Radio Navigation
Radio wave properties and propagation, modulation and antennae, and the ground/airborne radio navigation aids — Doppler, VDF, ADF/NDB, VOR and ILS. Chapter-wise notes from the Oxford ATPL Radio Navigation manual with practice Q&A.
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Chapters
Properties of Radio Waves
The electromagnetic spectrum, wavelength/frequency/velocity, phase and polarisation — the physical basis of all radio navigation.
Radio Propagation Theory
Ground, sky and space waves, surface attenuation, ionospheric refraction, critical angle, skip distance, fading and the factors affecting range.
Modulation
Amplitude and frequency modulation, sidebands, bandwidth, keying and the carrier/intelligence relationship used by nav aids.
Antennae
Antenna principles, dipoles and directional arrays, polar diagrams, gain and the aerials used by ground and airborne equipment.
Doppler Radar Systems
The Doppler shift principle, beam geometry, drift and groundspeed measurement, and Doppler navigation system operation.
VHF Direction Finder (VDF)
VDF principles, QDM/QDR/QTE/QUJ bearings, classes of bearing accuracy, range and operational use.
ADF / NDB
NDB and ADF principles, the loop and sense aerials, relative/magnetic bearings, RMI, errors and factors affecting accuracy and range.
VOR
VOR principle of operation, reference and variable phases, radials, Doppler VOR, cockpit display/CDI, errors, coverage and designated operational range.
ILS
Instrument Landing System — localiser, glidepath, marker beacons, categories, coverage, false glidepaths and ILS errors and limitations.