The Loss/Attenuation Calculation

Question 1

The loss due to reflection on the ground is dependent on the ____ of the ground and the ___.

Answer 1

total reflection coefficient,
phase shift

Question 2

_____ is dependent on the frequency, grazing angle (angle between the ray beam and the horizontal plane), polarization, and other ground properties

Answer 2

reflection coefficient

Question 3

Five types of Propagation Loss

Answer 3

Free-space path loss
Vegetation Attenuation
Gas Absorption
Attenuation due to Precipitation
Obstacle Loss

Question 4

___ contribution has a somewhat unpredictable and sporadic character, e.g., sandstorms and dust storms as well as fog, clouds, smoke, and moving objects crossing the path. In addition, poor equipment installation and less than perfect antenna alignment (field margin) may give rise to unpredictable losses.

Answer 4

Miscellaneous Losses

Question 5

___ sums all the individual, singleknife obstacle losses.

Answer 5

Epstain-Peterson method

Question 6

specific attenuation of rain is dependent on ___.

Answer 6

raindrops
polarization
rain intensity
frequency

Question 7

A major difference in propagation through the real atmosphere versus free space is that there is ___.

Answer 7

Air present

Question 8

___ is the mechanism responsible for obstacle loss/attenuation.

Answer 8

Diffraction

Question 9

___ is a radio wave propagation model that estimates the path loss due to the presence of vegetation on a point-to-point telecommunication link and gives slightly different results.

Answer 9

Weissberger’s Model

Question 10

The recommended models for diffraction loss are given by the ___.

Answer 10

ITU-R Recommendation P.526

Question 11

____ contribution comes from the hardware required to deliver the transmitter/receiver output to the antenna—e.g., waveguides as well as splitters and attenuators.

Answer 11

Branching losses

Question 12

____ assumes that all the obstacles can be replaced with one equivalent knife-edge obstacle

Answer 12

Bullington

Question 13

main parameter used in the calculation of rain attenuation

Answer 13

rain intensity

Question 14

the lowest value (Amin) is for a phase angle of ___

Answer 14

180-degrees

Question 15

___ is also known in the literature as diffraction loss or diffraction attenuation.

Answer 15

Obstacle Loss

Question 16

highest value (Amax) of signal strength is obtained for a phase angle of __

Answer 16

0-degree

Question 17

____ contribution comes from the losses due to the Earth’s atmosphere and terrain— e.g., free-space as well as gas, precipitation (mainly rain), ground reflection, and obstacles.

Answer 17

Propagation losses

Question 18

____ the main contributor in the frequency range used by commercial radio links and increases with frequency and becomes a major contributor in the frequency bands above 10 GHz.

Answer 18

Rain Attenuation

Question 19

____ determines the largest obstacle and focuses on the calculations related to it.

Answer 19

Deygout Method

Question 20

One powerful but simple method for calculation of obstacle loss is ___ , which is based on the knife-edge approximation.

Answer 20

Single-peak method

Question 21

Since the absorption bands of nitrogen are located far from the microwave radio communications region of the spectrum, the atmosphere is considered to be composed of a mixture of two “gases” ___.

Answer 21

dry air (oxygen molecules)
water vapor (water molecules)

Question 22

____ is continuously growing, and the rate of growth is very important. It is important to include a provision for at least ten years of vegetation growth.

Answer 22

Vegetation