Name the part of electromagnetic magnetic spectrum used in satellite communication and radar system
Answers
Answer:
Explanation:
FOR RADAR SYSTEM
There are different slots across the e-m spectrum designated by Spectrum Management authorities around the world for “radio echolocation”.
Radar people use designations like “X-band” (8–10 GHz) to describe some portion. Confusingly, these same bands are described by other design stirs by those who detect operation in these bands. (So X-band is also called I-band).
Not all of these licenced slots are consistent across the globe, so you can buy a rescue helicopter in the USA and its radar may not be able to be used to full capacity in Australia.
There is a good intro in this Radar Tutorial from which this image comes;
Different frequency bands have different properties and applications. Low frequencies travel further with low loss, hugging the Earth surface, but need bigger antennas. Some are affected more by moisture in the atmosphere.
FOR SATELLITE COMMUNICATION
Frequency of microwave bands extends from about one gigahertz to three hundred gigahertz. This large frequency bandwidth can carry huge information through different band.
Velocity = wavelength x frequency
From the relation we get they have short wavelength.
Due to enough short wavelength, they less capable of bypassing the obstacles of dense media like walls, hills etc . But it is a matter of think that microwave propagate through less dense media like atmosphere, free space in satellite communication.
Large frequency signal can convey large power and less attenuated. This leads to an essential property of microwaves is that they travel in straight lines through the atmosphere (like a torch light), are not affected by the ionized layers. So they can travel long distance.
Also these waves are very less affected by temperature inversions and scattering. But these weather effects limit the distance between the transmitter and the receiver to a few miles. This problem is overcome by usage of repeater stations placed along the propagation path. As they do not rapidly disperse in the atmosphere (less attenuation) so the power does not need to be very high to reach a distant point.
Because of penetration and traveling property, main mode of propagation in the microwave range is line of sight. Line of sight means that the transmitter and receiver need to see each other. That is the prime destination of satellite communication.
Generation of microwave is not complicated. Simple devices like magnetron can be used. Using metal reflector antennas, they can be easily directed from earth to satellite and vice-versa.
Various modulation techniques are available for microwave. So possibility of interference among data is very low. Due to large frequency bandwidth, a huge number of variable services are available without blocking.