The Sun's effects on the radio propagation.

The sun is being the largest engine in our solar system. It has very great effect on radio propagation as its "exhaust" interacts with our Earth's Magnetic Field. The sun properties such as Sunspots, solar flare and mass ejection will help the amateur radio station take advantage of these effects to enhance his pleasure.

Sunspot

Solar Flare

Sunspots: Sunspots are dark spot, planet sized region that appear on the surface of the Sun. Sunspot are dark because they are cooler than the area around them. The sun sunspot might have temperature about 4000K.

Sunspots are only dark in contrast to the bright face of the Sun. If you could cut an average sunspot out of the Sun and place it in the night sky, it would be about as bright as a full moon. Sunspots have a lighter outer section called the penumbra, and a darker middle region named the umbra.

Sunspot are cause by the sun's magnetic field welling up to the photosphere, the sun's visible surface. The powerful magnetic field around the sunspot produce active regions on the sun, which often lead to solar flares and coronal mass ejection (CMEs). The solar activity of solar flare and CMEs are called Solar Storm.

Sunspots form over periods lasting from days to weeks, and can last for weeks or even months. The average number of spots that can be seen on the face of the Sun is not always the same, but goes up and down in a cycle. The sunspot cycle is recorded have the average cycle of 11 years.

The more sunspots on the surface of the Sun the higher the Maximum Usable Frequency(MUF) of the HF region. Which is the advantage for HF 10m band user 28MHz to 29.7MHz.

Solar Flares: A solar flare is a violent explosion in a like Sun atmosphere. Solar flares take place in the solar Corona and Chromosphere heating plasma to million of kelvins and accelerating electrons and protons and heavier ions to the near speed of light. They produce electromagnetic radiation across the electromagnetic spectrum wavelength from long range radio to the highest gamma rays.

X-rays and UV radiation emitted by solar flares can affect Earth's ionosphere and disrupt long-range radio communications. Direct radio emission at diametric wavelengths may disturb operation of radars and other devices operating at these frequencies. Sudden emission of solar flares of CMEs could results in disruption to the ionosphere properties and directly effecting the long range radio communication. Such event called SID(Sudden Ionosphere Disruption).