The Electromagnetic Spectrum - Radio Waves

Radio Waves in the Electromagnetic Spectrum

The radio waves are the electromagnetic waves, which have the longest wavelengths in the electromagnetic spectrum, so long that if you were to look at the sky with a radio telescope, instead of point sources like stars and clouds, you could see entire regions that promote star formation, distant quasars and possible remnants of supernovas. These waves have low energy levels and frequencies ranging from around 3 kHz to about 300 GHz.

How do you think FM/AM Radio works? Simply put, radio waves are generated and propagated by radio transmitters. These waves are then received by a radio receiver (tuned to a particular frequency/wavelength using a radio antenna), which converts these into mechanical waves, played through radios and other devices. Due to their wide range, they are primarily used in communication systems like broadcasting, communication satellites, computer networking systems, radar, and other kinds of navigation.

Read More: Electromagnetic Waves

Different Bands in Radio Spectrum

Radio spectrums can be divided further into 9 bands depending on their frequency and wavelength ranges as follows

• • Extremely Low Frequency (ELF)

Frequency Range	Less than 3 kHz
Wavelength Range	Greater than 100 km

• • Very Low Frequency (VLF)

Frequency Range	3 kHz to 30 kHz
Wavelength Range	10 km to 100 km

• • Low Frequency (LF)

Frequency Range	30 kHz to 300 kHz
Wavelength Range	1 km to 10 km

• • Medium Frequency (MLF)

Frequency Range	300 kHz to 3 MHz
Wavelength Range	100 m to 1 km

• • High Frequency (HF)

Frequency Range	3 MHz to 30 MHz
Wavelength Range	10 m to 100 m

• • Very High Frequency (VHF)

Frequency Range	30 MHz to 300 MHz
Wavelength Range	1 m to 10 m

• • Ultra-High Frequency (UHF)

Frequency Range	300 MHz to 3GHz
Wavelength Range	10 cm to 1 m

• • Super High Frequency (SHF)

Frequency Range	3 GHz to 30 GHz
Wavelength Range	1 cm to 10 cm

• • Extremely High Frequency (SHF)

Frequency Range	30 GHz to 300 GHz
Wavelength Range	1 mm to 1 cm

Following is the table with links that are related to radio waves:

Difference Between AM And FM

Frequency Modulation vs Amplitude Modulation

Modulation And Demodulation

Terminologies in Radio Waves

Following is the list of terminologies that are used in radio waves:

• AM radio waves: These are the waves that carry radio signals between 540 and 1600 kHz. The waves carried are commercial waves where the amplitude varies while the frequency remains constant.
• FM radio waves: These are the waves that carry radio signals between 88 and 108 MHz. The waves carried are commercial waves where the frequency is modulated while the amplitude remains constant.
• Radio waves: It is a part of the electromagnetic spectrum with frequencies ranging from 300 GHz to 3 kHz or with wavelengths from 1 mm to 100 km.

Watch the video and understand the relationship between frequency and wavelength.

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Frequently Asked Questions – FAQs

Q1

What is a radio wave?

Radio waves are the longest wavelength electromagnetic waves that are used for transmitting data from radio, satellites, and radar. These waves are a type of electromagnetic radiation and have a frequency from high 300 GHz to low as 3 kHz though around it is defined as above 3 GHz as microwaves. At 300 GHz, the wavelength is 1 mm and at 3 kHz is 100 km.

Q2

Write some properties of radio waves?

• Radio waves can travel for a long distance.
•  Radio waves can penetrate through materials.
•  Radio waves cannot be felt and they are invisible.
• Radio waves travel at the speed of light in vacuum.

Q3

Define frequency modulation.

Frequency Modulation is the encoding of information in a carrier wave by varying the frequency of the carrier wave at that instant corresponding to the variation of the base waveform to be transmitted.

Q4

What is amplitude modulation?

Amplitude Modulation is an electronic communication systems technique wherein the baseband signal is superimposed with the amplitude of the carrier wave i.e the amplitude of the carrier wave is varying with proportion to the base waveform being transmitted.

Q5

What is bandwidth?

Bandwidth refers to the frequency range over which the signal is transmitted or the range over which the equipment operates.