Near fading

As Nahschwund refers to the phenomenon that occurs when when electromagnetic waves with frequencies below 3  MHz the space wave and ground wave are superimposed.

Since the sky wave is strongly attenuated during the day at these frequencies, near fading only occurs at night. Close-up fading manifests itself in strong fluctuations in signal intensity . Distortion often occurs as a result of selective cancellation of the signal.

The distortions caused by near fading hardly appear in demodulation using demodulators for single sideband modulation .

Close fading only occurs at a certain distance from the transmitter location. Depending on the design of the transmitting antenna , the electrical conductivity of the ground and the transmission frequency, short-range fading occurs at a distance of 40 to 400 km from the location of the transmission system .

At distances of more than 400 kilometers, there is no more near fading, since in this area the signal only reaches the receiver via the sky wave. However, fading also occurs here, but mostly without selective cancellation of the signal.