Sunspots

As most hams know, the solar cycle controls the amount of sunspots on the sun, which in turn affects the propagation here on Earth.

The solar cycle tends to run in 11 year cycles, where the maximum activity occurs in the middle of the sunspot cycle and the minimum occurs at the bottom of the 11 yr cycle as it transitions from one cycle to the next.

Unfortunately, there is not usually a sharp transition, the bottom may hang around for 2 years or more.

Solar activity is defined as sunspots, solar flares, or even solar eruptions(eruptions of gas from the Sun.)

The last cycle reached its peak in 2001 and is currently at the end of its cycle transitioning into the new cycle.

What has scientists that track solar cycles concerned is that this minimum has produced no solar activity at all. While some inactivity is normal, this period of inactivity has stretched longer than normal.

In the past there have been some extended periods of inactivity. There was a period in the past where the sun did not produce sunspots for 50 years, from 1650 to 1700.

This affect ham radio operators, because during the sunspot minima low bands such as 160, 80 and 40 become the workhorse bands because the propagation does not get up to the 20-10 bands as easily.

Some links that talk about propagation:

N0HR's propagation page

N3KL's propagation page

Solar Cycle 24 Page (Excellent site)

WM7D Solar Page

N6RT's Propagation page

And a link to propagation software


So those spots on the sun do affect us more than you know!

Credit: http://www.sciencedaily.com/releases/2008/06/080609124551.htm

73, Jack K4SAC