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The K7RA Solar Update

08/14/2020

Tad Cook, K7RA, Seattle, reports: New Sunspot Cycle 25 continues to make a strong showing. Sunspots have appeared on every day for more than 3 weeks. Average daily sunspot numbers for the week slipped a bit from 19.6 to 14.3 this week, but average daily solar flux increased from 72.8 to 73.8. Geomagnetic indicators remain quiet. Both the average daily planetary and mid-latitude A index were 3.7.

Predicted solar flux for the next 6 weeks is 72 on August 14 – 15; 70 on August 16 – 21; 72 on August 22 – 27; 73 on August 28 – 29; 75 on August 30 through September 9; 73 on September 10 – 11; 72 on September 12 – 23; 73 on September 24 – 25, and 75 on September 26 – 27. This is a welcome change from recent forecasts, which saw predicted solar flux consistently below 70.

Predicted planetary A index forecasts continued quiet geomagnetic conditions; at 5 on August 14 – 23; 8 on August 24 – 25; 5 on August 26 – 28; then 8; 16 and 8 on August 29 – 31; 5 on September 1 – 19; 8 on September 20 – 21; 5 on September 22 – 24, then 8, 16, and 8 on September 25 – 27.

Geomagnetic activity forecast for the period August 14 – September 9 from F.K. Janda, OK1HH. The geomagnetic field will be:

  • quiet on August 15 – 16, September 5 – 7 

  • quiet to unsettled on August 14, 17 – 19, 22, (23,) 24 – 25, (26 – 29,) September 2 – 4, 8 – 9 

  • quiet to active on (August 20 – 21, 30 – 31, September 1) 

  • unsettled to active not expected 

  • active to disturbed not expected 

  • Solar wind will intensify on August (22 – 23,) 24 – 25, September 1 – 2 (4 – 6) 

Note: Parentheses mean lower probability of activity enhancement.

Jon Jones, N0JK (EM28 in Kansas), offered this comment about the mention of 6-meter sporadic E in last week’s bulletin. “Many of the reports I have received for July (including long-time 6-meter operator N0LL) reported great conditions on 50 MHz Es. On July 13, N0LL had his FT8 screen full of stations from Japan calling him on 50.313 MHz. Today, August 9, I had sporadic E on 6 meters to Florida, Texas, Mexico, and Arizona from Kansas.”

Jon is editor of the monthly “World above 50 MHz” column in QST.

Here’s a recent video from Space Weather Woman Tamitha Skov, WX6SWW.

Carl Luetzelschwab, K9LA, recently posted a survey of various Solar Cycle 25 predictions. He also did a presentation at on the same subject at the recent QSO Today Virtual Ham Expo. The material from that event will be up until September 9. Carl’s Basic Concepts resource is always good for a review.

Personally, I like the prediction that promises a repeat of the epic Cycle 19 of the late 1950s. I was a small child then, but my father had a low-band FM 2-way radio mounted in his company car, probably operating somewhere between 30 and 40 MHz judging from my hazy memory of the length of the bumper-mounted whip antenna. 

We were in Reedley, California, in the San Joaquin Valley. He sold agricultural chemicals to farmers and would use the radio to contact the office in Fresno. But at the peak of Cycle 19, local communications were often interrupted by skip from Texas and various midwestern states.

From correspondence I’ve received from readers, I know there were many new teen-aged hams at that time, and a lot of then likely assumed that the fantastic propagation of the day was normal. Many were disappointed by Cycle 20, which was when I got my Novice ticket.

So, I’d like to think we are due for another big cycle, but I try to avoid the gambler’s fallacy. That is the name of the logical fallacy in which, when observing a random series of events such as spinning a roulette wheel, we keep seeing the ball land on red, and conclude we are due for black to come up. But with independent random events, one result cannot predict the next.

Sunspot numbers for August 6 – 12, 2020 were 14, 14, 11, 13, 12, 12, and 24, with a mean of 14.3. The 10.7-centimeter flux was 73.1, 74, 74.7, 73.9, 74.2, 73.5, and 73.1, with a mean of 73.8. Estimated planetary A indices were 5, 4, 5, 3, 3, 3, and 3, with a mean of 3.7. Middle latitude A index was 4, 5, 5, 3, 3, 3, and 3, with a mean of 3.7.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check out K9LA’s Propagation Page.

A propagation bulletin archive is available. Monthly charts are no longer be updated on this page. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Instructions for starting or ending email distribution of ARRL bulletins are on the ARRL website.

Share your reports and observations.



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