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The K7RA Solar Update

12/10/2021

Tad Cook, K7RA, Seattle, reports: One new sunspot group appeared on December 4, but 4 days later it was gone, and on Thursday, December 9, we saw a second day with no sunspots.

Average daily sunspot number declined from 46.1 to 24.6. Average daily solar flux went from 90.9 to 82.6.

Predicted solar flux over the next month does not seem promising. The December 9 forecast shows 77 on December 10; 80 on December 11 – 14; 82 on December 15; 84 on December 16 – 17; 85 on December 18; 87 on December 19 – 22; 86 on December 23 – 27; 84 on December 28; 82 on December 29 – January 2; 80 on January 3 – 5; 82 on January 6 – 8; 80 on January 9 – 10; 82 on January 11; 85 on January 12 – 14, and 87 on January 15 – 18.

Predicted planetary A index is 10, 8, 10, and 8 on December 10 – 13; 8 on December 13 – 14; 5 on December 14 – 15; 10, 8, 12, 10, and 8 on December 16 – 20; 5 on December 21 – 26; 15, 18, and 12 on December 27 – 29; 8 on December 30 – January 3; 5 on January 4 – 5; 10, 8, 5, 12, and 10 on January 6 – 10; 5 on January 11 – 12; 15, 12, 10, and 8 on January 13 – 16, and 5 on January 17 – 22.

From F.K. Janda, OK1HH: Weekly Commentary on the Sun, the Magnetosphere, and Earth’s Ionosphere, December 9, 2021:

The only sunspot group on Active Region 2904, in which we observed three spots (=> R = 13) on December 7, was calm and decayed to plage. R = 0 applies, since December 8, so we register a minimum within the quasi-periodic 27-day fluctuation. At the same time, solar wind has weakened, the geomagnetic field has calmed, and as a consequence result are the lowest values of f0F2 (critical frequency of the F2 layer). However, the decreasing length of sunlight in Earth’s Northern Hemisphere also contributes to it.

Until the end of the year, we can expect a gradual rise in solar activity to the level of the end of November, an irregular alternation of the Earth’s magnetic field between quiet and unsettled, and a gradual rise in daily f0F2 values just slightly above average.

Email: ok1hh(at)crk.cz, ok1hh(at)rsys.cz

Pmail: OK1HH(at)OK0NAG.#BOH.CZE.EU

This weekend is the annual ARRL 10-Meter Contest! Solar flux should be rising a modest amount during the event. Debris from asteroid Phaethon could possibly enhance propagation on 10 meters during the Geminids meteor shower, peaking on December 13.

N0JK reported on Wednesday from Kansas:

“The Geminids meteor shower is predicted to peak December 13 – 14. Already, meteor rates are picking up.

“I was able to work NJ0W/r in grid DN82 on 50 MHz meteor scatter using MSK144 on December 7, at 0330 UTC. Dave, NJ0W, made other meteor scatter contacts as well. DN82 is considered a rare grid for the Fred Fish Memorial Award (FFMA) on 6 meters.”

The FFMA is awarded for working all North America grid squares on 6 meters. So far, Fred Fish, W5FF (SK), is the only ham who has done this.

Sunspot numbers for December 2 – 8, 2021 were 45, 29, 35, 36, 14, 13, and 0, with a mean of 24.6. The 10.7-centimeter flux was 86.6, 85.3, 88.1, 82.7, 80, 78.9, and 76.9, with a mean of 82.6. Estimated planetary A indices were 10, 8, 9, 9, 7, 5, and 5, with a mean of 7.6. Middle latitude A index was 7, 4, 7, 6, 6, 3, and 4, with a mean of 5.3.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check this propagation page by Carl Luetzelschwab, K9LA.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Instructions for starting or ending email distribution of ARRL bulletins are on the ARRL website.

Share your reports and observations.



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