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The K7RA Solar Update


The average daily sunspot numbers fell 13.5 points this week, from 61.1 to 47.6, while the average daily solar flux was about the same this week as last, rising 1.1 points to 102.7. Geomagnetic indices were even quieter this week than last. Sunspot numbers for December 6-12 were 49, 23, 35, 40, 49, 55 and 82, with a mean of 47.6. The 10.7 centimeter flux was 97.4, 97.1, 101.1, 103.7, 104, 103.7 and 111.9, with a mean of 102.7. The estimated planetary A indices were 1, 1, 1, 4, 3, 2 and 2, with a mean of 2. The estimated mid-latitude A indices were 2, 1, 1, 3, 3, 2 and 3, with a mean of 2.1.

The predicted solar flux is 115 on December 14, 120 on December 15-16, 115 on December 17-19, 110 on December 20-21, 115 on December 22-23, 110 on December 24-27, 100 on December 28-29, 95 on December 30-January 3, 100 on January 4-5, and rising to 105 on January 6-8. The solar flux then jumps abruptly to 125 and 130 on January 13-14. The predicted planetary A index is 5 on December 14-15, 8 on December 16, 10 on December 17, 5 on December 18-28, 8 on December 29, 5 on December 30-January 5, 7 on January 6-7, 5 on January 8-9, 8 on January 10-11 and back down to 5 on January 12-27.

Both NASA and NOAA have tweaked their predictions for the peak of the current solar cycle for next year. Click here to see the NOAA changes and select “PRF 1940” and go to page 12. Then open another browser window and select “PRF 1944” and go to page 16. Notice that in the November prediction, the cycle peaks at 90 for May-July 2013, and the smoothed sunspot number for January-April is 81, 83, 85 and 88. In the December prediction, we see two instead of three peak months, June and July 2013. The numbers for January-May are 79, 81, 83, 86 and 88. This is a marginally weaker predicted peak for Solar Cycle 24.

The latest NASA prediction is here The change here is from 73 to 72 for a smoothed sunspot number maximum in the December 10 prediction, compared to the November 2 prediction. The other change is last month they wrote that “the smoothed sunspot number (for 2012/02) is already nearly 67 due to the strong peak in late 2011, so the official maximum will be at least this high.” This month, the end of the line was changed to “at least this high and this late.”

Sen on Bob Kile’s, W7RH, Facebook page on Tuesday: “For those low band operators out there, the solar activity remains low and the solar wind is under 300km/sec. That means West Coast to Europe, boys! I have six in the log last Saturday night and there have been West Coast openings since last Friday.” I believe Bob is referring to 160 meters.

Lloyd Berg, N9LB, of Oregon, Wisconsin (Oregon is a town just south of Madison) wrote about the ARRL 10 Meter Contest: “This year required a continuous effort on Friday evening, all day Saturday and all day Sunday, including numerous ‘dead band’ times of waiting and wondering if the band was going to come back or not. I can see a large chunk of the band on my SDR’s panoramic display, and when I say the band went dead, I see it happening just like somebody turned down the RF gain -- it only took a minute or two to extinguish all signals. I’d actually transmit just to make sure the antenna was connected. I also looked out the window many times to see if the antenna was still there (it was). It was really odd.

“At the beginning of the contest, the solar numbers looked awfully low for decent 10 meter propagation: a solar flux index of 97, a smoothed sunspot number of 23, with the A index at 1 and the K at 0. Conditions were very weird from my Wisconsin station. The band kept going dead, then we’d have a bit of garden variety e-skip ‘here and there,’ then dead again. Then it would open up real wide, going way beyond simple E-skip, north, south, east and west all at the same time.

“I worked everything east of the Mississippi in North America (E-skip). I worked Hawaii, and more Alaskan stations than I ever have in any other single contest ever. I worked a lot of stations in British Columbia and even one in the Northwest Territory, but I never heard most of the Rocky Mountain states. It was easy to work every active station in South and Central America, and the Caribbean -- day or night. I saw nice and strong -- but short-lived openings -- to the Azores, Cape Verde and the Canary Islands. I also worked several stations in South Africa, Australia and New Zealand -- and even the South Cook Islands -- during a few short precious minutes of openings on Saturday evening and again on Sunday afternoon. I didn’t hear anything from Japan or Asia at all. My only European contacts were a couple of stations in Spain and Portugal, again during a very brief opening (well after their sunset).”

Thanks, Lloyd!

Jeff Hartley, N8II, of West Virginia wrote, also about the ARRL 10 Meter Contest: “Sunday was noticeably better than Saturday in the contest this past weekend. I only worked about 15 European stations all weekend, but conditions to the West Coast were extremely good and we had plenty of E-skip Friday night and Saturday night into Minnesota, Wisconsin, South Dakota, Iowa, Missouri, Kansas and Oklahoma, as well Maine and the western portions of Canada. In the last hour, there was E-skip into Puerto Rico and North Carolina, South Carolina, Alabama, Kentucky, Tennessee, Florida, Mississippi, Arkansas, Louisiana and Texas.

“The highlights included a great long path opening to Asia on Sunday, which lasted for hours, starting around 1250 UTC on CW. Sunday was extremely good to the West Coast from 1710-2235 UTC, with one station in Washington State running .5 W with a solid S4, and even mobiles had solid signals. All states were worked on CW, and only missed Alaska on phone. There was propagation of some sort to all states at one time or another, with only the very close states on backscatter only.”

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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