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The K7RA Solar Update


Tad Cook, K7RA, Seattle, reports: Solar activity declined this week — by a lot. Six and two meters yielded exceptional openings, however. The average daily sunspot number plummeted from 55.6 to 21.3, and the average daily solar flux slid from 88.9 to 72.9.

Geomagnetic indicators remained about the same, with average daily planetary A index at 6.6, although the daily value increased to 14 on July 14, due to increasing solar wind.

Predicted solar flux is 74 on July 16; 76 on July 17; 74 on July 18 – 20; 76 on July 21 – 22; 78 on July 23; 79 on July 24 – 28; 77 on July 29 – August 1; 75 on August 2; 74 on August 3 – 9; 73 on August 10 – 11; 75 on August 12 – 15; 79 and 81 on August 16 – 17, and 79 on August 18 – 24.

Predicted planetary A index is 10 on July 16; 5 on July 17 – 20; 8 on July 21 – 22; 5 on July 23 – August 1; 8 on August 2; 5 on August 3 – 7; 12, 16, and 12 on August 8 – 10; 8 on August 11 – 12, and 5 on August 13 – 28.

Here’s the geomagnetic activity forecast for July 16 – August 12 from F.K. Janda, OK1HH. The geomagnetic field will be:

  • quiet on July 16-18, 25, 30, August 4, 7, 12 

  • quiet to unsettled on July 20, 23-24, 28-29, August 2, 9 

  • quiet to active on July 19, 21-22, 31, August 1, 6, 11 

  • unsettled to active July 26-27, August 3, 5, 8, 10 

  • active to disturbed none


=Parentheses mean lower probability of activity enhancement.

=The previous prediction of increased geomagnetic field activity for July 12 was correct, but the solar wind from the equatorial coronal hole apparently traveled a longer path by lower speed than expected. That’s why it didn’t arrive until July 14.

Frank Donovan, W3LPL, reports:

Propagation crossing low- and mid-latitudes, the auroral ovals, and polar regions is likely to be normal through Sunday, July 18.

We are in the quiet geomagnetic activity season; only about half as many geomagnetically disturbed days occur in June and July, as compared to the more geomagnetically active equinox seasons.

Sporadic-E propagation occurs every day during June and July at mid-latitudes in the Northern Hemisphere, making long-distance propagation up to 15,000 km (9,300 miles) sporadically available on 17, 15, 12, 10, and 6 meters from sunrise through midnight and occasionally somewhat later.

The solar flux index (SFI) is likely to be 75 or less through Sunday. There are two small active regions on the solar visible disk with one small sunspot and one tiny sunspot.

160- and 80-meter propagation from North America to VK/ZL and the south Pacific is likely to be seasonably normal through Sunday.

40-meter short-path propagation to south Asia at about 0015 UTC is likely to be normal through Sunday.

40-meter short-path propagation from North America to east Asia after about 0930 UTC is likely to be normal through Sunday.

30-meter propagation through the auroral ovals and polar regions is likely to normal through Sunday. 30 meter propagation always significantly degraded within a few hours of local noon because of E-region blanketing of long-distance F2 propagation.

30-meter nighttime long-distance propagation in the Northern Hemisphere is likely to improve, due to increased ionizing solar radiation in the northern high latitude regions caused by higher solar elevation angles and short nights with no source of ionizing solar radiation.

20-meter daytime and evening propagation through the auroral ovals and polar regions is likely to be normal through Sunday. 20 meter northern transpolar propagation within a few hours of sunrise and sunset is improving, with longer-duration solar ionizing radiation on the northern polar region caused by high solar elevation angles 24 hours per day during the midnight sun season.

20 meter long-distance propagation is significantly degraded from mid-morning through late afternoon at low and mid-latitudes in the Northern Hemisphere by F1 region midday blanketing of low-angle, long-distance propagation during the summer.

20-meter late afternoon, nighttime, and early morning long-distance propagation in the Northern Hemisphere is likely to improve due to increased ionizing solar radiation in the northern high-latitude regions caused by higher solar elevation angles and short nights with no source of ionizing solar radiation.

17- and 15-meter daytime long-distance propagation in the Northern Hemisphere is likely to improve due to increased ionizing solar radiation in the northern high-latitude regions caused by high solar elevation angles and long days. Sporadic-E propagation up to 15,000 kilometers (9,300 miles) on 17, 15, 12, 10 and 6 meters is likely to be sporadically available from sunrise through midnight and occasionally later through late July.

Geomagnetic disturbances caused by coronal hole high-speed stream effects are likely to remain mostly brief, minor and somewhat less frequent at least through late 2021. The southward oriented (–Bz) component of the IMF plays a crucial, but unpredictable, role in triggering all geomagnetic storms. Brief minor to moderate geomagnetic storms may be gradually triggered when the IMF persists in a southward orientation (–Bz) with enhanced IMF field strength for several hours coincident with the effects of an Earth-directed coronal hole high-speed stream. More frequent, longer-duration minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF persists in a southward orientation (–Bz) with enhanced IMF field strength for several hours or more coincident with the effects of an Earth-directed fast CME.

The solar wind is expected to be at background state through Sunday. The geomagnetic field is likely to be mostly quiet through Sunday. Coronal hole high-speed stream and CME effects, geomagnetic storms and solar flares are not likely through Sunday.

Mid-latitude Northern Hemisphere sunset is now 5 minutes earlier and daylength is 19 minutes shorter than it was on June 21. Daylength and solar elevation angle in the northern polar region are slowly declining due to gradually waning summer solstice effects.

James O’Brien, W4AMP, in Dallas, Georgia, reports:

“A fantastic F2 opening on 6 meters was heard most of the morning of July 14 here in EM73nv. Worked EA7L, F4ARU, EB1A, F4GGQ, and I2PJA on SSB. Signals were strong with QSB.

Looking forward to more.”

Jon, N0JK, in Lawrence, Kansas, wrote:

“Another spot for WP4G on 2 meters (maybe Es) July 15, at 2319.”

Dick, KK2KA, reports more 6-meter excitement:

“The opening on July 14 from 0930 until 1900 UTC here in Massachusetts yielded seven new DXCC entities, including Hawaii. Now 49 of 50 for 6 meters WAS. I worked OD, 9K, YL, 4X, 5B, SV5. Now at 114 worked and 110 confirmed. This opening was the best I have ever seen. EU all day long [and] so many decodes in FT8 you had to scroll. FT8 on 313 and 323. Signals were strong and stable, not much QSB, which made it easier to work. This day goes down in the books as the best ever opening on the Magic Band.”

Rich, K1HTV, reports:

July 13, 2-meter FT8 operators from the Mid-Atlantic, the Carolinas, Georgia, Alabama, and Florida (and some in the midwest) experienced an extraordinary day.

As I was driving home from shopping, my son Andy, K1RA, came on the local 2-meter repeater to notify me that stations in the Philly area were working into Puerto Rico on 144.174 FT8. When I arrived home I swung the beam toward the Caribbean and started working 2-meter Es. Here is a partial FT8 log from K1HTV (FM18ap) log for July 13, 2021.




1,534 miles (2,469 km)




1,579 miles (2,541 km)




910 miles (1,460 km)




1,349 miles (2,171 km)


I thought that I did well until I started seeing spots from KA9CFD in EN40om working NP4BM in FK68lm, 2,070 miles (3,330 kilometers); WP4KJJ in FK68xf, 2,127 miles (3,423 kilometers); HI3T in FK58ak, 1,961 miles (3,156 kilometers), and HI8DL in FK58al, 1,959 miles (3,153 kilometers). And then I saw Jon’s (N0JK) even longer distance DX Cluster spots for WP4KJJ and WP4G. Extraordinary!

It sure looks like it took two separate, well placed highly ionized patches for this to happen, and a PSK Reporter Es MUF map shows the locations of the two. One was at EM64 and the other patch was at FL06.

The 2-meter Es opening that I observed from FM18ap in Virginia to Puerto Rico went from 1518 – 1558 UTC and then again, briefly from 1630 – 1633 UTC.

The opening to W4AS in EL95 at 1605 UTC only lasted 2 minutes and then was gone.

The opening from FM18ap to ZF1EJ in EK99 started at 1606 UTC and lasted until 1624 UTC.

So, it was an incredible 144-MHz propagation day here in North America. I called a few CQs on 144.200 SSB but had no luck. All of the activity was on the 144.174 MHz FT8 frequency.”

KA3JAW reports:

Bryce, K4NBF, in Mashpee, Massachusetts (FN41sp), heard the following stations on Tuesday, July 13:

1255 UTC       104.3   WZIN “The Buzz” in Charlotte Amalie, Virgin Islands, running 44 kW — 1,641 miles (2,640 kilometers). Single-hop E skip.

1956 UTC       93.7     HILS-FM “Latidos” in Santo Domingo, Dominican Republic, running 5 kW — 1,601 miles (2,576 kilometers) Single-hop E skip.

2034 UTC       95.6     “Radio Uno” in Barranquilla, Colombia, at 2,745 miles (4,417 kilometers), plus another unidentified station on 98.6 in Barranquilla. Double-hop E skip.

2040 UTC       98.7     WUKQ-FM “La Primera” in Mayaguez, Puerto Rico, running 25 kW — 1810 miles (2912 kilometers). Double-hop E skip.”

HI8T in the Dominican Republic reports:

“July 13, 6 meters was as crowded as 20 meters. I checked my radio twice to see if it was really on 6 meters. FT8 signals were very loud on 50.313. At around 1650 UTC, I switched to the 2-meter FT8 frequency, 144.174, and worked KA9CFD in Illinois with very good signals. After him, many other stations came in. Later that day in my car, I heard one FM radio station from Alabama and one from Georgia. It seems that Solar Cycle 25 will be full of surprises, and one thing that helps is that with FT8, everybody is captive on the same frequency.”

Finally, I’ve enjoyed hunting for 10-meter CW propagation beacons from 28.2 – 28.3 MHz, sometimes using remote WebSDR receivers. I put up my own beacon (with tremendous help from Vlodymyr, AA7DJ) last Friday after IARU assigned me a frequency, 28.2833 MHz. K7RA/b is now running about 5 W, 24 × 7 from CN87uq with a half-wave vertical dipole. If you hear it, email me a report or send a QSL card.

A regularly updated comprehensive 10-meter beacon list is here.

Sunspot numbers for July 8 through 14 were 23, 23, 24, 23, 22, 11, and 23, with a mean of 21.3. The 10.7-centimeter flux was 73.4, 73.8, 74, 73.6, 71.6, 72, and 72.1, with a mean of 72.9. Estimated planetary A indices were 5, 5, 6, 4, 7, 5, and 14, with a mean of 6.6. Middle latitude A index was 5, 7, 8, 4, 7, 7, and 10, with a mean of 6.9.

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



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