The process of superimposing a message signal on a high-frequency carrier wave is called:

The frequency band for uplink satellite communication is

What type of modulation is employed in India for radio transmission?

$A$ $TV$ transmitting antenna is $98\,m$ high and the receiving antenna is at the ground level. If the radius of the earth is $6400\,km$,the surface area covered by the transmitting antenna is approximately $.........\,km^2$

To radiate a wave of frequency $1 \text{ kHz}$ efficiently,what should be the minimum length of the antenna in $km$?

$A$ communications Earth satellite: