K7RA Solar Update

The following is quoted from ARRL News:

12/12/2019

Tad Cook, K7RA, Seattle, reports: Spaceweather.com says that Wednesday, December 11, was the 28th consecutive day of no sunspots. To date in 2019, 77% of days had no sunspots. Compare this to the previous solar minimum: In 2008, 73% of days were spotless, and in 2009, 71% of days had no sunspots.

The average daily solar flux for the December 5 – 11 reporting week was 70.7, up marginally from the previous week’s 70.2.

At the bottom of the solar cycle, hardly any geomagnetic activity occurs, with average daily planetary A index at 3.7 and average middle latitude A index at 1.9. This is very quiet and is favorable to propagation on 160 meters.

As was the case in last week’s bulletin, the predicted solar flux is 70 on each of the next 45 days — until January 25.

The predicted planetary A index is 5, 8, and 8 on December 12 – 14; 5 on December 15 – 17; 12 on December 18; 10 on December 19 – 21; 5 on December 22 – January 4; 8 on January 5; 5 on January 6 – 8; 8 on January 9 – 10; 5 on January 11 – 13; 12 on January 14; 10 on January 15 – 17, and 5 on January 18 – 25.

Sunspot numbers for December 5 – 11 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. The 10.7-centimeter flux was 70.7, 70.3, 70.2, 71.6, 70.7, 70.6, and 70.7, with a mean of 70.7. Estimated planetary A indices were 3, 4, 2, 3, 4, 4, and 6, with a mean of 3.7. Middle latitude A index was 1, 2, 1, 2, 2, 2, and 3, with a mean of 1.9.

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.

Share your reports and observations.

Website: ARRL News

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