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The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: Sunspots were only visible on 4 days of the current reporting week — on April 3-6 — and now on Friday morning, still no sunspots.

As a result, average daily sunspot number declined from 11.9 last week to 6.4 currently. Average daily solar flux also dropped from 77.4 to 73.4. On Thursday the daily solar flux was 74, just above the average for the previous 7 days, 73.4. The sun remained blank.

Average daily planetary A index declined from 8.9 to 6.6, and average mid-latitude A index slipped from 7.7 to 5.6.

Predicted solar flux for the next month is 74 on April 9 – 15; 72 on April 16 – 20; 74 on April 21 – 26; 73 on April 27 – May 1; 72 on May 2 – 5; 70 on May 6 – 10, and 71 on May 11 – 12; 74 is not a high 10.7-centimeter flux value, but it should be there on May 18 and beyond.

Predicted planetary A index is 5, 10, and 8 on April 9 – 11; 5 on April 12 – 13; 8 on April 14 – 15; 15 and 18 on April 16 – 17; 8 on April 18 – 19; 5 on April 20 – 21; 8 on April 22 – 24; 5 on April 25 – May 1; 8 on May 2 – 4, and 5 on May 5 – 12.

Here’s the geomagnetic activity forecast for April 9 – May 4 from F.K. Janda, OK1HH.

The geomagnetic field will be:

quiet on April 25, May 1 – 3
quiet to unsettled on April 18, 20, 22, 26, 28 – 30
quiet to active on April 19, 23 – 34, 27
unsettled to active April (9 – 11,) 17, 21 – 22
active to disturbed April 16, May 4
Solar wind will intensify on April (9 – 11, 16,) 18 – 19,( 21 – 22, then irregularly between April 23 – May 1,) May 3 – 4

Remarks:

Parentheses mean lower probability of activity enhancement.

Predictability of changes remains very low, as there are a lack of indications and contradictions between them.

Des, ND3L wrote: “I was off the air for 28 years. Got back on a year ago. I’m in the process of inputting my old logs into QRZ.com logbook. Back in 1989 I had a stretch of 11 pages of all 10-meter contacts with 25 contacts per page. Found five new countries that I never had confirmed. Operators were still around and had old logs and confirmed. Took me from 284 to 289 confirmed in 1 week! In early 1989, daily sunspot numbers ranged from 134 to 161. We didn’t know we had it so good!”

Ken Brown, N4SO on Alabama’s Gulf Coast reports on 17-meter FT8. On March 28, he worked ZD8HZ on Ascension Island at 2117 UTC, over a distance of 5,509 miles.

Later, from 2207 to 2345 UTC he worked “JA5AQC, JR7VHZ, JG1SRB, JR1FYS, JR7TEQ, JL1UXH, JA2KVD, JA1JAN, JA0MRW, JA3FQO, JA3PCQ, JO1LVZ, JA3APV, JA2QXP, and on the 29th and 30th worked a total of 10 more Japanese stations, some call signs repeated from the 28th.”

WB8VLC in Salem, Oregon, is seeing consistent 10-meter activity, which is a nice surprise considering the very low solar activity and probably too early in the year for e-skip.

He reported: “As usual 10 meters has been open here in northwestern Oregon pretty much every week to South America, but the interesting openings were on two weekends in March, when E51JD in Rarotonga South Cook Islands has been in on 10 meter SSB along with KH6ZM on RTTY and the usual South Americans.” (KH6ZM is on the Big Island).

JQ2UOZ wrote: Hi, Tad-san, K7RA. Thank you very much for mentioning me in the latest bulletin. By the way, I have found a very interesting article about the solar cycle. “Gradual onset of the Maunder Minimum revealed by high-precision carbon-14 analyses.” (Scientific Reports, vol 11, article number 5482 [2021]).

The author describes in the Abstract, “Here we show that the 11-year solar cycles were significantly lengthened before the onset of the Maunder Minimum (1645 – 1715 CE) based on unprecedentedly high-precision data of carbon-14 content in tree rings. It implies that flow speed in the convection zone is an essential parameter to determine long-term solar activity variations. We find that a 16 year-long cycle had occurred three solar cycles before the onset of prolonged sunspot disappearance, suggesting a longer-than-expected preparatory period for the grand minimum. As the Sun has shown a tendency of cycle lengthening since Solar Cycle 23 (1996 – 2008 CE), the behavior of Solar Cycle 25 can be critically important to the later solar activity. I hope to have an active Solar Cycle 25.”

Some readers may find this article from 1997 of interest.

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

Sunspot numbers for April 1 – 7 were 0, 0, 12, 11, 11, 11, and 0, with a mean of 6.4. The 10.7-centimeter flux was 77.9, 72.1, 72.8, 70, 71.9, 73.6, and 75.7, with a mean of 73.4. Estimated planetary A indices were 8, 6, 4, 3, 5, 3, and 17, with a mean of 6.6 Middle latitude A index was 8, 4, 2, 2, 5, 3, and 15, with a mean of 5.6.

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.

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