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Observations of sounder‐pulse‐induced modulations on the reception of broadcast signals in the ionosphere
Author(s) -
McAfee John R.
Publication year - 1974
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 - 10.1029/rs009i004p00469
Subject(s) - ionosphere , pulse (music) , antenna (radio) , physics , modulation (music) , rocket (weapon) , amplitude , amplitude modulation , sporadic e propagation , acoustics , frequency modulation , radio frequency , geophysics , telecommunications , optics , computer science , geography , detector , archaeology
Observations of pulse‐stimulated transient effects on the behavior of received signals were made during a portion of a rocket‐borne RF sounder flight. These consisted of the amplitude modulation (often severe) of various ground‐based broadcasts which were received. Their occurrence was synchronous with the sounder pulses and dependent (at least qualitatively) upon the relationship between the broadcast frequency and the local plasma resonant frequencies. The exact nature of the physical processes which cause the modulation is unknown, but could lie in the modification of the sheath‐controlled antenna impedance by the pulse. The possibility that such modulations are present in experiments may be important in terms of explaining other observations and in rectifying misinterpretations.