Level 1 · Lesson 1.2

How radio works

Jimmy Bob, a friendly cartoon mountain man in a trucker cap and overalls

“Radio waves are like ripples on Coal River, just a whole lot faster.”

You'll be able to

describe a radio wave, relate frequency and wavelength, name the parts of a station.

A radio wave is electromagnetic energy that travels at the speed of light, about 300,000,000 meters per second. is how many cycles happen each second, measured in (Hz), kilohertz (kHz), and megahertz (MHz). is the distance one cycle covers, and wavelength in meters equals 300 divided by frequency in MHz. A station needs a transmitter to create the signal, a receiver to hear it, and an to launch and catch it; a combines transmitter and receiver.

Tap an underlined word for its meaning.

Try it

Wavelength slider

146.0 MHz→2.1 m

Wavelength (m) = 300 ÷ MHz. Try the presets:

Half-wave dipole for this frequency: about 3.2 ft.

Quick check

Get 2 of 3 right to complete the lesson.

1. About how fast does a radio wave travel?
2. What is the wavelength of a 150 MHz signal?
3. A transceiver is…

How radio works

You'll be able to

Try it

Quick check

Words from this lesson