The K7RA Solar Update
Sunspot excitement continues, as we continue to see daily images of our Sun peppered with spots. The average daily sunspot numbers for the week were about the same as the previous week, increasing from 96.1 to 96.7, while the average daily solar flux dropped from 155.5 to 132.6. The three month moving average of sunspot numbers puts us into activity levels last seen in mid-2004. Sunspot numbers for September 29-October 5 were 99, 89, 86, 92, 85, 126 and 100, with a mean of 96.7. The 10.7 cm flux was 136.6, 138.1, 136.9, 130.9, 128.9, 130.3 and 126.7, with a mean of 132.6. The estimated planetary A indices were 15, 8, 9, 11, 6, 6 and 20, with a mean of 10.7. The estimated mid-latitude A indices were 16, 5, 12, 7, 3, 4 and 12 with a mean of 8.4.
September is over, so now let us look at our three month moving average of sunspot numbers. The three month moving averages for this year -- centered on January through August (August would include numbers from July, August and September) -- were 35.3, 55.7, 72.3, 74.4, 65.9, 61.5, 63 and 79.6. The jump to 79.6 is a big increase. The three month moving average centered on June 2004 was 80.8, which was the last time the average was near 80.
The latest NOAA/USAF forecast shows solar flux at 125 on October 7, 130 on October 8-13, 110 on October 14-16, 115 and 120 on October 17-18 and 125 on October 19-29. Planetary A index prediction shows 10 on October 7, 8 on October 8 and 5 on October 9-27, followed by 8 on October 28-30. Geophysical Institute Prague predicts quiet to unsettled conditions on October 7-8, unsettled October 9-10 and quiet on October 11-13. The monthly sunspot maximum prediction from NASA has the next sunspot maximum moving forward a month from May to April 2013, with the sunspot maximum 7 points higher. Last month, the smoothed sunspot number was predicted to peak at 70 in May 2013, and now the number is 77 in April 2013. You can read it here. Note that these are International Sunspot Numbers, which are much lower than the Boulder numbers reported in this bulletin.
Last week, we had a report from Fred Honnold, KH7Y, of Hawaii with 6 meter news. A week ago, he sent this follow-up, so when he refers to Wednesday night that is September 28 and “last night” is Thursday, September 29. Fred writes: “On Wednesday night, I worked 21 VK4s. Earlier in the evening, I worked LU5FF. Yesterday, I worked ZP5SNA, TI7/N5BEK, LU5FF, 3 Brazilian stations, but Australian or Philippine stations, just Central and South America. I had a station in Venezuela and Ecuador call me, but I didn’t have QSOs with them. Another very interesting QSO I had last night is worth chatting about. I worked Peter, PP5XX, that is a 12,500 km path, and within a few minutes, Peter worked BV2DQ, long path, 20,000 km path. Not bad for 6 meters. That 20,000 km QSO between PP5XX and BV2DQ is exciting for sure.
Joe Flamini, W4BXG, of White Hall, Virginia writes: “I worked Cardiff, Wales on 10 meters mobile on my way to work on September 27, and Puerto Rico on my way home. Wow!”
Bill Tynan, W3XO, of Kerrville, Texas, says that Sunday, October 2 was his best day in the new solar cycle for 6 meters. He lists a bunch of calls from South America and notes, “Although many classify all north/south propagation as TEP, I contend that much of it is F2. Certainly the Ecuadorian stations who are north of the geomagnetic equator are not TEP. On 6 meters, I run 700 W to a 50 foot boom at 70 feet.” TEP refers to trans-equatorial propagation.
Carl Luetzelschwab, K9LA, was interviewed in a Tampa, Florida television news story about “solar storms.” Carl hadn’t seen it when reached in England, where he was headed to an RSGB convention, perhaps to give a presentation on propagation. Read it here. The RSGB also has an educational web page on VHF propagation.
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.