Calculate the range of wavelength correspondent to the baseband audio frequency range (20Hz-20kHz) and comment on the implications on the size of antenna requirements

The baseband audio frequency range is $20 \text{ Hz}$ to $20 \text{ kHz}$. The speed of electromagnetic waves (speed of light) $c = 3 \times 10^8 \text{ m/s}$.

For the lower frequency $f_1 = 20 \text{ Hz}$:

For the higher frequency $f_2 = 20 \text{ kHz} = 20 \times 10^3 \text{ Hz}$:

The range of wavelength is $\boxed{\text{15 km to 15,000 km}}$.

Antennas are typically designed to be a significant fraction of the wavelength (e.g., $\frac{\lambda}{2}$ or $\frac{\lambda}{4}$) for efficient transmission and reception of electromagnetic waves. The calculated wavelengths for the baseband audio frequency range are extremely large, spanning from 15 kilometers to 15,000 kilometers. Building physical antennas of such immense sizes is practically impossible. Therefore, baseband audio signals are not transmitted directly as electromagnetic waves. Instead, they are used to modulate higher-frequency carrier waves, which have much shorter and more manageable wavelengths, allowing for practical antenna sizes.