- Ionospheric sounding
In
telecommunication and radio science, an ionospheric sounding is a technique that provides real-timedata onhigh-frequency ionospheric-dependentradio propagation , using a basicsystem consisting of a synchronized transmitter and receiver.The time
delay between transmission and reception is translated into effective ionosphericlayer altitude. Vertical incidentsounding uses a collocated transmitter and receiver and involves directing a range of frequencies vertically to theionosphere and measuring the values of the reflected returned signals to determine the effective ionosphere layer altitude. This technique is also used to determine thecritical frequency . Oblique sounders use a transmitter at one end of a given propagation path, and a synchronized receiver, usually with an oscilloscope-type display (ionogram), at the other end. The transmitter emits a stepped- or swept-frequency signal which is displayed or measured at the receiver. The measurement convertstime delay to effective altitude of the ionosphericlayer . The ionogram display shows the effective altitude of the ionospheric layer as a function of frequency.ee also
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Kennelly-Heaviside layer
*Edward V. Appleton
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