ARRL

Secure Site Login

News

The K7RA Solar Update

04/02/2021

Tad Cook, K7RA, Seattle, reports: Average daily sunspot numbers declined this week from 17.9 to 11.9. Why? Because on the final 2 days of the March 25 – 31 reporting week sunspots disappeared. That’s right. We’re back to the blank sun again, unfortunately.

Spaceweather.com reported on Wednesday that we may soon see a potential sunspot that’s currently on the far side of our sun.

Average daily solar flux dropped from 78.6 to 77.4. Geomagnetic indicators softened as well, with average daily planetary A index declining from 13.3 to 8.9, and middle latitude A index from 10.4 to 7.7.

Predicted solar flux over the next month does not look promising, with values way down in the 70s, although this forecast improved some over the past couple of days. Expect 10.7-centimeter flux at 73 on April 2 – 3; 71 on April 4 – 9; 73 on April 10 – 13; 74 on April 14 – 16; 76 on April 17 – 24; 75 on April 25 – 27; 74 and 73 on April 28 – 29, and 72 on April 30 – May 5.

Predicted planetary A index is 5 on April 2 – 5; 8 on April 6 – 7; 5, 10, and 20 on April 8 – 10; 5 on April 11 – 15; 20 and 18 on April 16 – 17; 8 on April 18 – 19; 5 on April 20 – 21; 8 on April 22 – 24; 12 on April 25; 8 on April 26 – 27; 5 on April 28 – 30; 8 on May 1 – 2; 5 on May 3 – 4, and 12 on May 5 – 7.

Here’s the geomagnetic activity forecast for April 2 – 27 from OK1HH. The geomagnetic field will be:

  • quiet on April 12 – 13, 24 – 26

  • quiet to unsettled on April 5, 14, 23

  • quiet to active on April (2 – 7, 15, 20 – 22, 27)

  • unsettled to active April (8, 11, 18 – 19)

  • active to disturbed April (9 – 10,) 16 – 17

  • Solar wind will intensify on April 3, (4-5, 8-9,) 10-11, (12, 16-17,) 18, (19-22, 27)

Parentheses mean lower probability of activity enhancement. Predictability of changes remains very low, as there are  ambiguous and quickly changing indications.

This article in The Irish Times asks, “Was space weather the cause of the Titanic disaster?”

NN4X reported a 15-meter long path opening to Asia: “Nice opening to Asia here in Central Florida on the morning of April 1.

“On FT8, I worked BA7LP, YD7ACD, BG7PHA, and VR2VLY, and heard 9V1PL and BD7LMA.

“It was very concentrated. Note, no JA/HL/DU. Typically, I've been seeing more YBs than anything on 15-meter LP, but certainly not today.”

Many years ago we reported in this bulletin the results JQ2UOZ was getting running one-half watt using simple wire antennas on his apartment balcony. Check out his blog.

Another blast from the past on flares and CMEs:

This article in The Conversation discusses, “Why we need to get better at predicting space weather.”

The Carrington Event, mentioned in this article, “Extreme solar storms may be more frequent than previously thought,” continues to fascinate.

AL7LO has a collection of his favorite ARRL Propagation Bulletins, and he shared this one from 8 years ago.

Sunspot numbers for March 25 – 31 were 24, 24, 11, 11, 13, 0, and 0, with a mean of 11.9. The 10.7-centimeter flux was 78.8, 79.6, 80.4, 75.1, 74.4, 79.5, and 73.8, with a mean of 77.4. Estimated planetary A indices were 18, 12, 9, 6, 4, 3, and 10, with a mean of 8.9. Middle latitude A index was 18, 11, 7, 4, 3, 4, and 7, with a mean of 7.7.

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. 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. 



Back
pan>Share
-->