MT63

MT63 is a digital radio modulation mode for transmission in high-noise situations developed by Pawel Jalocha SP9VRC. MT63 is designed for keyboard-to-keyboard conversation modes, on HF amateur radio bands.

Features and Attributes

MT63 distributes the encoding of each character over a long time period, and over several tones. This code and symbol spreading implementation is key to its robustness under less than ideal conditions. The MT63 mode is very tolerant of mistuning, as most software will handle 120 Hz tuning offsets under normal conditions.

MT63 Latency

One shortcoming of MT63 is that robustness is somewhat compromised with the short interleaver.

Latency (delay between transmitted characters) is more than 6 seconds with the long interleaver.

The typical character transmission delay is 12.8 seconds with Long Interleave Mode.

Media

MT63 is seeing a resurgence in its popularity on shortwave with the VOA Radiogram but the software used to encode the text is not using the Varicode that MT63 used in its original design.