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RECOMMENDATION ITU-R P.684-5
Prediction of field strength at frequencies below about 150 kHz
1 Introduction
2 Wave-hop
propagation theory
2.1
General description
2.2
Calculating the ray-path field strength
2.2.1 Angles of elevation
and ionospheric incidence
2.2.2 Path length and differential time delay
2.2.3 Focusing factor
2.2.4 Antenna factors
2.2.5 Ionospheric reflection coefficients ||R||
2.3
Numerical method for calculating resultant field strength and phase
2.3.1 Path geometry and factors to be calculated
2.3.2 Reflection height model
2.3.3 Focusing factor
2.3.4 Antenna factor
2.3.5 Ionospheric reflection coefficient
2.3.6 Ground reflection loss
2.3.7 Sky-wave field strength
2.3.8 Ground wave
2.3.9 Resultant field strength and phase
2.3.10 Distance variations of 40 kHz and 60 kHz
standard frequency and time signal
2.3.11 Temporal variations of field strength and
phase of standard frequency and time signal at 60 kHz
2.4
Prediction for propagation paths exceeding 4 000 km
3 Calculating field strength by waveguide modes:
full wave solution
3.1 The
ionospheric reflection matrix, R(θ)
3.2 The
ground reflection matrix, (θ)
3.3 The mode
finding method (“MODESRCH”)
4 Calculation of field strength
4.1 Required
parameters
4.2
WKB and horizontally homogeneous mode sums
4.3 Mode
sums using mode conversion
4.4
Ionospheric parameters
4.5 Geomagnetic
and geophysical parameters
5 Discussion
Annex 1 Example of a complete calculation of field in amplitude and
phase using the wave‑hop method of § 2
Annex 2 Accuracy of the methods
Annex 3 Some example calculations using the waveguide mode
method