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The K7RA Solar Update


Solar activity remains quiet, but on May 16 the daily sunspot number reached 212. I had to keep searching farther and farther back in the records to find a higher sunspot number. One year, six months and one week earlier -- November 9, 2011 -- the sunspot number was almost that high, at 208. Going back seven years, 10 months and 12 days to July 4, 2005, it was 192. To find activity beating the May 16 number, we have to go back nearly a decade to November 1, 2003 when the daily sunspot number was 277. This was on the downward slide of Solar Cycle 23 -- nine years, six months and 15 days earlier than our recent high number. Let’s hope for many more days like this. That seems likely, as the peak of this solar cycle is predicted for this fall, which begins about four months from now on Sunday, September 22.

This week, the average daily sunspot numbers this week were down more than 12 points to 144, while the average daily solar flux declined nearly 6 points to 134.2. Geomagnetic activity was higher, with the average daily planetary A index up 3.7 points to 9.7, and the average daily mid-latitude A index rose 4.4 points to 10.3. Sunspot numbers for May 16-22 were 212, 198, 146, 113, 113, 119, and 107, with a mean of 144. The 10.7 centimeter flux was 144.7, 136.4, 132.1, 135.3, 132, 125.3, and 133.4, with a mean of 134.2. The estimated planetary A indices were 14, 9, 21, 12, 7, 7, and 12, with a mean of 9.7. The estimated mid-latitude A indices were 12, 9, 16, 11, 6, 8, and 10, with a mean of 10.3

The latest prediction from NOAA/USAF has the solar flux at 135 on May 24-25, 130 on May 26-27, 135 on May 28-29, and then 130, 115, 105 and 110 on May 30-June 2, 120 on June 3-5, and 125 on June 6-8, before rising to a short-term peak of 140 for June 12-13. This prediction is a bit far off, but it also shows a minimum flux value of 100 on June 26-27. Turning to geomagnetic activity, the predicted planetary A index is 15, 20, 12 and 8 on May 24-27, 5 on May 28-June 10, and then 8, 12 and 8 on June 11-13, 5 on June 14-17, and then 15, 12, 8 and 5 on June 18-21. On June 24, a month -- and about on solar rotation -- from now, they show the planetary A index rising from 5 to 15, perhaps an echo of current geomagnetic activity.

The CQ World Wide CW WPX Contest weekend begins tonight/tomorrow at 0000 UTC May 25. The geomagnetic activity predicted for this weekend may add some additional challenges to the test, which has a new set of rules. The multiplier used is the number of unique call sign prefixes of stations worked.

The current geomagnetic activity is due to an M5 class solar flare on May 22; it is expected to deliver a glancing blow to our geomagnetic field today, May 24.

Jon Jones, N0JK, of Lawrence, Kansas, reports that during a 6 meter E-layer opening last Sunday evening, a rare Australia-to-North America opening took place. From 2355 UTC on May 19 until 0032 UTC on May 20, VK4MA worked W9FF, NW0W, K9ZM, WZ8D, W9WZJ and K0GU on CW. It appears the longest distance was to WZ8D, about 9041 miles. Jon believes the propagation path was via E-layer linked to trans-equatorial propagation.

On May 17, Jim Smith, K3RTU, of Aston, Pennsylvania, took his backpack rig into Ridley Creek State Park in Southeastern Pennsylvania (grid square FM29). He wrote: “After some hiking, I stopped around 1730 and set up my Buddistick vertical and new transceiver. I tried 15 meters first, but I had no luck and only heard a few stations, so I readjusted the antenna for 17 meters. After a few minutes, I worked Duncan, EA5ON/M via SSB and got a 5-4 report. Not too bad for vertical-to-vertical, but the interference on his end was troublesome. Duncan told me it was raining there with lots of atmospheric noise; later contacts with Western Europe confirmed that the bad weather was pretty widespread. Over the next two hours, I worked Dave, VP5/W5CW (my report 5-9); Mario, DJ2OR (5-5); Carolyn, W5/G6WRW, near Santa Fe, New Mexico (5-3); Al, VE7WJ (5-3); Jo, DF9ZP (5-9), and Mike IF9ZWA (5-5), on Favignana Island off the coast of Sicily. What amazed me the most was that I had good propagation both east and west of my location, which I don’t always find to be the case.”

And finally, I just ran across a previously overlooked e-mail from Wayne Mills, N7NG, of Jackson Hole, Wyoming, that was sent on January 4, 2013, reflecting on Solar Cycle 19. Wayne said: “I have seen all of the solar peaks since 1956. What I have to say, however, is that I had absolutely no expectation of what Solar Cycle 20 might be like. The reason was that when I was a sophomore in high school in 1958, I had no idea what sunspots were! I started working DX in 1956 with 90 W and a low 40 meter dipole. I was on 20 meter CW only. I had no worries about other bands, what might be open, what long paths might be open; I just listened and worked what I heard. It was just a few high school friends and me; we had very little contact with local DXers. Eventually, I ran into W6MX (Honor Roll 1955) and W6BAX, a serious DXer and I learned a few things. Soon, I put up a 2 element 20 meter beam, and then I had to worry about where to point it! Still, it took more than two years to earn DXCC. Things will never be the same.”

All times listed are UTC, unless otherwise noted.

Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears each Thursday in The ARRL Letter. You can find a guide to articles and programs concerning propagation here. Check here and here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.



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