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November 2020 was a great month for Cycle 25 sunspots (I might have to change the scale on the vertical axis next month!). This really helped the higher bands (15m and 10m) in the CQ WW DX CW contest. Hopefully Cycle 25 activity will continue for the ARRL 10 Meter contest.

The above is a plot of the EUV (extreme ultraviolet) radiation from the Sun, which is the true ionizing radiation for the F2 region. The 26-34 nm band contributes significantly to the F2 region. Beginning in October and continuing in November, the amount of EUV has increased greatly, giving us good propagation on the higher bands (remember that sunspots and 10.7 cm solar flux are proxies for EUV).

ARRL DX CW 2012 - Which 10M Path

Is the ionosphere really lower

Grand Solar Minima

Butterfly Diagrams and Solar Minimum

A Look at All Twenty Three Solar Cycles

The Robust Equatorial Ionosphere

 

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