K1TTT MOF/LOF Propagation Program
Algorithms used in K1TTT MOF propagation prediction program
The MOF algorithm devides the prediction up into the following major
1. Geophysical and Solar constants
2. The Ionosphere
a. Critical Frequency
3. Path factors
Like most MUF algorithms the basic flow proceeds as follows for a
given path prediction:
1. Calculate the position of the sun, length of day, time of
local noon, and solar zenith angle for later use.
2. Calculate Ionosphere factors based on sun, magnetic
field constants, polar effects, time and date, etc.
End result is Critical Frequency, the highest frequency
reflected for a wave traveling straight up.
3. Calculate path factors like distance, bearing, number of
hops, takeoff angle, angle of incidence at the
ionosphere, etc. Need locations of reflections off the
ionosphere, and angle of incidence.
4. Find the minimum critical frequency at all the hops along
the path, multiply that by the Path Factor which is
calculated from the angle of incidence with the
ionosphere for that path.
Shortcomings of this model.
1. The ionosphere changes height along many paths so that the
angle of incidence is not the same at every point.
2. It does not handle skew paths
3. It does not handle chordal hops( two ionosphere reflections
without an earth reflection), E, F1, F-E, etc combination
hops or ducts. It only handles basic F2 Layer hops.
This is a very simple cos(chi) (chi=solar zenith angle) absorbtion