| SB PROP @ ARL $ARLP042
ARLP042 Propagation de K7RA
ZCZC AP42
QST de W1AW
Propagation Forecast Bulletin 42 ARLP042
From Tad Cook, K7RA
Seattle, WA November 1, 2024
To all radio amateurs
SB PROP ARL ARLP042
ARLP042 Propagation de K7RA
Solar activity increased this week. Average daily sunspot number went from 127.7 to 197.4 and average solar flux from 170.5 to 240.2.
Predicted solar flux is 270 on November 1-2, 265 and 260 on November 3-4, 250 on November 5-7, 214, 195 and 182 on November 8-10, 172, 168, 174 and 165 on November 11-14, and 162 on November 15-16.
Predicted planetary A index is 5, 8, 15, and 10 on November 1-4, 5 on November 5-15, then 5, 8, 5, 12, and 8 on November 16-20, and 5 on November 21 through December 5
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere – October 31, 2024 from OK1HH:
“We know only approximately what the Earth’s ionosphere looked like between March 1755 and June 1766 thanks to observations of the Sun in Solar Cycle 1. But we do know what it looked like in Solar Cycle 19, which ran from April 1954 to October 1964. Although I was a novice radio amateur at the time, I can testify that the shortwave propagation conditions at the peak of Solar Cycle 19 (1958) were wonderful!
“As of December 2019, Solar Cycle 25 is in operation. It was supposed to be low, fortunately it is not. Its maximum is now underway, perhaps a second will follow next year. It is fabulous, judging by the above and the many interesting effects, including, for example, auroras. But unfortunately, not if we judge them by the current conditions of ionospheric shortwave propagation. An explanation of why this is now the case will surely be forthcoming – but perhaps Solar Cycle 26 will be underway.
“A week ago, as expected, large active regions and corresponding groups of spots appeared at the southeastern limb of the solar disk. We are now seeing them near the central meridian. This has increased the likelihood of Earth being hit by particles that will eject subsequent flares. It seems that not only these, but also disturbances in the geomagnetic field and then fluctuations in the ionospheric propagation field can be counted on with certainty in the coming days. Given that we have already seen simultaneously observed active regions on the Sun during the last solar rotation, presumably a 27-day recurrence will be a good aid to prediction.”
How NASA tracks the Solar Cycles:
https://www.dailymotion.com/video/x98c2di
The latest from the Solar-Terrestrial Centre of Excellence Newsletter: https://www.stce.be/newsletter/newsletter.php
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 24 through 30 2024 were 138, 157, 181, 198, 288, 220, and 200, with a mean of 197.4. 10.7 cm flux was 196.6, 209.3, 238.4, 246.2, 255.5, 265.6, and 269.8, with a mean of 240.2. Estimated planetary A indices were 13, 3, 14, 10, 17, 12, and 15, with a mean of 12. Middle latitude A Index was 10, 2, 11, 8, 11, 10, and 10, with a mean of 8.9.
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