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The K7RA Solar Update


On May 30 at 0005 UTC the Australian Space Forecast Centre issued a warning: “On 1 June geomagnetic activity is expected to increase to Active and Minor Storm levels due to arrival of the co-rotating interaction region and high-speed solar wind streams associated with the recurrent trans-equatorial coronal hole.”

On May 31 issued this Solar Wind Alert: “NOAA forecasters estimate a 60% chance of minor G1-class geomagnetic storms on June 1st, increasing to 65% on June 2nd, when a stream of high-speed solar wind is expected to reach Earth. The last time this gaseous stream lashed our planet's magnetic field, almost a month ago, it sparked bright ribbons of purple light (a.k.a. "STEVE") seen from multiple US states. Visit today's edition of for more information." 

The Sun remained active over the past reporting week. Average daily solar flux rose from 70.1 to 74.9, and average daily sunspot number rose from 7.7 to 26.3. During the previous week in which the average daily sunspot number was 7.7, the first four days had no sunspots.

New sunspot regions appeared on May 21, 23 and 24.

Predicted solar flux is 77 on June 1-3, 76, 74 and 72 on June 4-6, 70 on June 7-8, 71 on June 9, 72 on June 10-14, 70 on June 15-17, 72 on June 18-23, 73 on June 24, 72 on June 25-30, 70 on July 1-6, 72 on July 7-11, 70 on July 12-14 and 72 on July 15.

Predicted planetary A index is 25 on June 1-2, 15, 12 and 8 on June 3-5, 5 on June 6-12, 8 on June 13, 5 on June 14-18, 8 on June 19, 5 on June 20-23, 8 on June 24-25, 5 on June 26-27, then 15, 28, 15, 12, 10 and 8 on June 28 through July 3, then 5 on July 4-9, 8 on July 10, and 5 on July 11-15.


ARRL Field Day is June 23-24. Assuming the predicted numbers above, conditions should be good for Field Day. We want to see low geomagnetic activity, and planetary A index at 5 and 8 on Saturday and Sunday are good indicators. During this period of low solar activity solar flux at 72 and 73 is also good.


Ted Leaf, K6HI, of Kona, Hawaii reports that he is still in operation through the local volcanic activity, and asks “Are there beacons for the lower frequencies, especially now with the lower solar flux?"

I found this Wikipedia resource for HF beacons:

Of course, there are lower frequency HF resources on, but this is a bit different than showing what you can tune in and hear without using a special weak signal mode.

Any readers have suggestions for lower frequency HF beacons?

Note that Ted has a comment on page 56 of the June 2018 QST regarding preamps and attenuator effects on receiver noise.


From last week:


F.K. Janda, OK1HH, brings us this geomagnetic activity forecast for the period June 1-26, 2018.

“Geomagnetic field will be: 

Quiet on June 11-12, 16-17, 20-23 

Quiet to unsettled on June 10, 18, 24-25 

Quiet to active on June 8-9 

Unsettled to active on June 3-4, 7, 13-15, 19 

Active to disturbed on June 1-2, (5-7, 26) 

Solar wind will intensify on June 1-3, (4-8, 13–15), 16-17, (18-19, 22-24) 


- Parenthesis means lower probability of activity enhancement. 

- Forecasts remain less reliable.”


From Tamitha Skov, the Space Weather Woman:

"What's Old is New Again

“Dear Tad,

“I am still smiling at the huge response I got to a post I put up on Twitter this week. A newbie to our Space Weather community dared to talk about Amateur Radio as if it were an outdated hobby-- whoops, bad idea. I gently educated him. In doing so, I roused many radio amateurs and emergency communicators, who added their own comments and talked about their own personal experiences in the field. It was very gratifying. What I hadn't expected, however, was the strong interest in the concept that amateur radio will be critical to establishing over-the-horizon radio communications on planets like Mars in the near future.

“This idea brings me back to how we managed to communicate over long distances many decades before we had satellites, internet or cellular networks. In terms of wireless communications on Earth, we were very much in the same place back in the early 1900s that we find ourselves in now when we think about colonizing Mars. Yet few people realize that despite all our advanced technology, we can't bring a cell phone to Mars. We will need to fall back on our ‘old ways’ of doing things when it comes to communicating on other planets. Isn't it funny how ‘old’ things become ‘new’ again?

“Speaking of, this week brings us a new chance for a decent solar storm. Strangely though, the source of this storm is an old coronal hole that gave us a moderate level solar storm about a month ago. This old hole has survived its backside passage on the Sun and has now returned, with the new promise of bringing aurora views down to mid-latitudes again. Isn't it funny, what was old has become new again, in more ways than one!



Dr. Skov’s latest video report:


For more information concerning radio propagation, see 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 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 24 through 30, 2018 were 39, 32, 26, 27, 20, 22, and 18, with a mean of 26.3. 10.7 cm flux was 73.7, 75.7, 72.9, 74.6, 76.9, 74.9, and 75.3, with a mean of 74.9. Estimated planetary A indices were 4, 3, 4, 4, 4, 4, and 4, with a mean of 3.9. Estimated mid-latitude A indices were 5, 4, 5, 5, 4, 5, and 5, with a mean of 4.7.





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