The K7RA Solar Update


The Sun remained spotless over the past week, and by September 27 the period with no sunspots was over two weeks. Average daily solar flux declined from 68.6 to 67.9. Average planetary A index increased from 9.7 to 10.9, while average mid-latitude A index declined from 8.3 to 7.9.

Predicted solar flux is 68 on September 28 to October 2, 70 on October 3-10, 68 on October 11-28, 70 on October 29 through November 6, and 68 on November 7-11.

Predicted planetary A index is 5 on September 28-30, then 8 and 12 on October 1-2, 5 on October 3-6, then 20, 35 and 10 on October 7-9, 18, 15 and 8 on October 10-12, then 5, 10 and 8 on October 13-15, 5 on October 16-17, 10 and 25 on October 18-19, 15 on October 20-21, then 10 and 8 on October 22-23, 5 on October 24-27, 10 and 12 on October 28-29, 5 on October 30 through November 2, then 20, 35, 10 and 18 on November 3-6, then 15, 8, 5, 10 and 8 on November 7-11.

Geomagnetic activity forecast for the period September 28 to October 24, 2018 by F.K. Janda, OK1HH.

Geomagnetic field will be:

Quiet on October 4, 16-17, 20-21

Quiet to unsettled on September 28-30, October 3, 5

Quiet to active on October 1, 6, 11-13, 22-24

Unsettled to active on October 2, 8-10, 14

Active to disturbed on October 7, 15, 18-19

Solar wind will intensify on October 1-3, 7-8, 12-15, 19-20, (21-22)


– Parenthesis means lower probability of activity enhancement.

Thanks to Dick Bingham, W7WKR for forwarding this article by Alex Schwartz, VE7DXW on his automated space weather station, run with Raspberry Pi:

If you like his article, Alex would appreciate it if you will recommend it by clicking on the heart toward the bottom.

An article about a previously overlooked pioneer of radio astronomy:

The latest from Dr. Skov: “You may be wondering why we’ve had so many solar storms lately. You might even have noticed since the last solar storm a week ago that we haven’t yet settled down to quiet conditions. In fact, high latitude aurora photographers continue to enjoy some decent light shows despite the solar storm being long over. Just a few months ago, we seemed to go weeks without any significant activity here at Earth. So, what has changed? The answer is simple: Fall is here.

“You may think I’m nuts. Few people tend to look at Space Weather as having seasons like terrestrial weather does. But in truth Space Weather seasons are very real! As you can imagine, this has very little to do with the Sun changing its weather patterns during the year, but it has everything to do with the way the Earth tilts with respect to the Sun. During the summer and winter, the Earth tilts towards the Sun in such a way as to lessen the impact of Space Weather. During the spring and fall, however, the sideways tilt of Earth relative to the Sun magnifies Space Weather effects. So just like terrestrial weather, this changing tilt results in seasons. Generally speaking, Space Weather at Earth maximizes at the equinoxes and minimizes at the solstices. I will be sure to go into this phenomenon in more detail in an upcoming live mini-course, so I can share the particulars of how it works. It’s called the ‘Russell-McPherron effect’ and it’s really pretty cool.

“This week we are feeling the effects of the fall equinox in full swing. Although we don’t really have any strong solar storms en route, nor are we being battered by any serious fast wind, we just can’t seem to quiet down. We have been sitting at unsettled conditions for over five days now and we may have a few more days of this ‘Space Weather drizzle’ before things relax. Till then, all I can say is keep your proverbial umbrella handy. Some of this drizzle can actually help stabilize the upper atmosphere, which improves GPS reception and Amateur Radio propagation, so maybe it’s worth getting a little wet.”

See her latest video here:

Steve Sacco, NN4X, wrote: “Perhaps this is the enabling factor for SSSP (Short-path Summer Solstice Propagation) on 6 meters?”

“These Electric Blue Clouds Are Made from Ice Crystals and Meteor Debris”

NASA’s PMC Turbo mission captured new views of polar mesospheric clouds from a five-day balloon flight over the Arctic.

More about SSSP:

Steve also (along with Max, M0VNG) also sent info about World War II bombings and their effects on the ionosphere:

Evan Rolek, K9SQG, who has been contemplating 40 meters wrote: “My observation about 40 meters is that it is virtually dead during the daytime hours here in Dayton, Ohio. The MIDCARS net hasn’t been heard here in weeks whenever I have checked. However, in the evening after 9 PM or so, I can hear and work stations all over the country and there is plenty of space for many, many more QSOs. Fading isn’t bad, and signals are strong, enabling lengthy QSOs. And if one waits until after 11 PM local time, working into Germany, Italy, Canary Islands, etc. is quite easy and all I’m using is a horizontal loop 20 feet off the ground! But, overall, 40 meters is not what it used to be years ago.”


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 September 20 through 26, 2018 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 66.6, 66.9, 67.9, 68.4, 68.6, 67.6, and 69, with a mean of 67.9. Estimated planetary A indices were 2, 9, 27, 12, 7, 11, and 8, with a mean of 10.9. Estimated mid-latitude A indices were 2, 6, 20, 9, 5, 7, and 6, with a mean of 7.9.

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