why is it that short wave is clerly at night and morning and noisely in the afternoon.?

Question

In telecomunication engineering : Why is it that shortwave is clerly in the morning and night and noisely at afternoon?
Answer me with reference into details.

Answer 1

Short waves can reflect from the Kenelly-Heaviside layer, an ionised region around the Earth at 90-150km above the ground. Therefore, when this is active, certain frequencies of radio waves can then be propagated beyond the line of sight distance.

During the day, the solar wind "pushes" this ionised layer closer to the Earth's surface, so the increased transmission distance possible from reflection from it is minimised, whereas during the night, this ionised layer moves further away from the Earth allowing reflection over a greater distance.

Answer 2

Joseph is right. Also, cold dense evening air reflect the signals better. Short wave radio is propagated by atmospheric scattering.

Answer 3

Radiation from the Sun interacts with the ionosphere and create electromagnetic waves which make interference with all types of telecommunication. Not only short wave.