MAP STUDY FOR MICROWAVE COMMUNICATION SYSTEM

1
MAP STUDY FOR MICROWAVE COMMUNICATION SYSTEM
2
Frequency Spectrum
Bandwidth Frequency range Audio
Frequency 0.3 - 3 KHz Low Frequency
(LF) 3-3000 KHz High Frequency (HF) 3-30
MHz Very High Frequency (VHF) 30-300
MHz Ultra-High Frequency (UHF) 300-3000
MHz Microwave 3-300 GHz L 1-2 GHz ,S2-4
GHz, C4-8 GHz, X 8-11 GHz, Ku 11-18 GHz,K
18-27 GHz Ka 27-40 GHz
3
For Path Planing
LOS - Line of Sight

• Line of sight is the direct free-space path that
  exists between two points.
• Obstruction

• Kind of Obstructions
• Topographic features, such as mountains
• The curvature of the Earth
• Buildings and other urban developement
• Trees /Vegetation

4
How to improve LOS?

• Raise the antenna mounting point on the existing
  structure
• Build a new radio tower, which is tall enough to
  mount the antenna
• Increase the height of an existing tower
• Locate a different mounting point, i.e. building
  or tower, for the antenna

5
Fresnel Zone

• An elliptical area surrounding the visual path
• Area occupied by strongest radio signal

d1.d2 D.F
R 72.1
d1 distance from Tx antenna to the
obstruction d2 Distance from Rx antenna to the
obstruction D Total distance f Transmitting
frequency in GHz R Height of the First Fresnel
zone
6
Earth Bulge

• Curvature of the earth

Diffraction

• Spreading of waves

Around Edge
Narrow Gap
Wide Gap
7
Refraction

• Bending of M/w beam beyond Optical horizon -
  direction changes
• Upper wavefront travel faster compared to lower
  wavefront

Reflection

• Electric field vector of wave perpendicular to
  earth surface
• Sea water - good RF Reflector with reflection
  coefficient of 1.0

8
Requirement of map study comes here !

• Types of maps
• Reference map - Topographic map
• Thematic map

Reference map

• Topographic map is location based
• Scaled map ( Ratio 150,000)
• Two-dimensional representations
• Latitude Longitude

9
Contour Lines

• Contour Lines are lines drawn on a map
  connecting points of equal height.
• Contour lines are parallel lines with a
  difference of elevation of atleast 20m between
  them.
• Elevation means height above sea level
  ( HASL)

10
CONTOUR LINES
11
(No Transcript)
12
(No Transcript)
13
(No Transcript)
14
STEP - I
Location a point with given coordinates on the Map

• Select the Map which contains the point.
• Calculate the distance on the map , equivalent to
  change
• in coordinates by one second.
• Draw the line corresponding to latitude of the
  point.
• Draw the line corresponding to longitude of the
  point.

The point of intersection of the two lines gives
the location of the point on the Map.
15
Select the Map that contains the point
Lets say the point is (15º 25 30 S , 30º 42
40 E )
16
Calculate the distance on the map , equivalent
to change in coordinates by one sec
Dx 54 cm / 15 x 60 sec 0.06 cm/sec
60 cm
Dy 60 cm / 15 x 60 sec 0.066 cm/sec
54 cm
17
Draw the line corresponding to latitude of the
point
(15º 25 30) Minus (15º 25) 30 sec
Dy x 30sec
15º 25 30 S
18
Draw the line corresponding to longitude of the
point
(30º 42 40) Minus (30º 40) 240 sec
(2x60)40 sec 160 sec
15º 25 30 S
Dx x 160sec
30º 42 40 E
19
Reading Contours
At point 0 closest Contour 500 Reading ?
20
STEP - II

• Joining of 2 points
• Draw Line b/w these points
• If other point not in the same map
• Joining of 2 map of more if required
• How to join?
• Index to adjoining sheets

A1
C1
B3
B2
A2
B1
C2
B4
A3
21
(No Transcript)
22
For calculating Link budget

• Link Budget - A rough calculation of all known
  elements of the
• link to determine if the signal will have proper
  strength when it
• reaches the other end of the link.
• Frequency of the link
• Free space path loss
• Power of the transmitter
• Antenna gain
• Length of the cable loss per unit length at
  the specified frequency
• Number of connectors used
• Path Length

23
Calculate FSL - Free Space Loss

• Absorption
• Scattering
• Beam Diversion
• Atmosphere - Rain, fog, wind, lightening

FSL (dB) 32.45 20 log D 20 log F
dB Decibel (Signal/Noise ratio) D Path
length in km F Frequency in Mhz
24
THANK YOU