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Results Concerning the Sunrise Effect of VLF Signals Propagated Over Long Paths
Author(s) -
Ries G.
Publication year - 1967
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1002/rds196726531
Subject(s) - sunrise , amplitude , mode (computer interface) , maxima and minima , physics , sunset , phase (matter) , interference (communication) , computational physics , signal (programming language) , optics , mathematics , telecommunications , mathematical analysis , quantum mechanics , computer science , channel (broadcasting) , programming language , operating system
Periodic field strength variations which were observed during sunrise on VLF signals propagated over long paths are discussed. The stepwise phase increase and the minima of the signal amplitude may be explained by the waveguide‐mode theory; they are caused by interference between the first and the converted second mode. Owing to a weak second mode at lower frequencies, the sunrise effect at lower frequencies in general is only weakly developed. The reversed stepwise phase variation observed at higher frequencies may be explained by a strong converted second mode whose amplitude exceeds that of the first mode.