12/09/2022

Tad Cook, K7RA, of Seattle, Washington, reports for this week's ARRL Propagation Bulletin, ARLP049:

Solar activity bounced back in our reporting week, December 1 - 7. With solar flux and sunspot numbers dramatically higher and geomagnetic activity lower, what could be better? Well, even more sunspots, I guess. But this sunspot cycle is already progressing better than the prediction consensus, so I am grateful.

Average daily sunspot numbers increased from 46 to 85, while average daily solar flux rose from 108.3 to 137.5.

Average daily planetary A index dropped from 18.6 to 14.4, while middle latitude numbers declined from 14 to 9.1.

Predicted solar flux for the next few days is high, at 150 on December 8 - 11; 140, 130, 120, and 115 on December 12 - 15; 110 on December 16 - 19; 115 on December 20 - 22; 120 on December 23 - 28; 125, 130 and 135 on December 29 - 31; 140 on January 1 - 6, 2023, and 135 and 130 on January 8 - 9.

The planetary A index prediction is 20 and 8 on December 8 - 9; 5 on December 10 - 16; 10 on December 17 - 18; 5 on December 19 - 21; 20, 15, and 12 on December 22 - 24; 20 on December 25 - 28; 12, 10, 12, and 8 on December 29 - January 1, 2023; 5, 12, 15, and 8 on January 2 - 5, and 5 on January 6 - 12.

Don't forget the ARRL 10 Meter Contest this weekend; https://www.arrl.org/10-meter[1]. In North America, that starts on Friday evening, and the latest prediction shows a promising high solar flux with low geomagnetic numbers, ideal conditions.

In Friday's bulletin look for a report on 8-meter propagation from experimental stations in the United States from Mike Schaffer, KA3JAW.

Sunspot numbers for December 1 - 7, 2022 were 49, 66, 68, 93, 89, 123, and 107, with a mean of 85. The 10.7-centimeter flux was 118.7, 124, 133.8, 143,7, 149.8, 144.2, and 148, with a mean of 137.5. Estimated planetary A indices were 28, 16, 10, 17, 8, 4, and 18, with a mean of 14.4. Middle latitude A index was 18, 11, 7, 10, 7, 2, and 9, with a mean of 9.1.

Send your tips, questions, or comments to k7ra@arrl.net[2].

A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. For more information concerning radio propagation, visit[3] the ARRL Technical Information Service, read[4] "What the Numbers Mean..." and check out[5] the Propagation Page of Carl Luetzelschwab, K9LA.

A propagation bulletin archive[6] is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio[7] website.

Share[8] your reports and observations.

A weekly, full report is posted on ARRL News[9].


[1] https://www.arrl.org/10-meter
[2] mailto:k7ra@arrl.net
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] http://arrl.org/w1aw-bulletins-archive-propagation
[7] https://www.voacap.com/hf/
[8] mailto:k7ra@arrl.net
[9] http://www.arrl.org/news

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