Radio Theory Flashcards
Describe Radio Waves
A form of electromagnetic energy that are similar in behaviour to light waves
In which areas of ATC are Radio Waves used?
Voice Comms VHF/UHF
Navigation VOR/NDB
Surveillance Systems
Weather Radar
Data Transmission
According to Amperes Law, which way does a current produce a magnetic field?
Perpendicular to the flow direction
What speed do radio waves travel at?
300,000,000 meters per second
The speed of light
How do radios transmit audio over very large distances which would otherwise be impossible?
Audio (sound wave) is converted into very high frequency EM wave, which can then be transmitted and propagated over large distances. Radio equipment then converts the high frequency EM waves to audio (sound wave) for us to hear.
What is wave Oscillation?
How a wave changes from maximum to minimum. Represented as a sine wave.
What is the cycle of wave?
One travel from zero to maximum to minimum and back to zero
What is amplitude?
The maximum displacement attained by the wave from its mean value during a cycle.
What is wavelength and what is it represented by?
The distance in meters between corresponding points in consecutive waves. Represented by Lambda.
What is the frequency of a wave?
The rate of repetition of the cycle in one second.
One cycle per second is known as one Hertz.
Describe the frequencies of longer and shorter wavelengths
The longer the wavelength, the lower the frequency
The shorter the wavelength, the higher the frequency
How can velocity of a wave be calculated?
Velocity = frequency x wavelength
C = f x λ
What is a carrier wave?
The electromagnetic wave which carries information through being modulated, by the local modulator.
How is audio transmitted via carrier wave?
The carrier wave is modulated in direct proportion to the signal that is to be transmitted.
What are the two ways to modulate carrier waves?
AM - Amplitude Modulation
FM - Frequency Modulation
