The bulletin appears a day early this week because ARRL Headquarters is closed for the Good Friday holiday.
Over the past week, the average daily sunspot number and solar flux values rose slightly, even though as the week progressed, each day had a lower number than the day before. The daily sunspot number began the week at a high of 100, but ended at 60. Likewise, the daily solar flux started a…
American Radio Relay League | Ham Radio Association and Resources
Eight new sunspot groups appeared this week, but the average daily sunspot number declined four points to 71.1; the average daily solar flux rose by less than two points to 103.7. Sunspot numbers for March 22-28 were 86, 74, 65, 84, 56, 63 and 70, with a mean of 71.1. The 10.7 cm flux was 102.4, 104.8, 102.7, 101.3, 102.4, 105.6 and 107, with a mean of 103.7. The estimated planetary A indices w…
American Radio Relay League | Ham Radio Association and Resources
Solar activity declined this week: The average daily sunspot numbers were off by more than 13 points to 75.1, while the average daily solar flux dropped over 32 points to 102.1. The solar flux dropped barely below 100, but rounded up to 100 as shown on the NOAA SEC site. The next short-term peak in solar flux is expected at the 135 level for April 3-6. The predicted solar flux for March 23-25 i…
American Radio Relay League | Ham Radio Association and Resources
The average daily sunspot numbers over the past reporting week (March 8-14) were 88.3, a rise of nearly 19 points; the average daily solar flux rose more than 12 points to 134.2. Sunspot numbers for March 8-14 were 86, 96, 89, 103, 89, 80 and 75, with a mean of 88.3. The 10.7 cm flux was 139.5, 145.5, 148.9, 131.2, 114.9, 140.7 and 118.8, with a mean of 134.2. The estimated planetary A indices …
American Radio Relay League | Ham Radio Association and Resources