Seven new sunspots emerged this week: one on September 2, two on September 3, two more on September 4, one on September 5, and one on September 6.
The average daily sunspot number was up from 78.7 to 95.4, while the average daily solar flux decreased from 140.9 to 137.6.
Geomagnetic activity was higher. On September 2, the planetary A index was 38 when Earth moved through a high-speed solar wind. In Alaska, the college A index at Fairbanks was 59.
The average daily planetary A index increased from 7 to 15.4, and the average middle latitude A index rose from 8.9 to 16.3.
Predicted solar flux is 150, 155, 155, and 150 on September 7 – 10; 140 on September 11 – 13; 145, 150, 150, and 155 on September 14 – 17; 150, 155, and 150 on September 18 – 20; 145 on September 21 – 22; 150 on September 23 – 24; 145 on September 25; 140 on September 26 – 27; 135 on September 28 – 30; 130, 135, 130, and 135 on October 1 – 4, and 140 on October 5 – 6.
Predicted planetary A index is 12, 10, 5, and 5 on September 7 – 10; 8 on September 11 – 13; 10, 8, 12, 8, and 8 on September 14 – 18; 5 on September 19 – 22; 12 on September 23; 5 on September 24 – 27; 8, 12, 5, and 12 on September 28 through October 1; 12, 10, 12, and 10 on October 2 – 5, and 5 on October 6 – 10.
I observed some interesting 12-meter propagation via PSK Reporter while using FT8 at 1745 UTC on September 4. My signal was received only over a narrow, 300-mile band hugging the east coast from Maine to Florida. The signals were between 2,200 – 2,500 miles away, and nowhere else.
Three hours later, at 2045 UTC, the reception reports along the coast expanded to 600 miles, and then 2,000 – 2,600 miles.
Later, at 2300 UTC, there was the same pattern, but it was a 200-mile band spanning 2,300 – 2,500 miles wide.
The next day, at 1700 UTC, there was an arc from Virginia to south Texas stretching 1,700 – 2,300 miles wide. At 1715 UTC, it drifted to a coverage of 1,750 – 2,600 miles.
Before
FT8 and PSK Reporter, there was no practical way to observe propagation.
Sunspot numbers for August
31 through September 6, 2023, were 77, 83, 77, 79, 100, 121, and 131, with a
mean of 95.4. The 10.7-centimeter flux was 139.9, 135.8, 131.2, 130.5, 136,
142.9, and 147.1, with a mean of 137.6. Estimated planetary A indices were 6,
12, 38, 25, 8, 11, and 8, with a mean of 15.4. Middle latitude A index was 8,
15, 25, 28, 14, 14, and 10, with a mean of 16.3.