The K7RA Solar Update
Tad Cook, K7RA, Seattle, reports: No sunspots again this week, and as of Wednesday, we’ve seen 15 spotless days in a row. This is the solar minimum. The current Cycle 24 is expected to end by year’s end.
The average daily solar flux dipped from 69.4 to 68.1, while average daily planetary A index declined slightly from 8.9 to 8.3, while the average daily mid-latitude A index rose from 7.7 to 8.
Predicted solar flux is 68 on September 19 – 26; 69 on September 27 – October 6; 70 on October 7; 68 on October 8 – 19, and 69 on October 20 – November 2.
Predicted planetary A index is 5 on September 19 – 21; 8 on September 22 – 23; 5 on September 24 – 26; 35, 45, 20, and 10 on September 27 – 30; 8, 10, and 8 on October 1 – 3; 5, 5, and 12 on October 4 – 6; 5 on October 7 – 9; 8, 5, and 8 on October 10 – 12; 5, 8, and 10 on October 13 – 15; 5 on October 16 – 19; 8, 5, and 5 on October 20 – 22; 8, 25, 30, and 18 on October 23 – 26; 8, 5, and 8 on October 27 – 29; 5 on October 30 – November 1, and 12 on November 2.
Sunspot numbers for September 12 – 18 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. The 10.7-centimeter flux was 69.4, 68.3, 68.6, 67.7, 68.7, 67.5, and 66.3, with a mean of 68.1. Estimated planetary A indices were 7, 8, 6, 8, 11, 9, and 9, with a mean of 8.3. Middle latitude A index was 7, 8, 7, 8, 10, 8, and 8, with a mean of 8.
A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. For more information concerning radio propagation, visit the ARRL Technical Information Service, read "What the Numbers Mean," and check out K9LA’s Propagation Page.
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