The K7RA Solar Update
The predicted Field Day geomagnetic storm never appeared, although conditions were unsettled leading up to last weekend. The average daily sunspot numbers for the week were down 13 points compared to the previous week, while the average daily solar flux was off by more than 7 points. Sunspot numbers for June 23-29 were 47, 62, 47, 26, 30, 37 and 45, with a mean of 42. The 10.7 cm flux was 96.3, 96.2, 93.6, 90.1, 89.2, 86.9 and 87.3, with a mean of 91.4. The estimated planetary A indices were 18, 10, 7, 7, 5, 4 and 2, with a mean of 7.6. The estimated mid-latitude A indices were 16, 10, 5, 6, 4, 2, and 2 with a mean of 6.4
The planetary A index was 7 for both Saturday and Sunday, and mid-latitude A index numbers were 5 and 6. The predicted solar flux for the near term is quite a bit lower than recent numbers. The forecast shows solar flux at 87 for July 1-5, then 90 on July 6-8, 88 on July 9, 92 and 96 on July 10-11, and 100 on July 12-15, then back to 88 on July 16. Expected planetary A index is 8, 10, 12 and 8 July 1-4, 5 on July 5-7, 7 on July 8-9, and 5 again on July 10-18. Geophysical Institute Prague says to watch for unsettled conditions July 1, unsettled to active July 2, unsettled July 3, quiet to unsettled July 4-5 and quiet July 6-7.
The Space Weather Prediction Center has decided not to drop the hourly geophysical report, and due to all the feedback, they may actually expand it. See the official announcement here.
Now that June has passed, let’s look at the three month moving average of sunspot numbers. Centered on June 2010 through May 2011, the moving average of daily sunspot numbers was 20.4, 23.2, 28.9, 33, 35.6, 31, 30.1, 35.3, 55.7, 72.3, 74.4 and 65.9. We have to look quite far back to find moving averages of daily sunspot numbers as high as the last few months. Back in 2004, the three month moving average of daily sunspot numbers -- centered on June through December -- was 80.8, 78.1, 69.3, 66, 66.3, 61 and 52.2.
Mel Frost, KD7DCR, of Whitehall, Montana (DN35), reports that on June 29 at 0301, he worked NZ5E and AB5F on 6 meters, both in Eastern Arkansas. AB5F faded from S6 into the mud about 35 minutes later; NZ5E started at S9 +10 and faded to S8 until they finally signed off at 0420. He couldn’t find any evidence on DX Sherlock of others enjoying this path.
Jon Jones, N0JK, of Wichita, Kansas (EM17jr), wrote that on June 25 he worked PJ6D at 1704: “They came up on a QSB peak, worked AC0A then me. I sent the usual 599, but it was more like a 579. They had a solid clear signal and a clean confirmed QSO. I heard them earlier at 1600, but they were very weak, like on scatter. They are running an amp, so I was hearing them better than they me. I had to call several times to get a response. PJ6D faded down shortly after I worked them. I had just come in the apartment after helping my wife load some furniture in our car. I could have easily missed PJ6D. I could not go out portable today due to thunderstorms.”
Also on June 25, Bill Hohnstein, K0HA, of Seward, Nebraska (EN10lx) wrote: “I worked PJ76 at 1502 and PJ6D at 1506. Both were strong then. The PJs and others in that area were stronger with 120 degree Yagi phasing. That’s how my antenna was set when I worked them. By 1520, signals from that area were better with 0 degree Yagi phasing. I think that I had my earliest run of JAs today: 29 between 2137 and 2216, with two more around 2240. I think that JA6LCJ in PM52 was my furthest (10,457 km). I did a lot of antenna checks while working the JAs. All that I checked were stronger with 120 degree phasing between two of my Yagis! Most were pretty much unworkably weak with 0 degree phasing and with just my 6M7 being fed. My adding the phasing option is definitely a success!”
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.