TRIAD
 | |
|---|---|
| Mode | NFM |
| Modulation | ASK |
| ACF | — |
| Emission Designator | — |
| Bandwidth | 12.5 kHz |
| Location | Worldwide |
| Short Description | TRIAD is an amateur radio digital mode developed by Hunter McCann (KO6NGX) meant for automatic environmental observation systems. |
| I/Q Raw Recording | — |
| Audio Sample | |
TRIAD is an experimental digital amateur radio mode developed for automatic environmental observation and telemetry beacons. It is designed to transmit information such as weather observations using a distinctive audio signal that is more pleasant and less intrusive to listen to than many conventional digital modes, while retaining efficient data encoding.
TRIAD represents data using simultaneous three-tone chords selected from an Ionian (major) scale. Each symbol consists of three tones transmitted together, producing a distinctive musical sound and a recognizable pattern on a radio waterfall display.
The current implementation is a Python-based prototype capable of encoding messages into audio, decoding received audio, generating test transmissions, and rendering waterfall visualizations. It is being developed with narrowband FMFrequency Modulation (NFMNarrowband Frequency Modulation) operation in mind, particularly for automatic weather stations and unattended telemetry beacons.
The prototype uses a 720 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). tonic, a symbol rate of 2.5 baudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second., and 64 possible chord symbols, providing six bits per symbol before framing overhead. Packets include a preamble for synchronization and an end-of-transmission marker.
TRIAD is experimental, and its current decoder assumes relatively clean audio and known symbol timing. Further development is needed to improve synchronization, error correction, and reliability under real-world radio conditions.
Samples[edit]
File:Triad.wav
- TRIAD demonstration audio
- TRIAD encoded audio sample
- TRIAD over-the-air test recording
- TRIAD test with synthesized voice introduction
Frequencies[edit]
TRIAD uses three simultaneous audio tones per symbol. The default audio configuration uses a tonic frequency of 720 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz)., with the other tones determined by equal-tempered intervals in the Ionian major scale.
- ‘’‘Audio tonic:’’’ 720 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz)..
- ‘’‘Symbol rate:’’’ 2.5 baudBaud (unit symbol Bd) is the unit for symbol rate or modulation rate in symbols per second., corresponding to 0.4 seconds per symbol.
- ‘’‘Modulation:’’’ Multi-tone audio using simultaneous three-tone chord symbols.
- ‘’‘Intended radio mode:’’’ Narrowband FMFrequency Modulation (NFMNarrowband Frequency Modulation).
The actual radio frequency used for transmission depends on the station and band being tested. No single RFRadio Frequency operating frequency is specified as the official TRIAD frequency.
TRIAD is currently being developed and tested as an audio signal intended to pass through an FMFrequency Modulation transmitter and receiver. Occupied bandwidth, FMFrequency Modulation deviation, receiver behavior, and performance under realistic noise conditions remain areas for testing.
Decoding Software[edit]
- TRIAD Python Prototype — The reference implementation, including audio encoding and decoding, command-line tools, test generation, and waterfall rendering.
The software uses Python and NumPy. It currently supports decoding compatible mono, 16-bit PCM WAV files at the configured 48 kHzKiloHertz (kHz) 10^3 Hz sample rate.
Decoding Tutorials[edit]
- TRIAD GitHub Repository — Source code, installation instructions, command-line examples, and details of the current encoding and decoding implementation.
To generate and decode a demonstration packet, install the project dependencies and run the included example. The command-line interface can also encode messages into WAV files and decode compatible recordings.
Video Examples[edit]
- No public video demonstrations currently documented.
