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The K7RA Solar Update


Lots of solar activity livened up HF conditions over the past reporting week, March 31 to April 6. Average daily sunspot number rose from 90.1 to 94.6, and daily solar flux from 132.7 to 135.3.

It looks like solar flux may peak this month at 140 on April 24-28.

Since March 18 we were unable to get daily solar flux from the observatory in Penticton, British Columbia, so for a couple of weeks we relied on secondary sources which were all in whole numbers, instead of resolving to 0.1. Multiple inquiries to the observatory led nowhere, but now the data is back online at .

I had to fudge the flux value for March 31, because the value of 239.5 was obviously an error, probably due to a CME overwhelming the 10.7 cm receiver at the observatory, so I averaged the morning and afternoon readings to 149.3. The official daily flux value is always from the 2000 UTC local noon reading.

Geomagnetic conditions were quite active on March 31 through April 2. Average daily planetary A index for the week increased from 10 to 14.4, and middle latitude A index from 8.1 to 10.9. reported 146 solar flares over the month of March and predicts even more for April. They also report that cycle 25 is progressing faster and stronger than earlier predictions. A new sunspot group appeared on March 31, two more on April 1, another on April 2 and one more on April 3, and one more on April 5.

The predicted solar flux is 108 on April 8-9, 105 on April 10-11, 100 on April 12-14, then 110, 115 and 120 on April 15-17, 125 on April 18-19, 130 on April 20-23, 140 on April 24-28, 135 on April 29-30, 130 on May 1, 120 on May 2-3, 125 on May 4-5, 120 on May 6, 115 on May 7-8, 110 on May 8-9, 115 on May 11, and 120 on May 12-14.

Predicted planetary A index is 12, 15, 10 and 8 on April 8-11, 5 on April 12-19, 10 on April 20-21, then 5, 15, 10 and 8 on April 22-25, 5 on April 26-28, then 18, 12, 10 and 8 on April 29 through May 2, 5 on May 3-7, then 12 and 10 on May 8-9, and 5 on May 10-16.

Solar wind in the news:

F.K. Janda, OK1HH reports: “Total solar activity has been declining. Recent CMEs generated by solar flares have usually not been headed to Earth. On April 6, the solar wind was expected to intensify from a CME generated by a filament eruption on April 3rd, but only a small portion of the solar plasma cloud reached Earth.

“The Earth's magnetic field was unsettled to active until April 2 and partly on April 4 and 7. The increased geomagnetic activity on the night of April 3 to 4 worsened diurnal short wave propagation conditions on April 4. Thereafter, despite the continuing decline in solar activity, shortwave propagation conditions improved.

“In further development, we first expect a decline in solar activity. Its growth in the second half of the month will again cause an improvement of shortwave propagation. However, the development will be slightly irregular.”

Another informative video forecast from WX6SWW, Dr. Tamitha Skov:

WB8VLC reports from Oregon: "Another fun week on 10 meters but only SSB/CW and not much FM activity. However, the SSB/CW activity was strong with signals to South Africa, Taiwan, Philippines, Norfolk Island and Australia.

It is interesting that I have not heard any European stations during any morning or afternoon openings to the east, just South Africa."

A small portion of his log:

April 3 it was New Zealand in the morning and Australia at night, followed by China and Philippines 

2344 UTC   N7ET/DU7  28.014  CW 599 Philippines

2340 UTC   BV1EL     28.010  CW 599 Taiwan

2311 UTC   VK3NX    28.015  CW 599 Australia

1900 UTC   ZS3Y      28.373  SSB 55 South Africa

K5JRN reports on 6 meters from Austin, Texas: “Interesting conditions observed here on April 4 and 6. Using FT8 on 6 meters on 4/4/22, I worked HK3X (FJ24) in Columbia and HC1MD/2 (EI97) in Ecuador while running 30 W to an indoor dipole wrapped around a couple of bamboo tomato stakes glued end to end.

“That same combo helped me snag HC2DR (FI07) in Ecuador today (4/6). My signals were not strong, ranging from -13 to -24 in Columbia and Ecuador. I've also been heard in Argentina and have copied several Argentinian hams, including LU9AEA (GF05), but have not yet worked an Argentinian on 6.

“Today, I've also been heard in Uruguay by CX7CO (GF15) but have not heard any CX stations yet. Indeed, I'm not receiving anyone else on 6 except a few locals and those South American stations. The north-south paths seem like narrow pipelines.”

Speaking of “narrow pipelines,” from here in the northwest I often see this on 10 and 12 meters using FT8. Monitoring, on April 7 at 1630 UTC on 12 meters my signal was only reported by stations on the East Coast over a narrow band, all from 2296-2359 miles from me, at first only by many stations in Virginia and North Carolina, but not South Carolina.

Later at 1645 UTC coverage expanded to Florida and Georgia, but still within that narrow mileage limit. Later by 1720 UTC reports had spread to New York, Georgia and  Florida, and the mileage range expanded slightly to 2119-2489 miles. But there was one major exception, HK3A in Bogota, Columbia at 4091 miles.

The night before (local time) at 0220 UTC on 17 meters I was copied only into a specific area about 2300 miles away in Ohio, Virginia, Pennsylvania, and Maryland, then suddenly at 0232 UTC the coverage expanded to California, Oregon, Texas, Alabama, and Florida.  All of this with low power and a crude end-fed indoor antenna, fed with an UnUn and autotuner.

Thanks to KA7F for this link:

Cycle 25’s increasing activity is drawing the attention of the media. In this instance it is KTAR in Arizona:

And more from Southgate Amateur Radio:

Fascinating solar phenomena:

EarthSky reports an exciting week for solar observers:

 N0JK reports: “On Saturday April 2, 2022, NØLL (EM09) I copied LU5VV, CE2SV, LU1WFU and PV8DX on 50.313 MHz FT8 TEP. I copied CE2SV on TEP and KØSIX (EN35) calling PY5CC on 50.313 MHz Es at 2109 UTC.”

For more information concerning shortwave radio propagation, see and the ARRL Technical Information Service at For an explanation of numbers used in this bulletin, see

An archive of past propagation bulletins is at More useful information and tutorials on propagation are at

Instructions for starting or ending email distribution of ARRL bulletins are at

Sunspot numbers for March 31 through April 6, 2022, were 84, 109, 118, 129, 86, 75, and 61, with a mean of 94.6. 10.7 cm flux was 149,3, 146.6, 143.3, 140.2, 128, 122.4, and 117, with a mean of 135.3. Estimated planetary A indices were 27, 17, 22, 10, 11, 6, and 8, with a mean of 14.4. Middle latitude A index was 18, 12, 19, 7, 8, 6, and 6, with a mean of 10.9.




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