QO-100: FT8 through the geostationary satellite on 10489.540 MHz

What you hear

The fifteen-second FT8 chorus described in the FT8 article, coming down from the satellite instead of bouncing off the ionosphere. On 10489.540 MHz the stripes are steady, because there is no fading on a geostationary path, and the decodes carry locators from three continents at once: Europe, Africa, the Middle East, India, Brazil. The satellite, its transponder and the dish receivers are described in the main article.

Who transmits and why

Amateurs with a 2.4 GHz uplink who want a digital contact through the satellite, often as their first one: FT8 needs less power than voice and forgives a small antenna. Award hunters use it for the 3 cm band, which the satellite put within reach of ordinary stations. The frequency sits at the bottom of the narrowband transponder, in the segment set aside for narrow digital modes.

When and where to listen

Any hour; the path is open around the clock, and the callsign mix follows the local evenings across the footprint. Only receivers with a dish on the satellite hear it, so the catalogue binds the entry to those.

In ShackDeck

Station catalogue → Amateur radio → QO-100 satellite: FT8 10489.540. The program picks a receiver with a dish, tunes it to 10489.540 MHz in FT8 mode, handles the converter offset and runs the decoder: decodes every fifteen seconds in the On air list and on the map, and a click on a callsign fills the log with the 3 cm band, frequency, mode, report and locator. No receiver, dish or account of your own is needed.