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The ionosphere is a part of the upper atmosphere, from about 85 km to 600 km altitude, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere. It has practical importance because, among other functions, it influences radio propagation to distant places on the Earth.[1]
these ionised particles,reflect the radio wave to earth back.depending on the density of the ionosphere,at the time determins the amound of radio waves.this will affect clear reception.the height of the ionosphere involves reflecting angle,which gives long length hops.in this way long distance communications are affect by ionosphere.
It is the ionosphere, a general region that includes all of the thermosphere and parts of the two bordering layers. In this region, between 60 and 1000 kilometers above the Earth, ionized particles refract and reflect radio waves back toward the ground. This enables radio transmissions that are normally "line of sight" only to reach over the horizon for hundreds or thousands of miles. This includes broadcast radio (HF) and shortwave bands.
Sky wave propagation is possible because of ionosphere. Ionosphere is the region consisting of ions produced in the higher level of atmosphere almost at a height of 90km. The scientific fact is that the refractive index is inversely related to the ionic density. Because of various concentration of ions in the ionosphere, the refractive index is different. As radio waves make an entry through this region, the ray has to pass from the region of higher refractive index to lower, so the radio waves get deviated from the normal. So stage by stage, the radio waves get turned back towards the earth. This seems as if it has been reflected by the ionospheric layer. So short waves, also known as sky waves, with a range of frequency 3 to 30 MHz are better sent back to the earth. That is why irrespective of the curvature of the earth, the signals transmitted at London will be received by a radio in a town in TamilNadu, India.
The Ionosphere.
Question: Why do low freqs reflect from the ionosphere while high freqs go straight thru?ANS:- ANSWER: -for the same reason that high freqs can pass thru a parabolic dishof screen but the low freq reflects off the screen.The spacing of the screen wires have to be a small % of wavelength.The ionosphere must have ions that are spaced further apart than say 1 meter---so that a 300MHz signal (wavelength = 1 meter) will not see it as a "solid"whereas a 1MHz AM-band signal (wavelength =300 meters) will see the ion fieldas as as a "solid" wall to bounce off. (PhilDragonetti, RF Engineer)
The term skywave is used to refer to the reflect radio waves from the ionosphere. ?æSkywave is used most frequently in shortwave radio broadcasts.
Short wave broadcast services use sky wave propagation because short waves can be reflected off the ionosphere, allowing the signals to travel long distances around the Earth. This allows for global coverage with relatively low power transmissions. Additionally, short waves are less affected by weather conditions compared to other frequency bands.
decreses
The ionosphere has nothing to do with radioactivity, and there is nothing in nature that is called a "radio active wave."Because the ionosphere contains electrical charges, it is able to reflect radio waves.
shortwave radio band
first of all thing considered, its ionosphere. and to the question it is 60000000 millimeters into the sky or 60 kilometers in the sky.
When the ionosphere increases its height at night, radio wave propagation improves as higher frequencies are able to reflect off the ionosphere back to Earth. This can enhance long-distance communication, making it easier for radio signals to travel over longer distances during nighttime hours.
The ionosphere layer affects radio wave propagation by reflecting or refracting the waves back to Earth. Different layers of the ionosphere interact with radio waves of different frequencies, allowing for long-distance communication via multiple hops. Changes in the ionosphere's density and ionization levels can also affect radio wave propagation by absorbing or attenuating signals.
these ionised particles,reflect the radio wave to earth back.depending on the density of the ionosphere,at the time determins the amound of radio waves.this will affect clear reception.the height of the ionosphere involves reflecting angle,which gives long length hops.in this way long distance communications are affect by ionosphere.
If you really do mean the ionosphere, and the astronaut is falling back to earth, the ionosphere is one of the upper layers - my best guess is that the heating effect of the rarified ionosphere would not be enough to cause death.Once you get into the lower atmosphere, though, the heating effect is large (the Concorde supersonic airliner expanded measurably while at full flight speed due to heating), and will cause burning up.
Radio waves are reflected by particles in the ionosphere. These waves are commonly used in long-distance communication because they can bounce off the ionosphere and travel long distances by reflecting and refracting off the charged particles in the Earth's upper atmosphere.
A direct wave is a radio wave that travels directly through space without getting refracted by the ionosphere. In other words, it travels straight to the receiving antenna without being refracted.