The K7RA Solar Update


Here we are, on the last day of the year, with finally some very positive indicators for Solar Cycle 24. Each day since December 9 (except for Christmas Day), sunspots have been visible. The average daily sunspot numbers for the week December 24-30 were 12.9, an 18.5 point drop from the previous week, which was a 10.3 point rise from the previous week, December 10-16. Sunspot numbers for December 24-30 were 11, 0, 13, 17, 17, 17 and 15 with a mean of 12.9. The 10.7 cm flux was 77.1, 76, 75.9, 76.8, 75.8, 75.1 and 76.9, with a mean of 76.2. The estimated planetary A indices were 2, 2, 3, 2, 1, 0 and 0, with a mean of 1.4. The estimated mid-latitude A indices were 1, 3, 2, 1, 1, 0 and 0, with a mean of 1.1.

The average daily solar flux dropped from 82.8 to 76.2 from the December 17-23 reporting week, but the December 30 forecast from the US Air Force predicts a solar flux value of 79 from December 31-January 3, 80 for January 4-9 and 85 for January 10-18. They also predict a steady and stable planetary A index of five through February 13. Geophysical Institute Prague predicts quiet for the first week of January. You can get an update on the Air Force/NOAA prediction after 2100 UTC.

Since December 26, we've been blessed with new sunspot group 1039, which is now just past the 0 degree meridian, referenced to Earth. This is the spot in the center of the solar image. This is the sixth new sunspot group to emerge in December. After today, we will know the three-month moving daily sunspot average centered on November, and it looks close to the average centered on August, 2007, which was 10.17; the moving average has not been above 10 since then. The daily average for the month of December should be close to 15.7, the highest monthly average since March 2008.

A number of sharp-eyed readers caught the major gaffe in the last bulletin -- when I dozed off, and with my fingers on autopilot, I typed spring equinox when I should have said winter solstice. Needless to say, spring is not six months off. The vernal (spring) equinox is only 79 days from today. Thanks to (in order of notification) N5UWY, WE5I, KW6G, KF7FIU, W3DM, N0LNO and WA3VKG for noticing -- and not having too much fun at my expense.

Joe Reisert, W1JR -- an exceptional low band DXer -- sent some comments about the solar minimum. I commented that the exceptionally quiet conditions are remarkable, and may partially make up for a lack of solar activity -- at least we aren't bothered by large flares. Joe responded: "I really don't think the low bands are that improved over times when the sunspots were there. Yes, it was nice to work TX3A and K4M on 160 meters for new ones, but I still can't get JT1CO to hear me! Sometimes JAs spot me on 160 meters, but no JAs call me! Except for early last February when one morning I worked seven(!) JAs in a row starting at my sunrise(!), I haven't seen any really great Asian openings. I guess I just have to hang in there. I did land VK9XX on 80 near our sunset for #341 about a month ago. That was a real thrill as he was only working Europeans and somehow I broke the pile up."

Rod Vorndam, K9ROD, of Rye, Colorado, wrote last week: "The past couple of weeks have seen openings to Europe at sunrise on 20 meters. This gray line effect has made for several strong contacts. I worked I2OHO (Italy), ON5CD (Belgium), HB9RDE (Switzerland) and received several others, including OZ1IKY (Denmark) and S51ZZZ (Slovenia). These are my first European contacts into the Western part of the US."

Mark Lunday, WD4ELG, of Greensboro, North Carolina, has a nice blog with observations on DX from his new location. Mark had this to say on Christmas Day: "One thing I have noticed recently, with the slight uptick in solar activity, is that 40 meters now reminds me of 20 meters during the solar peak. Even during daylight, there is DX open to somewhere on 40 in winter months; the exception is high noon. But mornings and late afternoons have lots of activity on 40. This afternoon, I copied HS0CZY/4 on 40 meters about an hour before my sunset. The last time I remember something like this was January 1, 2005 when I worked YB1A on 40 meters CW late in the afternoon. On Monday at 0100 local, I heard a fluttery signal RST 529, I copied JA7DLE, call him twice, he gets my call -- bam, he is in the log. I have one JA QSO all-time on 80, and this is my second ever on 40. This is with a single vertical and 100 W. What is neat about this is that it happens at 0100 local while I can hear EU stations 599 and South Cook Islands DXpedition 559. So I am copying Pacific, JA and Europe at the same time. When the Sun throws lemons, make your own DX/lemonade. I heard 4S7NE on 40 meters CW at 2030 local, just after his sunrise. I have tried to hear Nelson since I worked him on 17 meters back in 2005, but I have never heard him since. Amazing!" Thanks Mark.

Bob Doherty, K1VV, of Lakeville, Massachusetts, reminds us that tonight is ARRL Straight Key Night!

Jose Nunes, CT1BOH, of Lisbon, Portugal, sent some fascinating material that he posted to the cq-contest e-mail list titled "Listen to what happens when a X4.0 Solar Flare hits your contest operation." He referred to K9LA's article, "Solar Flares at ZF2RR." Jose writes: "It just happens that while operating P40E during the 2000 CQWW CW Contest, I was recording the event. And I still remember the black-out that followed the big X4.0 Solar Flare. I thought it would be interesting to share the story and the audio clip of the impact of the solar flare. First take a look at the Goes X-ray Flux (5 minute data) on November 25 and 26, 2002. I marked with an arrow the big solar X4.0 flare that occurred at 16:38 on Sunday, November 26 of the contest. P40E was QRV on 21.050 MHz. In the 40 minutes before the solar flare impacted P40E operation, 16:00 - 16:39, I had worked 107 QSOs at a rate of 160.5 QSOs per hour. In the 20 minutes after the solar flare impacted P40E operation 16:40 - 16:59, first there was a 7 minute black-out and then I managed to work 10 QSOs at a rate of 30 QSOs per hour. Very interesting is the surge of noise right after the Solar Flare until almost total black-out of the bands and during the 7 minute black-out. You will listen to a vanishing pile-up, to a dead band, and then the recovery of activity. You can check P40E log here to follow audio clip from 16:36 UTC until 17:02 UTC. Listen to the 26 minute audio clip here and note this was an SO2R operation so you should use headphones. You will listen on the left ear to the run radio on 21 MHz and the right ear to the S&P radio on 28 MHz before the QSY to 10." Fascinating! Thanks so much, Jose.

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 in The ARRL Letter. Check 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.