Reduction in the height of antenna.
For the transmission of radio signals,the antenna height must be multiple of(
λ/4).Here λ is the wavelength. λ=c/f where c is velocity of light and f is the frequency of the signal to be transmitted.The minimum antenna height required to transmitted is baseband signal of f=10 kHz is calculated as follows:
we know that,
λ=c/f
where
λ= it is wavelength c=velocity of a light, f=it is a frequency of the signal to be transmitted.now take a example
f=10Hzantenna height= λ/4=(c/4f)=(3x100000000)/(4x10x1000) =7500meters now we see that antenna size is too large it is impossible
Now, let us consider a mdulated signal f=1MHz.
antenna height=λ/4 =c/4f =3x100000000/4x1x1000000 =75 meternow we see that this antenna can be easily installed practically.
Thus, modulation reduces the height of the antenna
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| example of a micro antenna |
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