The fastest digital mode ever created
First contact in the world completed on February 16, 2026. DECODIUM Fast Track 2 · Raptor Engine · −23 dB SNR · QSO in ~6 seconds · ADIF 3.1.7 Certified — SUBMODE=FT2.
The ADIF Development Group voted 22 YES — 0 NO to officially include FT2 as a certified submode in ADIF 3.1.7. Historic record: highest participation ever in ADIF history. All major logging platforms voted YES: LoTW/ARRL (K1MU, K0GW), DXLab (AA6YQ), Log4OM (G4POP), Swisslog (EA3GCV), Cloudlog (MM9SQL), TR4W (NY4I), Wavelog (DJ7NT), DXLog (SM7IUN), Fldigi (W1HJK), eQSL (N5UP), and 12 more. Special thanks to Graham G3ZOD for guiding FT2 through the process with integrity.
🏆 ADIF 3.1.7 OFFICIAL 22:0 UNANIMOUS SUBMODE=FT2 → See all 22 votersThe most significant update since launch. +2 dB sensitivity (−21→−23 dB SNR), 4× faster decode→TX latency (850→200 ms), QSO completion rate from ~30% to ~90%. TX timing fixed thanks to LZ2HV Christo's WAV analysis. Auto-sequence 100% working. Async collisions −80% with freq hopping ±25 Hz.
🦅 SHANNON BUILD 2603xxDECODIUM 3.0 Codename Raptor features Asynchronous Transmission: FT2 transmits within 300ms of decoding — no period boundary, no NTP, no GPS. The waveform duration is optimised to 2.47s (−34% vs standard). 378 lines of legacy DT/NTP code removed. Full backward compatibility preserved.
⚡ ASYNC TX BUILD 2603080007IU8LMC e IZ8XXE completano il primo QSO FT2 al mondo su 40m. SNR -12dB, tempo totale 11 secondi.
WORLD FIRSTRaptor Engine · Build 2603xx · March 2026
Claude Shannon proved that every noisy channel has a maximum information capacity — and that codes approaching this limit must exist. For 78 years, mathematicians searched for them.
"More power is not the answer. Better math is." — IU8LMC
| System | Eb/N₀ required | Distance from Shannon | Block size | Notes |
|---|---|---|---|---|
| Shannon absolute limit | −1.59 dB | 0.00 dB | ∞ (theoretical) | Physical boundary |
| Turbo Codes (Berrou 1993) | ~0.00 dB | +1.6 dB | ~6,000 bits | First practical proof |
| LDPC long (5G NR) | ~0.10 dB | +1.7 dB | 8,000–50,000 bits | Incompatible with FT2 T/R |
| ⭐ LDPC (174,91) FT2 — Fast Track 2 | ~2–3 dB | ~+4 dB | 77 bits | Practical limit for 77-bit HF |
| FT8 — same LDPC (174,91) | ~−1 dB (SNR) | ~+3 dB | 77 bits | 15s T/R cycle |
| CW | +3–5 dB | +6 dB | variable | Operator skill dependent |
| SSB voice | +10–15 dB | >+10 dB | — | Far from Shannon limit |
Within the real constraints of HF operation — 77 bits · 3.75s T/R · 167 Hz · ionosphere — DECODIUM Fast Track 2 with Raptor Engine is at the practical limit of Shannon's theorem. Nothing comparable exists today for these operating conditions.
FT2 is a revolutionary digital mode for amateur radio, developed by IU8LMC with the support of ARI Caserta. It uses the same codec as FT8 and FT4 (77-bit payload, LDPC 174/91, 4-GFSK modulation) but compresses the transmission cycle to just 3.8 seconds.
Complete QSO in ~6 seconds with Fast Track 2. Theoretical rate of ~450 QSO/hour.
77-bit payload, LDPC(174,91), 4-GFSK modulation. The protocol core is identical to FT8/FT4.
Verified February 16, 2026. 2,000+ active operators, 500,000+ QSOs logged. QRZ Logbook active.
Official ADIF submode: SUBMODE=FT2. Vote 22:0 unanimous. 22 March 2026.
| Parameter | FT8 | FT4 | FT2 |
|---|---|---|---|
| T/R Cycle | 15 s | 7.5 s | 3.8 s |
| Effective TX Time | 12.64 s | 5.04 s | 1.89 s |
| Async TX Duration | — | — | 2.47 s ⚡ |
| Async TX Delay | — | — | ~300 ms |
| Modulation | 8-GFSK | 4-GFSK | 4-GFSK |
| Bandwidth | 50 Hz | 83 Hz | 167 Hz |
| Payload | 77 bit | 77 bit | 77 bit |
| FEC | LDPC(174,91) | LDPC(174,91) | LDPC(174,91) |
| Sensitivity (Raptor) | −21 dB | −16.5 dB | −23 dB ★ |
| Full QSO | ~60 s | ~30 s | ~6 s |
| QSO Rate | ~60/h | ~120/h | ~450/h |
| ADIF Submode | FT8 | FT4 | FT2 🏆 |
167 Hz bandwidth · 4-GFSK modulation · 3.8-second cycles · ⚡ Async TX: 2.47s waveform, 300ms delay, no clock sync
With Raptor Engine: −23 dB SNR — at the practical limit of Shannon's theorem for 77-bit HF blocks.
| Mode | Averaging | Total Time | Sensitivity | Gain |
|---|---|---|---|---|
| FT2 Fast Track 2 | Raptor Engine | 3.8 s | −23 dB ★ | +2 dB vs prev |
| FT2 | 4-period avg | 15.2 s | −14.5 dB | +5 dB |
| FT2 | Single period | 3.8 s | −9.5 dB | — |
| FT4 | Standard | 5.04 s | −16.5 dB | ref |
| FT8 | Standard | 12.64 s | −21.0 dB | ref |
Raptor Engine · −23 dB SNR · 5 decode passes · 4× faster
Raptor Engine · −23 dB SNR · 5 decode passes · 4× faster
Beta software for Linux x86_64
Beta software for macOS · by 9H1SR
Compact portable FT2 stations · by LU7DZ
Screenshots from the first FT2 QSOs in history — February 16, 2026