The K7RA Solar Update


Solar activity quieted down over the past week. There were no sunspots on Wednesday and Thursday -- October 6-7 -- and the average daily sunspot number declined nearly 18 points to 27.6, compared to the previous week. The average daily solar flux values were off more than 3 points to 81. Sunspot numbers for September 30-October 6 were 45, 44, 42, 28, 23, 11 and 0, with a mean of 27.6. The 10.7 cm flux was 89.9, 86.7, 85, 80, 76.1, 75.4 and 74.2, with a mean of 81. The estimated planetary A indices were 1, 3, 2, 3, 3, 6 and 8, with a mean of 3.7. The estimated mid-latitude A indices were 1, 0, 0, 1, 2, 6 and 5, with a mean of 2.1.

The predicted solar flux for the next 10 days -- October 8-17 -- is 76, 78, 78, 80, 80, 80, 80, 82, 81 and 83. The same forecast predicts a planetary A index of 5 on October 8-10, 10 on October 11, 7 on October 12-14 and 5 on October 15-17.

The STEREO image early Friday morning shows an active region in our Sun’s southern hemisphere passing over the eastern horizon. This has not yet manifested any sunspot groups. Currently, the STEREO image covers about 94.8 percent of the Sun’s surface. That coverage should reach 96 percent at the end of October, 97.4 percent at the end of November, 98.7 percent at the end of this year and 99.8 percent at the end of January 2011. Finally, on February 7, 2011, STEREO should reach 100 percent coverage.

Jeff Hartley, N8II, of Shepherdstown, West Virginia, sent in a report nearly a week ago concerning Wednesday, September 29: “Wednesday was a very good day for propagation. I worked lots of Asiatic Russians with good signals around 0100 on 20 meters. I also heard JAs after 2300 on 20 meters for the first time in quite a while; JT1BV was near S9 on SSB. Thursday, my day off, was not as good with 15 meters opening around 1300 (late) to Europe, with some good signals mostly from Southern Europe. I heard no signals all morning on 12 meters, except for beacons including ZS6DN; CQs toward Africa yielded nothing. In the evening, I heard a weak XW1B on 17 meters CW (I worked him a few days prior with better signal), and on 20 CW at 0030, he was about S7 and commanding a CW pile-up. I had quite a struggle catching 9M6XRO/P or 9M6DXX/P due to a disturbance at first, and then my 20 meter amp failed and I couldn’t crack the Europeans calling on Sunday. I also had no luck Monday around sunrise on 40, then finally succeeded on 17 meters CW around 2200 Monday and that QSO was easy.”

Larry Godek, W0OGH, of Gilbert, Arizona, send in this report on October 1: “What a week it’s been on 15 meters. Europeans galore: VP8, DU, 5R8, YY0, 5X1, 8R1, 4Z5, EA7, YU, A71, OE, YO and HZ. Early mornings for the Europeans and Middle East, around noon for Africa and the South Atlantic/South Americans. On the 19th, I worked 7V2, 9H1 and ER4 on SSB. Makes you want to jump up and shout! Now for that TS7 who everyone is working and I can’t even hear him. Some of the SSB contacts have been rough because I only have 100 W, but playing the propagation game has paid off. Getting through the Atlantic and Midwest wall is a chore indeed. Trouble is that you can’t hear much of the folks to the east when they are working east and south and you’re working the same directions. I put up a 5 element 15 meter beam at 25 feet this spring expecting great results; I think it's helping a bit. A kilowatt or bit more power would do wonders, but I’m sticking to my guns and doing it with 100 W and better antennas.”

Gordon Curling, VE3KKL, of Kars, Ontario, asked why the solar flux numbers presented in this bulletin are not the same numbers he hears on WWV. The solar flux values are actually from the same source at Penticton in British Columbia. The difference here is we present them resolved to 0.10 of a point, but WWV rounds them off to whole numbers. So on March 13, Gordon shows 92 from WWV and the observatory reported 91.8. Or on February 8, Gordon recorded 94 from WWV and the observatory reported 93.7.  The same numbers are reported on WWV and you can go to here to see the original numbers. Just look at the noon daily reading (there are readings in the morning and afternoon, but the noon reading is the official daily number) and look at the observed solar flux in the “fluxobsflux” column.

Bob Karpinski, WB8B, of Clinton Township, Michigan, reports: “With the recent spike in solar flux into the high 80s, 12 meters produced a quick, but nice little opening for me into Europe around 1630 on October 2 with a 5 WQRP CW QSO with S57DX. By being in the right spot at the right time of the day, QRP DX is still achievable and should only get better on the higher HF bands this winter with the flux finally perking upwards.”

On Oct 5 at 1530 Joe Kraft, CT1HZE/ DL8HCZ, from Southern Portugal reports a 2 meter sporadic-E opening to France. Although the opening was just 8 minutes long, and only one QSO was made with a French station over a distance of about 1800 km, Joe notes this event is quite remarkable as it is the first time that 2 meter Es was reported in the month of October in Europe.

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 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.