S. L. Arora Solutions for Chapter: Communication Systems, Exercise 4: Problems For Practice

On a particular day, it was found that frequencies higher than $9\mathrm{MHz}$ are not reflected by the ionosphere. Calculate the maximum electron density of the ionosphere. 

The electron density of a layer of ionosphere is ${10}^{12} {\mathrm{m}}^{-3}.$ Calculate the critical frequency of reflection of radio waves from this layer.

A TV tower has a height of $500 \mathrm{m}$ at a given place. Calculate its coverage range, if the radius of the earth is $6400 \mathrm{km}.$

A TV tower has height of $100 \mathrm{m}$. How much population is covered by TV broadcast? Given radius of the earth $=6.4\times {10}^6 \mathrm{m}$ and average density of population $={10}^3 {\mathrm{km}}^{-2}.$

On a particular day, the maximum frequency reflected from the ionosphere is $10 \mathrm{M}\mathrm{H}\mathrm{z}.$ On another day, it was found to decrease to $8 \mathrm{M}\mathrm{H}\mathrm{z}.$ Calculate the ratio of the maximum electron densities of the ionosphere on the two days.

A transmitting antenna at the top of a tower has a height of $45 \mathrm{m}$ and the height of the receiving antenna is $80 \mathrm{m}.$ What is the maximum distance between them, for satisfactory communication in LOS mode? (Radius of earth$=6400 \mathrm{km}$) 

A TV transmission tower antenna is at a height of $20 \mathrm{m}.$ How much range can it cover if the receiving antenna is at a height of $25 \mathrm{m}?$