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The K7RA Solar Update


The average daily sunspot numbers for the past week rose nearly 25 points, or about 27 percent, to 117.3. The big day was Monday, May 14 when the daily sunspot number jumped to 156. This was the day after four new sunspot groups, numbered 1481 through 1484 arrived. Sunspot numbers for May 10-16 were 93, 102, 85, 138, 156, 125 and 122, with a mean of 117.3. The 10.7 cm flux was 130.7, 136.4, 129.5, 130.5, 130, 129 and 130.9, with a mean of 131. The estimated planetary A indices were 12, 12, 10, 12, 6, 5 and 9, with a mean of 9.4. The estimated mid-latitude A indices were 11, 10, 8, 10, 7, 5 and 8, with a mean of 8.4.

The average daily solar flux rose 12 points to 131, an increase of 10 percent. For the near term, the predicted solar flux is 135 on May 18-20, 130 on May 21-22, 125 on May 23, 120 on May 24, 115 on May 25-31, 120 on June 1, 125 on June 2-3, 130 on June 4, 135 on June 5-9, and then 130 on June 10-12. The projected planetary A index is 15 on May 18, 8 on May 19, 5 on May 20-22, 8 on May 23, 5 on May 24-June 4, then 8, 12, 18 and 10 on June 5-8, 5 on June 9-11, and then 8 on June 12-13.

Check out this video for a wonderful look at sunspot group 1476 as it transits the Sun over the week of May 5-11. The images also have a lovely orchestral accompaniment.

If you plan to be in Washington, DC on June 5, you may want to attend the Space Weather Enterprise Forum 2012, held at the National Press Club.

The “Monster Sunspot” (group 1476) is all over the news, and here, as well. Be sure to follow the story all the way down the page below the video. A large scale photo of the spot, taken a week ago on May 11, is also available. Don’t miss a National Geographic article and photo gallery on solar activity. Sunspot size comparisons are all the rage this week, including this article from Universe Today.

Jim Hadlock, K7WA, of Seattle, Washington, is now in a limited antenna space, and just uses a couple of 17 meter mobile whips pointing out horizontally from a center feedpoint. Jim writes: “It's not that great an antenna -- I often hear West Coast stations working DX that I cannot hear myself. I check the band a couple of times a day for activity, since I'm trying to work 100 DXCC entities in 2012. On Tuesday, I worked number 50 (Scotland) and yesterday around local noon I worked Brunei. In addition to listening on the band for activity, the NCDXF Beacons at 18.110 and W1AW at 18.0975 provide a check on real-time propagation.”

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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