| Popis: |
Observations of the HF skywave ionospheric channel during one year over three paths within Sweden are reported. The major aim of the work was to gain insight into prevailing propagation effects on representative fixed circuit paths at auroral latitudes, with a view to being able to assess prediction accuracies, and to exploit abnormal propagation modes so improving circuit reliabilities. The main instruments in the study were chirpsounders, HF FM-CW sounders covering the frequency range from 2 to 30 MHz. A data base of about 250,000 recordings was built up during the campaign, which covers the maximum of solar cycle 22. Some measurements were made with transmissions on fixed frequencies, mostly > 20 MHz. |
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