The K7RA Solar Update
Tad Cook, K7RA, Seattle, reports: No sunspots appeared over the January 16 – 22 reporting week. On January 22, Spaceweather.com reported the consecutive period of spotless days is 11, but all recent sunspots have had Cycle 25 polarity.
The average daily solar flux dipped from 72.5 to 71.2. The average daily planetary A index went from 5.6 to 4.1, and the middle latitude A index dropped from 3.7 to 3.
Predicted solar flux is 72 on January 23 – February 5; 71 on February 6 – 20; 72 on February 21 – March 3; 71 on March 4, and 70 on March 5 – 7.
Predicted planetary A index is 5 on January 23 – 31; 10 on February 1 – 5; 5 on February 6 – 27; 10 on February 28 – March 3, and 5 on March 4 – 7.
When there are no sunspots, 160 meters seems to improve, probably because of lower associated geomagnetic activity. The CW portion of the CQ World Wide 160-Meter Contest takes place this weekend.
Sunspot numbers for January 16 – 22 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. The 10.7-centimeter flux was 71.8, 70.1, 71.3, 71.8, 71.2, 70.5, and 71.9, with a mean of 71.2. Estimated planetary A indices were 5, 3, 4, 3, 2, 6, and 6, with a mean of 4.1. Middle latitude A index was 4, 2, 3, 2, 2, 4, and 4, with a mean of 3.
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.
A propagation bulletin archive is available. Monthly charts offer propagation projections between the US and a dozen DX locations.
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