FT8 on 20 metres: 14074 kHz, the busiest digital frequency on shortwave

What you hear

Tune to 14074 kHz in upper sideband and you hear a chord of warbling tones, like a choir of slightly off-key flutes. It starts at the top of each quarter minute, holds for about thirteen seconds, and comes back with a different set of voices. On the waterfall the same thing is a row of thin vertical stripes, each about fifty hertz wide, packed side by side across the passband from 14074 to 14077 kHz. The stripes come in fifteen-second blocks, alternating between stations on the even and the odd slots. That is FT8, and on 20 m it runs from dawn until well after dark with anything from twenty to sixty signals in the passband at once.

Each stripe carries one short message. A station calls CQ with its callsign and a four-character grid locator; someone answers with their own call and locator; the two exchange signal reports in decibels, confirm with RR73 and part with 73. Six transmissions, a minute and a half, and the contact is done. The reports are often negative numbers, because FT8 decodes signals down to about twenty decibels below the noise, far past the point where an ear hears only hiss.

Who transmits and why

The mode was released in 2017 by the WSJT-X team for contacts that are brief, weak and reliable, and within a year it was the most used mode in amateur radio. The operators are ordinary licensed amateurs on every continent: some chase countries and grid squares for awards, some check whether a new antenna works, many simply enjoy that a hundred watts and a wire in the garden reach Japan at breakfast and Brazil after dinner. Expeditions to rare islands use it heavily too, usually on a frequency of their own, often 14090 kHz on this band, so that the main frequency stays free.

14074 kHz is the agreed FT8 frequency on 20 m, and 20 m is open to somewhere in the world for most of the day, so this is the busiest single digital frequency on shortwave. Since every decode carries a callsign and a locator, the traffic doubles as a live propagation map once receivers everywhere report their decodes to PSK Reporter.

When and where to listen

20 m wakes up about an hour after sunrise and stays alive until a few hours after sunset; in summer at mid-latitudes it often never closes. From Europe, mornings bring Asia and Oceania, the afternoon is European and African, and from late afternoon into the night the Americas come in. Receivers in quiet rural places show the weakest signals; weekends and the hours after European dinner time are the thickest.

The dial frequency is 14074.0 kHz and the mode must be USB: the decoder expects the tones between roughly 200 and 3000 Hz above the dial. If the stripes are there but nothing decodes, the usual reason is timing: FT8 needs the slots to line up within a second or two.

In ShackDeck

Station catalogue → Amateur radio → FT8 20 m. The program picks a public receiver that covers 14074 kHz, tunes it, sets the FT8 mode and runs the decoder on the receiver's audio. Every fifteen seconds the decodes appear in the On air list, the callsigns land on the map with their locators, and a click on one fills the logbook form with the band, frequency, mode, report and grid. No receiver, antenna or account of your own is needed, and the program only listens: answering a station still takes a transmitter and a licence at home. If you wish, the decodes go to PSK Reporter under your callsign; that is off by default.