[SFDXA] ARLP050 Propagation de K7RA

Mon Dec 30 10:55:26 EST 2024

ARLP050 Propagation de K7RA

SB PROP @ ARL $ARLP050

ARLP050 Propagation de K7RA

ZCZC AP50

QST de W1AW

Propagation Forecast Bulletin 50 ARLP050

From Tad Cook, K7RA

Seattle, WA December 30, 2024

To all radio amateurs

SB PROP ARL ARLP050

ARLP050 Propagation de K7RA

Strong solar activity continues, with worldwide propagation on 10 and 12 
meters quite commonplace.

Predicted solar flux is 255, 250, 210, 200, and 195 on December 30, 2024 
through January 3, 2025, 190 on January 4-5, 170 on January 6, 160 on 
January 7-8, then 165, 170 and 165 on January 9-11, 170 on January 
12-13, 175 on January 14-15, 180 on January 16, 185 on January 17-18, 
200 on January 19-23, 185 on January 24-26, 175 on January 27, and 180 
on January 28-30, 2025.

Predicted planetary A index is 8, 50, 20 and 8 on December 30, 2024 
through January 2, 2025, 5 on January 3-4, 8 on January 5-6, 5 on 
January 7-9, then 12, 10 and 8 on January 10-12, 5 on January 13-15, 
then 8, 10 and 10 on January 16-18, 8 on January 19-23, and 5 on January 
24-31.

The latest from F. K. Janda, OK1HH:

"A cooling water pipe burst in the server room of the Joint Science 
Operations Center (JSOC) at the Solar Dynamics Observatory (SDO) in 
California on 26 November 2024. Since then, data from the Helioseismic 
and Magnetic Imager (HMI) and Atmospheric Imaging Array (AIA) 
instruments have been unavailable.

"On the popular website www.solarham.com 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQxNQ/index.html> 
on the bottom left, we usually find information on activity on the far 
side of the Sun (at www.solarham.com/farside.htm 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQxNg/index.html>) 
that would be needed to predict developments around the Christmas 
season, for example. This is because we were expecting the rise of 
active regions on the Sun that were very active during the last solar 
revolution and whose high activity we know about thanks to CMEs and the 
influx of protons from flares on the Sun's far side.

"As expected, active regions on the Sun did appear and they were not 
alone. Moderate solar flares are the order of the day, while we have 
been expecting a geomagnetic disturbance during the Christmas holidays 
since after the CME registration. But the particle clouds missed the 
Earth, the disturbance did not take place, and ionospheric shortwave 
propagation conditions remained above average.

"But even better propagation conditions are likely to await us next 
year. The high solar activity in October this year was probably not yet 
the peak of the 25th cycle - that is yet to come!"

From Space.Com, "The Sun in 2025: How the solar cycle will shape our 
year ahead":

https://bit.ly/3DA4N7L 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQxOA/index.html>

The latest report from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/qPI4_otUAME 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQxOQ/index.html>

For more information concerning shortwave radio propagation, see 
www.arrl.org/propagation 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyMA/index.html> 
and the ARRL Technical Information Service web page at, 
www.arrl.org/propagation-of-rf-signals 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyMQ/index.html>. 
For an explanation of numbers used in this bulletin, see 
www.arrl.org/the-sun-the-earth-the-ionosphere 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyMg/index.html>.

An archive of past propagation bulletins is at: 
www.arrl.org/w1aw-bulletins-archive-propagation 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyNA/index.html>. 
More good information and tutorials on propagation are at, 
http://k9la.us 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyNQ/index.html>.

Also, check this article:

"Understanding Solar Indices" from September 2002 QST.

https://bit.ly/3Rc8Njt 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyNg/index.html>

Instructions for starting or ending email subscriptions to ARRL 
bulletins are at, www.arrl.org/bulletins 
<https://arrl.informz.net/z/cjUucD9taT0zMjIxMDc3JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNjM1OTQyNw/index.html>.

Sunspot numbers for December 19 through 25, 2024 were 96, 148, 152, 176, 
199, 219, and 218 with a mean of 172.6. 10.7 cm flux was 175, 184, 
201.2, 223.3, 238.3, 258.5, and 252.7 with a mean of 219. Planetary A 
index was 11, 13, 16, 14, 12, 12, and 5 with an average of 11.9. Middle 
latitude A Index was 9, 10, 13, 15, 11, 9, and 5, with a mean of 10.3.

NNNN

/EX

ARRL® The National Association for Amateur Radio®

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