Short Wave Radio Blackout
Sunspots and Solar Flares
Space Weather and Radio
There have been several reports that the AR2781 sunspot let off a C-class flare with a pulse of X-rays and UV radiation which ionized the top of Earth's atmosphere, causing a brief short wave radio blackout over Australia and the Indian Ocean.
Mariners, aviators, and ham radio operators in the region may have noticed unusual propagation at frequencies below 10 MHz.
(Source: NASA, NOAA, ICQ Podcast, 22nd November 2020; Colin Butler)