Daily damping
As days attenuation a is attenuation of radio waves called on the day side of the Earth. This occurs with space waves that are reflected off the ionosphere . This effect is related to the ionization of the D-layer .
process
The daily attenuation occurs in the entire range of long , medium and short waves and decreases with increasing frequency of the radio waves. It occurs in the area of the earth's atmosphere lit by the sun and begins at sunrise, reaches its highest value around noon and disappears again shortly after sunset. This effect is strongest in summer. It can be determined with every radio receiver when stations cannot be received or are poorly received during the day and can be heard more strongly with increasing dusk.
The reason for this is that the ionization in the D-layer changes over the course of the day. During the day, the ionized D-layer dampens the waves. At night the D-layer disappears completely, whereby the waves reach the F-layer and are reflected on it.
Web links
- Entry in the radio lexicon ( memento from October 22, 2008 in the Internet Archive )