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Current Solar/Ionospheric Data



Interpretation of Data

A-INDEX 1-6 Best; 7-10 Fair; 11+ Bad: This represents the global level of ionospheric geomagnetic disturbance over the previous 24-hour period.

K-INDEX 0-1 Best; 2 Okay; 3-4 Bad; 5+ Very Bad: This is the level of geomagnetic ionospheric disturbance averaged around the planet over the past 3 hours. Values >4 indicate the presence of geomagnetic storms and noise levels on all HF bands increase appreciably. With values >6 overall HF conditions degrade significantly. Generally, HF conditions are best when the A-Index is 10 or lower and the K-Index is 3 or lower.

SFI (SOLAR FLUX INDEX) 70 Not Good; 80 Good; 90 Better; 100+ Best: This is a measure of the total radio emissions from the sun. A higher SFI generally suggests better propagation on the 10, 12, 15, 17, & 20 meter Bands. It rarely affects the 30, 40, 60, 80, & 160 meter bands. When it is >70 then 20m opens and when it is >90 then 15m opens.

SN (SUNSPOT NUMBER) The higher the SN, the higher the level of UV and X-ray radiation that is striking our atmosphere and producing ionization in the D, E and F layers. As ionization increases, the MUF goes up. The higher bands (15M, 12M, 10M and 6M) become active with good propagation when there is a high SN

X-RAY Strong solar X-Ray emissions will cause shortwave fadeouts and radio blackouts. Classification from weak to strong X-Ray emissions is A, B, C, M, X.

Thanks to Barry Siegfried, K2MF, for these explanations.

The banner is provided by Paul Herrman, N0NBH, via his website at http://www.hamqsl.com/solar.html. Steve Saint Andrea, AG1YK, offers more details in an article, "Solar Banners - A Propagation Resource," p. 78 of QST for February 2014.









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