The World of Cassiano Mendonça PY3CSM
Welcome to the story of the Brazilian radio amateur who recovers old AM transmitters, welcome to the world of Cassiano Mendonça (PY3CSM)
Currently, the “Río de la Plata” region is home to more than 100 amateur radio stations that use AM (Amplitude Modulation) as their preferred way of communicating and experimenting. They can generally be heard on the 80 and 40 meter bands.
AM has now become a specialized and highly valued mode within our hobby.
Some might say it is “old school”, but I prefer to think that it keeps the origins of amateur radio alive.
In this new article, our collaborator in South America, colleague Martin Butera (PT2ZDX – LU9EFO), visits Cassiano Mendonça (PY3CSM), a passionate AM mode transmitter collector who has also been recovering homebrewing transmitters since the early 90s.
I recommend you read this interesting article by Martin, which has been translated and adapted especially for all of you.
Introduction
AM operation and experimentation was the pioneering way to use voice after Morse.
In the early years, most radio amateurs built their own equipment since there was no commercial equipment readily available at the time. This process was called “homebrewing” construction.
Between 1930 and 1950, radio amateurs had managed to build AM transmitters of reasonable quality with vacuum tubes.
Even in the late 1960s, tube radios predominated. From the 1970s onwards, home-built AM transceivers were somewhat forgotten by the arrival of the transistor.
Today I am traveling to the south of Brazil, more specifically to Peña, a Brazilian municipality in the State of Santa Catarina.
In Penha there are beautiful beaches with a more natural or wild look in Brazil, my interviewee Cassiano Mendonça (PY3CSM), lives just 100 meters from these beaches, so you can imagine the paradise where his QTH is located.
Cassiano Mendonça (PY3CSM), is passionate about recovering homemade valve transmitters from the early years of Brazilian amateur radio, he gets involved with simple modifications to large projects.
Entering Cassiano’s radio room is like going back to the times where it all began, surrounded by valves and radios that are true relics.
I invite you to meet Cassiano Mendonça (PY3CSM), a Brazilian radio amateur who thanks to his talent, passion and many hours of work, helps preserve the “Memory of broadcasting in Brazil”.
Let’s get started!!
Before starting you can have a 360 view of the radio room of Cassiano Mendonça (PY3CSM)
MB: How did you get started in radio?
Cassiano Mendonça: Well, my father had already been a radio amateur in the seventies and one God gave me a transmitter as a gift.
I remember that at the end of the 80s, more precisely in 1988, the transmitter was what is known as CB (Citizens Band) or free band, of the Audiovox MCB-500 brand with 23 channels in amplitude modulation at the frequency of 27 MHz, manufactured in Japan in 1976.
Then around 1991 a friend from my city, with whom I spoke on the citizen band, called Fabio Cunha, today (PU3FSC), who knew a little about electronics and valves, decided to build a pair of transmitters so that we could talk on the 49 meters, so we operated near 6700 KHz.
I remember that the transmitter was armed with a 6L6 valve, modulated in a network by another 12AX7 valve.
After that experience, I got a couple of transmitters from a national brand called Delta for AM, that was in 1997, I got my radio callsign and I never stopped.
MB: There are radio amateurs who are passionate about AM modulation all over the planet, but why do you think that, curiously enough, here in South America, there is a phenomenon whereby the operators who transmit in AM are mostly from Brazil, Argentina and Uruguay and are all from an area or region called “Río de la Plata”?
Cassiano Mendonça: AM has always been very strong in the South of Brazil, more specifically in Porto Alegre, capital of the state of Rio Grande do Sul.
I think that due to the great distances between towns, almost all of which were rural at that time, radio was the only more effective form of communication. SSB did not yet exist and AM began with amateur equipment that covered part of the commercial bands, to talk as if it were a telephone (laughs)…
In this way, many people developed a taste for amplitude modulation and so the modality gained strength mainly among older radio amateurs.
The area or region called “Río de la Plata” is formed by the union of the Paraná and Uruguay rivers, in the Southern Cone of America and flows into the South Atlantic.
The main port cities of the South American continent are located in the Rio de la Plata area, which are Buenos Aires (capital of Argentina) and Montevideo (capital of Uruguay). These two important capitals, together with Porto Alegre, which has always been an important industrial center in southern Brazil, were where all the technological trends of the time passed through, and where electronic components for the construction of radio transmitters could be obtained most easily.
Even after 1968, with SSB already popular in Brazil, Uruguay and Argentina, AM continued in full force to this day in that area or region.
MB: In Argentina and Uruguay, Spanish is spoken, while in Brazil, Portuguese is spoken. How did all the radio amateurs manage to communicate and integrate?
Cassiano Mendonça: In the south of Brazil, many people speak “Portuñol”, a fusion and mixture of words from Portuguese and Spanish. This usually happens mainly in border cities between Portuguese and Spanish speaking countries.
This has allowed us for decades to maintain our contacts with Buenos Aires in Argentina and with the stations of Montevideo in Uruguay.
Then we are united by a great common passion which is football (laughs…).
MB: How important are American pioneer brands such as Atlas, Swan, Hallicrafters, Drake, Collins, Hammarlund, Heathkit, among others, for Brazilian radio amateurs who like AM mode?
Cassiano Mendonça: Imported equipment was of great importance to Brazilian radio amateurs, of course for the wealthiest ones and also for national manufacturers, who were forced to manufacture quality equipment to compete with the classic imported ones, for example the national transmitters “Centauro”, are based on the Swan, another national one like the “Eudgert”, is based on the Drake.
Imported equipment from brands such as Hallicrafters and Hammarlund became popular among Brazilian radio amateurs, who managed to buy the surplus of equipment manufactured for military purposes from the Second World War that became “cheap” to buy in warehouses or stores of old military objects.
Heathkit, for example, provided study material and possibilities for radio amateurs with average purchasing power and who were more inclined to assemble their own equipment.
MB: I see in your collection transmitters of Brazilian national manufacture, especially of the Delta and Eudgert brands. What do these national brands mean or represent for you and for Brazilian radio amateurs?
Cassiano Mendonça: Delta and Eudgert are the pioneer companies in Brazilian telecommunications, they are extremely important for the development of amateur radio in our country.
In the early sixties Brazilian radio amateurs only had access to expensive foreign equipment, the most popular was the “Geloso”, founded in 1931 by Giovanni Geloso, it was an Italian radio manufacturer and its headquarters were located in Milan.
Delta was founded in 1950 by Felicíssimo de Oliveira Junior and others in the city of São Paulo. That same year they imported monoblocks from the Italian Geloso, starting to produce the Delta 208, an AM receiver.
They then launched the Delta 209 receiver, with BFO and Delta 309. In 1962 they launched the Delta 310 transmitter, with the 807 valve at the output. Shortly after, some changes were made to this transmitter, and it was renamed Delta 310-I, and shortly after, Delta 310-II.
In 1975, Delta launched the Delta DBR 500, a 400-watt multiband SSB transceiver, using two 6KD6 tubes at the output, with transistorized reception.
The Delta factory closed in 1987.
The history of the Eudgert transmitters is sensational. The company was the brainchild of Gert Wallerstein, (PY7ALC-SK), who was born in Germany and during the Nazi regime, his family, who were Jewish, were forced to leave that country in 1936.
He first lived in the city of São Paulo, where he worked in several radio stations maintaining transmitters, then he moved to the city of Recife (capital of the state of Pernambuco, northeast of Brazil), where in 1965 he founded “Eudgert”.
Eudgert manufactured on a large scale a modern SSB transceiver with mechanical filter, following the line of the imported Drake and Swan, which quickly became popular among Brazilian radio amateurs.
Eudgert was a company that lasted only 10 years, closing its activities in 1975, but the revolution and acceptance of the transmitters was so great that a legend says that Yaesu itself tried to buy Eudgert in the early 1970s.
These two brands are without a doubt, for me and I believe for all Brazilian radio amateurs, the most popular or important national manufacturers in Brazil.
Mentioning of course that there were other brands such as “Centauro”, manufactured in the city of São Leopoldo in Rio Grande do Sul or Intraco and PCM manufactured in São Paulo, among others.
MB: I can see that you have a complete library related to amateur radio topics, have you ever thought about digitizing those books and magazines?
Cassiano Mendonça: I like paper, I have immense difficulties reading technical topics in digital magazines, so what people no longer want and put up for sale, they end up buying.
The biggest contributor to my collection of books and magazines, he was also my main teacher and driver for my interest in electronics, is my friend Marcinio Stabile (PU5KRO), he gave me a variety of handbooks and collections of different magazines. I also visit bookstores whenever I can and buy old books and magazines related to the subject.
MB: Radio amateurs who practice AM like to maintain a certain audio quality. There are many microphones: dynamic, condenser, ribbon, electret, large diaphragm, cardioid, omnidirectional, among many others. Based on your experience, what type of microphone would you recommend using?
Cassiano Mendonça: As for microphones, to avoid making mistakes, I usually recommend using electret microphones, which are cheap, they are even sold in pharmacies (laughs)…
Over time, studio microphones with capacitive capsules, such as Behringer, began to be more affordable and I think they are the best options for those who want to have a voice closer to natural in its modulation.
Many people like modulations with more low tones, but I think these are not good options. The ideal is to maintain your natural modulation tone and to do so equalize the mids and lows in the center of the band and slightly positive the highs.
Nowadays there are small sound consoles with phantom power (48V power supply for studio microphones), which are very cheap on the market and there are good equipment options for all budgets. Remembering once again that the natural tone of the voice, without forcing the bass, is the one that reaches greater depth and is therefore easier to hear on the other side of the receiver.
MB: Is there a subtle difference between the word restore or recover a transmitter?
Cassiano Mendonça: If there is a difference, I would say that he recover the transmitters, because I do not consider myself a restorer.
Restorers are concerned with leaving the equipment completely as new, as if it had come from the factory, but I am concerned with leaving the electronics of the equipment fully functional inside and without deviating too much from the original circuit, and I am not very concerned about the exterior aesthetics.
MB: In this room I see several transmitters, could you tell me what those recovered transmitters are?
Cassiano Mendonça: If there are some recovered transmitters in this room, others have already left my collection and others are lost in other parts of the house (laughs)…
As for the recovery of equipment, I was very interested in doing it as the pioneers did. I am interested in learning everything about radio amateurs who assemble transmission equipment by hand. One of the assemblers who interested me the most was José Blaya Perez (PY3CD – SK), who was a famous baker who assembled transmitters.
Of the radios manufactured by Blaya, I had the pleasure of bringing five transmitters back to life, one of those transmitters that I recovered was an SSB exciter that I gave to the great Brazilian collector and dear friend, colleague Adinei Brochi (PY2ADN), who many of you Japanese readers already know, because Hamworld published a nice article by you, in the November 2023 edition. Another curious thing to tell, a while ago I bought an AM transmitter from my friend Mauricio Sinigaglia (PP5BMS) and to my surprise when I recovered the equipment and turned it back on, I discovered that the original circuit had been assembled by my great friend Guilherme Hobbus (PY2UP-SK), imagine what a feeling, now it is one of the favorite transmitters of my station.
See Cassiano Mendonça (PY3CSM) in action, recovering a Nocar Geloso VFO
MB: Speaking of favorite transmitters, if you had to quickly name a few more, which ones would they be?
Cassiano Mendonça: It’s hard to name my favorite radios quickly, because all the transmitters in this collection tell a story, but I can name a few, let’s start… Well, the refrigerator (laughs), this transmitter is a classic circuit of an 813 modulated by two 811s, it was originally assembled as I told you by my friend Guilherme Hobbus (PY2UP-SK), unfortunately when it reached my hands it no longer had the original circuit, I made modifications to the power supply, the output and the modulator circuit and the equipment became the support of my AM station, it was originally assembled in 1997 and although it is working, it is still in the process of recovery.
Another important transmitter was the one made by colleague Escobar (PY3BMX-SK), from the city of Porto Alegre RS and was built especially for my great-grandfather, called Antenor Tournon (PY3EF-SK) in the 60s. This transmitter is a classic circuit of two 807 modulated by two others, to this day, it was the longest recovery and the one that cost me the most to make it work.
Another one without a doubt, as I mentioned, “The last Blaya”, a transmitter manufactured by the legendary José Blaya Perez (PY3CD-SK), the famous baker from the city of Cachoeira do Sul, in the state of Rio Grande do Sul. This transmitter was the last one he assembled in 1986, shortly before he died.
Another curious thing, it could be a JRC NRD receiver, manufactured in 1968, that belonged to a Japanese fishing boat, called Naikai Maru No. 8.
This boat was docked in the port of Porto Alegre, which is the largest river port in Brazil in terms of area, that is, the largest port located outside the sea.
Part of the boat was dismantled and I got the receiver, it is said that now the Naikai Maru No. 8 was bought by a businessman to make a boat using its fittings.
MB: Speaking about Japan, I know you also have a collection of Japanese motorcycles, what can you tell us about that?
Cassiano Mendonça: Besides radios, motorcycles and old cars are things that my wife “Vanessa” and I have in common.
I love classic Japanese motorcycles from the mid-70s. I have a Honda CB-200, and then my wife Vanessa gave me a Honda CB-400 from 1981, and we made several trips through the cities and municipalities of the state of Rio Grande do Sul and Santa Catarina with that motorcycle.
I have a good anecdote to tell you about. On a trip we made to Melo, which is a city in Uruguay, to attend a meeting of motorcyclists, we traveled on a Suzuki motorcycle. The tire got punctured three times on the same day (laughs…)
We had a hard time that day and after overcoming those problems, we decided to get married, because we knew we were prepared for anything (laughs…)
Final Conclusions
This concludes my interview with colleague and friend Cassiano Mendonça (PY3CSM), a true craftsman in the recovery of AM transmitters.
Cassiano Mendonça, in this interview, showed us that this primary mode of communication that followed Morse, continues to be one of the best and most fascinating forms of radio experimentation.
Cassiano Mendonça shows that amateur radio operation in AM is not only about recovering or modifying old transmitters, but it is also about expressing a way of thinking and acting, a feeling for creating and sharing the technical experience learned.
If you are an experimenter or regular operator of the AM bands, do not fail to keep your station active as much as possible, I am sure that all over the world, there will be colleagues like Cassiano Mendonça, attentive to answer your call and share their experiences.
I would like to thank Cassiano and his wife Vanessa for welcoming us into their home and spending such a wonderful afternoon. After the interview, they took us to discover the charms of the beaches of Pena, which are a true paradise.
Extras
You can visit Cassiano’s Blog where you can find some interesting articles about mechanics, electronics, technology and much more: https://transceptoresclassicos.blogspot.com/
Enter Cassiano’s YouTube channel, where he shows many of his projects. I recommend it!
https://youtube.com/channel/UCIl3E44JckqsjnueAw1Du-Q?si=DPGhENJGB1wlIbdA
