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The K7RA Solar Update


Tad Cook, K7RA, Seattle, reports: Sunspot activity continues this week, although the average daily sunspot numbers and solar flux have not really changed since last week’s report. This was not expected, because on the first day of the reporting week in last week’s bulletin ARLP020, there was no sunspot activity.

Average daily sunspot number hardly changed, from 21.1 to 20.3, and average daily solar flux went from 74.3 to 74.2. I am surprised that solar flux still remains below 80, since April 20.

Geomagnetic indicators were quiet, but values were slightly lower. Average daily planetary A index changed from 9.1 to 6.6, and average daily middle latitude A index went from 7.4 to 6.3.

Predicted solar flux for the next 30 days is 72 on May 21 – 27; 73 on May 28; 75 on May 29 – 31; 77 on June 1; 78 on June 2 – 12; 73, 77, and 77 on June 13 – 15, and 75 on June 16 – 27.

Predicted planetary A index is 10 and 8 on May 21 – 22; 5 on May 23  –  June 10, 8, 5, 10, and 8 on June 11 – 14; 5, 10, and 8 on June 15 – 17, and 5 on June 18 – 30 and beyond.

The Thursday (May 20) planetary A index rose dramatically due to increasing solar wind. The STEREO website at has been a good indicator of approaching sunspot activity about to rotate over the sun’s eastern horizon, and currently on early Friday I can see a bright active region about to become geo-effective.

Here’s the geomagnetic activity forecast from J. K, Janda, OK1HH, for May 21 – June 15, 2021. The geomagnetic field will be:

  • quiet on May 25-26, (27-31,) June 9-10, 12-13

  • quiet to unsettled on May 24, June 1-8

  • quiet to active on May (21-23, June 11, 14)

  • unsettled to active (June 15)

  • active to disturbed none

  • Solar wind will intensify on May (21-25,) 28-30, June (7,) 9, (14-15)


- Parenthesis means lower probability of activity enhancement.

- Contradictory indications significantly reduce the accuracy of the forecast.

WB6VRN spotted a new location for the NOAA solar cycle progression page, and notes the site is interactive.

K1HTV reports:

“On 17 meters during the late afternoon on May 18, 2021, I completed WAC (Worked All Continents), using the FT8 mode, in 11 minutes. Around 3:15 AM EDT the next morning, after awaking from a restless sleep and while still horizontally polarized, I turned on my Android phone. I connected to my shack computer and its three video monitors using the VNC app.

“At that early hour (0715 UTC) here at my Virginia QTH, I found 17 meters was already open to Europe. I switched down to 30 meters FT8 and proceeded to work some DX. To my amazement, I was able to make FT8 contacts with all continents to complete WAC (Worked All Continents) in 6 minutes even! Below is the K1HTV log for those contacts, which may be a world record for WAC in the shortest time, at least for the FT8 mode.

OC – VK4PN – 2021-0519 07:25:00 started 1st QSO

EU – F2YT – 2021-0519 07:26:30 send 73 to end 2nd QSO

AF – EA8AT – 2021-0519 07:27:45 sent 73 to end 3rd QSO

AS – JH1CCN – 2021-0519 07:28:30 sent 73 to end 4th QSO

NA – CO8LY – 2021-0519 07:29:30 sent 73 to end 5th QSO

SA – CE3ALY – 2021-0919 07:31:00 sent 73 to end 6th QSO and complete WAC

“All QSOs were made while running 75 W to the 30 meter trap dipole of an A3WS antenna.”

N4SO in Southern Alabama reports:

“I often listen to 28 MHz propagation beacons starting with 28.175 VE3TEN, ending at 28.300 MHz. I also have about ten 28 MHz beacons in the log from 0000 to 0100 UTC.

“From the HF Beacon Reflector and WJ5O for May 20 Evening “GREYLINE” my location. 0025-0030 UTC, 20 May 2021, I can hear/identify ten 10-meter beacon signals into EM71as.




1074 km

667 miles




1424 km

885 miles




1424 km

885 miles




1364 km

848 miles




1449 km

869 miles




1112 km,

691 miles




1144 km

715 miles




1763 km

1095 miles




1900 km

1181 miles




1172 km

733 miles

Jeff Hartley, N8II, wrote:

“The sporadic E season has gotten off to a great start. Just in the past 2 days, there were the sporadic E 28-MHz openings into Europe! On the 18th, I saw a spot for F4DSD in France on 10 meter SSB. We worked, but just barely; after a struggle to copy my call, he gave me a 3 × 3 report at 2016 UTC. Hearing nothing else, I QSYed down to 15 CW and worked GW3TMP in Wales and EA8TL in Canary Islands. Then I managed to catch Hugh, EI2HI, in Ireland and we exchanged 4 × 2 reports.

“The morning of the 19th featured a fairly widespread but weak opening to EU on 10 meters.

“My first EU QSO was at 1410 UTC with ON7HJA in Belgium on SSB. Then I heard Gyuri, HA5JI, in Hungary who was the loudest of the opening, S-7 when we worked, then later near the end at 1433 UTC S5. Also worked F8DGY and Germany on CW. I finally got back to the radio at 2015 UTC and quickly found DK7LX in Germany on 10 CW who was S-7. As we finished, Ron, SP8ARY, was calling me; we moved up and made a QSO; he was my first 10-meter Polish QSO in my log started January 2017.

“Next I called a CW CQ once and was rewarded with a string of EU callers from Germany, England, Czech Rep., Serbia, France, Denmark (OZ4VW, first Danish op in my 10 meter log — new band slot), Netherlands and two more Poles including SQ1921PS. Many were rather weak. I then switched to SSB to find stronger signals as the opening improved. Ady, G6AD, in England was S-6 and Karel, ON2KP was S-8. 3Z1921PS in Poland was a new SSB band slot, as was 5P1B, Denmark 6 minutes later. Of course, I found Ian, MM0TFU in Scotland about S-7 who always seems to be there when 10 opens to North America. Calling CQ on SSB, I worked a long string of EU stations with few if any CQs needed to log the next station. The majority were in western EU, only one weak Italian. Additional SSB countries logged were France, Netherlands, Northern Ireland, Germany, and Austria. I made many QSOs with England. After 2128 UTC, I searched out stations and found Nick, LZ3ND, in Bulgaria who was peaking over S-9 — no wonder with his four stacked 7-element Yagis. Also worked LZ5DD. PI4DX also with stacked 6-element Yagis was S-9.

“My last SSB QSO before dinner at 2158 UTC was S52WW, Slovenia, for a new band slot. Returning at 2238 UTC, I found Tom, 9A2AJ, Croatia on CW (new slot), OA4DX, Peru on 12 CW for new slot, and Gordon, MM0GPZ who was S-7 – S-8 on 10 SSB, S-7 on 12 (my antenna only 2-element Yagi), and a solid S-9 on 15. Despite the great conditions on 15, there was very little SSB or CW activity. My last 10-meter QSO was EI7HBB, Ireland, on SSB at 2318 UTC — a very long opening. I made in total 64 10-meter QSOs with Europe.”

Wow, Jeff!

Russ W4NI reports from Nashville:

“The solar storm on 12 May 2021 was not too bad. Despite K=7 at both 1200 and 1500 UTC, I was able to work DK, EA, LZ, 9A, on 20 CW from TN."

Sunspot numbers for May 13 – 19 were 24, 24, 24, 11, 11, 24 and 24, with a mean of 20.3. The 10.7-centimeter flux was 74.7, 70.9, 73.3, 73.2, 74.8, 76.4, and 75.9, with a mean of 74.2. Estimated planetary A indices were 7, 4, 8, 5, 6, 10, and 6, with a mean of 6.6. Middle latitude A index was 7, 4, 8, 4, 6, 10, and 5, with a mean of 6.3.

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.

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