[amsat-bb] What influences LEO propagation?

The last couple of days the Fox birds haven't been coming in as well as before. Signal strengths are down, fading has increased and it is almost impossible for me to open them. Now the sporadic E season also has kicked off in the last few days, with increased activity here in east Asia. Is this a coincidence or do the two have a connection? And are there other factors that influence LEO propagation? I know satellite tumbling is one factor that causes fades, but are there also ionospheric or atmospheric influences? Thanks for the insight. 73 de Hans (BX2ABT)