Ground-Wave Propagation, Earth Surface Dielectric Properties

Compute the attenuation of a LF Ground Wave for a given permittivity and conductivity. Model the complex permittivity of Earth surface.

This code translates the vintage FORTRAN model FCCGW documented in Eckart, Robert (1986) Modern Methods for Calculating Ground-Wave Field Strength Over A Smooth Spherical Earth, FCC/OET R86-1. The purpose of the model is to calculate the AM broadcast propagation theoretical value of ground-wave radio field intensity at given frequencies and distances and for given electric ground constants.

There are 4 inputs to the original program:
1) distance of field point from transmitter
2) real component of the relative permittivity of the ground
3) conductivity of the ground
4) frequency of the ground wave

Modifications:
1) The program is vectorized for Frequency Arrays
2) The user can input pressure, temperature, relative humidity, and whether or not the ground is ice covered to compute the atmosphere refraction parameterization based on surface weather conditions
3) LF Dielectric Properties (complex relative permittivity, conductivity, and complex index of refraction) . The routines are not full spectrum and do not include the space charge effects. Emissivity and conductivity of ocean water for given temperature, pressure, and salinity; pure ice of given temperature; and 4 different rock samples with optional water saturation.

Numerical:
SALZER is a complementary error function taking complex input for the upper half of the complex plane.