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K7RA's Solar Report

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Last update: Friday, 15-Oct-2021 08:25:14 GMT

SB PROP @ ARL $ARLP042
ARLP042 Propagation DE K7RA
QST DE W1AW
Propagation Bulletin 42 ARLP042 From Tad Cook, K7RA
Seattle, Washington October 15, 2021
To all radio amateurs

Although we saw sunspots on every day of this reporting week (October 7-13), solar activity declined somewhat. Average daily sunspot numbers went from 30.7 to 23.7, and average daily solar flux from 86.9 to 85.6. Geomagnetic indicators were higher, with average daily planetary A index rising from 8.1 to 12.4, and average daily middle latitude A index from 6.7 to 10.1.

On Saturday, October 9 Spaceweather.com reported a strong earth-directed M1.6 class solar flare and CME erupting at 0640 UTC, causing a shortwave radio blackout over the Indian Ocean. This caused the planetary A index on October 12 to hit 45, and Alaska's College A index to read 60.

Predicted solar flux is 82 on October 15, 80 and 78 on October 16-17, 76 on October 18-22, 85 on October 23-24, then 90, 100, 95 and 90 on October 25-28, 88 on October 29-30, 85 on October 31 through November 5, 88 on November 6, 85 on November 7-13, 88 on November 14-15, 90 on November 16, 88 on November 17-18, and back to 100 on November 22.

Predicted planetary A index is 8 on October 15-16, 5 on October 17, 12 on October 18-19, 8 on October 20, 5 on October 21-24, 10 on October 25, 5 on October 26 to November 1, 8 on November 2, 5 on November 3-5, 10 on November 6-7, 8 on November 8-9, 5 on November 10-12, then 10, 12, 12, 10 and 8 on November 13-17, and 5 on November 18-20, then 10 on November 21, and 5 through the end of the month.

Geomagnetic activity forecast for the period October 15 til November 09, 2021 from F.K. Janda, OK1HH.

Geomagnetic field will be quiet on: October 16-17, November 3, 5 quiet to unsettled on: October 20-22, 24, 26-27, 30-31, November 4 quiet to active on: October 23, 25, November 6 unsettled to active on: October (15, 18-19, 28-29,) November (1 - 2,) 7-9 Active to disturbed: Nothing predicted

Solar wind will intensify on October (19, 22, 25,) 27-31, November 1, 9

Parenthesis means lower probability of activity enhancement."

On October 12, Spaceweather.com reported in an email alert: "Last night, a coronal mass ejection (CME) struck Earth's magnetic field, sparking a moderately strong geomagnetic storm. Auroras were sighted in the USA as far south as Nebraska with lights so bright in some places that onlookers successfully photographed them using cell phones."

The November 2021 issue of QST arrived, and the article on page 70, "Propagation Tools and Resources for Contesting'D by WO1N, KC2G and members of the Yankee Clipper Contest Club shares some great resources, not only of interest to contest operators.

Interesting article on 60 meters propagation:

https://bit.ly/2YNlHLN

The latest from Dr. Tamitha Skov:

https://youtu.be/XrPW4337IHI

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere.

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/.

Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .

Sunspot numbers for October 7 through 13, 2021 were 13, 13, 14, 38, 35, 26, and 27, with a mean of 23.7. 10.7 cm flux was 85.7, 92.4, 81, 84.5, 88.5, 83.5, and 83.5, with a mean of 85.6. Estimated planetary A indices were 5, 4, 5, 9, 13, 45, and 6, with a mean of 12.4. Middle latitude A index was 3, 3, 4, 9, 15, 32, and 5, with a mean of 10.1. NNNN


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