Amateur Radio

Digital mode setup guide

How to set up your station for FT8, FT4, JS8Call, and other digital modes. Step-by-step from radio to first QSO.

Digital mode setup guide

Step-by-step guide to getting on FT8 and other digital modes.

What you need

Digital modes (FT8, FT4, JS8Call, WSPR, PSK31, RTTY) require your radio connected to a computer for audio and control. The computer generates the transmit audio and decodes the received audio. Here is what you need and how to connect it.

Connection methods (choose one)

Method 1: Built-in USB audio (modern radios)

If your radio has a USB port with built-in audio codec, you need only a USB cable. No external interface.

Radios with built-in USB audio: Icom IC-7300, IC-7610, IC-705, IC-9700. Yaesu FT-991A, FT-891, FT-710, FTDX10, FTDX101D. Kenwood TS-590SG, TS-890S. Elecraft K3S, KX2, KX3, K4.

Setup: Connect USB cable from radio to computer. The radio appears as a USB sound device. Select it in WSJT-X or your digital mode software as both the audio input and output device.

Method 2: External USB interface (older radios)

If your radio does NOT have built-in USB audio, you need an external interface.

Radios that need an external interface: Yaesu FT-857D, FT-897D, FT-817/818, FT-450D, FT-950. Icom IC-718, IC-746, IC-756 series. Kenwood TS-480, TS-570, TS-2000. All radios manufactured before approximately 2012.

Interface options:

  • SignaLink USB ($100-130): The established standard. Radio-specific cable required ($15-25 extra). VOX-based PTT.
  • Digirig Mobile ($50-70): The compact modern alternative. Radio-specific TRRS cable required. Handles audio and CAT control.
  • Radio-specific cables: Some radios have direct USB audio cables available (e.g., Yaesu SCU-17).

Method 3: QRP Labs direct (QDX/QMX)

The QRP Labs QDX and QMX have built-in USB audio and are designed exclusively for digital modes. Connect the USB cable and the radio IS the interface.

Software

  • WSJT-X: FT8, FT4, WSPR, JT65, JT9. The standard. Free. Available for Windows, Mac, Linux.
  • JS8Call: Keyboard-to-keyboard messaging over HF. Based on FT8 protocol. Free.
  • fldigi: PSK31, RTTY, and dozens of other modes. Free.
  • N1MM+: Contest logging with integrated digital modes. Free. Windows only.

Radio settings for digital modes

  1. Mode: USB (upper sideband) for all digital modes on HF. Some radios have a dedicated DATA or DIGI mode — use it if available.
  2. Power: Start at 25-50% power. Digital modes are 100% duty cycle (continuous transmit), which generates more heat than SSB. Full power sustained may overheat the finals.
  3. ALC: Adjust the drive level so the ALC meter shows ZERO or minimal deflection on transmit. Over-driving causes splatter that interferes with adjacent signals.
  4. Compression/processing: OFF. Speech processors distort digital mode signals.
  5. Filters: Set bandwidth to 2.5-3 kHz for FT8. Narrower filters may cut off signals.

The #1 mistake

Over-driving the transmitter. If your ALC meter is moving during digital mode transmit, your drive level is too high. Reduce the computer audio output until the ALC shows zero deflection. Over-driven digital signals are wider and dirtier than they need to be, and they interfere with other operators. Run 25-50W with proper drive levels rather than 100W with ALC compression.