Question

What is sky wave propagation

Answer 1

In radio communication, skywave or skip refers to the propagation of radio wavesreflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper atmosphere. ... Most long-distance shortwave (high frequency) radio communication—between 3 and 30 MHz—is a result of skywave propagation.

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Answer 2

Hey !!

                SKY WAVE PROPAGATION

1. The sky waves are the radio waves of frequency between 2 MHz to 30 MHz.
2. These radio waves can propagate in atmosphere and are reflected back by the ionsphere of earth's atmosphere.
3. The sky waves can go from transmitter antenna to receiver antenna, while travelling through sky and after reflection from ionsphere. Hence, their propagation is called sky wave propagation.
4. Critical frequency (fc) is that highest frequency of radio waves, which when sent straight (normally) towards the layer of ionsphere gets reflected and returns to the earth. If the frequency of radio waves is more than the critical frequency, it will not be reflected by the ionsphere.
5. The value of C.F is found to be 3 MHz , 5 MHz and 6 to 8 MHz for D (part of stratosphere), E (part of stratosphere), F₁ (part of mesosphere) and F₂ (Thernhosphere) layers of ionosphere which are at heights about 110 km , 180 km  and 300 to 350 km respectively from the surface of earth.
6. Its range is very large as compared to range of ground wave. Range can't be targeted and can be increased by multiple transmitters.

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