Radio waves are electromagnetic waves that have wavelengths longer than infrared radiations. The range of radio waves is between 30 kHz and 300 GHz in an electromagnetic spectrum.
(Image to be added soon)
Radio waves have the best use in communication systems like television, mobile phones, radios, etc.
Natural radio waves occur or emit by lightning, astronomical objects, while artificial radio waves are produced with the help of transmitters, and radio receives it by using antennas. These signals are transformed into mechanical vibrations in speakers to generate sound.
Radio waves have many real-life applications. In this article, we will learn about the radio electromagnetic spectrum and its uses.
Radio Waves Uses
Radio waves in the electromagnetic spectrum are located in the low range frequencies. The wavelength of these waves ranges from 30 cm to 1 km and Radio electromagnetic spectrum is a part of the electromagnetic spectrum with frequencies from 30 Hz to 300 GHz. These waves have great use in communication systems.
In the air, radio wave communication signals traverse a straight path, emit clouds/layers of the ionosphere, or are relayed by satellites in space.
Radio Waves Are Employed in Various Places; These Are:
Radio Wave Frequency Spectrum
A radio band is a continuous series of the radio wave frequency spectrum. These bands are called the channels and each channel has its specific purpose. To overcome the interference and the overlapping of bands and allow for the efficient use of the radio wave spectrum, alike services are allocated in bands.
(Image to be added soon)
For each channel, ITU (International Telecommunication Union) has a band plan that indicates how each channel has to be used and shared, to prevent interference, overlapping and to set protocol for the affinity of transmitters and receivers.
What Does ITU Do?
ITU radio bands are specified in the ITU Radio Regulations. It divides the radio frequency spectrum into 12 bands, each of which begins at a wavelength with a power of 10n, with the respective frequency of 3 x 108-n Hz.
The table mentioned below discusses the radio wave frequency bands with their respective ITU band numbers and functions. These recommendations were approved by the International Radio Conference held at Atlantic City, New Jersey, in 1947. Let’s look at these:
|
Name of the Band |
Abbreviation of the Band Name |
ITU Band Number |
Frequency Range of Radio Waves & Radio Waves Wavelength |
Functions |
|
Extremely low frequency |
ELF |
1 |
3-30 Hz 100,000 – 10,000 km |
In communication with Marines |
|
Super low frequency |
SLF |
2 |
30-300 Hz 10,000 – 1000 km |
These are also used for communications in submarines |
|
Ultra low frequency |
ULF |
3 |
300 – 3,000 Hz 1,000 – 100 km |
Communication with submarines; communication in mines |
|
Very low frequency |
VLF |
4 |
3 – 30 kHz 100 – 10 km |
Navigation Time signals Submarine communication Wireless heart rate motors Geophysics |
|
Low frequency |
LF |
5 |
30 – 300 kHz 10 – 1 km |
Navigation Time signals Amplitude modulation longwave broadcasting in Europe and parts of Asia RFID Amateur radio |
|
Medium frequency |
MF |
6 |
300 – 3,000 kHz 1,000 – 100 m |
Amplitude modulation (medium-wave) broadcasts, amateur radio, avalanche beacons |
|
High frequency |
HF |
7 |
3 – 30 MHz 100 – 10 m |
Shortwave broadcasts Citizens band radio Amateur radio and over the horizon aviation communications RFID ALE (Automatic link establishment) or NVIS (near-vertical incidence skywave radio) communications Marine communication Mobile phone telephony |
|
Very high frequency |
VHF |
8 |
30 – 300 MHz 10 – 1 m |
Frequency modulation Television broadcasts Line-of-sight communications for the ground to aircraft and aircraft to aircraft Land mobile maritime and mobile communications Amateur radio, weather radio communications |
|
Ultra-high frequency |
9 |
300 – 3,000 MHz 1 – 0.1 m |
Television broadcasts microwave devices or communications Microwave oven radio astronomy mobile phones wireless LAN Bluetooth ZigBee GPS Two-way radio communications viz: land mobile FRS GMRS radio communication Amateur radio Satellite radio Remote control Systems |
|
|
Super high frequency |
SHF |
10 |
3 – 30 GHz 10 – 1 mm |
Radio astronomy Microwave communications Wireless LAN DSRC, Modern radars Communications satellites Cable and satellite television broadcasting DBS Amateur radio Satellite radio |
|
Extremely high frequency |
EHF |
11 |
30 – 300 GHz 10 – 1 mm |
Radio astronomy high-frequency microwave radio relay, ADSB microwave remote sensing amateur radio directed-energy weapon millimeter-wave scanner wireless LAN (802.11ad) |
|
Tremendously high frequency (or TeraHertz) |
THF (or THz) |
12 |
300 – 3,000 GHz 1 – 0.1 mm |
Ultrafast molecular dynamics, Experimental medical imaging to replace X-rays Condensed-matter physics Terahertz time-domain spectroscopy terahertz computing or communications remote sensing |
From the above table, we can see the descending order of frequency and wavelengths. Also, the electromagnetic waves radio waves specifically designate a section of the electromagnetic spectrum having frequencies ranging between 300 GHz and 3 kHz and wavelengths ranging from 1 millimeter to 100 kilometers.