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Circular of Basic Indices for Ionospheric Propagation

​​​​​​​​​​​​​​​​​​​​​​​​​​The ITU Radiocommunication Bureau has prepared the following document that contains a table of values of basic indices, based on data kindly supplied by the Solar Influences Data analysis Centre (SIDC, Brussels), the National Geophysical Data Center, Boulder, Colorado and the National Research Council, near Penticton, British Columbia, Canada.
Date of circular: 05​/2022