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The K7RA Solar Update


We are more than halfway through the winter season, and today -- February 17 -- is 58 days after the winter solstice. Propagation should improve as we approach the vernal equinox on March 20, which is just 32 days from now. Solar activity is still in the temporary doldrums, with sunspot numbers below 100, but the weekly average of daily sunspot numbers rose this week by more than 15 points to 55.6. Sunspot numbers for February 9-15 were 33, 51, 62, 80, 59, 64 and 40, with a mean of 55.6. The 10.7 cm flux was 99.2, 110.8, 112.3, 110.4, 108.4, 107.4 and 104.6, with a mean of 107.6. The estimated planetary A indices were 4, 4, 4, 4, 8, 10 and 22, with a mean of 8. The estimated mid-latitude A indices were 4, 4, 3, 3, 7, 8 and 18, with a mean of 6.7

There was a geomagnetic storm on Wednesday, February 15 (UTC). Early in the UTC day (Tuesday night in North America), the planetary K index went to 5 and the planetary A index was 22. The College A index in Fairbanks was estimated at 46, which is quite high. The disturbance was probably from a CME a few days earlier. Aurora in North America was seen as far south as Minnesota.

The latest forecast has solar flux about 65 points lower than last month’s prediction for the ARRL International CW DX Contest this weekend. The latest predicted flux values are 105 on February 17-18, 100 on February 19, 110 on February 20-21, 115 on February 22-26, 110 on February 27-29, and 105 on March 1-3. The predicted flux values go back to 115 on March 14-16 and again on March 20-24. The predicted planetary A index for February 17-19 is 5, 8, 8, and then 5 on February 20-March 1.

The latest sunspot cycle prediction from NASA is in, and it doesn’t look good. Two weeks ago, NASA released a revised prediction stating the cycle should peak in late 2013 at a smoothed sunspot number of 96. The latest outlook estimates a peak in early 2013 at 63, about 35 percent lower than the prediction from two weeks ago. We hope it isn’t true.

Tom Little, WA9BOT, of West Frankfort, Illinois (EM57), reports: “On Wednesday, January 25, I heard a couple of 6 meter QSOs. While I heard no call signs, I was able to determine the stations were in New Mexico and Florida. They were using 50.165 MHz. I heard another QSO at 50.150 MHz, but could not pick up a call sign as what I heard was only one side of the QSO. I am new to 6 meters, and just recently put up a 5 element beam. I am waiting for a good opening.” Thanks, Tom.

Dan Bates, N5TM, of Katy, Texas, wrote: “ZL1RS was loud into South Texas on 50.105 MHz starting around 0230 on February 8, and lasted for about an hour. I personally worked Bob three times, twice on CW and once on SSB. He also worked WD5IYT, and many others. At times, he was S9.” That’s loud!

Jon Jones, N0JK, of Wichita, Kansas, writes: “FK8CP had an extensive opening on 50 MHz to the Midwest on February 12. States hearing and working Remi included Arkansas, California, Iowa, Illinois, Indiana, Kansas, Mississippi, Missouri, Nebraska, Ohio, Oklahoma and Texas. This was an E-s link to TEP opening. FK8CP peaked up to 5×9 in Kansas and Ohio between 0200-0220 on February 13.”

Not all articles about solar activity in the popular press are accurate. Leave it to Britain’s Fleet Street tabloids to make normal solar activity sound like the end of the world. Of course, the Sun is massive and the amount of energy involved in solar events is huge, but check the headline for this article: Massive Sunspot that has DOUBLED in Size in Recent Days Could Send Solar Storms Careering toward Earth. You’ll note that these journalists reserve the right side of paper for the really substantial news. Note they get their information from the Spaceweather website, but check the archive in the upper right corner, dialing back to February 11. Yes, the sunspot doubled in size, twice actually.

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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