THE
PILOT
radio
navigation
ATPL
STUDENT
pilot
resume
all info you need to pass atpl exams
, Radio theory
• Phase: Fraction of one wavelength expressed in degrees from 000 - 360
• Cycle: A complete series of values of a periodical process
• Frequency: Number of oscillations/cycles per second of an electromagnetic wave
• Phase difference: ANGULAR difference between two cycles of equal wavelength
• Wavelength (λ) = Speed of light (m/s) ÷ frequency (Hz)
• SSB: Used in HF & VOLMET, AM
• Modulation: Addition of a low frequency signal onto high frequency carrier wave
• Phase modulation: Used by GPS, Helical antennas as GPS have circular polarization
• Pulse modulation: Radar
• NON A1A modulation/keying: Interrupting carrier wave to break it into dots & dashes does not change
frequency or amplitude
• MSI: Modulation, signal, information
• Keying: Interrupting the carrier wave to break it into dots & dashes
Antennae
• Electrical field E same direction as aerial
• Magnetic field H perpendicular to aerial
• Antennae length = half wavelength (λ)
• POLARIZATION: Orientation of the plane of oscillation of the electrical component E
• AC induced parallel to wire, but remote from it
• First wire radiates energy to space, second wire induces AC
• Flat (Slotted) plate eliminates/generates less side lobes than parabolic
• Helical antennae used by GPS due to circular polarization
• Radar uses one antenna for both transmitting and receiving
• Directional antennas: Loop(ADF), parabolic, slotted planar, helical
• Dipole antennas: Are the simplest. Needs the receiver & transmitter of electrical field on the same
planes
Radio propagation
• Electromagnetic wave : Sky wave, Radio wave: Space wave
• Absorption: Energy taken up by atmosphere
• Attenuation:
- Weakening of the radio wave.
- Lower frequency, greater attenuation. (RANGE)
• Diffraction: Passing/bending over impenetrable obstacles with dimensions close to wavelength
• Reflection: Change in direction of radio wave after reaching a boundary (Used by HF)
• Refraction: Change in direction/bending due to a change in speed, as it passes area of different
electrical conductivity. (SKYWAVES) (Used by HF)
• Interference: Superimposition of two radio waves of same frequency
• Night effect/Fading: Occurs at night, Interference of ground wave with sky wave, Ionospheric
reflection. HF frequency should be reduced at night, higher frequency & higher Ionospheric layer
= larger skip distance
• ONLY HF propagates via SKYWAVE for practical use and the ground wave is really small
Direction finding
• Range = 1.23 x (√Transmitter + √Receiver)
• QUJ: True TO station (To Juliet)
QTE: True FROM station
QDM: Magnetic TO station (To your Mom)
QDR: Magnetic FROM station
PILOT
radio
navigation
ATPL
STUDENT
pilot
resume
all info you need to pass atpl exams
, Radio theory
• Phase: Fraction of one wavelength expressed in degrees from 000 - 360
• Cycle: A complete series of values of a periodical process
• Frequency: Number of oscillations/cycles per second of an electromagnetic wave
• Phase difference: ANGULAR difference between two cycles of equal wavelength
• Wavelength (λ) = Speed of light (m/s) ÷ frequency (Hz)
• SSB: Used in HF & VOLMET, AM
• Modulation: Addition of a low frequency signal onto high frequency carrier wave
• Phase modulation: Used by GPS, Helical antennas as GPS have circular polarization
• Pulse modulation: Radar
• NON A1A modulation/keying: Interrupting carrier wave to break it into dots & dashes does not change
frequency or amplitude
• MSI: Modulation, signal, information
• Keying: Interrupting the carrier wave to break it into dots & dashes
Antennae
• Electrical field E same direction as aerial
• Magnetic field H perpendicular to aerial
• Antennae length = half wavelength (λ)
• POLARIZATION: Orientation of the plane of oscillation of the electrical component E
• AC induced parallel to wire, but remote from it
• First wire radiates energy to space, second wire induces AC
• Flat (Slotted) plate eliminates/generates less side lobes than parabolic
• Helical antennae used by GPS due to circular polarization
• Radar uses one antenna for both transmitting and receiving
• Directional antennas: Loop(ADF), parabolic, slotted planar, helical
• Dipole antennas: Are the simplest. Needs the receiver & transmitter of electrical field on the same
planes
Radio propagation
• Electromagnetic wave : Sky wave, Radio wave: Space wave
• Absorption: Energy taken up by atmosphere
• Attenuation:
- Weakening of the radio wave.
- Lower frequency, greater attenuation. (RANGE)
• Diffraction: Passing/bending over impenetrable obstacles with dimensions close to wavelength
• Reflection: Change in direction of radio wave after reaching a boundary (Used by HF)
• Refraction: Change in direction/bending due to a change in speed, as it passes area of different
electrical conductivity. (SKYWAVES) (Used by HF)
• Interference: Superimposition of two radio waves of same frequency
• Night effect/Fading: Occurs at night, Interference of ground wave with sky wave, Ionospheric
reflection. HF frequency should be reduced at night, higher frequency & higher Ionospheric layer
= larger skip distance
• ONLY HF propagates via SKYWAVE for practical use and the ground wave is really small
Direction finding
• Range = 1.23 x (√Transmitter + √Receiver)
• QUJ: True TO station (To Juliet)
QTE: True FROM station
QDM: Magnetic TO station (To your Mom)
QDR: Magnetic FROM station
