Live print of the whole passband
Every decoded JTTY message between 300 and 2700 Hz scrolls up as it arrives, with time, audio frequency and S/N. Signal subtraction means overlapping stations print too. Your own overs echo back like a teleprinter.
JTTYAF brings JTTY — the new keyboard-to-keyboard mode in WSJT-X 3.2 — to your Android phone. Type, press Send, and a coded 4-tone signal carries your text at RTTY speed through noise that would shred Baudot. Every station in the passband prints live. Your rig keys over USB CAT. No laptop, no sound-card tangle.
Every decoded JTTY message between 300 and 2700 Hz scrolls up as it arrives, with time, audio frequency and S/N. Signal subtraction means overlapping stations print too. Your own overs echo back like a teleprinter.
JTTY has no time slots. Type up to 80 characters, watch the hint count frames, press Send — JTTYAF keys the rig and plays the whole GFSK buffer with continuous phase, sync first, never clipped.
%M your call, %H the DX call, %E 599 + serial. Defaults map to the one-frame JTTY atoms — CQ %M CQ, %H %E, TU %M CQ — and RTTY Roundup or Field Day profiles pack the exchange tight.
Icom, Yaesu, Kenwood, Elecraft, Xiegu, FlexRadio, Guohe, truSDX and Hamlib-driven rigs over USB, Bluetooth or the network — FT8AF's battle-tested cable stack, with per-band TX level, ALC auto-volume and SWR protection.
Tap a received line to pick the DX call, tap Log QSO and the serial bumps. Contacts log as MODE=JTTY with ADIF export and Cloudlog, Wavelog, QRZ and World Radio League upload.
CRC-12, a K=10 tail-biting convolutional code, list-Viterbi decoding and signal subtraction — written from the published design notes under MIT, no GPL code, and proven against WSJT-X's official sample recording.
Grab the APK from GitHub today. A one-tap Google Play build — with automatic updates — is in review now.
The full app, MIT-licensed and built in the open. Grab the APK or build it yourself.
A Play Store build is in review — one-tap install and automatic background updates, delivered the moment it's live.
Want a heads-up when it lands on Play? See the FAQ →
JTTY landed in WSJT-X 3.2 on September 23, 2026. JTTYAF followed within weeks — the FT8AF codebase with the FT8 engine pulled out and a clean-room JTTY codec written from the published design notes, Claude in the loop, a radio on the bench, and the official sample recording as the judge. If it decodes K1JT's test file, it decodes the band.
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JTTYAF shares its radio stack, logbook and look with four sibling apps for Android. Run the mode you're in the mood for.
Native FT8 on Android — live band decoding, USB CAT control, the full auto-sequence QSO monitor. The codebase JTTYAF is built from.
Slow-scan television on Android — receive and send SSTV images straight from your phone, in the same clean Material 3 shell.
Classic Baudot RTTY on Android — mark/space waterfall, real FSK transmit, macros and contest logging. JTTY's 45-baud ancestor.
FlexRadio FLEX-6000 client for Android — panadapter, waterfall and remote receive audio over the LAN or worldwide via SmartLink.