[SFDXA] ARLP027 Propagation de K7RA

Sat Jul 20 08:12:25 EDT 2024

ARLP027 Propagation de K7RA

SB PROP @ ARL $ARLP027

ARLP027 Propagation de K7RA

ZCZC AP27

QST de W1AW

Propagation Forecast Bulletin 27 ARLP027

From Tad Cook, K7RA

Seattle, WA July 19, 2024

To all radio amateurs

SB PROP ARL ARLP027

ARLP027 Propagation de K7RA

Big increase in solar activity this week, with average daily sunspot 
number rising from 129 to 215.9, and solar flux from 176.6 to 226.5.

Fourteen new sunspot groups emerged. Two were on July 11, one on July 
12, three on July 13, one on July 14, two more on July 15, three more on 
July 16 and two more on July 17.

On Thursday (after the reporting week) the daily sunspot number was 276, 
the highest value for cycle 25, according to Jon Jones, K0JK. A new 
sunspot group appeared that day.

Average planetary A index was quiet at 6, and the middle latitude number 
was 8.

More quiet geomagnetic indicators are forecast for the entire month of 
August, with planetary A index predicted at 5 on every day.

Predicted solar flux is 210 on July 19-21, 200 on July 22-25, 180 on 
July 26-27, 175 on July 28, 170 on July 29-31, 165 on August 1-2, then 
170, 180 and 190 on August 3-5, 200 on August 6-11, and 230 on August 
12-14, then 210 on August 15, 200 on August 16-18, then 195 and 185 on 
August 19-20, and 180 on August 21-23.

Predicted planetary A index is 8, 16, 20 and 8 on July 19-22, and 5 on 
July 23 through the entire month of August and possibly the first week 
in September.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's 
Ionosphere for July 18, 2024.

Increased solar flare activity continues. M-class eruptions are almost 
the order of the day and X-class eruptions are no exception. Their main 
source is currently the largest AR3751. While it is still in the 
southeast quadrant of the solar disk, it will cross the central meridian 
as early as July 19. After that the probability of an Earth impact by a 
possible CME will increase. In the southwest quadrant we observe five 
sunspot groups: AR 3742, AR3743, AR3745, AR3747 and AR3758, which were 
formed by the spill of the original extremely active May AR3664 
(designated as AR3697, AR3723 in subsequent solar rotations).

Solar activity remains high and geomagnetic disturbances are less 
frequent and do not last long. Ionospheric shortwave propagation 
conditions, although mostly slightly above average level, vary 
irregularly. The sporadic layer E will continue for a few more weeks. We 
will continue to see fading during the day, in particular at lower 
shortwave frequencies (on the 7 MHz band and much more often and longer 
on 3.5 MHz) during moderate flares. Entire shortwave bursts will die 
down here and there during the largest flares, especially long-lasting 
X-class flares. F. K. Janda, OK1HH

Recent video from Tamitha Skov: https://youtu.be/GLBIY3bbdQE 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTIzNg/index.html>

Solar Flare: https://bit.ly/3Wp9wjA 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTIzNw/index.html>

Martian aurora: https://bit.ly/4cJ2L21 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTIzOA/index.html>

Blackouts: https://bit.ly/468L89c 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI0MA/index.html> 
https://bit.ly/3LrTxex 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI0Mg/index.html>

https://bit.ly/3Lx0ye6 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI0NA/index.html> 

https://bit.ly/3Y7Lgnq 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI0Ng/index.html>

Cycle 26: https://bit.ly/3YaG02h 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI0OA/index.html>

Send your tips, reports, observations, questions and comments to 
k7ra at arrl.net <mailto:k7ra at arrl.net>. When reporting observations, don't 
forget to tell us which mode you were operating.

For more information concerning shortwave radio propagation, see 
http://www.arrl.org/propagation 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI1MA/index.html> 
and the ARRL Technical Information Service web page at, 
http://arrl.org/propagation-of-rf-signals 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI1Mg/index.html>.

For an explanation of numbers used in this bulletin, see 
http://arrl.org/the-sun-the-earth-the-ionosphere 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI1NA/index.html>. 

An archive of past propagation bulletins is at

http://arrl.org/w1aw-bulletins-archive-propagation 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI1Ng/index.html>. 

More good information and tutorials on propagation are at 
http://k9la.us/ 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI1OA/index.html> 

Also, check this: https://bit.ly/3Rc8Njt 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI2MQ/index.html> 

Instructions for starting or ending email distribution of ARRL bulletins 
are at http://arrl.org/bulletins 
<https://arrl.informz.net/z/cjUucD9taT0zMDg4MDQ4JnA9MSZ1PTUyNTQ3MzY2NCZsaT0zNDQxMTI2NA/index.html>. 

Sunspot numbers for July 11 through 17 2024 were 188, 162, 214, 217, 
205, 250, and 275, with a mean of 215.9. 10.7 cm flux was 205, 209.7, 
238.3, 233.9, 233.2, 241.9, and 223.8, with a mean of 226.5. Estimated 
planetary A indices were 6, 5, 4, 5, 7, 10, and 5, with a mean of 6. 
Middle latitude A Index was 7, 7, 6, 9, 8, 12, and 7, with a mean of 8.

NNNN

/EX

ARRL The National Association for Amateur Radio®

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