2.4 Prohibited Transmissions, Commercial Ban & Encryption Rules
Key Takeaways
Section 13 limits class-licensed stations to amateur purposes and prohibits gain or reward, messages enabling gain or reward, and advertisements.
Section 13 generally prohibits encoding a radio signal for the purpose of obscuring its meaning.
Section 13(3) covers control signals to a space station in the amateur-satellite service or an unattended amateur station, and amateur-to-amateur signals for emergency services operations or training.
Sections 11 and 17 allow a guest to operate under a qualified person’s supervision, subject to the privileges of the applicable qualification.
A message sent to an overseas amateur station must meet the Spectrum Plan restriction in section 13(2)(d)(iii).
Identify the purpose before evaluating the message
The Radiocommunications (Amateur Stations) Class Licence 2023 defines amateur purposes in section 5. They include self-training, intercommunication, technical investigations, and passing news and information about amateur station operation as a means of facilitating intercommunication. A club can use its station to discuss an antenna experiment or share a notice about an amateur operating exercise. A programme of general entertainment for public reception falls outside those amateur purposes.
Section 13 applies several separate tests. Ask what the operator is using the station to do, whether the message enables any person to obtain financial gain or reward, and whether the message contains an advertisement. The rules apply to messages sent on behalf of someone else as well as messages for the operator's own benefit. An on-air advertisement for a used transceiver falls under the advertising prohibition even when it is a one-off private sale.
| Proposed traffic | How to apply the class licence |
|---|---|
| Discussing how two antennas performed in a club experiment | An example of technical investigation or intercommunication. |
| Announcing the frequency and operating procedure for a club training net | Amateur operating information can facilitate intercommunication. |
| Dispatching a paid technician to a customer | Commercial work traffic involves financial gain or reward. |
| Announcing that a personal transceiver is for sale and giving the price | Section 13(2)(d)(ii) prohibits messages that are or include an advertisement. |
| Relaying a station's transmission during an amateur technical exercise | ACMA operating procedures require the other station's permission and an indication that it is a retransmission. |
Codes, digital modes and obscured meaning
Section 13(2)(d)(iv) prohibits a signal encoded for the purpose of obscuring its meaning, subject to section 13(3). Encoding can also be used to represent letters, synchronise a digital receiver or detect errors. International Morse code and standard Q codes are familiar examples of representations that allow communication. The regulatory question is the purpose of the encoding and whether a specific exception applies. A digital transmission must still use a permitted frequency, power and bandwidth and carry the required call sign.
The exceptions in the class licence are defined by destination and purpose. ACMA's operating procedures group the last two together as emergency services operations or exercises.
| Signal sent from an amateur station | Scope of the exception |
|---|---|
| To a space station in the amateur-satellite service | To control the operation of that space station |
| To an unattended amateur station | To control the operation of that unattended station |
| To another amateur station | For the purposes of an emergency services operation |
| To another amateur station | For a training exercise related to emergency services |
For example, an operator can send an obscured shutdown command to an unattended amateur station. The same operator cannot use that control link as justification for obscuring an ordinary conversation. Section 13(4) separately sets conditions for unattended operation, including a shutdown timer in case a malfunction causes an unintended transmission to last longer than 10 minutes. An amateur beacon or repeater station requires a transmitter licence, so look up its own licence conditions before applying rules to its operation.
Supervised operation and third-party messages
A visitor speaking at a station and a message forwarded on behalf of another person raise different issues. Under sections 11 and 17, a person without amateur qualifications can operate under the supervision of a qualified person and within that person's privileges. In an ordinary demonstration, the supervisor should have effective control throughout. For example, the supervisor can choose the frequency and mode, show the guest how to use push-to-talk, and be ready to stop the transmission. Under section 12(2), the supervised operator may use the supervisor's call sign to meet routine identification requirements.
When an operator relays a message on behalf of someone else, the amateur-purpose, gain, reward and advertising restrictions still matter. In ordinary operation, intercommunication means two-way communication between an Australian amateur station and another amateur station in Australia or overseas. It does not include a routine contact with a non-amateur radio service. A message for another person still has to meet the conditions on purpose and content. Emergency and distress cases involve additional rules. Section 49 of the Radiocommunications Act 1992 addresses operation or possession reasonably believed necessary for specified emergencies, including risks of death or injury. An emergency services exercise is a distinct context with specific class licence rules, including section 14 on identification.
For a message to an amateur station in another country, section 13(2)(d)(iii) also prohibits a transmission whose purpose conflicts with the Australian Radiofrequency Spectrum Plan's allocation table or a footnote to it. ITU Radio Regulations Article 25.3 addresses international third-party traffic in emergencies or disaster relief and allows national administrations to determine its applicability to their stations. Check the relevant national rules as well. The person who speaks at your station, the destination and the purpose of the message are separate facts to establish.
Which transmission falls within an exception to the class licence prohibition on encoding a signal to obscure its meaning?
An obscured radio command sent to shut down an unattended amateur station.
An encoded advertisement for privately owned second-hand radio equipment.
An encrypted conversation between friends on a routine club net.
An encrypted report from a commercial dispatch desk to its drivers.
During a local two-metre net, an operator wants to advertise a personal transceiver for sale and give an asking price. What does the class licence say?
The message is permitted if it uses a club call sign.
The message is permitted if the price is below the original purchase price.
The prohibition on messages containing an advertisement applies.
The message is permitted if transmitted only once per month.
A club volunteer with a Standard qualification wants to let an unqualified visitor make a short contact under the class licence. Which arrangement satisfies the qualification condition?
The visitor uses a spare club call sign alone after watching a demonstration.
The visitor operates alone within Foundation power limits.
The visitor registers with ACMA and operates alone while the volunteer is away.
The volunteer supervises the visitor throughout and the station operates within Standard privileges.
Sections you finish are checked off in the contents.