August 1970 | Technical Memorandum NTIA TM 243
A Numerical Method for Predicting the F1 Layer Critical Frequency
Cite This Publication
Donald H. Zacharisen, Rayner K. Rosich, and G. R. Enoch, “A Numerical Method for Predicting the F1 Layer Critical Frequency,” Technical Memorandum NTIA TM 243, U.S. Department of Commerce, Environmental Science Services Administration, Institute for Telecommunication Sciences and Aeronomy, August 1970.
Abstract:
The F1 layer is not explicitly included in current ITS high frequency radio propagation predictions. Numerical maps of F1 layer characteristics, similar to those for F2, E, and Es characteristics now in use, were rejected in favor of a more concise representation by a formula expressing the strong dependence of monthly median f0F1 on the sun's zenith angle. Three formulas for predicting monthly median f0F1 were tested against 8 months of monthly median f0F1 data observed in 1958 and 1964, years of maximum and minimum, respectively, of the solar cycle. The root mean square residuals between observed data and predictions from the three formulas were compared. Recommendations are made for deriving an improved formula.
Keywords: HF propagation prediction; F1 layer
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