FT8 Digital Mode — What It Is and How to Get Started

What FT8 Is

FT8 (Franke-Taylor design, 8-FSK modulation) is a digital weak-signal mode developed by Joe Taylor (K1JT) and Steven Franke (K9AN) and released in 2017. It encodes a 13-character message into a 15-second transmission that can be decoded reliably at signal-to-noise ratios as low as −20 dB — 100 times weaker than a signal the human ear can detect. The result: FT8 makes contacts across continents using milliwatt-level signals on poor antennas during mediocre propagation.

FT8 has transformed HF amateur radio. On any given day, more operators are using FT8 on the 20-meter band than all voice modes combined. It is the gateway through which most new HF operators make their first international contacts.

How FT8 Works

FT8 contacts follow a rigid automated sequence. Each transmission is exactly 15 seconds. The exchange is compressed: CQ call → response with grid square → signal report → confirmation → 73. A complete contact takes 90 seconds. The software (WSJT-X, free) decodes incoming signals, displays them in a list, and handles much of the exchange automatically when you click on a station to work.

Because the exchange is so compressed, FT8 is not conversational — it conveys only the minimum information required to log a valid contact. This is a trade-off: you gain the ability to make contacts under conditions where voice or CW would be impossible, but you sacrifice conversation. Many operators use FT8 to accumulate contacts in specific grid squares, countries, or states, then switch to voice modes for actual conversation when conditions allow.

What You Need

FT8 requires: an HF transceiver (General Class license), a computer with a sound card, a sound card interface (SignaLink USB ~$120, or Digirig ~$60) connecting the radio's audio to the computer, and WSJT-X software (free at physics.princeton.edu/pulsar/k1jt/wsjtx.html). The interface connects your radio's speaker/mic audio to the computer's line in/out, allowing the software to generate and decode FT8 audio tones.

Time synchronization is critical — FT8 transmissions must start within ±1 second of UTC for decoding to work. Sync your computer's clock to an internet time server or GPS time source. Windows "Set time automatically" is usually sufficient.

FT8 as a Technician

FT8 is primarily an HF mode requiring a General Class license for full access. However, Technicians have access to FT8 on the 10-meter band (28.074 MHz is the FT8 calling frequency for 10 meters) — and during solar maximum, 10-meter FT8 is spectacular. When the band opens, Technicians can log contacts across the continent and around the world. This is one of the most compelling reasons to upgrade to General if you find FT8 on 10 meters exciting.

• Is FT8 considered cheating because the software does most of the work?
  This is a genuinely debated topic in the amateur radio community. Purists argue that automation diminishes the skill element. FT8 enthusiasts point out that designing and building a station that can make contacts at −20 dB SNR still requires real skill in antenna design, feed line efficiency, and interference management. The FCC allows FT8 operation — what "counts" as a satisfying contact is a personal decision.
• What are the FT8 calling frequencies?
  FT8 has standard calling frequencies on each HF band: 80m: 3.573 MHz, 40m: 7.074 MHz, 30m: 10.136 MHz, 20m: 14.074 MHz, 17m: 18.100 MHz, 15m: 21.074 MHz, 12m: 24.915 MHz, 10m: 28.074 MHz, 6m: 50.313 MHz. These are the frequencies where WSJT-X is configured by default and where the most activity occurs.
• What is the difference between FT8 and JS8Call?
  FT8 is optimized for contest-style logging contacts — minimal exchange, maximum efficiency. JS8Call is a derivative mode that uses similar weak-signal technology but allows free-form text messaging between operators. JS8Call is slower and less efficient than FT8 for logging contacts but allows actual conversation at signal levels where voice or CW would fail. Both run on similar equipment.