For WSJT-x AND JTDX

Installing JTDX

June 18, 2026

JTDX is a fork of WSJT-X focused on weak-signal DXing. It has a more aggressive decoder, a busier interface, and contest-friendly features that DXers love. If you chase weak signals or work pile-ups, JTDX is worth installing alongside (or instead of) WSJT-X. This guide gets you from zero to your first FT8 contact.

What you need

  • A computer running Windows, macOS, or Linux
  • An HF transceiver (JTDX also works on VHF/UHF for 6m, 2m, 70cm FT8)
  • A way to get audio between the computer and the radio — built-in USB sound interface or external (SignaLink, RigBlaster, Tigertronics)
  • A CAT cable so JTDX can control frequency and PTT

Step 1 — Download and install JTDX

Go to jtdx.tech and download the latest stable release for your platform. Install with the default options.

JTDX and WSJT-X can coexist on the same computer — they install to separate folders and don’t conflict. Many operators keep both installed and choose which to launch based on band conditions.

Step 2 — Set your callsign and grid

  1. Open JTDX
  2. File → Settings (or press F2)
  3. On the General tab, enter your Callsign and Grid square (6-character Maidenhead, like EL59vh)

Step 3 — Configure your radio (CAT and PTT)

  1. Connect your radio to the computer via USB
  2. Make sure CAT is enabled in the radio’s menu and note the baud rate (usually 38400 or 115200)
  3. In JTDX, click the Radio tab
  4. Rig: pick your exact radio model
  5. Serial Port: pick the COM port (Windows) or /dev/tty.usbserial-XXXX (Mac) that appeared when you plugged in the radio
  6. Baud Rate: match what’s set in your radio’s menu
  7. PTT Method: CAT for most modern radios; RTS or DTR if you have a separate PTT line
  8. Mode: Data/Pkt
  9. Click Test CAT — should turn green. Click Test PTT — radio should briefly key. Click again to release

Step 4 — Configure audio

  1. Click the Audio tab
  2. Soundcard Input: pick your radio’s USB audio input (usually “USB Audio CODEC” or your interface’s name)
  3. Soundcard Output: same device for output
  4. Click OK to save

Step 5 — JTDX-specific settings worth knowing

This is where JTDX differs meaningfully from WSJT-X. A few settings to understand on the Behavior tab:

  • Auto Sequencing — controls how JTDX advances through a QSO. Mode 3 (“Call based on end of decoding”) is the most common choice and works well for general operating
  • RR73 to log — when checked, JTDX automatically logs the contact when RR73 is sent. Most operators want this on
  • Decode all signals in receive bandwidth — turn this on. JTDX’s decoder is its main advantage; let it work
  • Tx watchdog — defaults to 5 minutes; this stops TX if a QSO stalls. Reasonable default for most operating

Step 6 — Make your first FT8 contact

  1. Tune your radio to 14.074 MHz USB (20m FT8 calling frequency)
  2. Watch the waterfall — you should see vertical streaks every 15 seconds
  3. Decodes appear in the right-hand panel
  4. Make sure the Auto Seq checkbox at the bottom of the JTDX main window is checked — this is the master ON switch for sequencing
  5. Double-click any station calling CQ
  6. JTDX queues your reply. Click Enable Tx if it’s not already lit
  7. At the next 15-second window, your radio transmits
  8. JTDX advances through the exchange automatically and logs the QSO at RR73

Common gotchas

  • JTDX accepts your call but stalls on message 1 — the most common JTDX problem. The “Auto Sequencing” dropdown in Settings sets the behavior, but the Auto Seq checkbox on the main window is the master switch. Both must be active
  • Test CAT fails — another program (logging software, rig control) has the COM port open. Close it and retry
  • Decoder seems too aggressive — lots of garbage decodes — JTDX is designed to be sensitive. If you don’t want the noise, lower the decoder depth in Settings → Advanced
  • Computer clock drift — FT8 needs your PC clock accurate within 1-2 seconds. Make sure your time sync is working

When you want to operate hands-free

JTDX gives you a sharper decoder and contest-grade features, but the QSO loop still needs you watching the screen — picking which decode to call, managing filters, calling CQ when the band’s quiet, dismissing the Log QSO dialog after every contact.

That’s what we built Hamilton Auto FT8 for. It drives JTDX (and WSJT-X, and MSHV) over the standard UDP interface — picks callable stations from your filters, runs the sequence, auto-closes the Log QSO popup, optionally pushes QSOs to QRZ Logbook, and offers Hunter and Activator (POTA/SOTA) CQ modes.

Try it free: autoft8.com/downloads.

73 and good DX.