> The most likely mode of propagation was marine ducting with the signal being trapped close to the ocean.
> There is a whole truckload of Sahara dust getting across the Atlantic this week. I blame it for the modification of the normal atmosphere into a superrefractive one, supporting communications for the first time on this band. Sahara dust dryes the air around it by absorbing moisture and thus modifying the refraction index. Like a G-Line feeder or an optical fiber, the difference in refraction index between different layers allows the propagation path to curve down following the Earth curvature to allow these fantastic QSOs.
> I read about this phenomenon many years ago in an old ITU Bulletin justifying the enhanced superrefraction conditions usual between Cape Verde and the Western African Coast.
> Jose, CO2JA
From you:
> this radio contact was made possible by the recently-developed FT8 digital modulation scheme
My questions:
1. which factor was more important, or were they equal?
2. Is it COVID related? ie, atmospheric conditions are suddenly different around the world due to shutdown of industry.