Radio Technology: From Hertz to Wireless Communication


Explore how messages are sent using electromagnetism, from allocating frequencies to the intricacies of AM and FM radio. Dive into the rise of radio waves.



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Welcome to “Radio Technology: From Hertz to Wireless Communication“. This guide makes understanding communication technology simple and engaging for everyone. It’s perfect for students, teachers, and anyone curious about how we send messages. Explore the basics of the advancements in electromagnetic communication with us.

Discover Communication’s Core

Dive into the fascinating realm of electromagnetic communication, where every frequency band and modulation method tells a story of innovation and connectivity. Learning about this technology isn’t merely academic; it’s understanding the backbone of how we share information in the modern world. This guide acts as your navigator, illuminating each concept with precision, from the early development of radio waves to the nuanced properties of AM and FM radio.

Inside Your Guide

Foundational Knowledge: Start with the basics of electromagnetism and its role in communication. Discover how allocating specific frequencies enables us to send countless messages simultaneously, without interference.

The Spectrum of Frequencies: Explore the significance of frequency bands and how they are chosen and used for different types of communication, ensuring clarity and reach in the transmission of information.

Evolution of Radio Waves: Journey through the development of radio waves and understand how this discovery revolutionized the way we communicate, laying the groundwork for future technological advances.

The Mechanics of Sending Sound: Unpack the methods of transmitting sound through carrier waves. Learn the differences between Amplitude Modulation (AM) and Frequency Modulation (FM), and how each plays a crucial role in radio broadcasting.

AM and FM Properties: Delve into the properties of AM and FM radio, understanding their strengths, limitations, and why they continue to be pivotal in broadcasting despite the advent of digital communication.

Why This Guide?

Clarity and Simplicity: We’ve distilled complex scientific concepts into easy-to-understand language. Short sentences and a straightforward narrative ensure the material is accessible and enjoyable for all readers.

Active Learning: By emphasizing direct engagement with the content through examples and practical insights, this guide fosters a deeper understanding and a more enjoyable learning experience.

Comprehensive Exploration: From the foundational principles to the latest advancements, this guide offers a thorough examination of electromagnetic communication, preparing you for further study or practical application in this exciting field.

Empower Your Understanding of Communication: Armed with the knowledge from this guide, you’ll approach the topic of electromagnetic communication with newfound confidence. Understanding these principles is crucial for navigating and appreciating the technological world around us.

Start Your Tech Journey

Radio Technology: From Hertz to Wireless Communication” is more than just a study aid; it’s a portal to the captivating world of communication technology. Whether you’re aiming for academic success, seeking to enhance your teaching methods, or simply indulging in your passion for science, this guide offers a clear, engaging pathway to understanding how we connect across distances.

Embark on this enlightening journey today. With “Science of Communication,” you’re not just learning about electromagnetic communication; you’re unlocking the door to a world where information travels at the speed of light. Start your adventure now and discover the magic behind sending a message.

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Additional information

Sending a Message

Communicating with Electromagnetism The production and detection of electromagnetic waves has produced a revolution in communication.
Today, a large portion of the electromagnetic spectrum is used for various different types of communication.

Allocating Frequencies
Atmospheric absorption limits the range of electromagnetic frequencies that we can use.
Governments regulate the use of the spectrum and allocate licences to users.
In Australia, all appropriate “bands” of frequencies have been allocated to commercial and amateur users.

Frequency Bands
Frequency Name Wavelength Use
30-3000 Hz ELF 100 km submarine link
3-300 kHz VLF 100-1 km defence use
0.3-3 MHz MF 1000 to 100 m “medium wave” sound radio
3-30 MHz HF 100 to 10 m “short wave” sound radio
30-300 MHz VHF 10 to 1 m sound radio
0.3-3 GHz UHF 1 to 0.1 m television

The Development of Radio Waves
Radio waves were first discovered by the physicist Heinrich Hertz in 1887.
By 1903, inventors were able to send messages between the United States of America and the United Kingdom.
Since then, ways of encoding sound have been developed.

Carrier Waves
Radio signals use a carrier wave to transmit messages.
The carrier wave is a simple, predictable radio wave of a fixed frequency.
Radio receivers can be tuned to receive only a single frequency, so that you listen to one radio station at a time.

Sending Sound
Sound waves can be combined with the carrier wave for transmission.
There are two different ways to combine the sound wave with the carrier wave.
These are amplitude modulation (AM) and frequency modulation (FM).

Amplitude Modulation (AM)
In amplitude modulation, the sound wave is used to alter the carrier’s amplitude.
The resultant wave has the same frequency as the carrier.
The receiver can then “subtract” the carrier wave, leaving the sound wave.

Properties of AM Radio
Amplitude modulation is susceptible to interference.
A lightning flash or a spark will produce a change in the received amplitude.
If the carrier wave is faint, the decoded signal will also be faint.

Frequency Modulation (FM)
In frequency modulation, the sound wave is used to alter the carrier’s frequency.
The resultant wave will have a frequency that varies slightly.
The amplitude of the wave does not change.

Properties of FM Radio
Messages sent by frequency modulation are not as susceptible to interference.
This is because the amplitude of the wave does not affect its message.
However, it is possible for two stations with similar frequencies to overlap.

Digital Information
Digital information (in 1s and 0s) can also be encoded in carrier waves.
The information is changed to an analogue signal, sent to a receiver, and then changed back into its original form.
The device which transforms it is a modulatordemodulator (modem).

Question 6
What are the two different ways of encoding a sound wave onto a carrier wave?
(A) Modulation and demodulation
(B) Amplitude modulation and frequency modulation ←
(C) Velocity modulation and intensity modulation
(D) Wavelength modulation and period modulation

Question 7
Which of the following is not a use of radio waves?
(A) Broadcasting music
(B) Broadcasting news reports
(C) Broadcasting television
(D) Broadcasting electricity ←
Radio waves are used to broadcast electromagnetic waves, not electricity.

Question 8
(a) Is this wave a result of FM or AM encoding?
Amplitude modulation (AM): its frequency does not change. ↙
(b) Sketch the decoded wave.

Question 9
(a) Is this wave a result of FM or AM encoding?
Frequency modulation (FM): its amplitude does not change. ↙
(b) Sketch the decoded wave.

Question 10
Why do governments restrict the use of the electromagnetic spectrum?
Not all frequencies of electromagnetic wave can be used to communicate, and only one transmission at a time can be sent over a given frequecy.
This means that there is a limited amount of bandwidth that can actually be used for transmissions at any given time.
Permission to broadcast on a given frequency is licensed by the Australian Communications and Media Authority (the ACMA; a branch of the Australian government).