The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: On March 11 at 0431 UTC, Australia’s Space Forecast Centre issued this warning: “A slow coronal mass ejection has been observed late on 10 March, and event modeling suggests arrival at the Earth late on 13 March. Increased geomagnetic activity is expected for 14 March 2022.”

We observed an active sun this week. Geomagnetic indicators peaked on Saturday, March 5, when Alaska’s high latitude college A index reached 42.

Again this week, sunspots covered the sun every day. Average daily sunspot numbers rose from 44 to 87.4, and average daily solar flux went from 98.5 to 115.5. Geomagnetic indicators were also higher. Average daily planetary A index increased from 7.3 to 11.4.

Predicted solar flux is 120 on March 11 – 12; 115 on March 13; 110 on March 14 – 16; 105 on March 17; 100 on March 18 – 21; then 101 and 103 on March 22 – 23; 104 on March 24 – 27; then 110, 115, and 116 on March 28 – 30; 118 on March 31 – April 1; 120 on April 2; 116 on April 3 – 4; then 115 and 112 on April 5 – 6; 110 on April 7 – 9, 108, 102, 98, and 99 on April 10 – 13, and 100 on April 14 – 17.

Predicted planetary A index is 12 on March 11; 5 on March 12 – 13; 10, 18, 15, 5, and 8 on March 14 – 18; then 12 on March 19 – 20 15 on March 21 7 on March 22 – 24; then 5, 10, and 8 on March 25 – 27; 5 on March 28 – 29; then 10, 12, 25, 20, and 10 on March 30 – April 3; 5 on April 4 – 6; then 15, 20, and 12 on April 7 – 9; 5 on April 10 – 13; 8 on April 14, and 10 on April 15 – 16.

F.K. Janda, OK1HH, wrote, “The power density of solar radio noise at a wavelength of 10.7 centimeters — more briefly referred to as “solar flux” — remains above 110 for a week. Because we see two more active areas beyond the eastern limb of the solar disk (thanks to the STEREO Ahead satellite), solar flux should stay that way for another week.

“The concurrence of increased solar activity with seasonal changes during the approaching equinox results in improved conditions for short-wave ionospheric propagation.

“Occasional irregular occurrences of a slight increase in geomagnetic activity (as was the case on March 5 – 6) cause only a slight deterioration. Possible recurrent disturbance is expected until the beginning of April, probably already in its first days.”

Russ Hunt, WQ3X, wrote on March 4: “Yesterday I heard WA2BOT on 10 meter FT8 working DX on the long path and aimed my beam due south. In just over a half hour’s time I worked 33 JAs, two DUs, and VR2XYL. I had a pileup six deep at times while using 250 W and a five-element Yagi at 50 feet. It was probably the most exciting time I’ve had in the last 20 years. Today I worked two more VR2s and three JAs, also long path, just after sunrise.”

A few hours later he wrote, “During the middle of the day we get some VK/ZLs starting around 3 PM local time. But try sunrise and sunset and you will find a lot of DX.

“I hear the 6s and 7s working a lot of Asia in the evening. Here we get EU, Africa, and the Middle East in the mornings. I’ve done WAC about four or five times a week, but now running out of new stations to work.”

Robert Strickland, KE2WY, asked about a good source for the latest daily sunspot numbers, and I sent him to this site.

On March 10, N9II sent some observations of last week’s ARRL International DX Contest (SSB). “I operated single band 15 meters in the ARRL DX contest but made a few QSOs on other bands. Twenty was open well to Africa and south in the 0100 UTC hour Saturday, some very loud Caribbean signals. Ten was open for many hours to the south. Some booming signals even from low-power stations in Puerto Rico and the Turks and Caicos, as well as many high-power stations such as J68HZ on St Lucia, PJ4G on Bonaire, and PJ2T on Curacao.

“On 15, a disturbance and slightly low solar flux made for some challenging conditions to Asia and northern Europe.

“Saturday evening the disturbance rendered Japan nearly completely closed, with Sunday evening conditions fair with most signals less than S-9.

“I made 600 15-meter QSOs, working 86 DXCC entities.

“On 10 CW starting at 1414 UTC on March 8, I worked three new ones in a row: 7Q6M in Malawi, 5X1NA in Uganda, and JY5HX in Jordan.

“Then on 10 SSB, Dov, 4Z4DX, in Israel. On 10 CW, V26K Antigua, and OA1F Peru.

“Later on 17 CW V4/G0TLE St. Kitts, then topping off with E51BQ South Cook Islands on 10 SSB at 2325 UTC.

“On 12 meter CW on March 9 at 1550 UTC I worked V26K. I called CQ on 10 SSB at 1557 UTC and was called by Spain, then Francisco, TT8FC, in Chad, ZS1PPY in South Africa, then 3B8HE in Mauritius! March 10, featured excellent high-band propagation with the solar flux climbing to 127. I heard Indonesia peaking at S-8 on 15 SSB at 1340 UTC, then worked 4L1AN in Georgia at 1344 UTC (new) and VU2DSI India at 1353 UTC.

“Turning to 10 SSB, I found Selki, S01WS, Western Sahara, and CU1EZ in the Azores for #100 on 10 SSB. Then at 1551 UTC for the next hour, 10 blew wide open to Europe starting with Bulgaria, Italy, and Hungary.

“Several stations with simple end-fed wires were S-9, and the loudest signals were S-9 + 20 dB or a bit stronger. This was one of the best openings all winter, but others were more widespread farther north.”

Here is an email list for operators of, or anyone interested in, HF beacons.

The vernal equinox arrives in just over a week from now, at 1533 UTC on Sunday, March 20. That’s when Earth will be bathed in an equal amount of solar radiation over both southern and northern hemispheres — good for HF propagation. It is the first day of spring in the northern hemisphere, and the first day of fall in the southern.

Sunspot numbers for March 3 – 9 were 92, 77, 95, 82, 84, 93, and 89, with a mean of 87.4. The 10.7-centimeter flux was 110.9, 113.1, 120.1, 115.7, 118.3, 115.3, and 114.8, with a mean of 115.5. Estimated planetary A indices were 5, 10, 27, 18, 9, 6, and 5, with a mean of 11.4. Middle latitude A index was 3, 7, 19, 13, 7, 5, and 4, with a mean of 8.3.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check this propagation page by Carl Luetzelschwab, K9LA.

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.

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