Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin ARLP028:

Rising solar activity over the past reporting week, July 7 – 13, 2022, was reflected in increased sunspot numbers, solar flux, and rising geomagnetic activity.

Average daily sunspot numbers increased from 62.6 to 102.1, with the peak value at 134 on Monday, July 11. Average daily solar flux rose from 103.5 to 147.4, with peak values at 164.9 and 164.8 on Tuesday and Wednesday.

New sunspots emerged on July 7, July 10, and July 11. Total sunspot area peaked on July 11.

Planetary A index averaged out at 12.4 (up from 9.8 last week) while the middle latitude A index went from 9.7 to 10.6.

Toward the end of the day on July 7, Alaska’s college A index was 46 (a very high value), while the last four K index readings of the same day and the next two were 6, 6, 7, 5, 5, and 5.

This was caused by a corotating interaction region, sparking a G1-class geomagnetic storm.

Visit the following links for info on corotating interaction regions:

https://bit.ly/3P91Xrp

https://bit.ly/3IBOtlm

https://bit.ly/3yDwxlU

The Wednesday-night prediction from the United States Air Force shows solar flux at 165 on July 14 – 15; 160 on July 16 – 18; and 155, 150, and 135 on July 19 – 21. A prediction of 130 is shown July 22 – 24; 138 and 148 on July 25 – 26; 150 on July 27 – 29; 160 on July 30 – August 7; and 155, 145, and 135 on August 8 – 10. August 11 – 12 is 138, then 128 and 125 on August 13 – 14, and 130 on August 15 – 17.

Predicted planetary A index is 8 on July 14 – 21, then 15, 20, and 12 on July 22 – 24. Eight is predicted again on July 25 – August 2, then 12 and 10 on August 3 – 4, and 8 on August 15 – 17.

I often see news items that mention solar flares and are written as though the world is about to end.

A few recent examples, for our collective amusement:

https://bit.ly/3yCXV3h

https://bit.ly/3RA5Bfy

https://bit.ly/3P5KakF

Sunspot numbers for July 7 – 13, 2022, were 80, 81, 89, 113, 134, 117, and 101, with a mean of 102.1. The 10.7-centimeter flux was 121.3, 129.6, 136.9, 153, 161, 164.9, and 164.8, with a mean of 147.4. Estimated planetary A indices were 20, 19, 6, 7, 12, 18, and 5, with a mean of 12.4. Middle latitude A index was 15, 14, 6, 8, 10, 16, and 5, with a mean of 10.6.

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

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 the Propagation Page of Carl Luetzelschwab, K9LA.

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

Share your reports and observations.

Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin ARLP027:

Sunspot activity increased this week, with average daily sunspot numbers going from 49.1 to 62.6. But oddly, average daily solar flux was down slightly from 105.3 to 103.5.

Taking a longer view, solar activity is stronger than it was a year ago, when the average daily sunspot number was 34.7 and average solar flux was 86.9.

Spaceweather.com reported that a Coronal Mass Ejection (CME) missed Earth on July 1, but it pushed dense solar wind plasma toward us, causing a G1-class geomagnetic storm. In the few hours past midnight UTC, planetary K index was 4, then 5. Alaska’s high latitude college A index was 25 on July 2.

Predicted solar flux for the next month is 120 on July 7 – 8, 130 on July 9 – 11, then 120, 125, 110, and 108 on July 12 – 15, then 110, 100, 95 and 98 on July 16 – 19, 95 on July 20 – 21, 98 on July 22 – 23, 100 on July 24 – 25, 102 on July 26, 105 on July 27 – 28, 100 on July 29, 110 on July 30 – 31, 112 on August 1 – 2, 115 on August 3 – 6, 112 on August 7 – 8, 110 on August 9, and 108 on August 10 – 11.

Predicted planetary A index is 14 and 8 on July 7 – 8, 5 on July 9 – 12, 10 on July 13 – 14, then 15, 12, and 10 on July 14 – 17, 8 on July 18 – 21, then 12, 15, 10, and 8 on July 22 – 25, 5 on July 26 – 31, then 8, 25, 12, and 8 on August 1 – 4, and 5 on August 5 – 9.

Sunspot numbers for June 30 through July 6, 2022, were 40, 30, 57, 42, 79, 92, and 98, with a mean of 62.6. The 10.7-centimeter flux was 95.7, 98, 100.2, 102.2, 104.4, 109.4, and 114.6, with a mean of 103.5.

Estimated planetary A indices were 5, 7, 19, 8, 21, 4, and 5, with a mean of 9.8. Middle latitude A index was 5, 8, 17, 11, 18, 4, and 5, with a mean of 9.7.

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

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 the Propagation Page of Carl Luetzelschwab, K9LA.

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

Share your reports and observations.

Tad Cook, K7RA, Seattle, Washington, reports:

Solar activity took a dramatic plunge over the recent reporting week (June 23 – 29), but geomagnetic activity stayed the same. ARRLField Day weekend saw rising geomagnetic numbers, with the planetary A index at 8, 16, and 23, Friday through Sunday.

On Sunday, June 25, 2022, the geomagnetic activity was a problem, although not severe, with many stations on Field Day reporting increased absorption. The planetary K index peaked at 5 (a big number) at the end of the day on Saturday (UTC time) and continued into the early hours of Sunday, which was early Saturday evening on the West Coast.

This happened because of a crack in the Earth’s magnetosphere, detailed here:

https://bit.ly/3ONZdQ9

Compared to the previous 7 days, average daily sunspot numbers declined from 124.6 to 49.1, while average daily solar flux dropped from 140.5 to 105.3.

Planetary and middle latitude A index averages were both the same as the previous week, all numbers around 11.

The prediction from the United States Air Force (USAF) 557th Weather Wing is not very optimistic, with solar flux peaking at 140 on July 11 – 16.

The prediction shows 10.7-centimeter solar flux at 90 on June 30 and July 1; 95 on July 2; 105 on July 3 – 7; 130 on July 8 – 9; 135 on July 10; 140 on July 11 – 16; 135, 130, 125, and 120 on July 17 – 20; 115, 110, 105, and 100 on July 21 – 24; 95 on July 25 – 26; 100 on July 27 – 29, and 105, 110, 115, and 120 on July 30 through August 2.

Predicted planetary A index is 8, 10, and 8 on June 30 through July 2; 5 on July 3 – 7; 8, 8, 12, and 8 on July 8 – 11; 5 on July 12 – 13; 12 on July 14 – 16; 10 on July 17; 8 on July 18 – 21; 12, 15, 15, and 10 on July 22 – 25, and 5 on July 26 through August 4.

In Friday’s bulletin, look for updated forecasts and observations emailed by readers to k7ra@arrl.net.

Sunspot numbers for June 23 through 29 were 69, 60, 31, 33, 32, 71, and 48, with a mean of 49.1. The 10.7-centimeter flux was 121.4, 115.4, 108.1, 102, 98.2, 96.1, and 96.2, with a mean of 105.3. Estimated planetary A indices were 10, 8, 16, 23, 12, 8, and 6, with a mean of 11.9. Middle latitude A index was 12, 8, 14, 15, 15, 11, and 7, with a mean of 11.7.

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 the Propagation Page of Carl Luetzelschwab, K9LA.

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

Share your reports and observations.

Tad Cook, K7RA, Seattle, Washington, reports:

Hard for me to believe, I had to blink to make sure. On Wednesday, June 8, 2022, for the first time this calendar year there were no sunspots, even though two new sunspot regions appeared on June 4.

Average daily sunspot number declined to 44 from 52.9 last week. Average daily solar flux was only 98, down from 104.3 last week and 158.8 the week before.

Predicted solar flux is 100 on June 9; 105 on June 10 – 11; 110 on June 12 – 14; 115 on June 15 – 17; 120 on June 18; 125 on June 19 – 20; 150 on June 21; 110 on June 22; 100 on June 23 through July 3; 105 on July 4 – 5; 110 on July 6 – 10, and 115 on July 11 – 13.

Assuming the above prediction is true, that would mean average daily solar flux rising from 98 to 107.9 over the next week and 123 the next.

Predicted planetary A index is 5 on June 9 – 15; 10 and 8 on June 16 – 17; 5 on June 18 – 22; 12, 18, 10, and 8 on June 23 – 26; 5 on June 27 through July 9, then 12, 8, 12, and 10 on July 10 – 13.

Despite the recent downturn, Solar Cycle 25 activity exceeds the official forecast, which can be seen at helioforecast.space/solarcycle.

According to Spaceweather.com, May sunspot activity was the highest in 8 years.

To see solar images and useful links, visit bit.ly/3xlrB4 and bit.ly/3x9WNna.

In Friday’s bulletin, look for interesting 6-meter observations.

Sunspot numbers for June 2 – 8 were 59, 52, 75, 57, 45, 23, and 0, with a mean of 44.4. The 10.7-centimeter flux was 100.9, 100.7, 100.9, 98.7, 96.4, 98.4, and 99.9, with a mean of 98. Estimated planetary A indices were 5, 4, 4, 4, 10, 8, and 5, with a mean of 5.7. Middle latitude A index was 5, 4, 4, 5, 10, 11, and 5, with a mean of 6.3.

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 the Propagation Page of Carl Luetzelschwab, K9LA.

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

Share your reports and observations.