Day 3
Electromagnetic waves consist of oscillating electric and magnetic fields that travel at the speed of light. Radio waves are electromagnetic waves with the lowest frequencies and lowest wavelengths in the electromagnetic spectrum.
1. Wavelength (λ)
The wavelength is the backbone of a radio wave. It’s the distance between identical crests (or troughs) of the wave. In amateur radio, you will see references to wavelength all the time. The amateur radio spectrum is chopped up into a “Band Plan” with each section having a specific wavelength. For example, with your Technician Class license, you will spend most of your radio time operating the 2-meter and 70-centimeter bands, which use wavelengths of - you guessed it - 2 m and 70 cm, respectively.
Unit: Meters (M)
2. Frequency (f)
Frequency is the measure of how many times a signal oscillates through it’s highest and lowest point over a period of time, usually 1 second.
Most radios “tune” by selecting a specific frequency. You probably even have a favorite radio frequency, or station, that you listen to on your car stereo. Frequency describes how many times the radio wave cycles through its wavelength each second.
Unit: Hertz (Hz)
3. Amplitude (X)
The amplitude of a radio wave measures the height of its crests (or depth of its troughs).
Amplitude affects signal strength: louder music, clearer voices, and stronger signals.
