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The K7RA Solar Update


Average daily solar flux and sunspot numbers rose over the past week. The average daily sunspot number rose 5 points to 64.1 while average daily solar flux was up 11.6 points to 100.4. Geomagnetic indices were quieter, with average planetary A index decreasing from 22.6 to 9.9 and average mid-latitude A index dropping from 14.6 to 10.9.

USAF and NOAA predict solar flux at 100 on May 20-24, 95 on May 25-26, 90 on May 27-28, 95 on May 29, 100 on May 30 through June 1, 95 on June 2-7, 100 on June 8-9, then 95, 100, and 105 on June 10-12, 100 on June 13-16, 95 on June 17-21, 90 on June 22-24, 95 on June 25 and 100 on June 26-28.

Predicted planetary A index is 22, 16, 12 and 6 on May 20-23, 5 on May 24-27, then 15, 25, and 10 on May 28-30, 5 on May 31 and June 1, 12 on June 2-3, then 35, 30 and 15 on June 4-6, 5 on June 7-9, then 8, 15, 25 and 12 on June 10-13, then 8, 18, 25 and 12 on June 14-17, then 8, 5 and 10 on June 18-20, and 5 on June 21-23.

F.K. Janda, OK1HH, of the Czech Propagation Interest Group sends a weekly geomagnetic activity forecast for the period May 20-June 15, 2016.

Geomagnetic field will be:
Quiet on May 23, 26-27, June 9-10
Mostly quiet on May 24, June 3, 14-15
Quiet to unsettled on May 25, 28, June 1-2, 7-8, 11,
Quiet to active on May 20-22, 29, 31, Jun 4-5, 12-13
Active to disturbed on May 30, June 6

Increased solar wind from coronal holes is expected on May 22-26, June 1-2, 6-8, 14-15.

Jeff Hartley, N8II, of Shepherdstown, West Virginia sent this report about what he is hearing in FM19ck.

“It seems like low MUF conditions are here to stay, but 15 meters is open to southern Europe most days starting around 1400-1500 Z.

“I operated the 7th call area QSO party May 7-8 until 0320Z on the 8th. Fifteen meter activity was way down, especially on phone, and propagation was poor, but there were solid signals from AZ and NV from 1600Z through past 2130Z, and all states of the 7th area were worked during the opening, but the more northern areas MT, ID (worst), WA and OR were mostly not that loud and in and out. The peak was around 2000Z. My 15 meter QSO total was 49 vs 167 in 2015; SSB was 10 vs 65.

“What was lost on 15 meters was gained on 20 meters with noticeably less absorption mid-day due to lower solar flux allowing for more QSOs, although some mobiles were still lost in the noise. Things really started cooking around 1940Z through 0100Z and I was able run quite a few stations on phone and even some on CW. Mobiles were easy copy, but phone activity did not seem all that high. The total tally was 350 20 meter QSOs (my best ever) vs 258 last year.

“Forty meters was affected by the beginning of the solar storm, but not that badly. I made more QSOs than last year and most stations were easy copy. It is about 0300Z (2300 EDT) before the Sun sets on the west coast at this time of year, so I did not start working OR/WA until around 0215Z. Almost all of the signals, even AZ, sounded hollow with flutter, but the signal levels were down only slightly from what I would expect. In fact, W7RN in NV was S9+ 25-30 dB without flutter. Obviously, the K index was high. It was very easy to tell the New England QSO party W1s from the 7s just by their signal quality. I did not wait long enough for 80 meters to open before going QRT. I operated low power, 150 W.

“Sunday propagation was very poor due to the solar storm and that lingered into Monday with 15 meters almost totally dead.”

We received a couple of comments from W6ELProp users.

Lloyd Rasmussen, W3IUU, of Kensington, Maryland wrote: “I am blind and use the Window-Eyes screen reader. The text output of W6ELProp works just fine for me under Windows 7 and 10.”

John Leroy, W4JKL of Mount Sterling, Kentucky wrote: “W6ELProp can be installed and run under Wine for Linux. I run it on my Debian 8 Jessie box with Wine set to emulate Windows XP. I installed it on Wine drive_c in the root directory. Once you run an on-screen path prediction and close the window, you must minimize the program and then maximize it again to see the menu entries. The other functions don't require this. The mapping functions work correctly. Thanks for reminding me to try this. I normally use HamCap by VE3NEA under Wine and it works correctly. IonoProbe by VE3NEA also works correctly under Wine and will feed the latest online data to HamCap, but another tool is always welcome!”

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 May 12 through 18 were 67, 76, 88, 78, 76, 36, and 28, with a mean of 64.1. 10.7 cm flux was 92, 93.4, 101.2, 108.4, 102, 103.2, and 102.3, with a mean of 100.4. Estimated planetary A indices were 4, 8, 10, 13, 13, 13, and 8, with a mean of 9.9. Estimated mid-latitude A indices were 4, 9, 10, 12, 15, 14, and 12, with a mean of 10.9.





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