I was surprised to see tons of signals on the 15 meter ham band this weekend. Solar cycles effect how well radio signals propagate, and latest cycle has not been very good.
Humans love to make sense of patterns. Consider how we use solar system patterns to figure out time: years, seasons, days, months and hours. All of these are derived from patterns in nature.
Most radio folks know a lot about one very important pattern: solar cycles. These measure variation in solar magnetic activity. When this activity is high, the ionosphere becomes more ionized or activated by photons and cosmic rays. These changes to the ionosphere also effect the highest frequencies available for short wave radio communications.
These cycles rise and fall over eleven years on average. We have tracked them for hundreds of years. First of all, by counting visible sunspots. Finally, by measuring solar flux. We are currently in the tail end of Cycle 24, which has been the weakest cycle for a century. The next cycle will start in 2019. It may be even weaker, due to a recent decline in magnetic activity on the sun. Consequently, ham radio operators will not be happy. It seems like the glory days of long distance ham contact will not return any time soon. You can find out more here.
Solar cycles and climate change?
Controversy exists about the relationship between solar activity and climate. You would think there would be a clear relationship, as the sun is our primary source of energy. But scientists disagree on the amount of solar impact on climate versus human activities. So, again, humans search for patterns.
However, there are two points we can agree on. First, almost everyone believes we are heading into a long period of minimal solar activity, perhaps lasting for the rest of this century. Second, previous periods of minimal solar activity do correlate with cooling climate. So, we seem to be ready to conduct an experiment as to whether or not solar activity has a stronger effect on climate than man.