Tad Cook, K7RA, Seattle, reports: Sunspot activity was up over the past week, with the average daily sunspot number rising from 28.7 to 59.4, and average daily solar flux up 11.4 points to 89.8. Nice to see our sun peppered with spots again as we move into the second week of fall in the Northern Hemisphere.

The 10.7-centimeter solar flux was 101.6 at noon on Wednesday, September 29. That’s the highest value since December 3, 2020, when it was 102.9. Unfortunately the following day that value slipped 7 whole points back to 94.6

Geomagnetic indicators were quiet, with average daily planetary A index values declining from 9.1 to 7.3, and average middle latitude A index from 8.4 to 6.3.

Predicted solar flux as of Thursday is much lower than it was the day before.

The updated flux values are 95 on October 1 – 3; 90 on October 4 – 5; 85 on October 6 – 7; 74 on October 8 – 9; 78 on October 10 – 12; 80 non October 13; 84 on October 14 – 15; 86 on October 16 – 17; 88 on October 18 – 22; 86 on October 23 – 25, 84 on October 26; 80 on October 27 – 29; 78 on October 30 – 31; 76 on November 1, and 74 on November 2 – 5. Flux values may rise back to 88 by mid – November.

Predicted planetary A index is 24, 10, and 8 on October 1 – 3; 5 on October 4 – 9; 12 on October 10; 5 again on October 11 – 17; 10, 12, 10, and 8 on October 18 – 21; 5 on October 22 – 23; 18, 15, and 12 on October 24 – 26; 5 on October 27 – 30; 8 on October 31; 12 on November 1; 5 on November 2 – 5, and 12 on November 6.

Here’s the geomagnetic activity forecast for October 1 – 26, 2021 from F.K. Janda, OK1HH. The geomagnetic field will be:

• quiet on October 13, 16 – 18, 22 – 23

• quiet to unsettled on October 3 – 4, 6 – 9, 12, 20 – 21

• quiet to active on October 2, 5, 10 –  11, 14 – 15

• unsettled to active on October 1, (19, 24 – 26)

• Active to disturbed — nothing predicted

• Solar wind will intensify on October (3,) 11, (19, 22-23, 25)

Remarks:

* Parentheses mean lower probability of activity enhancement.

* Contradictory indications currently reduce the accuracy of the forecast.

I often use FT8 and pskreporter.info to check propagation on different bands, and over the past week there were days when I saw no reception reports of my station on 10 meters, but plenty of activity on 12 meters. The 12-meter openings were typically to stations 2,000 miles east of me over a narrow swath along the eastern seaboard of North America. This was with a very simple end-fed, non-resonant wire antenna and 30 W.

Check this link about Sunspot, New Mexico.

Bob, AA6XE, wrote:

“September 2021 is winding down, and here is a preview of the solar numbers we can expect this Friday. The solar flux for September looks to be 86.5 measured and 88 adjusted for 1 AU. This is the second-highest reading of the new solar cycle, topped only by the dramatic run-up of last November. Take a good long last look at those numbers, as the current ramp-up in solar activity will easily blast through them in October. In the closing 36 hours of the month the 10.7-centimeter [solar flux] had jumped up 12 points to 101 and was rising fast as this reported was being prepared.

“The monthly mean sunspot number for September will be in the low to mid 50s (new scale); when converted to the old scale so we can compare it to traditional counts it equates to (38 old scale). The smoothed sunspot number (SSN) for September is 46 (new scale) 32 (old scale). September’s sunspot numbers are easily the highest of the new solar cycle thus far.

“And the good news doesn’t stop there. On September 14, Scott MacIntosh from the National Center for Atmospheric Research, announced that he expects the termination event concluding Cycle 24 is imminent and a rapid run-up in solar activity to commence in mid-November. Solar minimum was recorded in November 2019, the last SWPC numbered SC24 sunspot was observed in July 2020, the last un-numbered SC24 active region was observed on August 14, 2021. It appears that Cycle 24 is over.”

Here’s more sunspot coverage from local newspapers. And this.

Bil Paul, KD6JUI, of Dixon, California, who operates from his kayak, sent this on September 27:

“You’re probably getting reports of a great opening to Europe Sunday, but here’s my story:

“I was operating from my kayak with 10 W and a small homebrew loop on Sunday around noon when I allowed the wind to orient the boat and the antenna in the direction it chose. That was toward the northeast from California — fortunate because Europe was coming in gangbusters. Operating SSB, I first contacted IK7YTT in Italy on 17, followed by Spain and Hungary on 20. They all had a little trouble making out my call sign, but make it out they did. My location was Lake Berryessa in Napa County, California.

“This opening certainly provides hope for further such openings during the coming solar cycle peak. I’m not too surprised when I can contact Japan or Australia from California, but Europe is something else entirely!”

Here’s exciting news from Space Weather Woman Tamitha Skov, WX6SWW.

Sunspot numbers for September 23 – 29 were 75, 75, 38, 67, 30, 57, and 74, with a mean of 59.4. The 10.7-centimeter flux was 89.7, 88.4, 88.4, 86.3, 85.3, 88.9, and 101.6, with a mean of 89.8. Estimated planetary A indices were 11, 8, 7, 3, 7, 10, and 5, with a mean of 7.3. Middle latitude A index was 10, 6, 7, 2, 6, 9, and 4, with a mean of 6.3.

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.