 The uto-observatory has been found to be effective in detecting ducting in the archipelago C, providing a reliable method for over-the-horizon detection of ducting in the open sea. This study has shown that the combination of measurements at the uto-observatory, including vertical profiles of temperature, humidity and wind, provide a reliable means of detecting ducting in the archipelago C. Furthermore, the horizontal wind profiles reveal the low-level jet at the radar height that often coincides with the ducting observations. This article was authored by Laura Rashinen, Yanni Tainila, Miko Lensu and others.