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The K7RA Solar Update


After two days of no sunspots on August 3-4, solar activity resumed with both sunspot number and solar flux rising into the 90s. Average daily sunspot numbers rose from 10.7 in the last reporting week to 52 this week (August 4-10). Both averages were suppressed by having a sunspot number of zero on the last day of the old week and again on the first day of the most recent week.

Average daily solar flux rose from 72.1 to 87.9. Average planetary A index went from 13 to 14.6, and average mid-latitude A index from 11.9 to 13.7.

The latest solar flux prediction from USAF/NOAA shows 95 on August 12, 90 on August 13-15, 95 on August 16-18, then 90 and 85 on August 19-20, 75 on August 21-26, 80 on August 27 through September 1, then 85, 95, 100 and 105 on September 2-5, 100 on September 6-9, 95 on September 10-13, with flux values dropping to 75 on September 17-22 before rising again.

Predicted planetary A index is 12 and 8 on August 12-13, 5 on August 14-15, then 8, 12, 10 and 8 on August 16-19, 5 on August 20-23, 15 on August 24-25, 5 on August 26-28, then 15, 25 and 18 on August 29-31, 15 on September 1-2, then 12, 8 and 5 on September 3-5, 12 on September 6-7, 8 on September 8, 5 on September 9-10 and 12 on September 11-12.

Petr Kolman, OK1MGW sends this:

Geomagnetic activity forecast for the period August 12-September 7, 2016

Geomagnetic field will be:
Quiet on August 26-27
Mostly quiet on August 12-14, 17-18, 22, September 7
Quiet to unsettled on August 15, 19, 23, 31, September 1-3, 6
Quiet to active on August 16, 20-21, 24-25, 28-30, September 4-5
Active to disturbed on August (29-30)

Increased solar wind from coronal holes are expected on August 20-21, 23-24, 28-30, September 4-5

Parenthesis means lower probability of increased activity.

Max White, M0VNG, of Worcester, England sent this fascinating piece from New Scientist about the US Air Force deploying micro-sats to release plasma into the ionosphere. This creates artificial clouds of ionization which should improve HF propagation:

Richard Ferry, K2KA, of Westford, Massachusetts worked HH2AA (call sign of Radio Club D'Haïti) in Port-au-Prince, Haiti at 1552 UTC on August 9, 2016. This was a 6 meter CW QSO.

Fifteen minutes later it's confirmed on LOTW!

“That is awesome and for the life of me can't figure out why it takes some stations months to upload to LOTW? I upload every day.”

I believe the club station at HH2AA is an HF remote base station, and they have devised some way to automatically send confirmations to LOTW, frequently and in real time.

“Later in the day I worked Europe, nothing new but did work CT1HZE at 1827Z and heard CS5BALG/B.

“I also worked CO8LY on July 24th at 0021 on JT65 and again on CW on July 25 1447Z. He also has a good QSL system. Send to his manager EA7ADH. Have worked him on 40 through 6 meters now. Always get a card.

“My station here is the ICOM IC-7700 (160 to 6, 200W), an IC-7100 (160 to 70 centimeters, 100W), Ameritron AL811H amplifier for 160 to 10 meters, dipoles on HF bands, a 5 element M2 6 meter Yagi at 40 feet, a 10 element and 19 element Yagis on 2 meters and 70 centimeters at 30 feet.”

In 1967, the US government mis-interpreted a strong solar storm and thought the Soviet Union was jamming all our radar. Allegedly this took us to the brink of Armageddon.

Thanks to Max White and David Moore for the above articles.

For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of the numbers used in this bulletin, see An archive of past propagation bulletins is at More good information and tutorials on propagation are at

Monthly propagation charts between four USA regions and twelve overseas locations are at

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

Sunspot numbers for August 4 through 10 were 0, 36, 33, 63, 91, 72, and 69, with a mean of 52. 10.7 cm flux was 76.3, 79.8, 83.1, 92.7, 96.4, 92.3, and 95, with a mean of 87.9. Estimated planetary A indices were 18, 16, 14, 12, 12, 14, and 16, with a mean of 14.6. Estimated mid-latitude A indices were 17, 16, 13, 12, 9, 15, and 14 with a mean of 13.7.




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