Signals travels from the transmitter (object) to the receiver (your eye) along this straight line. This type of travel is called line of sight propagation. Radio waves with frequencies greater than about 2MHz have line of sight propagation characteristic. If the earth were flat, everything would be fine with this type of propagation. This file consists of the following things related to line of sight propagation INTRODUCTION LINE OF SIGHT PROPAGATION NON LINE OF SIGHT PROPAGATION DISTANCE B/W TWO ANTENNA RELATIONSHIP B/W HEIGHT OF ANTENNA AND RADIUS OF EARTH LOS WIRELESS TRANSMISSION IMPAIRMENTS APPLICATION OF LINE OF SIGHT PROPAGATION LIMITATION OF LINE OF SIGHT PROPAGATION REFERENCES

1. PRESENTED BY
VAISHALI.K
M.Tech (ECE) - Ist yr
21304023
DEPARTMENT OF ELECTRONICS ENGINEERING
PONDICHERRY UNIVERSITY
SUBMITTED TO
Dr.R.NAKKERAN,
Head of the department,
Dept.Of Electronics Engineering

2.  INTRODUCTION
 LINE OF SIGHT PROPAGATION
 NON LINE OF SIGHT PROPAGATION
 DISTANCE B/W TWO ANTENNA
 RELATIONSHIP B/W HEIGHT OF ANTENNA AND
RADIUS OF EARTH
 LOS WIRELESS TRANSMISSION IMPAIRMENTS
 APPLICATION OF LINE OF SIGHT PROPAGATION
 LIMITATION OF LINE OF SIGHT PROPAGATION
 REFERENCES
2

3.  Signals travels from the transmitter (object) to the
receiver (your eye) along this straight line. This type
of travel is called line of sight propagation.
 Radio waves with frequencies greater than about
2MHz have line of sight propagation characteristic.
 If the earth were flat, everything would be fine with
this type of propagation.
3

4.  But the earth is round. So the radio transmission at
high frequency can reach a maximum distance at
which a straight line from the transmitter just touches
(i.e. becomes tangential to) the round surface of the
earth.
 Beyond this distance, the wave shoots out into space
and is no longer available to a receiver on earth. So,
only a circular region centred at the transmitter with a
radius equal to this distance can receive the
transmission.
 The distance increases with the height of the
transmitter above ground. This is why TV transmitting
antennas are put so high up on top of a TV tower. 4

5.  Line of sight (LoS) is a type of propagation that can
transmit and receive data only where transmit and
receive stations are in view of each other without
any sort of an obstacle between them.
 As the signals are sent in a straight line from the
transmitter to the receiver, in order to prevent
attenuation and loss of signal strength.
5

6.  Non-line of sight (NLOS) refers to the path of
propagation of a radio frequency (RF) that is uncertain
(partially or completely) by obstacles, thus making it
difficult for the radio signal to pass through.
 Common obstacles between radio transmitters and
radio receivers are tall buildings, trees, physical
landscape and high-voltage power conductors.
 While some obstacles absorb and others reflect the
radio signal; they all limit the transmission ability of
signals.
6

7.  Non-line of sight is a term often used when the
radio transmitter and receiver are not in the direct
visual line of sight, and this is dealt with by the use
of multiple paths in signal propagation.
7

8. 8

9. 9

10. 10

11.  The height of the antennas and distance between
them can be given as:
Dm = sqrt(2HrR) + sqrt(2HtR)
Where,
Dm: distance between the two antennas
R: radius of the earth
Ht: height of transmission antenna
Hr: height of receiver antenna
11

12.  In line-of-sight propagation there should be no obstacle
between the transmitting antenna and the receiving
antenna.
 In line-of-sight propagation, space waves are very
powerful, the signals are very clear, the bandwidth is very
large and a huge amount of information can be
transmitted.
 In line-of-sight propagation, direct waves get blocked at
some point by the curvature of the earth. If the signal is
to be received beyond the horizon then the receiving
antenna must be high enough to intercept the line-of-
sight waves.
12

13. 13

14. 14

15. 15

16. 16

17. 17

18.  Attenuation and attenuation distortion
 Free space loss
 Noise
 Atmospheric absorption
 Multipath
 Refraction
 Thermal noise
18

19.  It is used in various communication systems like
• A line of sight communication and satellite
communication
• Radar communication
• Microwave linking
19

20.  These waves are affected by the curvature of the
earth.
 The propagation of these waves happens along
the line of sight distance which is defined as the
distance between the transmitting antenna and the
receiving antenna which is also known as the
range of communication.
20

21.  https://www.slideshare.net/mehak30_1/chapter5-47929334
 https://technav.ieee.org/topic/line-of-sight-propagation
 https://www.doubtnut.com/question-answer-
physics/microwave-link-or-line-of-sight-propagation-9775133
 https://en.m.wikipedia.org/wiki/Line-of-
sight_propagation#:~:text=Line%2Dof%2Dsight%20propagati
on%20is,traveling%20in%20a%20straight%20line
21

22. 22