The height of a $T.V.$ tower is $75 \ m$. What is the maximum distance in $km$ up to which $T.V.$ transmission can be received (in $.98$)? (Radius of the Earth $= 6.4 \times 10^6 \ m$).

The characteristic impedance of a coaxial cable is typically in the range of ..........

$A$ sinusoidal carrier voltage is amplitude modulated. The resultant amplitude modulated wave has maximum and minimum amplitude of $120 \, V$ and $80 \, V$ respectively. The amplitude of each sideband is $.......... \, V$.

The height of a transmitting antenna is $h \ m$ and the height of a receiving antenna is $45 \ m$. The distance between them is $40 \ km$. For satisfactory $Line\, of\, Sight$ $(LOS)$ communication between the two antennas,the height of the transmitting antenna $h$ must be ....... $m$. (Radius of the Earth $R = 6400 \ km$)

In the given detector circuit,the suitable value of carrier frequency is

Broadcasting antennas are generally