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

Although images of the sun this week showed plenty of sunspots, only two new spots emerged: one on July 21, and another on July 25.

Average daily sunspot number declined from 137.3 to 91.1, and the average daily solar flux softened by 50 points to 107.6.

Geomagnetic indicators began this reporting week fairly active, with planetary A index at 22, then it quickly quieted down to an average of 11.7 for the week, higher than the 9.4 average reported last week. Average middle-latitude A index increased from 9 to 10.4.

A look back a year ago shows this cycle is progressing nicely. In ARLP030 in 2021 average daily sunspot number was just 48.9, and average daily solar flux only 81.3.

A year prior, the average daily sunspot number in 2020 was just 3.1! That is because there were five days with no sunspots, and then two days with a sunspot number of only 11, which is the minimum non-zero sunspot number.

A sunspot number of 11 does not mean 11 sunspots. It means there was just one sunspot group (which counts for 10 points) and one sunspot in that group (counting for 1), producing a total of 11, because of the arcane historical method of counting sunspots.

Predicted solar flux shows it peaking at 130 on August 11. Predicted flux is 98 on July 28, 96 on July 29 – 30, 98 again on July 31 and August 1, 96 on August 2 – 3, 98 on August 4, then jumping to 115 on August 5 – 6, 113 on August 7 – 8, then 120, 125, 130 and 125 on August 9 – 12, 120 on August 13 – 15, 118 on August 16 – 17, then 114 and 110 on August 18 – 19, 108 on August 20 – 21, then 106 and 102 on August 22 – 23, 100 on August 24 – 27, and 108 on August 28 – 29.

Predicted planetary A index is 8 on July 28-29, 12 on July 30, 8 on July 31 and August 1, 5 on August 2 -3, 8 on August 4, 5 on August 5 -10, 8 on August 11 -12, 5 on August 13 – 16, 22 on August 17, 15 on August 18 – 19, 8 on August 20 -21, 5 on August 22 – 25, 10 and 12 on August 26 – 27, and 5 on August 28 – 29.

Sunspot numbers for July 21 – 27, 2022 were 124, 107, 96, 80, 100, 78, and 53, with a mean of 91.1. 10.7-centimeter flux was 121.7, 114.7, 110.5, 107.1, 102.3, 98.8, and 98, with a mean of 107.6. Estimated planetary A indices were 22, 11, 17, 9, 6, 8, and 9, with a mean of 11.7. Middle latitude A index was 14, 11, 15, 9, 8, 7, and 9, with a mean of 10.4.

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:

Solar activity increased over this reporting week, July 14 – 20, with average daily sunspot number rising from 102.1 to 137.3, and average daily solar flux from 147.4 to 157.6.

Peak sunspot number was 166 on July 17, and peak solar flux was

171.4 on July 15.

Geomagnetic activity peaked on July 19 when planetary A index was 26 and middle latitude A index at 19. Alaska’s high-latitude college A index was 43, with the K index at 6, 5, 5, 6, and 5 at 0900 – 2000 UTC.

Average daily planetary A index decreased this week from 12.4 to 9.4.

A crack opened in the Earth’s magnetic field on July 19, allowing solar wind to stream in. It is documented at

https://www.spaceweather.com/images2022/19jul22/data.jpg

At 2241 UTC on July 20, the Australian Space Forecast Centre issued a geomagnetic warning. “An increase in geomagnetic activity is expected over 22 – 24 July due to the onset of coronal hole high speed wind streams.”

Here is the latest forecast from the United States Air Force (USAF). Predicted solar flux seems promising with flux values peaking around 160 on July 30 through August 7 and again from August 26 through early September.

Predicted flux values are 130 on July 21 – 22, then 120, 115, 110, 105, 100, 110, and 150 on July 23 – 29, then 160 on July 30 through August 7, then 155, 145, and 138 on August 8 – 10, then 138 on August 11 – 12, then 128 and 125 on August 13 -14, 130 on August 15 – 17, 135 on August 18 – 20, 138 and 148 on August 21 – 22, and 150 on August 23 – 25.

Predicted planetary A index is 22 on July 21 – 22, then 20, 12 and 8 on July 23 – 25, 5 on July 26 – 28, 8 on July 29 through August 2, then 12 and 10 on August 3 – 4, 8 on August 5 – 7, then 15, 28 and 12 on August 8 – 10, 8 on August 11 – 17, then 15, 20 and 12 on August 18 – 20, and 8 again on August 21 until the end of the month.

Here are weekly highlights and forecast from National Oceanic Atmospheric Administration (NOAA), dated July 17:

https://bit.ly/3okGEY8

In Friday’s bulletin, look for details on 40 MHz activity among special experimental licensees, which I misidentified as 49 MHz in last week’s bulletin. There will also be 6-meter reports.

Send your tips, reports, observations, questions, and comments to k7ra@arrl.net.

Sunspot numbers for July 14 through 20, 2022 were 133, 141, 153, 166, 125, 114, and 129, with a mean of 137.3. 10.7 – centimeter flux was 169, 171.4, 176.2, 161.2, 149.4, 144.1, and 132.2, with a mean of 157.6. Estimated planetary A indices were 5, 8, 7, 5, 8, 26, and 7, with a mean of 9.4. Middle latitude A index was 5, 7, 9, 6, 10, 19, and 7, with a mean of 9.

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 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.