FT4 on 20 metres: 14080 kHz, the fast contest cousin of FT8

What you hear

On 14080 kHz in upper sideband the sound is close to FT8, a chord of warbling tones, but the rhythm is twice as fast: the chord lasts about five seconds, there is a short gap, and the next one starts, eight exchanges a minute instead of four. On the waterfall the stripes are wider, roughly 80 Hz instead of 50, and they come in rows 7.5 seconds tall. A single station sounds a little rougher than in FT8, because four tones spaced further apart replace eight close ones.

The messages are the same as in FT8: a CQ with a callsign and locator, an answer, two signal reports, an RR73 and a 73. Because every turn is half as long, a complete contact takes about forty-five seconds, and in a contest an operator can log one station after another at a rate that FT8 cannot match.

Who transmits and why

FT4 was released by the WSJT-X team in 2019, two years after FT8, for one purpose: digital contests. FT8 had become so popular that contest organisers wanted a mode in the same family, and FT4 traded a few decibels of sensitivity, it decodes to roughly 17 dB below the noise instead of 20, for twice the speed. Outside contests it is used by people who find FT8 slow, by expeditions with large pile-ups, and by anyone testing a path when the band is good enough that the extra sensitivity does not matter.

On ordinary days 14080 kHz has a few stations; on a digital contest weekend it is as crowded as 14074, and the crowd sometimes spills across the RTTY segment that begins at the same frequency, a known source of friction between the two communities.

When and where to listen

The same hours as FT8 on 20 m: from mid-morning until a few hours after sunset, longer in summer. Weekends are busier than weekdays, and the big digital contests, several a year, turn the frequency into a wall of stripes for 24 or 48 hours. From Europe, mornings show Asia, afternoons Africa and the Americas. The dial is 14080.0 kHz in USB.

If you see stripes that look like FT8 but nothing decodes, check that the decoder is in FT4 and not FT8: the two are not compatible, and the stripe width is the giveaway.

In ShackDeck

Station catalogue → Amateur radio → FT4 20 m. The program picks a public receiver that covers 14080 kHz, tunes it and sets the FT4 mode; FT4 has its own decoder, separate from the FT8 one, and it runs when the mode is FT4. The decodes appear every 7.5 seconds in the On air list, the callsigns land on the map with their locators, and a click on a callsign fills the logbook form. No receiver, antenna or account of your own is needed; the program only listens.