MF skywave propagation

The paper relates skywave signal strength to lower ionosphere modeling. The variability of the ionosphere is described in statistical terms, and the resulting signal is specified as a mean estimate with confidence intervals assumed to be normally distributed. Lower ionosphere electron density profiles, which represent a range of locations, seasons, sunspot numbers and times of day, are used in regression analyses to obtain models for electron density variability as a function of location and time. Reflection coefficients are computed to obtain signal variability, and ionospheric modeling and predicted sensitivities are reported with demonstrations of applications in estimating field strength variability. The need for an expanded data base is also demonstrated. The approach allows the estimation of skywave signal strengths, their variability, and the errors of prediction in a useful form.