There was a modest increase in solar activity this reporting week, May 4 – 10.

Average daily sunspot numbers nudged up from 114 to 119.3, and average daily solar flux went up from 151.5 to 167.1.

Average daily planetary A index changed from 13.6 to 15.1, and average middle latitude A index remained the same at 11.9.

Predicted solar flux is 170, 168, 166, 162, and 160 on May 11 – 15; 162 on May 16 – 17; 155 on May 18 – 21; 150 on May 22; 145 on May 23 – 25, then 140 and 145 on May 26 – 27; 155 on May 29 – 30; 160 on May 31 through June 1; 155 on June 2 – 3; 160 on June 4 – 7, then 165, 160, and 150 on June 8 – 10.

Predicted planetary A index is 46, 30, 12, and 8 on May 11 – 14; 5 on May 15 – 22, then 12 and 20 on May 23 – 24; 15 on May 25 – 26; 10 on May 27 – 28; 8 on May 29; 5 on May 30 through June 1, then 16, 12, 16, and 12 on June 2 – 5; 8 on June 6 – 8, and 5 on June 9 – 13.

Read about possible geomagnetic stormy space weather at:

https://www.space.com/sun-reverse-sunspot-auroras-supercharge.

Sunspot numbers for May 4 through 10, 2023, were 139, 90, 99, 99, 103, 151, and 154, with a mean of 119.3. 10.7-centimeter flux was 162, 161.9, 151.8, 157.2, 171.9, 194.7, and 170.1, with a mean of 167.1. Estimated planetary A indices were 6, 5, 30, 9, 16, 14, and 26, with a mean of 15.1. Middle latitude A index was 7, 4, 21, 8, 13, 11, and 19, with a mean of 11.9

At 0134 UTC on April 27, The Australian Space Weather Forecasting Centre of the Australian Bureau of Meteorology issued a geomagnetic disturbance warning, stating, “An equatorial coronal hole is currently elevating solar wind speeds. Combined with the anticipated impact from a recent CME on April 27, geomagnetic activity is expected to be at G0-G1 levels over April 27 – 28, with a slight chance of an isolated period of G2.”

Solar and geomagnetic indicators moved in opposite directions this week. Average daily sunspot numbers over April 20 – 26 made a dramatic drop from 146.9 to 91.4, and average daily solar flux dropped from 164.5 to 139.4.

Average daily planetary A index more than tripled from 8.1 to 26.9, while average middle latitude A index more than doubled from 7.3 to 15.6.

Solar wind and explosions caused all of this grief.

Spaceweather.com reported that on April 21, a large magnetic filament on the sun exploded and hurled debris toward Earth.

Later, they reported that on April 23, at 1737 UTC a CME hit Earth, which sparked a severe G4-class geomagnetic storm. Aurora was visible as far south as southern New Mexico and Texas.

The planetary K index went as high as 8 over April 23 – 24.

Predicted solar flux over the next month is 135 on April 27 – 30; 140 on May 1 – 6, then 145, 150, 155, 160, and 165 on May 7 – 11; 170 on May 12 – 13, then 165, 160, 155, 150, 145, and 140 on May 14 – 19; 135 on May 20 – 21; 130 and 125 on May 22 – 23; 120 on May 24 – 25, and 125, 130, and 135 on May 26 – 28.

Predicted planetary A index is 18, 25, and 12 on April 27 – 29; 8 on April 30 through May 3, then 10, 8, 12, and 10 on May 4 – 7; 8 on May 8 – 9, then 5, 5, and 12 on May 10 – 12; 5 on May 13 – 15; 8 on May 16 – 17; 5 on May 18 – 22, then 15 and 18 on May 23 – 34, and 15 on May 25 – 27.

Here is a link to the aurora as observed in China:

https://bit.ly/41KyY3w

Here is a link to explaining the aurora:

https://bit.ly/3n7ROm2

Sunspot numbers for April 20 through 26, 2023, were 97, 114, 87, 86, 88, 87, and 81, with a mean of 91.4. 10.7-centimeter flux was 147, 151.2, 141.2, 135.2, 133.9, 130.7, and 136.5, with a mean of 139.4. Estimated planetary A indices were 5, 9, 7, 66, 76, 10, and 15, with a mean of 26.9. Middle latitude A index was 5, 8, 6, 32, 39, 7, and 12, with a mean of 15.6.

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.

For this week’s ARRL Propagation Bulletin ARLP016:

This week’s sunspot numbers and solar flux were higher than the week before.

Average daily sunspot numbers were more than doubled, from 70.6 to 146.9, and average daily solar flux increased from 141 to 164.5. Both figures represent a substantial increase in solar activity.

Planetary A index averages went from 7.6 to 8.1, while middle latitude A index advanced from 6.4 to 7.3.

Predicted solar flux over the next few weeks is 145, 140, and 135 on April 20 – 22; 130 on April 23 – 24; 125 on April 25 – 26; 160 on April 27 – 29; 165 on April 30; 172 on May 1 – 3; 170 on May 4; 172 on May 5 – 7; 178 on May 8; 182 on May 9 – 12, then 175, 178, and 170 on May 13 – 15; 168 on May 16 – 17; 175 on May 18, and 172 on May 19 – 21.

Predicted planetary A index is 20, 16, 12, and 10 on April 20 – 23, then 8, 5, 15, and 18 on April 24 – 27; 15 on April 28 – 30, then 12 and 10 on May 1 – 2; 8 on May 3 – 4; 5 on May 5 – 6; 12 on May 7; 5 on May 8 – 10, then 8 on May 11 – 12; 5 on May 13 – 18, then 10, 8, 5, and 5 on May 19 – 22.

Dan Handa, W7WA, commented on the news item last week about the current solar cycle reaching a peak earlier than predicted, perhaps by the end of this year.

I told him I hope it will not peak early because I want to see several more years of increasing activity.

Dan sent a detailed graph of Solar Cycle 19, from 1954 to 1966, and wrote, “I have read more than once [that] a slow rise means a low sunspot max. The previous [Solar] Cycle 24 took 5 years to reach a relatively low maximum. A rapid increase can mean a high sunspot maximum. The granddaddy of our lifetime, [Solar] Cycle 19, peaked in three years!” I was unaware of this.

Sunspot numbers for April 13 – 19, 2023, were 154, 153, 151, 155, 162, 140, and 113, with a mean of 146.9. 10.7-centimeter flux was 159.5, 171.3, 175.8, 177.8, 166.6, 153.2, and 147, with a mean of 164.5. Estimated planetary A indices were 6, 7, 9, 4, 6, 13, and 12, with a mean of 8.1. Middle latitude A index was 5, 10, 8, 4, 6, 9, and 9, with a mean of 7.3.

Solar activity was up for this reporting week, April 6 – 12.

Seven new sunspot groups appeared: one on April 6, another on April 9, two more on April 10, another on April 11, and two more on April 12.

The average daily sunspot number rose from 53.4 to 70.6, and the average daily solar flux increased from 132.5 to 141.

Geomagnetic conditions were calm. The average daily planetary A index dropped from 15 to 7.6, and the middle latitude average dropped from 11.7 to 6.4.

Predicted solar flux is 155 and 160 on April 13 – 14; 165 on April 15 – 16; 160 on April 17 – 18, then 155 and 152 on April 19 – 20; 155 on April 21 – 22; 158 on April 23; 155 on April 24 – 25, then 152, 148, 145, and 142 on April 26 – 29; 140 on April 30 and May 1; 142 and 140 on May 2 – 3; 135 on May 4 – 5, then 130, 140, 145, 150, 152, 155, and 158 on May 6 – 12, and 160 on May 13 – 15.

Predicted planetary A index is 5 on April 13 – 15; 12 on April 16; 8 on April 17 – 18, then 5, 10, 15, and 10 on April 19 – 22; 5 on April 23 – 25, then 15 and 18 on April 26 – 27; 15 on April 28 – 30, then 12 and 10 on May 1 – 2; 8 on May 3 – 4; 5 on May 5 – 6, then 8, 10, and 8 on May 7 – 9, and 5 on May 10 – 13.

Spaceweather.com released this news on Wednesday:

“Evidence is mounting that Solar Cycle 25 might peak much earlier than expected. New research by a leading group of solar physicists predicts maximum sunspot activity in late 2023 or early 2024 with a peak that could be twice as strong as the previous solar cycle.”

It is all explained in this paper:

https://bit.ly/41gZnW4

Look in the Spaceweather.com archive for April 12 – 13 to read more.

I noticed some odd 10-meter propagation at 2000 UTC on April 11. While running FT8 and a one wavelength end-fed wire at my home in Seattle, the only stations that heard me, according to pskreporter.info, were one in New Zealand, another in Hawaii, and only five stations in Florida over a 200-mile strip from 2,512 to 2,712 miles. Checking again at 2015 UTC, it was still the same.

Sunspot numbers for April 6 – 12, 2023, were 33, 38, 49, 52, 92, 103, and 127, with a mean of 70.6. 10.7-centimeter flux was 137.1, 136.3, 135.9, 140.3, 139.8, 143.4, and 154, with a mean of 141. Estimated planetary A indices were 9, 8, 6, 6, 14, 6, and 4, with a mean of 7.6. Middle latitude A index was 7, 7, 5, 5, 11, 6, and 4, with a mean of 6.4.

HAM is a short documentary that follows a group of Montanan amateur radio enthusiasts that show the loyal community of amateur radio, explore what it means to be a ham, and how they are trying to keep the hobby alive. Thank you to everyone who made this documentary happen, to all of our peers at UM, to the awesome people who let us into their lives, and to everyone who cheered us on the whole way. Special thanks to the School of Visual and Media Arts at the University of Montana and Montana PBS. Produced by students from the School of Visual and Media Arts program at the University of Montana in 2022. Aired on Montana PBS on November 24th, 2022.

Here is the link to that documentary: https://www.youtube.com/watch?v=wt5wZhC5crI

Average solar flux and sunspot numbers went down this week. Sunspot numbers are down by half, from 112.6 last week to 53.4 this week. Average daily solar flux declined from 156.1 to 132.5.

Geomagnetic indicators also declined this week. The average daily planetary A index went from 23.3 last week to 15 this week. Average daily middle latitude A index went down from 13.7 to 11.7.

The middle latitude A index for April 1 was not available, so my guess for it is 11.

Predicted solar flux is 140 on April 6 – 8; 135 on April 9 – 11; 140 on April 12 – 13; 130 on April 14; 135 on April 15 – 17; 140 on April 18 – 20; 135 on April 21 – 23, then 130, 125, and 120 on April 24 – 26; 115 on April 27 – 29; 125 on April 30; 120 on May 1 – 2; 115 on May 3 – 4, and 110 on May 5 – 7.

Predicted planetary A index was 8 on April 6; 5 on April 7 – 10, then 8, 8, and 5 on April 11 – 13; 8 on April 14 – 15, then 12, 10, and 15 on April 16 – 18, then 5, 20, 15, and 10 on April 19 – 22; 5 on April 23 – 25, then 15 and 18 on April 26 – 27; 15 on April 28 – 29; 8 on April 30; 10 on May 1 – 2; 8 on May 3, and 5 on May 4 – 6.

This video from Tamitha Skov features flares and wind, and came out right after last week’s bulletin:

https://youtu.be/F8ERhLiOK88

Sunspot numbers for March 30 through April 5, 2023, were 99, 61, 23, 54, 56, 44, and 37, with a mean of 53.4. 10.7-centimeter flux was 140.3, 129.3, 125.3, 126.9, 133.6, 135.7, and 136.6, with a mean of 132.5. Estimated planetary A indices were 17, 21, 13, 15, 15, 13, and 11, with a mean of 15. Middle latitude A index was 11, 17, 11, 13, 11, 10, and 9, with a mean of 11.7.

Solar activity increased this week. The average daily sunspot number rose from 68 to 112.6, and the average daily solar flux changed from 145.6 to 156.1.

Due to solar wind at the beginning of the reporting week, average daily planetary A index increased from 10.6 to 23.3, while average middle latitude A index went from 8.4 to 13.7. Many reports of aurora came in this week, some down to lower latitudes in North America.

Predicted solar flux is 150 on March 30 through April 1; 140 on April 2 – 3; 130 on April 4 – 5; 132 on April 6 – 8, then 130, 132, 135, and 135 on April 9 – 12, then 140, 145, and 148 on April 13 – 15, then 150, 150, 155, 155, and 158 on April 16 – 20; 160 on April 21 – 23, then 155, 145, and 145 on April 24 – 26, and 135 on April 27 through May 1.

Predicted planetary A index is 18 on March 30 – 31, then 16, 12, 10, and 8 on April 1 – 4, then 5 on April 5 – 9, then 15, 12, 8, and 5 on April 10 13; 8 on April 14 – 15, then 12, 20, 15, and 5 on April 16 – 19, then 20, 15, and 10 on April 20 – 22; 8 on April 23 – 24; 5 on April 25 – 26, then 12, 15, 10, and 8 on April 27 – 30.

Sunspot numbers from March 23 through 29, 2023, were 73, 108, 105, 125, 128, 114, and 135, with a mean of 112.6. 10.7-centimeter flux was 151, 157.5, 160.3, 159.4, 158.2, 158.7, and 147.8, with a mean of 156.1. Estimated planetary A indices were 60, 66, 15, 8, 3, 5, and 6, with a mean of 23.3. Middle latitude A index was 28, 40, 12, 6, 2, 4, and 4, with a mean of 13.7.

I am a HAM that has been into Capitol Forest many times. I’ve been on the dirt back roads in dry, muddy, and snowy conditions. Yesterday’s adventure was no different. I started into the forest on a beautiful late afternoon. I like to go up in elevation so I can operate on HF with minimal power and use the height as the advantage. I decided to go up to a favorite spot I know of near the repeater site. The road was completely dry, and then I saw some small patches of snow. I rounded a corner and the snow became very deep. By the time I made the decision to stop I was in it. I started to back down only to find I was being pushed towards ditch. By the time I went forward to correct I was stuck.

Upon realizing my predicament, I grabbed the HT and called out on the repeater. Luckily it was shortly before a net, so there were plenty of ears listening. Hearing my issue, Duke,KK7EGK and Josh,WA7AW contacted me and soon they formulated a plan. In under 2 hours they had arrived with tools to help get my vehicle freed.  

Now would I have got this response from anywhere else on a late Sunday afternoon? Probably not.

Thank you to everyone on the Capital Peak repeater that assisted with ideas, input, and general uplifting chat. As mentioned I have been into Capitol Forest many times to operate for Parks On The Air (POTA). Although I hold the top spot for this location, It wouldn’t be possible without the fellow HAMs that know the peak roads even better than me. We all make mistakes, and my lesson has been learned.

Thank you Capital Peak Repeater Group!

73 Eric Mallek – K7EVM

Sunspot numbers were lower again this week, with the average declining from 143.6 two weeks ago to 118.7 last week, and now 68 this week. Average daily solar flux sank eight points, from 153.6 last week to 145.6 this week.

Six new sunspot groups emerged over the week: one on March 17, another March 18, three more on March 19, one more on March 21, and another on March 22.

Predicted solar flux is 155, 150, and 145 on March 23 – 25; 140 on March 26 – 27, then 130, 130, and 140 on March 28 – 30; 138 on March 31 through April 1, then 136, 136, and 134 on April 2 – 4; 132 on April 5 – 7; 130 on April 8 – 9, then 132, 135, 138, and 140 on April 10 – 13; 142 on April 14 – 15; 143 on April 16; 140 on April 17 – 18; 142 on April 19 – 21, and 144 on April 22.

Predicted planetary A index is very active over the next few days, at 20, 40, 30, 20, and 15 on March 23 – 27; 8 on March 28 – 29; 20 and 18 on March 30 – 31; 12 on April 1 – 2; 10 and 8 on April 3 – 4; 5 on April 5 – 9, then 15, 12, 8, and 5 on April 10 – 13: 8 on April 14 – 15, then 12, 10, 5, and 5 on April 16 – 19, then 10, 36, 20, 10, and 8 April 20 – 24.

Sunspot numbers for March 16 through 22, 2023, were 84, 58, 35, 73, 75, 70, and 81, with a mean of 68. 10.7-centimeter flux was 135.4, 134.2, 140.3, 142.7, 156.1, 151.6, and 158.9, with a mean of 145.6. Estimated planetary A indices were 8, 7, 8, 10, 13, 8, and 17, with a mean of 10.6. Middle latitude A index was 6, 7, 6, 8, 10, 8, and 14, with a mean of 8.4.

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.

Six new sunspot groups emerged over the past week: two on March 9, another on March 10, one more on March 12, and another two on March 14.

Sunspot numbers and solar flux declined this week.

Average daily sunspot numbers softened from 143.6 to 118.7, and average daily solar flux went from 181.6 to 153.6.

Predicted solar flux is 142, 150, 148, 146, 148, and 146 on March 16-21; 160 on March 22-23; 155 on March 24-26; 150 on March 27-28; 145 on March 29-30; 140, 145, 150, 155, and 160 on March 31 through April 4; 165 on April 5-8; 170 on April 9-11, and 175, 180, 180, 175, 170, and 165 on April 12-17.

Predicted planetary A index is 25 and 10 on March 16-17; 5 on March 18-19; 8 on March 20-21; 5 on March 22-23; 12, 16, 26, 18, 10, 8, 24, and 22 on March 24-31; 16 on April 1-2; 14, 12, 8, and 10 on April 3-6; 8 on April 7-8; 5, 8, 22, and 8 on April 9-12; 5 on April 13-14, and 8 and 16 on April 15-16.

Before Friday’s bulletin, check out the information on this DR2W propagation modeling site, recently from WB6MPH and last fall, from KB2S:

https://dr2w.de/dx-propagation/

Send your tips, reports, observations, questions, and comments to k7ra@arrl.net. When reporting observations, don’t forget to tell us which mode you were operating.

Sunspot numbers for March 9 through 15, 2023, were 155, 135, 126, 135, 87, 97, and 96, with a mean of 118.7. 10.7 cm flux was 178.8, 171.2, 157.4, 150, 143.3, 138.5, and 135.7, with a mean of 153.6. Estimated planetary A indices were 17, 11, 7, 8, 3, 17, and 29, with a mean of 13.1. Middle latitude A index was 14, 10, 5, 6, 2, 12, and 19, with a mean of 9.9.