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The K7RA Solar Update

11/13/2009

Sunspot region 1029 disappeared after October 30, but not because it faded away -- it was transiting over our Sun's western horizon on its trip around the back side. Six days after it was gone, a new region -- region 1030 -- appeared for several days, November 5-7. On November 8, this region had faded away and seemed like other weak spots we've seen over the past couple of years, except they appeared for one day with a sunspot number of 11. Sunspot region 1030 ran for three days with sunspot numbers of 15, 16 and 11. But then on November 9, the sunspot region re-emerged, with sunspot numbers of 14, 13, 11 and 11 through November 12.

While 1030 is passing over the Sun's western limb, we can still see sunspot region 1029 transiting the far side of our local star, and now it is approaching its eastern horizon. A short time ago, this observation would have been impossible, but with the STEREO mission, our total vision of the sun now approaches 85 percent. Old region 1029 appears as a bright area of magnetic disturbance; we can't actually determine what the sunspot number or the total area of the region might be, but it still appears to have a large and robust magnetic signature.

The 45 day Air Force and NOAA Ap and flux forecast gives us some clue about the dates it may emerge into view, and when it is most directly facing Earth. Predicted solar flux is 73 for November 13, 74 on November 14, 75 on November 15-21 and 80 for November 22-24. After that, the forecast shows it declining to 75, 72 and 70. This suggests it might reach the most geoeffective position, that is, the position where it is near the Sun's central meridian relative to the Earth, around November 22-24. Sunspot numbers for November 5-11 were 15, 16, 11, 0, 14, 13 and 11 with a mean of 11.4. The 10.7 cm flux was 70.5, 70.9, 70.6, 70.9, 72.1, 72.8 and 72.4 with a mean of 71.5. The estimated planetary A indices were 1, 0, 1, 6, 4, 1 and 1 with a mean of 2. The estimated mid-latitude A indices were 0, 0, 0, 4, 2, 0 and 0 with a mean of 0.86.

Conditions have been good, with continued weak or missing solar wind and very quiet geomagnetic indicators. As noted in previous weeks, a check of geomagnetic data shows day after day with K index values at zero, which is as low as it can go. During past times and previous cycles, it was common to see a constant K index of 3, and an A index of 12-15 for mid-latitudes. Note in the paragraph above that the average daily mid-latitude A index for the past week was less than one!

That same NOAA and Air Force prediction shows a low planetary A index of only 5 for November 13-18, 8 on November 19-20, 6 on November 21 and back to 5 again for November 22 and onward. Geophysical Institute Prague for November 13-19 predicts quiet November 13-14, quiet to unsettled November 15 and quiet again November 16-19.

Bernie Mitchell, KD8KEO, of Wayne, Michigan, said he is a new Amateur Radio operator (about 9 months) and had good luck on 40 meters with the Nightwatch Net in the evening, but around the end of October after 0000 UTC, he noted that the signals seemed weak. He didn't say where the other stations are, but running some numbers through a propagation program, such as W6ELprop, it shows quite a seasonal variation between the end of October and two months earlier when using targets such as the center of the continental United States, or Atlanta, for example. But looking west, the propagation is better on 40. Using California as a target, about 2000 miles away, propagation seems to be good day and night in August or October, whether we have sunspot activity or not. Atlanta is only about 600 miles from Bernie, and 40 meters seems to need a longer path at this time of year, and also note that signals to the west have sunlight over the path much later in the day.

Willis Cooke, K5EWJ, wrote in with a comment about backscatter: "I read the October 30 Solar Update with interest, especially about the QSO between W5ZIT and AE5PW. On November 2, I found HL3ERJ at 5×7 on 17 meters SSB at 2311 UTC. I gave him a quick call in the pile and received a prompt answer with a 4×4 report. Many others across the Western US were calling but he could not hear them. W5/VK2ACM came on and announced that he was in Louisiana and was the only other station to work Choi (HL3ERJ) while I was listening. A California station asked Clint (W5/VK2ACM) to QSY up and I followed. I found that Clint was 5×9 with my beam pointed toward Korea, but disappeared when I pointed it at about 17 degrees toward Shreveport (where Clint was), 229 miles to the north. After the California station finished, I called Clint and we talked for about 5 minutes before he disappeared during one of my short transmissions. An e-mail to Clint confirmed that he had not moved his beam from the NW and I had dropped out suddenly. This is what I think is an E-layer ion cloud lying over the Northwestern US and back scatter; W5ZIT with a fixed pattern antenna would not be able to detect his path. We see this fairly often on 10 meters where it is often the only mode of propagation available. It is also present on lower frequencies, but is sometimes masked by F-layer propagation, so the only clues are shorter than normal propagation to nearby stations. Actually, I think it is not really short when the signal bounces off a cloud 1 or 2 thousand miles away to return to Earth 1 or 2 hundred miles away. Usually back scatter signals are not so strong, but sometimes they are." Thanks, Willis!

Jon Jones, N0JK, of Wichita, Kansas, dropped a short line about 10 meters in the CQ Worldwide SSB DX Contest. On Saturday afternoon, October 24, HT2N in Nicaragua and several Brazilian stations were very loud. Using 10 W on 10 meter SSB into a shortened mag-mount CB whip on the roof of his car, he worked HT2N and PY5KD around 2100 UTC while driving around and listening.

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.

 



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