HF Sky-Wave Field Strength Predictions

摘要

A description is given on how the field strength of an HF signal, expressed indecibels (dB) above or below 1 microvolt per meter reference, is calculated by seven different HF propagation prediction programs, and on how the accuracy of the predicted field strength values from these programs can be determined and presented. These seven programs include three empirical based programs (Medusa PROPHET, FTZ, and FTZ4), and four analytical programs (HFTDA, IONCAP, ASAPS, and AMBCOM). AMBCOM is the only ray tracing program included. All of these prediction programs produce median predictions of the rms field strength. The accuracy of these seven programs will be determined for the Polar, Equatorial Near vertical incidence Experiment (PENEX) Project. A data screening program, DASCR3, will be used to assess the accuracy of these programs. DASCR3 allows the development and generation of powerful statistical descriptions of the characteristics of the measured field strength and of how well the candidate programs predict the observations. Useful statistical parameters for describing the accuracy of the programs are given. DASCR3's ability to allow and store up to 40 different auxiliary variables permits comparisons to be subdivided into many subcategories. Recommendations for these subcategories for the field strength accuracy study are given. DASCR3 also allows the determination of improvements that might possibly be made to these field strength prediction programs. Propagation, Propagation forecast, Expert systems, PROPHET. High frequency.