1. Radio Radio Waves

2. Reference
From the Ground Up Chapter 8.1: Radio Pages

3. Introduction
Radio is the transmission of signals through the air in the form of electromagnetic waves.
It’s good to have a background understanding on how radio wave work when flying an aircraft.

4. Outline
Wavelength
Frequency
Signal Characteristics

5. Wavelength Wavelength is the linear measurement of a wave (in meters)
A Cycle is the period that a wave vibrates between its crest and trough
Wavelength

6. Frequency The Frequency is the cycles per second (in hertz)
Radio is in the electromagnetic spectrum between 3 kHz and 300 GHz
Low Frequencies
High Frequencies

7. Frequency Low/Medium Frequencies (LF/MF) High Frequencies (HF)
30 KHz to 3000 KHz
Air navigation (NDB), short-wave radio
High Frequencies (HF)
3,000 to 30,000 KHz
Air-ground communication, AM radio
Waves reflect off ionosphere, therefore have longer range
Very High Frequencies (VHF)
30 to 300 MHz
Air navigation (VOR), aviation radio, FM radio
Ultra High Frequency (UHF)
300 to 3000 MHz
Government use, air navigation (ILS, DME)

8. Signal Characteristics
Ground Waves
Travel along earth’s surface
Dulled by obstacles
Sky Waves
Travels up into air
Certain frequencies reflect back to the surface from ionosphere
Skip Zone
Area between ground waves and sky waves
Transmissions very erratic or unheard
Line of Sight
VHF waves travels straight through air
Aircraft must see station to receive transmissions

9. Signal Characteristics
Receives sky waves
No signal
Radio station
Surface of Earth

10. Signal Characteristics
Ionosphere
In skip zone,
Receives no
signal
Receives ground waves
Receives reflected
sky waves

11. Next Lesson
6.2 – Radio Communication From the Ground Up Chapter 8.4: Radio Communication Procedures Pages