| SB PROP @ ARL $ARLP045
ARLP045 Propagation de K7RA
ZCZC AP45
QST de W1AW
Propagation Forecast Bulletin 45 ARLP045
From Tad Cook, K7RA
Seattle, WA November 22, 2024
To all radio amateurs
SB PROP ARL ARLP045
ARLP045 Propagation de K7RA
Solar activity was lower this reporting week, November 14-20, with the average daily sunspot number down from 141.6 to 99.3, and solar flux from 203.7 to 152.4. Geomagnetic indicators were quiet.
This follows a period during August and October when it seemed we must be at the peak of Solar Cycle 25. But we won’t know that until nearly a year after solar max, when a long moving average of daily sunspot numbers is examined.
Predicted solar flux is 170 on November 22, 175 on November 23-24, 180 on November 25-26, 175 and 180 on November 27-28, 250 on November 29-30, then 240, 230, 220, and 210 on December 1-4, 205 on December 5-6, then 200, 180, 170 and 150 on December 7-10, 145 on December 11-12, then 149, 145, and 230 on December 13-15, 235 on December 16-17, 240 on December 18-20, 245 on December 21-22, then 240, 245 and 255 on December 23-25.
Predicted planetary A index is 8 on November 22-25, 5 on November 26-29, then 10, 12, 9, 8, 7 and 5 on November 30 through December 5, 12 on December 6-7, then 10, 5, 5, 10, 15 and 10 on November 8-13, then 8 on December 14-15, then 5 and 12 on December 16-17, and 5 on December 18-21.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere – November 21, 2024, from F. K. Janda, OK1HH:
“During November, solar activity was relatively lowest in the middle of the month, which happened after the large sunspot groups in the west of the disk had set and before the larger groups in the east came out. The largest of these is designated AR3901 and will pass through the central meridian on November 23. Solar activity will therefore still increase slightly. A more significant rise could perhaps be expected after the rise of the other groups, but their current activity on the far side of the Sun does not appear to be great for now.
“The low number and small area of coronal holes are the likely cause of the geomagnetically quieter development, which is likely to continue.
“November belongs to the Autumn DX season, therefore we can expect continued above-average shortwave propagation. They were admittedly a little worse as a result of the drop in solar radiation, but the rest of the month could, yet, correct this. Which is true for the northern hemisphere of the Earth, where the season of favorable propagation conditions on the longer shortwave bands is already beginning!”
Images from the European Space Agency:
https://tinyurl.com/42r665y9
From “Space Daily,” solar orbiter images:
https://tinyurl.com/bdz33ake
https://tinyurl.com/yvkf66u2
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.
For more information concerning shortwave radio propagation, see www.arrl.org/propagation and the ARRL Technical Information Service web page at, www.arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see www.arrl.org/the-sun-the-earth-the-ionosphere.
An archive of past propagation bulletins is at www.arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us.
Also, check this:
https://bit.ly/3Rc8Njt
“Understanding Solar Indices” from September 2002 QST.
Instructions for starting or ending email subscriptions to ARRL bulletins are at www.arrl.org/bulletins.
Sunspot numbers for November 14 through 20, 2024 were 96, 71, 71, 117, 118, 109, and 113, with a mean of 99.3. 10.7 cm flux was 146.8, 148.9, 139.9, 146.3, 165, 157.2, and 162.6, with a mean of 152.4. Estimated planetary A indices were 11, 13, 8, 8, 4, 9, and 9, with a mean of 8.9. Middle latitude A Index was 10, 10, 8, 6, 3, 6, and 8, with a mean of 7.3.
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