Learn / Guide 13
What you can listen to and what you can publish
Listening and sharing are different things. What Brazilian law says about telecommunications privacy and what is public by nature.
beginner 6 min read
A warning first
I am an amateur radio operator, not a lawyer. What is here is my interpretation of the legal texts and how I decide what to publish. It is not legal advice. If you plan to go beyond the hobby, talk to a lawyer and to Anatel.
Three different acts
Almost all confusion comes from treating as a single thing what are actually three:
- Receive: the signal reached your antenna and you heard it.
- Save and use: you recorded, noted down, took advantage of the content.
- Publicize: you told another person or published it.
The radio wave passes through your house whether you want it to or not. In my reading, the weight of the law grows as you go down the list, and the problem lies chiefly in disclosing or using the content of a communication that belonged to other persons.
What the texts say
Constitution, art. 5, XII. Declares the inviolability of the secrecy of correspondence and of telegraphic, data and telephone communications. The exception, provided for telephone communications, is a court order, in the manner of the law, for criminal investigation or criminal procedure.
General Telecommunications Law (Law 9.472/1997), art. 3, V. Guarantees telecommunication service users the inviolability and secrecy of their communication, except in cases provided for by the Constitution and the law.
Brazilian Telecommunications Code (Law 4.117/1962). It is the old sector law. The General Law revoked most of it, but kept what deals with broadcasting and the criminal matters that the new law did not cover (Art. 215, I, of the General Law). Three points are of interest:
- Article 55 states that telecommunications are inviolable.
- Article 56 defines the crime of telecommunication violation. It applies to anyone who, by transgressing law or regulation, discloses, communicates, informs, captures, transmits to another or uses the content of a communication addressed to a third party. Paragraph 1 extends the crime to anyone who illegally receives, discloses or uses intercepted telecommunications.
- The single paragraph of art. 57 opens the exceptions, and is worth reading in full: radiocommunications intended to be freely received, those of amateurs, those relating to ships and aircraft in danger, or those transmitted in cases of public calamity are not included in the prohibitions.
Law 9.296/1996, art. 10. It makes it a crime, punishable by imprisonment from two to four years and a fine, to intercept telephone, computer or telematics communications without judicial authorization or for purposes not authorized by law. The current wording is from Law 13.869/2019.
The principle, as I read it, is the same for everyone: what is made for the public is free, and conversations between third parties are protected.
What is public by nature
| Signal type | Why I consider it open | Caution when publishing |
|---|---|---|
| Broadcasting (AM, FM, shortwave) | is made to be received by anyone; it is under the exception of the law | the program is copyrighted. A short snippet to identify the broadcaster is one thing, redistributing the programming is another |
| Radio amateur (voice, telegraphy, FT8, APRS, WSPR) | express exception in the law; the service is open and does not allow encrypted messages | there are people there. Avoid exposing personal details mentioned in a conversation |
| ADS-B | the aircraft transmits in the clear, for any nearby receiver | the law does not mention ADS-B. Framing it as freely received is my interpretation |
| Time signals, radiosondes, weather satellites | public reference and scientific data, in the clear | none in particular |
In many countries ADS-B data is treated as open, and there are collaborative networks that have published it for years. I have not found a Brazilian rule that states this explicitly. Therefore, this site does not publish aircraft data. Tracking a private aircraft is even more delicate, because the route can expose an individual.
What it is not
Aviation and maritime in voice. These are operational communications between an aircraft or ship and control, not broadcasting. The legal exception mentions only ships and aircraft in distress. In my reading, recording and publishing the content, or retransmitting it live, falls into the zone described by art. 56. I have not found any Brazilian court decision on this. The existence of foreign websites transmitting control towers does not change Brazilian law. I listen, and I do not publish the audio.
Citizens Band (CB, 11 meters). It is another service, not amateur radio, and the exception in the law for "amateur stations" does not mention it. As a precaution, treat it like a conversation between third parties: listening is fine; recording and publishing what was said, no.
Private services and public safety. Business, security, ambulance, and public agency radios. This is communication directed at third parties, with no exceptions whatsoever in the law. If you stumble upon one, keep moving: do not record and do not comment.
Telephony, data and any encrypted traffic. Cell phones, cordless phones, data links, networks. Law 9.296 mentions telephone, computer or telematics communications, and I understand that this covers these cases. Intercepting without a court order is a crime. And if the signal is encrypted, the owner made it clear that it is not for you.
What I cannot say for sure
- I do not know how a judge would apply article 56 of a largely revoked 1962 law today to a radio listener who published an aviation audio clip.
- Simple reception, without disclosure, of a communication not intended for the public falls into an area that the texts do not resolve well. Article 56 lists interception, always linked to breaking a law or regulation, and I am not sure how that applies to someone who only listened. In between, current interpretation holds that the problem starts with disclosure and use. This is custom, not a guarantee.
When in doubt, do not publish.
Transmitting is another story
Everything above is about listening. Transmitting without authorization is another matter: article 183 of the General Telecommunications Law penalizes anyone who clandestinely develops telecommunication activities, with detention from two to four years, increased by half if there is damage to a third party, and a fine of R$ 10,000. The legal path is in the guide How to become an amateur radio operator.
What about the LGPD?
An amateur radio callsign is personal data, pointing to an individual. The General Data Protection Law (Law 13.709/2018) allows the use of data that the data subject themselves made public, provided it is done in good faith and for the purpose for which it was published. In practice, here I follow three rules: I only show what the network itself already publishes openly, I use the minimum (on propagation maps, only the prefix), and I remove any callsign upon request, without asking why. Details at Privacy.
The owner of the remote receiver
In a WebSDR another person enters the story: the person who maintains the receiver.
- When publishing a recording or screenshot, give credit.
- Follow the page usage rules. Long recordings, live retransmission or continuous data collection only with the owner's authorization.
- Do not use someone else's receiver to listen to what you would not hear on yours. If a problem occurs, the address that appears is theirs.
How I decide
Before publishing anything I heard, I go through three questions:
- Was this transmitted to the public, or by radio amateurs?
- It was in the clear, without any attempt to protect the content?
- Does publishing expose anyone in a way they would not expect?
If any response is bothersome, the log remains in the notebook: date, time, frequency, mode, and signal type, without the content.