Empirical Models Representing the Error in the Predicted MUF and Field Strength from HFBC84.
Professional paper for May 87,
NAVAL OCEAN SYSTEMS CENTER SAN DIEGO CA
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Models of the probability distribution representing the residuals between the observed MOF and field strength and the corresponding predicted values from HFBC84, an ionospheric prediction program developed for the Broadcast WARC, are presented. A data base of 13,054 hours of oblique sounder MOFs measured on 70 paths was used to obtain the residuals in the predicted MUFs. A modified version of CCIR Data Base C was used to obtain the residuals in predicted field strength only the 81 paths for short path propagation were retained. The residuals for these models were fit to the Johnson system of frequency curves. This system of curves consists of three distributions 1 data that is unbound, called the SU distribution 2 data that is bound on one end called the SL distribution and 3 data that is bound on both ends, called SB distribution. Overall for the MUF residuals, it was determined that the data could be represented by a S distribution. Overall for the field strength residuals, a SU distribution fit the data for frequencies below or equal the predicted MUF, and a SB distribution fit the data for frequencies greater than MUF.
- Radiofrequency Wave Propagation
- Administration and Management