Space Wave Propagation

Introduction:

Generally the space wave propagation has the following components:

Direct wave
Reflected wave
Direct wave is getting from the transmitting antenna and the reflected wave is getting from the surface of the earth.

Space waves are the waves which are used for satellite communication and line of sight path. The waves have frequencies up to 40 MHz provides essential communication and limited the line of sight paths. Having problem with vector equation keep reading my upcoming posts, i will try to help you.


propagation of space waves:


The output signal which is received from the receiving antenna depends on the phase difference among the direct and reflected rays. The earth cause the reflection of phase difference of 1800. If the differences between the antennas are not too long then the direct and reflected waves which are arriving at the receiving antenna oppose the phase which cancelling each other.

By raising the heights of antennas space waves becomes more effective. The transmission of direct waves is not straight always. It may be refracted on the earth’s surface. Is this topic Regions of the Electromagnetic Spectrum hard for you? Watch out for my coming posts.


Antenna for space propagation:


Antenna:

One of the important components of the space wave propagation is antenna. It is located at both sides of the transmitter and receiver.

The transmitting antenna radiates the electromagnetic waves and the receiver antenna gets the transmitted signal from transmitting antenna. The antenna is acts as a conversion device.

Process of transmitting antenna: Converts the electrical energy into electromagnetic energy

Process of receiving antenna: Converts the electromagnetic energy into electrical energy

Normally the length of the antenna is `lambda/4` . Here the wavelength of radio frequency is `lambda`.


Television signals:


Television signal propagation:

The frequency range of Television signal is from 88MHz to 960 MHz.

Possibilities for transmitting TV signals:

With the help of satellite for communication which can reflect the signals back to earth
With the help of very height antennas
Coverage range: The TV signals can cover the range of d=`root()(2R_eh)` where h is the height of antenna

This covering range of TV signals is increased by increase in height of antenna.