[SFDXA] The K7RA Solar Update

[Bill]

The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: On November 4, the solar flux density 
reached 88.1, its highest level since October 14, 2016, when, during a 
waning solar cycle, it was 92.8, with an average daily flux for that 
week of 76.9, and average daily sunspot number of 18.7, similar to what 
we're seeing now.

The average daily planetary A index this week was 6.3, down from 12.3 
last week. The average daily mid-latitude A index was 4.9, down from 9.9 
last week.

Spaceweather.com <http://www.spaceweather.com/> reported on November 3 
that the new sunspot group produced a minor solar flare, and a pulse of 
UV radiation "briefly ionized Earth's upper atmosphere, causing a 
low-frequency radio blackout over the Indian Ocean." Check the STEREO 
satellite images: 360° view <https://stereo.gsfc.nasa.gov/beacon/> | 
Conventional format <https://stereo.gsfc.nasa.gov/>. A large, new 
sunspot group, AR2781, is the largest so far in new Solar Cycle 25, 
according to Spaceweather.com. It should be geo-effective (facing Earth) 
over the next 10 days.

Predicted solar flux is 88 on November 5 - 10; 83 on November 11; 
dropping to 75, 74, and 75 on November 12 - 14; 76 on November 15 - 21; 
75 on November 22 - 27; 74 on November 28 - 29; 72 on November 30 - 
December 5; 74 on December 6 - 10; 75 on December 11; 76 on December 12 
- 18, and 75 on December 19.

Predicted planetary A index is 5, 8, and 8 on November 5 - 7; 5 on 
November 8 - 16; 10, 5, 10; and 15 on November 17 - 20; 12 on November 
21 - 22; 8, 10, and 12 on November 23 - 25; 5 on November 26 - 27; 10 on 
November 28; 5 on November 29 - December 13; then 8, 5, and 8 on 
December 14 - 16; 12 on December 17, and 10 on December 18 - 19.

Sunspot numbers for October 29 - November 4 were 35, 32, 26, 12, 11, 15, 
and 18, with a mean of 21.3. The 10.7-centimeter flux was 84.6, 79.6, 
76.8, 77.3, 81.6, 82.9, and 88.1, with a mean of 81.6. Estimated 
planetary A indices were 14, 5, 6, 10, 3, 3, and 3, with a mean of 6.3. 
Middle latitude A index was 11, 4, 6, 8, 2, 2, and 1, with a mean of 4.9.

A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. 
For more information concerning radio propagation, visit 
<http://arrl.org/propagation-of-rf-signals> the ARRL Technical 
Information Service, read 
<http://arrl.org/the-sun-the-earth-the-ionosphere> "What the Numbers 
Mean...," and check out <http://k9la.us/> K9LA's Propagation Page.

A propagation bulletin archive 
<http://arrl.org/w1aw-bulletins-archive-propagation> is available. For 
customizable propagation charts, visit the VOACAP Online for Ham Radio 
<https://www.voacap.com/hf/> website.

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