Tad Cook, K7RA, Seattle, reports: New sunspot groups appeared on February 17, 19, 20, and 21, but solar activity declined, even though sunspots were covering the sun every day.

The average daily sunspot number declined by 21 points, from 75.3 last week to 54.3 in the February 17-23 reporting week. Average daily solar flux was down by nearly 15 points, from 110.1 to 95.4.

The average daily planetary A index went from 13 to 9.6, and the average daily middle latitude A index was off by a point to 7.3.

Predicted solar flux is 100 on February 24; 105 on February 25 – March 2; 110 on March 3 – 4; 108 on March 5 – 8; 105 on March 9 – 11; 103 on March 12 – 13; 100 on March 14; 98 on March 15 – 16; 102 on March 17 – 19; 104 on March 20 – 22; 108 on March 23 – 26; 110 on March 27; 115 on March 28 – 29, then 112 and 110 on March 30 – 31.

Predicted planetary A index is 5 on February 24 – 25; 10 on February 26; 8 on February 27 – March 2; 12, 15, 10, and 8 on March 3 – 6; 5 on March 7 – 10; 15, 12, and 10 on March 11 – 13; 5 on March 14 – 18; then 8, 5, 12, 18, 15, and 10 on March 19 – 24; 5 on March 25 – 29, and 12, 15, 10, and 8 on March 30 – April 2.

Sunspot numbers for February 17 – 23 were 103, 53, 51, 49, 48, 38, and 38, with a mean of 54.3. The 10.7 – centimeter flux was 96.7, 93.3, 95.7, 93.3, 97.8, 95.3, and 95.5, with a mean of 95.4. Estimated planetary A indices were 5, 6, 9, 13, 12, 16, and 6, with a mean of 9.6. Middle latitude A index was 4, 5, 6, 8, 11, 13, and 4, with a mean of 7.3.

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.

Tad Cook, K7RA, Seattle, reports: Although solar activity was generally lower this week, new sunspots appeared. A sunspot group emerged on February 10, two more on February 11, two more on February 14 and three more on February 16, when the daily sunspot number rose to 111, the highest value for this reporting week and well above the weekly average, which was 75.3. The average for the previous week was 83.9.

The February 16 count of 111 was the highest since the end of 2021, when sunspot numbers went as high as 147 following a few days with no sunspots at all.

Average daily solar flux declined from 126 to 110.1. Average daily planetary A index went from 14.4 to 13, and average daily middle latitude A index declined just 1.3 points to 8.3.

Why do we care about sunspot numbers? Because high values correlate with greater density in the ionosphere, which gives us better propagation at higher frequencies. Sixty-four years ago, sunspot numbers were so high that hams saw worldwide around-the-clock propagation on 10 meters. Sunspot numbers have never been so high before or since.

Predicted solar flux over the next month is 105 on February 17 – 18; 108 on February 19 – 27; 110 on February 28; 115 on March 1 – 2; 112 and 110 on March 3 – 4; 108 on March 5 – 8; 105 on March 9 – 11; 103 on March 12 – 13; 100 on March 14; 98 on March 15 – 16; 102 on March 17 – 19; 104 on March 20 – 22, and 108 on March 23 – 26.

Predicted planetary A index is 5 on February 17 – 18; 15, 18, and 15 on February 19 – 21; 8 on February 22 – 23; 15 and 10 on February 24 – 25; 5 on February 26 – March 2; 12, 15, 10, and 8 on March 3 – 6; 5 on March 7 – 10; then 15, 12, and 10 on March 11 – 13; 5 on March 14 – 18, and 8, 5, 12, 15, and 10 on March 19 – 23.

Sunspot numbers for February 10 – 16 were 78, 86, 54, 53, 72, 73, and 111, with a mean of 75.3. The 10.7-centimeter flux was 118, 113.1, 110.5, 105.4, 106.5, 114.3, and 102.9, with a mean of 110.1. Estimated planetary A indices were 21, 20, 13, 15, 8, 5, and 9, with a mean of 13. Middle latitude A index was 12, 12, 10, 9, 6, 3, and 6, with a mean of 8.3.

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.

After taking a few detours over the past couple of years due to the COVID-19 pandemic, ARRL Field Day rules are being updated on a permanent basis starting this summer. ARRL conducted a Field Day community survey with invitations propagated far and wide, and direct emails sent to more than 15,000 individuals and ARRL-affiliated clubs. After sorting through, reviewing, and discussing the survey results, the ARRL Programs and Services Committee recommended a number of rule changes for ARRL Field Day, which will take place this year over the June 25 – 26 weekend.

Starting this year, the maximum PEP output for a transmitter used by anyone submitting a Field Day log will be 100 W. The power multiplier of 2 will remain in place, and the high-power category will be removed from the rules. Until this year, the maximum low-power limit had been 150 W for most ARRL-sponsored operating events. The power multiplier will remain at 5 for QRP participants running a maximum of 5 W or less. As previously announced, 100 W is now the low-power category limit for all ARRL and IARU HF Contests, effective January 1, 2022.

A couple of changes instituted initially as accommodations for the COVID-19 pandemic will remain. Class D (Home) stations will continue to be able to earn points for contacts with other Class D stations. The club aggregate scoring change initiated in 2020 as a temporary measure will become part of the permanent rules. In the aggregate scoring plan, the scores of individual stations are combined under the score of a single club.

Another change, involving Rule 7.3.2 Media Publicity, has been modified. Rules to date have offered 100 bonus points for attempting to obtain publicity and demonstrating same. With the ease of posting via Facebook, Twitter, Instagram, and various other media websites, Field Day participants will now be required to obtain publicity, not just try to do so. Any combination of bona fide media hits would qualify for the bonus points. For example, posting the details of your upcoming or ongoing Field Day activity, or your Field Day results, on a club or news media site, on Facebook, or via Twitter and Instagram would meet the bonus criteria. Photos and videos are encouraged as part of media posts.

Tad Cook, K7RA, Seattle, reports: Our sun was much more active over the past week, with the average daily sunspot number more than doubling from 39.6 in the previous week to 81.3 in the current January 27 – February 2 reporting period.

Geomagnetic indicator average daily Planetary A index rose from 8.3 to 10.1, while average middle latitude A index was unchanged at 6.4.

Predicted solar flux for the near term is 130 on February 3 – 4; 125 on February 5 – 6; 120 on February 7 – 8; 118 on February 9 – 10; 128 on February 11 – 12; 125 on February 13 – 14; 120 on February 15 – 17; 128 on February 18 – 21; 125 on February 22 – 25; 128 on February 26; 132 on February 27 – 28; 135 on March 1 – 3; 125 on March 4 – 7, and 128 on March 8 – 11.

Predicted planetary A index is 10, 6, 12, 14, and 8 on February 3 – 7; 5 on February 8 – 9; 12 and 8 on February 10 – 11; 5 on February 12 – 16; 10, 12, 8, and 5 on February 17 – 20; 10, 8, 5, and 8 on February 21 – 24; 12, 8, 5, and 8 on February 25 – 28; 10, 5, and 5 on March 1 – 3; 20 and 12 on March 4 – 5; 5 on March 6 – 8; 12 and 8 on March 9 – 10, and 5 on March 11 – 15.

An interesting new Solar Cycle 25 update is available, thanks to K9LA and K1HTV.

Sunspot numbers for January 27 – February 2 were 85, 77, 74, 70, 100, 88, and 75, with a mean of 81.3. The 10.7-centimeter flux was 107.1, 113.4, 125.3, 129.6, 129.5, 128.6, and 128.2, with a mean of 123.1. Estimated planetary A indices were 7, 8, 17, 10, 10, 7, and 12, with a mean of 10.1. Middle latitude A index was 5, 5, 7, 7, 3, 10, and 8, with a mean of 6.4.

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.