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The K7RA Solar Update

10/08/2021

Tad Cook, K7RA, Seattle, reports: Sunspots were visible every day this week, but the numbers were lower. Average daily sunspot numbers declined from 58.4 to 30.7, and the average daily solar flux was down by 2.9 points to 86.9.

Geomagnetic activity was a little higher, with average daily planetary A index going from 7.3 to 8.1, and average daily middle latitude A index from 6.3 to 6.7.

Friday, October 1, was affected by a solar flare from sunspot group AR2871, driving the planetary A index to 15. This had a greater effect at higher latitudes, with Alaska’s College A index hitting 30 and 31 on Friday and Saturday. In the middle of the UTC day on Saturday the College K index hit 7 — a high number.

Predicted solar flux is 86 on October 8 – 9; 84 on October 10 – 14; 75 on October 15 – 16; 80, 85, 88, and 90 on October 17 – 20; 88 on October 21 – 22; 85 on October 23 – 24; 90, 100, 95, and 90 on October 25 – 28; 88 on October 29 – November 5; 85 and 80 on November 6 – 7; 75 on November 8 – 12, and 80, 85, 88, and 90 on November 13 – 16.

Predicted planetary A index is 8 on October 8 – 10; 12 and 8 on October 11 – 12; 5 on October 13 – 17; 10, 12, 10, and 8 on October 18 – 21; 5 on October 22 – 24; 10 on October 25; 5 on October 26 – 31; 8 on November 1 – 2; 5 on November 3; 8 on November 4 – 5; 5 on November 6 – 13, and 10, 12, 10, and 8 on November 14 – 17.

On October 4, Spaceweather.com reported, “Solar Cycle 25 continues to over-perform. Sunspot counts for September 2021 were the highest in more than 5 years. And, for the 11th month in a row, the sunspot number has significantly exceeded the official forecast.” The report was based on a forecast from the Space Weather Prediction Center. Spaceweather.com continued, “Higher-than-expected sunspot counts suggest a stronger cycle, with a peak occurring in late 2024, instead of mid-2025.”

Here’s the geomagnetic activity forecast for October 8 – November 2 from F.K. Janda, OK1HH. The geomagnetic field will be:

  • quiet on October 16-17

  • quiet to unsettled on October 8-9, 11-13, 20-22, 24, 26-27, 30-31

  • quiet to active on October 10, 15, 23, 25, November 2

  • unsettled to active on October 14, (18-19, 28-29,) November 1

  • Active to disturbed — Nothing predicted

  • Solar wind will intensify on October 11, (19, 22, 25,) 28

Remarks:

* Parentheses mean lower probability of activity enhancement.

After 0000 UTC on October 5, I (K7RA) was calling CQ using FT8 on 12 meters, and noted on pskreporter.info that only two stations outside my local (CN88uq) Seattle area were receiving me — W2PKY (EL88vi) and KZ4RB (EL99ic) in Florida, both more than 2,500 miles away. W2PKY noted in an email that 12 meters is a strange band, and reports such as this are quite common. He also noted that on Wednesday, October 6: “10 meters was really rockin’!”

I notice frequently that 12 meters has propagation for me across North America when 10 meters does not. This will change with more sunspot activity.

NN4X reported last Friday, October 1 from EL98jh in Florida:

“There were some good LP and SP openings on 12 meters to Asia yesterday. I worked HS3PJF at 1415 UTC and YB2HND at 1425 UTC via short path, over the North Pole. I also worked BA5CW at 1307 UTC, beaming long. Thursday evening, I worked RW0LT on 12 meters at 0022 UTC. So, we’re getting there!”

Carl, K9LA, noted in a recent email, “Events in the lower atmosphere coupling up to the ionosphere are another factor that can screw up (or enhance) the bands, not just geomagnetic field activity. With no parameters to define these lower atmospheric events, we’re really running blind in the short-term. And this is why our propagation predictions programs are not daily models.”

Space Weather Woman Tamitha Skov, WX6SWW has a three-hour course, “The Ionospheric Weather Ballet, Part 1.”

Sunspot numbers for September 30 – October 6, 2021 were 46, 28, 25, 38, 29, 27, and 22, with a mean of 30.7. The 10.7-centimeter flux was 94.6, 90.5, 87, 86, 83.5, 81.7, and 84.8, with a mean of 86.9. Estimated planetary A indices were 9, 15, 8, 6, 6, 5, and 8, with a mean of 8.1. Middle latitude A index was 6, 13, 6, 6, 4, 6, and 6, with a mean of 6.7.

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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