No doubt most of you know today was the summer solstice for us Northern Hemisphere inhabitants. It was also another day with 0 sunspots (33 in a row so far), as we are very near the minimum solar activity of the approximately 11 year long solar cycle number 24. Solar cycle 24 has been exceptionally low activity, and 2019 looks to be the least active year since records started in the 1700s.

The reduced activity allows an increased amount of galactic cosmic radiation exposure due to the weakening of the sun’s magnetic field. This is more pronounced at higher elevations ( for example, while flying in a plane).

One other downside of the reduction in solar activity is reduction in propagation of HF radio because of changes in the E and F atmospheric layers. As the solar activity gets smaller, propagation at higher frequencies gets worse. There is a slight reduction in D layer absorption for the very lowest frequencies, so the 40m and 80m bands can still be usable at night.

So, enjoy this especially long, especially solar spot free day.