QO-100: FT8 on 10489.540 MHz, decodes from the whole footprint every fifteen seconds

What you hear

To the ear FT8 is a chorus of warbling tones that starts and stops in fifteen-second bursts; on the waterfall it is a stack of short vertical streaks, each a station, packed into about 3 kHz above 10489.540 MHz. It is the narrowband digital spot of the transponder described in the main article, between the CW segment and the mixed-mode segment. The program's decoder reads the bursts and prints what they say: callsigns, Maidenhead locators, signal reports, the usual FT8 exchange.

Who transmits and why

Amateurs anywhere in the satellite's footprint, uplinking on 2.4 GHz. FT8 was made for weak signals, and through a geostationary transponder it has an easy life: no fading, no Doppler, only the small drift of the receiver's LNB, which public receivers correct by locking to the PSK beacon.

When and where to listen

Any hour; the busiest periods are European evenings and weekends, when a single fifteen-second slot can hold a dozen stations. Expect callsigns from Germany, Italy, Spain, the Gulf states, South Africa and India in one list.

In ShackDeck

Station catalogue → QO-100: the Es’hail-2 satellite → QO-100: FT8 10489.540. The program picks a public receiver with a dish on the satellite, does the converter arithmetic, sets FT8 and runs the decoder: the decoded callsigns appear as text and on the map, every fifteen seconds. No dish, receiver or account of your own is needed.