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The K7RA Solar Update

09/04/2020

Tad Cook, K7RA, Seattle, reports: As of Thursday night, no sunspots have appeared for the past 13 days. I know we are all hoping for more sunspots, and I’m sure they’ll be returning soon; the trends for this newly awakening solar cycle favor it. One event to look forward to this month is the autumnal equinox on Tuesday, September 22, which should favor worldwide HF propagation.

Average daily solar flux declined this reporting week (August 27 – September 2) from 70.4 to 69.6.

Geomagnetic indicators showed quite a bit more activity than they have in some time. Average daily planetary A index rose from 5.1 to 13.1. The most active day was August 31, when the planetary A index reached 26. The cause was a vigorous solar wind spewing from holes in the solar corona.

Predicted solar flux is 70, forecast for every one of the next 45 days. Predicted planetary A index is 5 on September 4 – 17; 8 on September 18 – 19; 5 on September 20 – 22; 8, 10, and 14 on September 23 – 25; 10 on September 26 – 27; 12 and 10 on September 28 – 29, and 5 on September 30 – October 18.

This article says the solar minimum most likely occurred last December.

F.K. Janda, OK1HH, offers his geomagnetic activity forecast for September 4 – 29.

The geomagnetic field will be:

  • quiet on September 5 – 8, 10 – 13, 16 – 17, 20 – 21

  • quiet to unsettled on September 4, 9, 14, 29

  • quiet to active on September 15, 18 – 19, 22 – 24, 26

  • unsettled to active on September 25, 27 – 28

  • active to disturbed not expected

  • solar wind will intensify on September (4, 15, 19,) 22 – 23

Note: Parenthesis means lower probability of activity enhancement.

OK1HH also wrote about his river cruise: “As a captain, I sailed on the MY Daisy (LOA 8 meters, 0.4 tons) on the Czech rivers Elbe and Vltava on the route Melnik to Zernoseky Lake, Usti, Melnik, Luzec, Melnik, a total of 217.4 kilometers. And it was a beautiful week!

Thanks to Carl, K9LA, for sharing this link to a fascinating and informative RSGB lecture about sporadic-e propagation.

Here’s an article about Europe’s most powerful solar telescope.

Tamitha Skov, WX6SWW, has a new video. I love Dr. Skov’s enthusiasm: “Whammo!” And also, of course, her expertise, which she shares so generously.

Sunspot numbers for August 27 – September 2 were 0, 0, 0, 0, 0, 0, and 0, for a mean of 0. The 10.7-centimeter flux was 70, 70.1, 70.2, 70, 69.2, 69.5, and 68.3, for a mean of 69.6. Estimated planetary A indices were 8, 10, 14, 9, 26, 16, and 9, for a mean of 13.1. Middle latitude A index was 7, 8, 14, 8, 19, 16, and 8, for a mean of 11.4.

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 are no longer be updated on this page. 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.

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