BasicB-001-007-006
When may an amateur radio station transmit an encoded message?
A
Answer
Regulations and administration
Type
A
Only when the encoding or cipher is not secret
B
Only when transmitting above 450 MHz
C
Only during a declared communications emergency
D
Only during contests
Answer Notes
A core principle of amateur radio is transparency; therefore, transmitting messages to hide their meaning from others is not allowed. You may only transmit an encoded message if the cipher or encoding method is open, publicly documented, and not a secret.
While amateurs frequently use complex digital modes and modulation schemes that sound like noise to the human ear, the technical specifications for these modes are publicly available. There are no blanket exceptions allowing secret encryption for contests, specific frequencies, or even emergencies.
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What are the restrictions on the use of abbreviations or procedural signals in the amateur radio service?