| SB PROP @ ARL $ARLP040
ARLP040 Propagation de K7RA
ZCZC AP40
QST de W1AW
Propagation Forecast Bulletin 40 ARLP040
From Tad Cook, K7RA
Seattle, WA October 18, 2024
To all radio amateurs
SB PROP ARL ARLP040
ARLP040 Propagation de K7RA
Average daily sunspot numbers changed from 160 to 129.3 and average daily solar flux from 261.3 to 194.3. Geomagnetic numbers were higher, with planetary A index rising from 21.4 to 39.3.
Seven new sunspot groups emerged this week, with two on October 10, two on October 13, two more October 14 and one more on October 15.
Predicted solar flux is 170, 160, and 165 on October 18-20, 170 on October 21-22, 165 on October 23-24, 220 on October 25-26, then 225, 245, 235, 260, 245 and 235 on October 27 through November 1, and 230 on November 2-3, then 225 and 220 on November 4-5, 215 on November 6-8, 210 on November 9, 200 on November 10-12, and 205 on November 13-14 and 210 on November 15-17.
Predicted planetary A index is 15, 18, 12 and 5 on October 18-21, then 15, 12 and 5 on October 22-24, then 5, 1, 2 and 8 on October 25-27, then 5 on October 28 to November 8, then 10 on November 9-10, then 5 on November 11-12, 8 on November 13 and 5 on November 14-17.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere – October 17, 2024 from OK1HH,
“A week ago, we witnessed a strong geomagnetic disturbance. It peaked on 10 October and its effects in the ionosphere were particularly evident on 11 October. The recovery from the disturbance continued until 14 October, but was interrupted by a further rise in geomagnetic activity on 15-16 October.
“Ionospheric shortwave propagation conditions were generally poor throughout the period. They did not even improve to average levels. This development was due to the coincidence with a decrease in total solar activity.”
The latest report from Dr. Tamitha Skov, WX6SWW:
https://youtu.be/warCdMmyE98
An article on the peak of Solar Cycle 25:
www.inceptivemind.com/blurb/sun-reaches-maximum-phase-11-year-solar-cycle
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 article:
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 October 10 through 16 2024 were 150, 130, 95, 108, 146, 141, and 135, with a mean of 129.3. 10.7 cm flux was 216.3, 213.9, 213.6, 194.9, 181.9, 172, and 167.7, with a mean of 194.3. Estimated planetary A indices were 96, 116, 20, 5, 8, 15, and 15, with a mean of 30.3. Middle latitude A Index was 50, 68, 16, 3, 6, 9, and 11, with a mean of 23.3.
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