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Guest Post: Photo tour and history of the PPE Observatório Nacional time signal station

Many thanks to the SWLing Post contributor, Martin Butera, who shares the following guest post:


Visiting the most important time signal station in South America – PPE Observatório Nacional

by Martin Butera

Still photographs by: Mark Van Marx (Marcos Melzi)

Video by: Ligia Katze

English adaptation and correction by: Sudipto Ghose (VU2UT)

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
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. [Audio sample below.]

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,

Dr. Ricardo Carvalho kindly gave me one such QSL.


Engineer Ozenildo de Farias Dantas and our journalist Martin Butera, entering the house of the shortwave transmitter.
Shortwave transmitter, Redifon Telecommunications Limited, used in the Service of the official Time of the National Observatory of Rio de Janeiro. There is a ubiquitous BIRD Wattmeter on top left of the transmitter.

From another angle, the short wave transmitter, Redifon Telecommunications Limited, used in the Service of the official Time of the National Observatory of Rio de Janeiro.
Engineer Ozenildo de Farias Dantas dismantles a part of the transmitter panel, to begin with his routine of calibration and maintenance of the transmitter.
The engineer Ozenildo de Farias Dantas and our journalist Martin Butera, along with the transmitter Redifon Telecommunications Limited.

The Antenna

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”.

Dipole wire antenna of the National Observatory
we can see a section of the dipole, supported by the old Observatory tower
Mr. Ricardo José Carvalho (head of the division), with a history book of the National Observatory of Rio de Janeiro, where he mentions about the first tower of the observatory. Behind we can see that the tower still remains intact. Old tower of the National Observatory
Here we can see that they have a tower with different antennas to receive different world time signals
Here we can see the antennas of the VHF transmitters

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 exclusive report for SWLing Post 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).

Click here to view on YouTube.

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.

Station History

Current entrance of the National Observatory, museum of astronomy and related sciences of Rio de Janeiro.

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.

Hill of the Castle in 1730 (File ON)

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.

Panoramic view of the domes of the meridian lunettes used for the determination of time. (File ON)
Building of the National Observatory built at the beginning of the 20th century, when it was moved to Morro de São Januário. (File ON)

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.

Visit of Albert Einstein to the National Observatory in 1925, after having tested his Theory of Relativity thanks to the work of the National Observatory of Rio de Janeiro. (File ON)

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 !!

Martin Butera at the entrance of the modern building of the Official Time Service of the National Observatory of Rio de Janeiro.

Small Museum

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.

Click here to view on YouTube.

These pieces are fundamental to understand the process of evolution in the measurement of time.

Different old instruments for measuring the time used by the Official Time Hour Service (DSHO), from the National Observatory of Rio de Janeiro.
Different old instruments for measuring the time used by the Official Timekeeping Service (DSHO) of the National Observatory of Rio de Janeiro.

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.

Another old chronograph
Another very interesting piece of the museum is the issuer of time signals from the manufacturer James Muirhead, famous British watchmaker.
We can also observe the first spoken recording system of the hour, it was a complex system of records made in Brazil.
In the same piece of furniture at the bottom of the piece mentioned in the previous photo, we can see a classic Collins Radio Company receiver, which was used in the mid-1950s to tune in to other world shortwave time signals.
Undoubtedly a very important piece is the first cesium clock, which began to work in Brazil in 1970, it is an HP5061A
Mr. Ricardo José Carvalho (Head of the Division) and our journalist Martin Butera, editor of this report, together in Brazil’s first atomic clock.

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.

Click here to view on YouTube.

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).

Click here to view on YouTube.

Racks of equipment for Generation, Conservation and Dissemination of Time, Service of the Hour (DSHO), of the national observatory Rio de Janeiro Brazil.

Racks of equipment for Generation, Conservation and Dissemination of the time, of the Service of the official hour (DSHO), of the national observatory Rio de Janeiro Brazil.
Different views of the Racks of equipment for Generation, Conservation and Dissemination of the time, of the Service of the official time (DSHO), of the national observatory Rio de Janeiro Brazil.
Different views of the Racks of equipment for Generation, Conservation and Dissemination of time, of the Service of the hour (DSHO), of the national observatory Rio de Janeiro Brazil.
Different views of the Racks of equipment for Generation, Conservation and Dissemination of time, of the Service of the hour (DSHO), of the national observatory Rio de Janeiro Brazil.
we can observe equipment, such as the monitoring of “no-break” phases.
Technician working in the room of the Racks of equipment for Generation, Conservation and Dissemination of the time, of the Service of the official hour (DSHO), of the national observatory Rio de Janeiro Brazil.


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.

Faraday cage

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 cage in use for calibration of the official Time of the National Observatory

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.

Our special correspondents Mark Van Marx (photographer), Martin Butera (journalist) and Mr. Ricardo José Carvalho (head of the division), inside the Faraday cage, together with the calibration equipment of the atomic clocks.

Racks of diverse equipment of the laboratory, of the Service of the hour (DSHO), at the national observatory Rio de Janeiro Brazil.

Racks of diverse equipments of the laboratory, of the Service of the hour (DSHO), at the national observatory Rio de Janeiro Brazil.
Our photographer Mark Van Marx, taking photograph of the various equipments of the laboratory, of the Service of the hour (DSHO), at the national observatory Rio de Janeiro Brazil.
Different signal and frequency counters, used in the calibration of watches.

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 the ‘DX Clube Sem Fronteiras’.

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.

Our special correspondents Mark Van Marx (photographer), Martin Butera (journalist) and Mr. Ricardo José Carvalho (head of the division), together with the most accurate atomic clock in Brazil as well as in South America.

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.

Different lenses used for optical frequency measurements.
Our photographer Mark Van Marx, taking photographs of optical frequency measurement lenses
A top view of the Quantum Optics measuring apparatus
Our special correspondents Mark Van Marx (photographer), Martin Butera (journalist), by the side of the sophisticated equipment of measurements of optical frequencies (Menlo Systems)

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.

Special Thanks

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.

They are: Mark Van Marx (Photographer) and Ligia Katze (Videographer), Engineer Ozenildo de Farias Dantas, Mrs. Vilma Madalena de Assis Souza (Assistant in the Service of the C & T Division of the National Observatory Time) and Miss Letícia Reitberger (journalist of the communications consultancy Target).

To my friend, the Argentine radio listener Daniel Camporini, for writing a special prologue for this report (included in the Spanish version).

To my editor in chief, dear Chrissy Brand, for giving me the opportunity to work in South America, as a journalist for the BDXC.

Chrissy brand is European DX Council Secretary-General – BDXC Communication (http://bdxc.org.uk/).

To the dear friend and listener from India, Sudipta Ghose (VU2UT) for his adaptation to English and correction, member of the Indian DX club International (www.idxci.in)

To my friend Ivan Dias da Silva Júnior, director of the Regional DX – Sorocaba-Sao Paulo- Brazil, who collaborates in the Portuguese translations and publishes this material in the form of a micro book, for the club he directs (https://ivandias.wordpress.com/).

Finally my friend Thomas Witherspoon, director “The SWLing Post”, for publishing this report and collaborating in this way to the world of radio listening.

From left to right Mark Van Marx (in photo), Martin Butera (Journalist), Ricardo Carvalho head of the Service Division of the Official Time (DSHO), Miss Letícia Reitberger (journalist of the communications consultancy Target) and the lady Ligia Katze (Videographer), in the Generation, Conservation and Dissemination room of the time.

From left to right Martin Butera (journalist), Engineer Ozenildo de Farias Dantas and Mark Van Marx (Photographer), in the Generation, Conservation and Dissemination room of the time.
From left to right, Mark Van Marx (in photo), Mr. Dr. Ricardo Carvalho, head of the Service Division, the Official Time (DSHO) and Martin Butera (Journalist), in the laboratory.


About the author

Martin is an Amateur Radio operator with more than 29 years of experience, and has participated in DXpeditions throughout South America, with the Argentine radio callsign LU9EFO and Brazilian callsign PT2ZDX.

It is to collaborate for the newsletter of the British Dx Club (United Kingdom).

Martín is the founder of the Brazilian CREW Radio Listeners’, called 15 point 61 (15.61). Martin is Argentinian, born in the city of Buenos Aires capital. He currently lives in Brasilia DF, capital of Brazil.

Martín Butera is a journalist, documentary maker and founding member of Radio Atomika 106.1 MHz (Buenos Aires, Argentina) www.radioatomika.com.ar

About the The British DX Club

Martin Butera is a contributing journalist for “Communication” magazine of the prestigious The British DX Club. We congratulate Martín Butera for this interesting report.
If you would like to be a member of the Briitish DX Club, you can find information here http://bdxc.org.uk/apply.html

Report made, visit to Rio de Janeiro Brazil, in May 2019, written completed and published in SWLing Post in the middle of September 2019.

Please contact Martin at the following email address: martin_butera@yahoo.com.ar

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Guest Post: Bolivian Mining Radio

Many thanks to SWLing Post contributor, Martin Butera, who shares the following guest post which was originally published in the June 2019 issue of the British DX Club magazine:

Bolivian Mining Radio

By Martin Butera

Radio Mineras Bolivianas are unique in the world, because they belonged to the unions of mining workers, and were created to defend the interests and the struggle of the workers’ movement.

Mining was fundamental in Bolivia long before the country reached its independence in 1825. When the Spanish conquistadores began to exploit the silver of Potosí in the 17th century they never imagined that there was such a quantity under the “silver mountain”. Bolivia’s exports were mainly based on silver and then tin, until the country’s economy was transformed in the last decades of the 20th century. For three centuries the silver extracted from Potosí was taken to Spain, until the mountain lost its original shape and gradually collapsed. It has been written that six million Aymara and Quechua Indians, plus a considerable number of African slaves, lost their lives in the mines during that period. Potosí was then one of the great cities of the western world. In 1625 it had a population greater than London or Paris, and more churches than any other city in the new world. Although isolated in the altiplano, at an altitude of 4,200 meters, in Potosí the most luxurious goods imported from Europe could be found.

From the independence of Bolivia in 1825 until the mid-1970s, mining continued to be the main economic activity generating income. Silver gradually became less important, but the country became the world’s second tin producer. In the mid-1950s minerals accounted for 70% of exports. A few thousand workers in the mining centres had on their shoulders the responsibility of sustaining the economy of the country and its five million inhabitants. No government could afford to ignore the political opinion of the miners, especially when their unions were reputed to be the most democratic and politically advanced in Latin America.

Station Resistance

The 1980 military coup of General Luis García Meza had triumphed in Bolivia, many citizens who resisted were killed or imprisoned, others escaped into exile. The army managed to completely control the cities. The first military objective was the media: all the radios, television channels and newspapers were closed and when they came to light again, it was under strict military censorship. Actually, not all radio stations …

The chain of approximately twenty stations in the mining districts of Potosí and Oruro, in the Bolivian highlands, continued transmissions under very high pressure. In order to know what was really happening in Bolivia after the coup, people searched the radio for the frequency of La Voz del Minero Radio Animas or Radio Pío XII. Even foreign correspondents based their news radios on mining radios. The army knew, that is why every day the troops came closer to the mining districts, breaking little by little the resistance of the workers who defended their stations with their lives.

Photo: The radio station door shattered by bullets, during the military coup of Garcia Meza

One of the last mining stations to fall under military control was Radio Animas. This is the transcript of the dramatic final live broadcast:

The troops are approximately five kilometres from Siete Suyos and very close to Santa Ana … so we are preparing to defend ourselves … The number of detainees reaches 31, who have been moved to the city of Tupiza according to the reports that have reached us … This is Radio Animas for all the south of the country … We are in this crucial hour, we are in constant mobilization, women have contributed greatly in the preparation of the defence … We will be to the last comrades, because that is our mission, to defend ourselves …

That was near the end. Minutes later shooting was heard at Radio Animas. The last thing the announcer managed to transmit was a message to the other stations, Pío XII and Radio Nacional de Huanuni, to take the signal and continue with the live broadcasts of the mining chain. Others continued until the army silenced the last one, destroying the equipment and killing those who defended their right to communicate.

La Voz del Minero, Radio Vanguardia de Colquiri, Radio Animas, Radio 21 de Diciembre, Radio Nacional de Huanunison are some of the radio stations created, financed and controlled by the mining workers of Bolivia.

In the Beginning

It all started around 1949, with a station that settled in the mining district of Catavi. During the following 15 years, other districts followed suit: they bought equipment, trained young people from the camps, financed by workers who gave a percentage of their salary to support the radio stations.

The stations started precariously, equipped with the bare minimum. Some managed to obtain international support and became more sophisticated broadcasters, with better equipment and facilities. Several even built an assembly hall next to the station, in order to broadcast the union meetings live. Radio Vanguardia decorated its living room with a large mural that tells the story of the Colquiri mining centre. A scene in the mural depicts the bombing of Bolivian Air Force aircraft in 1967, when the country was subjected to a military dictatorship.

At the beginning of the 1970s there were 26 stations in operation, almost all of them in the mining districts of the Bolivian highlands. At that time, the miners’ unions were still very important, considered as the political vanguard in Latin America.

In times of peace and democracy – which were not the most frequent – mining radios were integrated into the daily life of the communities. They functioned efficiently as alternatives to telephone and mail services. The people of the mining centres received their correspondence through the radio and sent messages of all kinds, which were read several times a day: calls for meetings of the Committee of Housewives, messages from the union leaders about their negotiations with the Government in the capital, messages of love between young people, sports activities, funerals, births and local festivities.

In times of political conflict, trade union radios became the only reliable source of information. While the military attacked newspapers radio and television stations in the cities, the only information available came through the mining radios. All of them joined in the “mining chain” until the army penetrated the mining districts and stormed the facilities, defended to the last by the workers. A movie of Jorge Sanjinés, El Coraje del Pueblo, rebuilds the  army attack in June 1967 in the mining district of Siglo XX and the seizure of union radio.

Click here to view on YouTube.

The mining radios were important insofar as the miners were important in the economy and politics of Bolivia. But also the influence of the miners grew during the decades in which they had at their disposal this powerful means of communication to express their ideas. As the importance of mining declined in the 1980s, trade unions weakened and many of the stations disappeared, at the same time the mines were closed.

Participatory Communication

The radio stations played a preponderant role in strengthening the mining unions in the struggle for unity. All unions were affiliated with the Bolivian Trade Union Federation of Mining Workers (FSTMB), which for four decades (1946 to 1986) was the vanguard of the powerful Bolivian Workers’ Central (COB). It is not simply coincidence that unions and radio stations shared premises in most of the mining districts, and that the union’s Secretary ofCulture was usually the director of the radio station.

The social impact of the radio stations of the mines was also important in the process of construction of a cultural identity in the mining centres and in the surrounding peasant communities. On a daily basis, the mining radios were open to participation. The visits to the stations were very frequent, whenever people needed to express themselves on any topic that affected their lives.

The most innovative in the experience of mining radios in Bolivia is community participation. The characteristics of this participation constituted a revolutionary event in the 1950s, as they still are today. Very few experiences of participatory communication have reached a level of total appropriation of a means of communication in terms of technology, day-to-day management, content and service to the community.

One of the most interesting aspects is that of training. The mining stations gave rise to new generations of journalists. The training was usually done locally, with the support of other organizations. Some journalists and broadcasters who began their professional activity in the mining radios later became well-known radialistas when emigrating to the cities.

The end of mining radio stations

Although the mining radios were oriented by the ideology of the unions, this did not represent an obstacle to participation insofar as they reflected the will of the workers. In the positions of responsibility of the union, leaders of different political parties were elected, but none of them intended to break the  sense of unity that was reflected in the radio programmes.

The real challenge of the mining radios was political repression, the same one that affected the mining class as a whole. Some stations were destroyed by the army six or seven times in the course of their existence. Several chose to preserve the traces of resistance on their walls: the bullet impacts received. Again and again, destroyed equipment was replaced by new equipment purchased with the contribution of the workers. Impoverished but worthy, they offered one day of their salary to their station.

Martin Butera with mining radio journalist (La Paz, Bolivia)

From the technical point of view, the mining stations suffered material deficiencies. The equipment of most of them was very elementary, although sufficient to carry out the work. When equipment was damaged it was repaired by local technicians who lacked the necessary replacement parts but were abundant in creativity. The low capacity to pay salaries to producers made the quality of programming low, especially in terms of educational content.

What finally caused the mining radios to end in the 1980s was the abrupt change in the country’s economy. Traditional mining ceased to be central in exports and the cost of producing tin was higher than the international price. The government closed state mines; workers moved to cities in search of employment, leaving ghost camps behind. The influence of the unions decreased, and few stations survived the transition to the new century.

On 28 August 2017, the Ministry of Mining presented a decoration to the directors of the mining radios that are still in force. The award also recognized the “high level of awareness of workers to convey their ideals against the editorial position of the commercial media that did not take into account these struggles.”

The Bolivian government recognized the mining radios for their contribution to the democratic political history, the defence of human rights and their consequences in defence of the working class and workers.

“One of the disastrous actions was when several military radios intervened in the military coup, the equipment was destroyed, many journalists and journalists were imprisoned, because the network of mining radios constituted a whole subversive network of communication for revolution and liberation. , that is why this type of media is important, “said the current Minister of Mining, Cesar Navarro Miranda, when he offered the tribute.

Likewise, he indicated that the political participation from the chain of mining radios in dictatorial processes was decisive for the return of democracy and that is why they constitute a political and democratic history, thanks to the sacrifice of the workers. Among those that stand out: Radio 21 December, National de Huanuni, Vanguardia de Colquiri, 16 March of the Bolívar mine, Ánimas and Chichas de Siete Suyos, among others. The event was nuanced with musical participation achieving great emotion among the participants.

One of the few survivors

On 24 June Huanuni National Radio will be 60 years old. The historic National Radio of Huanuni, one of the first miner-union radios in Bolivia, recognized for its active participation in the country’s social struggles, is ready for its re-launch with a powerful team and state support.

Now with a modern FM equipment (and on 92.5 MHz), it will be a witness to the new Huanuni radio that emerged to the ether in the 1950’s and was a faithful witness of the struggle of the mining unions and the popular classes.

Respondent since its birth, Radio Nacional de Huanuni became the inseparable companion of the workers of this mining centrw who bled tin for the benefit of the great powers and the so-called “tin barons”.

Since then, the union radio station has written an unprecedented story in Bolivia, as an inseparable companion of the workers’ struggles and vanguard of the resistance of the miners against totalitarian regimes between 1964 and 1982.

Also as a school of Bolivian broadcasting, by the passage of the brightest speakers and budding journalists by their microphones. Because of the station’s irrefutable identification with the social movements it suffered several attempts to silence its voice, through dictatorial governments that destroyed equipment and assassinated several miners.

Like the one perpetrated in 1967 in the ferocious massacre of San Juan when military forces razed all their equipment and looted their nightclub when the radio accompanied and encouraged a mining protest against the government of President René Barrientos Ortuño.



First documentary about one of the most important historical experiences of participatory communication: the radio stations of the mining workers of Bolivia. Made in 1983 for UNESCO by Eduardo Barrios and Alfonso Gumucio Dagron, in 16 mm.

Click here to view on YouTube.

Voices of the Socavón Two Argentines produced a documentary that highlights the struggle of mining radios in Bolivia during the dictatorships. Voces del Socavón, a production made by Argentine filmmakers Julia Delfini and Magalí Vela Vázquez and is about the radio La voz del minero from the Siglo XX mine in Potosí, which was the first station financed and controlled by workers, and a pioneer in America Latina

The voices of the tunnel tells the story of Bolivia’s mining radios, led by La Voz del Minero, and its role in the workers’ union struggle during the second half of the 20th century. The protagonists of this story, union leaders, women of the Housewives Committee, miners and announcers, relate the historical events they went through in search of the Bolivian workers’ revolution. The

film links the culture within the mining camps, accompanied by the poetry and stories of the famous Uruguayan writer Eduardo Galeano, in what is one of his last interviews.

Here you can see his trailer https://youtu.be/HUM40UGEQTA

Mining Radio Stations Today

Currently of the more than 20 mining radios that operated in the country of Bolivia, only three of them are on air. These are Radio Nacional de Huanuni (Huanuni- Oruro), Radio Vanguardia (Colquiri- La Paz) and Radio 16 de Marzo (Bolívar-Oruro).

National Radio of Huanuni (Huanuni-Oruro), that used to transmit by short wave, is on FM (94.5 MHz) and online: www.radionacionaldehuanuni.com/

Photos of Radio Vanguardia’s building and transmitter:

Radio Vanguardia of Colquiri, owned by the mining workers of that district, currently has a new transmitter on medium wave 1270 kHz with a power of 3 kW and an FM transmitter, 98.3 MHz with a power of 1 kW. The AM signal can be heard in the remotest corners of the department of La Paz and even nationwide.

About the author

Martín Butera is a journalist, documentary maker and founding member of Radio Atomika 106.1 MHz (Buenos Aires, Argentina) www.radioatomika.com.ar

Photo: Martín Butera visiting, Radio Club La Paz Bolivia CP1AA

Martín Butera

He is an Amateur Radio operator with more than 29 years of experience, and has participated in DXpeditions throughout South America, with the Argentine radio callsign LU9EFO and Brazilian callsign PT2ZDX.

It is to collaborate for the newsletter of the British Dx Club (United Kingdom).

Martin is Argentinian, born in the city of Buenos Aires capital. He currently lives in Brasilia DF, capital of Brazil

About the The British DX Club

This guest post by Martin Butera was originally published in the June 2019 issue of “Communication” magazine of the prestigious The British DX Club. It is now available for free from the club site http://bdxc.org.uk/, remembering that like this report many other very interesting ones can be downloaded.

We congratulate Martín Butera for this interesting report, as well as his editor Chrissy Brand.

If you would like to be a member of the Briitish DX Club, you can find information here http://bdxc.org.uk/apply.html

`Thank you for this fascinating look at the history of Bolivian Mining Radio, Martin!

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