronometers and other different equipment. These measurements are sent to the laboratory of the division where they are checked through other standard signals and by the official time synchronization network.
In the room where the Generation, Conservation and Dissemination time equipment racks are located, we can observe 11 racks in total, with different equipment such as generators and gong distributors, top, IRIG code, synchronism signals, NP generators, secondary clocks , temperature monitors, “no-break” phase monitors, electric power phase monitors,
internet talk time monitor, ZAG 500 talk time monitor, various distributors and amplifiers, cesium registers, audio and GPS distributors (time transfer system) and much more.
In the following videos, Mr. Dr. Ricardo Carvalho, Head of that division explains and details the operation of several of these teams, we invite you to see the following video links (in Portuguese language).
After leaving the modern room of Generation, Conservation and Dissemination of the time, we enter into another important room – the laboratory.
Here we will find various equipment for measuring, calibrating and adjusting the time, up to a faraday cage. Also in the laboratory are jealously guarded famous atomic clocks.
Currently, the service of the official Brazilian time (DSHO), has 2 atomic clocks of the Symmetricon MHM hydrogen maser (valued at approximately 250 thousand dollars each), 12 cesium standard clocks (valued at approximately 80 thousand dollars each), they are 3 three HP 5071A clocks, 3 three Agilent 5071A clocks, 4 four Symmetricon 5071A clocks, 1 a CS4000 clock, 1 a Datum 4310A, 1 a rubidio HP5065A standard clock and two GPS / glonass / galileo-TTs-4 receivers.
Having a laboratory is essential to keep exactly calibrated the national standards of time and frequency, some of these parameters are the basis of the Brazilian Metrological Traceability of Time and Frequency.
At the international level, the traceability of national standards and Brazilian official time is established with the International Bureau of Poids and Mesures (BIPM), also with Brazilian official time is compared in real time through the Inter-American Metrology System (SIM) that it is accessed through GPS Common-View.
Another surprise that we are not prepared to see was to get up close and to be able to enter a famous “Faraday cage”.
On one side of the laboratory there is a famous Faraday cage, which Dr. Ricardo Carvalho explains to us, it is a fundamental requirement for the measurement of atomic clocks, since no unknown entity can be present during the calibration process, we are talking about the calibration of atomic clocks costing 250 thousand dollars.
Faraday’s cage was an experiment conducted by Michael Faraday to demonstrate that an electrified conductive surface has a zero electric field inside it, since the charges are distributed evenly on the outermost part of the conductive surface (which is easy to try the Law of Gauss), for example we can mention the Van de Graaff generator.
In Faraday’s experiment a metal cage was used, where an insulation and a wooden chair were placed on which Faraday sat, an electric shock was given to him and nothing happened to him, which shows that a body inside the Cage could remain there, isolated as the electrons are distributed on the outer surface of the surface.
Next to the famous Clock Maser of Hidrogenio Symmetricon MHM
The most accurate watch of Brazil and also of South America, is located in the basement of the Time Service Division of the National Observatory in Rio de Janeiro, the clock is kept in a special room, with constant temperature and humidity, to be able to access to watch, you have to go through three sophisticated alarm controls, we had the honor of being able to access exclusively for you.
This watch comes from the United States. The approximate cost is US $ 250,000. This atomic clock “Maser Symmetricon”, which is expected to delay or advance only one second in 10 million years runs using hydrogen.
A curious fact is that from the confirmation of the order for its acquisition, the clock took six months to manufacture. The process went through the Department of Defense of the US government. To obtain an authorization of export, since it is a device that generates time with high precision.
From Atomic clocks to Quantum Optics
The search for the most accurate clock is an extreme challenge. Brazil does not want to be left out and like the leading countries are using “Quantum Optics”.
If you think that everything ends up in the measurement of the time produced by the atomic clock, you are wrong, in the service of the national observatory, you are already having experiences of quantum measurements through the laser system.
In another sector of the division, there is a sophisticated optical frequency measurement device. It is obtained from a company named Menlo Systems.
Menlo Systems is a German company, founded in 2001 by Professor Hänsch, Dr. Ronald Holzwarth, Dr. Michael Mei and Alex Cable as a spin-off of the renowned Max-Planck Institute for Quantum Optics.
It is a revolutionary technique for measuring the frequency of light. This invention has been called “… the greatest advance in precision electromagnetic measurements since people started measuring frequencies”.
The time division of the National Observatory of Rio de Janeiro has already begun to perform experiments with optical measurements of high precision in various applications such as optical clocks, cold atoms and molecules, metrology, distance measurements, Fourier spectroscopy and Lidar measurements.
They know that the world is increasingly ultra-precise and ultra-fast and are committed to delivering measurements made in Brazil that meet the highest standards of quality and reliability worldwide.
By way of final conclusion
From ancient times we have designed devices that allow us to measure time and keep it for records.
In the beginning it was carried out according to the nature, like the Sundials, which use the light to indicate the time; or the movement of grains of sand inside an hourglass, or water in the case of the clepsydra.
Subsequently, more precise devices were invented, whose operation occurs thanks to the standardisation of the time units (days, hours, seconds, etc.) of the International System.
Up to now, the most accurate of the clocks invented by humanity the atomic clock, calibrated from the vibrations of the atom of Cesium.
That now is our most modern and new starting point in what we refer as time.
Final thanks, once again to Dr. Ricardo Carvalho, Head of the Service Division, the Official Time (DSHO), for freely allowing the photographers who accompanied me to cover the subjects of this report.
About the author
He is a listener of Shortwave Radio and Amateur Radio since 1992 with the Argentine callsign LU9EFO and the Brazilian PT2ZDX.
Martin is a Radio Amateur with more than 30 years of experience, and has participated in DXpeditions throughout South America, with the Argentine radio callsign LU9EFO and the Brazilian callsign PT2ZDX.
Martin collaborates and writes for several Radio newsletters that cover the theme of world radio.
Martin is the founder of CREW called 15 point 61 (15.61), now called just 61 sixty one.
Martín Butera is a journalist, documentary filmmaker and founding member of Radio Atomika 106.1 MHz (Buenos Aires, Argentina) www.radioatomika.com.ar
He currently lives in Brasilia, capital of Brazil.
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