My Project Works

1. link budget satellite for
calculation system
Seminar presentation
Done by:
Taif Alawsi

2. Introduction
System noise calculations
• Gain, G, often expressed in decibels, the ratio of
the output to input voltages (or powers): GdB =
20 log10 (Vo/Vi).
• There is a logarithmic unit of power which
defines absolute power in dB above a specified
reference level.
• If the reference power is 1 mW the units are dBm
and if the reference is 1 W the units are dBW.

3. Radio communication link budgets
 Link budgets refer to the calculation of received
signal-to-noise ratio given a specification of
transmitted power, transmission medium
attenuation and/or gain, and all sources of noise.
 The calculation is based on applying Friis formula.
For radio systems the signal energy is usually lost
due radiation other than towards the receiver.

4. Fixed point satellite communications
• Satellites are one of the three most important
developments in telecommunications.
Geostationary satellites have an orbital radius
of 42,164 km and earth surface altitude of
35,786 km.
• Other classes of satellite orbit include highly
inclined highly elliptical (HIHE) orbits, polar
orbits and low earth orbits (LEOs).

5. Selection of especially useful satellite orbits: (a) geostationary
(GEO); (b) highly inclined highly elliptical (HIHEO); (c) polar orbit;
and (d) low earth (LEO).

6. Satellite link budgets
• On the uplink the earth pointing satellite antenna
has a noise temperature of 290 K.
• The noise temperature of the earth station
antenna, which looks at the sky, is usually in the
range 5 to 100 K for frequencies between 1 and
10 GHz, Figure 12.25.
• Above 10 GHz resonance effects of water vapor
and oxygen molecules, at 22 GHz and 60 GHz
respectively degrade the receiver performance.

7. Fade Margins
• The distance that a signal can travel, given
that it has proper line-of-sight, is dependent
on the strength of the signal minus the free
space path loss and the receiver sensitivity.
• signal rec = transmit EIRP - free space loss +
rec antenna - rec cable loss
• where free space loss = 32.4 + (20 * (log10
freq)) + (20 * (log10 distance))

8. • transmit EIRP= Transmitter power+ Eb/N0 - feeder
losses.
• rec antenna is given by:
Where: GR = Gain of the Receiver
λ = wavelength
d = diameter receive antenna