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The K7RA Solar Update

06/24/2011

Over the past week -- June 16-22 -- the average daily sunspot number rose nearly 20 points to 55, while the average daily solar flux readings increased by nearly 9 points to 98.6. All geomagnetic indices declined slightly. These increases or decreases are relative to the previous seven days before June 16. Sunspot numbers for June 16-22 were 62, 65, 67, 47, 43, 57 and 44, with a mean of 55. The 10.7 cm flux was 103.3, 104.3, 99.2, 99.1, 96.4, 95.1 and 92.9, with a mean of 98.6. The estimated planetary A indices were 4, 11, 4, 4, 7, 10 and 12, with a mean of 7.4. The estimated mid-latitude A indices were 3, 8, 4, 3, 7, 8, and 7 with a mean of 5.7.

For the past month, we’ve been looking nervously toward ARRL Field Day because a forecast from NOAA and USAF showed possibly unsettled geomagnetic conditions on Friday, June 24, and continuing through Field Day weekend. The forecast has evolved from troubling to frightening and back again. Early in June, the predicted planetary A index for June 24-26 was 18, 18 and 15. Then on June 7, it changed to 15, 15 and 10, a little better. Then a week later on June 14, things looked even more promising at 15, 10 and 5. But on June 17, it was revised upward to 30, 15 and 5. A planetary A index of 30 indicates a geomagnetic storm. The next day on June 18, the forecast shifted to 25, 18 and 8, and on June 19, it changed again to 25, 18 and 10. June 20 saw a slight change to 25, 18 and 8 again, then on June 21, it shifted to 15, 40 and 25. An A index of 40 on the first day of Field Day sounds ominous. On June 22 it changed again to 30, 10 and 10, and now the June 23 prediction for June 24-26 shows a planetary A index of 30, 18 and 12.

Basically, we would love to see the A index as low as possible, 5 or less would be wonderful. The latest news is that the solar wind from a coronal mass ejection (CME) which occurred on the solstice is moving slower than originally thought, which means a weaker effect here on Earth. A planetary K index of 5 is expected when the storm arrives, now predicted at 0700 on June 24, which is 35 hours before the start of Field Day, 1800 on June 25.

At 0640 on June 23, the Australian IPS Radio and Space Services released a bulletin stating that increased geomagnetic activity is expected on Jun4 23-24, due to the CME, but that the effect on June 23 is expected to be mild, with a small chance of isolated storm periods.

Geophysical Institute Prague predicts active conditions June 24, unsettled to active on June 25, quiet to unsettled June 26-27 and quiet on June 28-30. The most recent forecast from USAF and NOAA has solar flux at 95 on June 24-25, 90 on June 26-30, 85 on July 1, and 95, and 93 and 90 on July 2-4. The predicted planetary A index for June 24-26 is 30, 18, and 12, 8 on June 27-28, and 5 on June 29-July 1.

Check here for the last forecast before Field Day, which should be released after 2100 on Friday, June 24. Check here and here for the latest K indices. Click here for solar flux, sunspot number and other data such as sunspot area.

Ron Zond, K3MIY, of Clarion, Pennsylvania, found an interesting article in an old QST from a half-century ago. John Chambers, W6NLZ, wrote “After Sunspots -- What?” on pages 66-67 in the March 1960 issue. I was about to dig out that old issue when I remembered that ARRL members can access an archive of QST magazines running from December 1915 to December 2007. This article was written just after the peak of Solar Cycle 19 (which was huge!) and in it, the author speculates on what a future with little or no sunspots might hold. I thought W6NLZ seemed like a familiar call from my childhood, and he was known back then for his VHF records establishing contact with KH6UK. Click here for photos of both of them.

Thanks to a number of hams who sent in this article from Sky & Telescope about disappearing sunspots.

Jeff Hartley, N8II, of Shepherdstown, West Virginia, sent in his observations on recent conditions: “Conditions have seemed down from 2-3 weeks ago, but there has been a decent amount of sporadic-E as we near the peak of the season, which seems to me to be right around July 1 on average. Late into the evening, openings to Europe on 15 meters and higher have been much rarer, but there was some good propagation reported in the All Asia CW Contest by others. Around 0100 Sunday on 15 meters phone, I worked Jim, E51JD, in Rarotonga, South Cook, with a S9 signal. He was only running 100 W to a small low tribander. On Saturday, June 18, I was active in the West Virginia QSO Party and the sporadic-E continued to abound again this year, just as it did in 2010. Not much was happening right at the 1600 start, but by 1700, skip on 20 phone was short enough to work the other side of West Virginia, Southern Virginia and many in North Carolina. I even worked a guy in Weaverville, North Carolina in the Smoky Mountains where I had stopped for breakfast a day ago -- small world! There were plenty of Ohio and Kentucky stations for a while, then the band opened to the northeast and even as close as Delaware about 140 miles from here! I managed to work all states, except Alaska and Vermont (propagation and QSO total to neighboring New Hampshire was good) in a few hours. Ten meters was not quite good enough to spend much time there while I was able to operate, but at 0100, there was double hop E-skip to California, Nevada and Arizona. On Friday June 17 around 2200, 6 meters was open to FM5AA, FM5AN, V44KAI and FG5FR. There were about the normal amount of E-skip on 6 meters during the June VHF contest with C6, VP9 a few double hop stations in the Rockies, as well as lots of W4s, W5s and southern W0s logged.”

Lawrence, GJ3RAX, of the Isle of Jersey, observes: “I have had some comments from Nick, VE3OWV. I have known him for a long time as we were at university together in England in the early 1960s. He has also noticed that although the sunspots have been increasing recently, the propagation has not improved in the way it did at a similar stage of previous cycles. We have not been able to get back to our skeds on 17 that we used to keep, so e-mail has had to do instead. He did say that he has been having QSOs to Europe on 17 at about 11 to 12 PM my time. Normally, I only look on the bands during the afternoons, so I will start checking them again at that time. I used to enjoy late night QSOs when I was younger, but my stamina is now rather less than it used to be!”

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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