SATHEE: communication-systems Question 20

communication-systems Question 20

Question: Q. 8. What is space wave propagation ? State the factors which limit its range of propagation. Derive an expression for the maximum line of sight distance between two antennas for space wave propagation.

U] [2016; OD, North Set]

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Solution:

Ans. Space Wave Propagation :

The mode of propagation in which radio waves travel, along a straight line, from the transmitting to the receiving antenna.

Limiting Factors :

(i) Curvature of the earth

(ii) Insufficient height of the receiving antenna (Award this $1 / 2$ mark if the student writes any one of these two factors)

Derivation :

From the figure, we have

$\begin{aligned} (R + h)^{2} & = R^{2} + d^{2} Or & 2 R h & ≅ d^{2} (as h^{2} « 2 R h) & ∴ & d & = \sqrt{2 R h} \end{aligned}$

For a transmitting antenna of height $\mathrm{h}{\mathrm{T}} $, a n d r e c e i v i n g a n t e n n a o f h e i g h t$ h{R}$, the maximum line of sight distance becomes

$∴$

$d_{M} = \sqrt{2 R h_{T}} + \sqrt{2 R h_{R}}$

[Note: Give 1 mark if the student writes the expression of $d_{M}$ ]

[CBSE Marking Scheme, 2016]

Communication Systems

communication-systems Question 20

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Communication Systems

communication-systems Question 20

Table of Contents

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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