Digital Modes
FT8, PSK31, RTTY, APRS, SSTV and more — the backbone of modern HF operating on Linux. These tools handle everything from weak-signal DX to packet radio and image transmission.
Fldigi
Live interfaceThe most widely used multi-mode digital modem on Linux. Supports PSK31, PSK63, RTTY, CW, Olivia, MFSK, DominoEX, Throb, and many more. Integrates with Flrig for rig control and pairs with Flarq for ARQ file transfers. Has a built-in web server making it ideal for remote operation.
sudo apt install fldigi
WSJT-X
Log viewerThe reference implementation for FT8, FT4, JT9, JT65, and WSPR weak-signal modes. Developed by Nobel laureate Joe Taylor K1JT. Capable of making contacts at signal levels 10–15 dB below what SSB requires. Essential for DX work and the most active digital mode community on HF today.
sudo apt install wsjtx
JTDX
GuideA popular fork of WSJT-X with enhanced FT8 and JT65 decoding algorithms. Many DXers prefer JTDX for its ability to pull weaker signals out of the noise. Uses the same audio interface and log format as WSJT-X so switching between them is seamless.
Download AppImage from jtdx.tech
Direwolf
APRS mapA software AX.25 TNC (Terminal Node Controller) that replaces dedicated hardware. Used for APRS digipeating, iGating, and packet radio. Runs on a Raspberry Pi with a cheap radio and becomes a full APRS station. Can decode multiple simultaneous channels from a single sound card.
sudo apt install direwolf
QSSTV
GuideThe go-to Linux application for Slow Scan TV (SSTV) — transmitting and receiving still images over HF radio. Supports all common SSTV modes including Martin, Scottie, and Robot. Popular on 14.230 MHz and during special event stations. Also supports HAMDRM digital SSTV.
sudo apt install qsstv