The K7RA Solar Update
Our Sun has been very active this past week, with the average solar flux rising nearly 12 points to 155.5, while the average daily sunspot numbers dropped nearly 41 points to 96.1. This implies fewer, but more intense, sunspots. Sunspot numbers for September 22-28 were 86, 90, 88, 108, 103, 82 and 116, with a mean of 96.1. The 10.7 cm flux was 150.8, 158.2, 190.4, 168.8, 148.2, 139 and 133.4, with a mean of 155.5. The estimated planetary A indices were 3, 3, 4, 4, 67, 30 and 24, with a mean of 19.3. The estimated mid-latitude A indices were 2, 2, 3, 4, 20, 22 and 13, with a mean of 9.4.
A huge sunspot group numbered 1302 emerged on September 22. This was the source of a coronal mass ejection that triggered an immense geomagnetic storm. The planetary A index peaked at 67 on September 26, followed by 30 the next day and 24 on September 28. The planetary K index reached 8 for two of the three-hour reporting periods on September 26, indicating an intense geomagnetic storm. The resulting aurora was observed in many places, including Maine, Massachusetts, Michigan, Minnesota, New York, North Dakota and South Dakota. On September 22, there was a major X1.4 class solar flare at 1100 UTC, with a large CME, but this was when sunspot 1302 was just coming over the horizon, so it wasn’t Earth-directed. On September 24 sunspot group 1302 produced a larger X1.9 flare, and today the group is just past the point where it is directly facing Earth, but still in the middle of the visible solar disc. It could still produce more flares.
A sunspot group area is measured in millionths of a solar hemisphere, and for sunspot group 1302, the measure for September 22-28 was 480, 840, 1300, 980, 950, 980 and 1070. The combined area for all visible sunspot groups peaked at 1930 on September 24. This is the largest measure of sunspot area since January 15-16, 2005 in Solar Cycle 23, when the numbers were 1980 and 1960. The time period between those big numbers is six years, eight months and nine days. Other big numbers over the past decade for total sunspot area were 2420 on July 21, 2004, 5690 on October 30, 2003 (sunspot number was 293 that day) and 3940 and 3160 on March 29 and September 24, 2001. The sunspot number on both those days in 2001 was 315.
Another big number this week emerged on September 24 when the solar flux was 190.4. The number hasn’t been this high since November 2, 2003 when it was also 190.4. The days prior to that beginning on October 25, 2003 had solar flux values of 221.5, 298.3, 257.2, 274.4, 291.7, 271.4, 248.9 and 210.4. This was probably the last big blast of solar activity for Solar Cycle 23, as nothing since then comes anywhere near that level.
Currently, the latest forecast (which is actually from Thursday, September 29) from NOAA/USAF has solar flux at 140 for September 30-October 3, then 135, 130, 135 and 140 on October 4-7, then 145 on October 8-10 and 140 on October 11-17. The predicted planetary A index is 12 and 10 on September 30 through October 1, then 5 on October 2-7, then 8, 15, 12 and 8 on October 8-11, and 5 on October 12-21. Geophysical Institute Prague expects unsettled conditions on September 30, quiet to unsettled October 1-3 and quiet October 4-6.
A note from Tom Jerardi, K3CXW, corrects our reference to the autumnal equinox in the northern hemisphere, as it means equal day and night, which is independent of hemisphere.
Fred Honnold, KH7Y, is in Ocean View, Hawaii, on the southwest part of the Big Island. Fred reported that on Thursday night, September 23 he worked three new countries on 6 meters and that “Six is cooking.” He has worked 56 countries on 6 meters since 2006. He wrote that he worked “BV2DQ at 0324, PP5XX at 0404, DU7/PA0HIP at 0455 who most of the evening was 569, and LU5FF for an 11,000 km QSO at 0512, plus FK8CP (loud). It all ended at 0804.” After Fred worked PP5XX (in grid square GG55QW, 12541 km away), PP5XX worked BV2DQ via long path. BV2DQ was running 100 W into a small antenna.
Julio Medina, NP3CW, in San Juan, Puerto Rico, reports that on September 23, 10 and 12 meters were open for many hours to Europe. In four hours, he worked 75 stations from Europe on 10 meters and 4X4K in Azerbaijan. He had 60 contacts with Europe and some North America on 12 meters, and he worked 40 Japanese stations in one hour on 12 meters CW. On 6 meters, he worked a number of stations across South America.
Don Keith, N4KC writes: “I’ve been licensed for 50 years this year, since I was 13, but somehow, I always managed to be inactive during sunspot maxima. I’ve really been anticipating this cycle, and not so patiently, I admit. But tonight between 0015 and 0110 (September 23) made the wait worthwhile. In about an hour, I worked 4W6A in East Timor, JT1RF in Mongolia and JH7PKU in Japan, all with good signals on 12 meters. I only run 100 W and use a hexbeam on 12. The solar flux was reported as 173. Twelve meters is a totally new experience for me, since it wasn’t even a ham band when I was active before and has been spotty since 2005 when my interest was rekindled.”
Scott Avery, WA6LIE, of Salinas, California is also excited. On September 25 he wrote: “Wow! The solar flux up to 190 and solar activity is on the rise! Ten meters today was like Field Day. The band was open to Europe, Africa, Australia and New Zealand. I could randomly spin the dial in the SSB portion and find a signal. This reminds me of the late 1980s when 10 was open most of the time. I’m looking forward to the MUF getting up to 50 MHz. I saw a DX spot, F2 from a station in San Diego to New Caledonia on 6 meters. This looks promising. It’s time for the technicians to get in there and work some DX!”
On September 25, I received a note from Nagoya: “This is JQ2UOZ (Name: ‘Aki’) of Nagoya, Japan. The band conditions on 12 meters have been excellent recently. Using an output power of only 500 mW and a dipole antenna, I was able to work FG5FR in Guadeloupe (September 21) and YV1DIG in Venezuela (September 23) on 12 meters CW. The area around the Caribbean Sea is the most difficult area to work from Japan. In addition, using the same equipment, I was able to work K2ZJ in New York on 12 meters band CW (September 23). Surprisingly, according to an e-mail from him, he was using a very simple antenna, that is, a double extended Zepp for 17 meters band!” The double extended Zepp is a dipole 1.28 wavelengths long, or about 66 feet on 17 meters, but apparently K2ZJ used his on 12 meters.
Peter Laws, N5UWY, is net control on a local 10 meter net in Norman, Oklahoma. He wrote that he was surprised to hear Randy, KH6RC, of Hawaii (actually in the same Big Island village that KH7Y is in) check into his net on September 22 at 0130 with a great signal, and everyone could hear and work him. Peter was surprised, but with recent solar activity, that report is not surprising. A check with W6ELprop shows that path would probably be open until at least 0300. But run the same numbers again for July or August, and the results are much different: no likely propagation over that path.
Angel Santana, WP3GW, of Trujillo Alto, Puerto Rico, is also giddy with joy over recent propagation. He worked the CQ WW RTTY Contest and wrote: “What a roll! I made more than 350 contacts, something I have never made before on a digital contest. This included 63 DXCC entities, including 34 from Europe and three new countries on RTTY, including DXpedition OJ0X, UN1L and OD5HJ. My friend Jose Rivera, KP4JRS made 600 plus, and Victor, NP4BM, made almost 900. I later learned about the 190 solar flux number! Even Europe came strong on 10 meters as of 1315 on Sunday.”
Jon Jones, N0JK, of Wichita, Kansas is active on 6 meters, and reports: “I had a single hop F2 opening on 6 meters on September 26, due to the geomagnetic storm that day. From Kansas, I worked 9Y4VU and HP3TA, both on CW around 2215. I heard HC1HC, NP4A and the HK6FRC/b. I also heard the OA4TT/b FH16 on 50.077.”
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.