Size of Antenna
Signals are transmitted via EM waves. EM waves are transmitted by using an antenna. What will be the size of antenna?
Antena height must be multiple of λ/4 .
Where λ = c/f. λ is inversely proportional to frequency.
λ = c/f = 300000000/3000 = 100000 =100Km
Antena height = λ/4 = 100000/4 = 25000= 25Km
P = 1/ λ2
λ = c/f
P = 1/ (c/f)2
P = f 2 / c 2
- To minimize the interference from other signals.(commercial FM stations transmits voice without any interference).
- High frequency carrier travel a greater distance.Low frequency signal carries low energy.
- Multiplexing is possible.Multiple signals can use same medium.