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www.southgatearc.org
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Propagation de K7RA07 March, 2009 No new sunspots since the recent brief three-day appearance of quickly fading sunspot 1013 on February 24-26. It was another Cycle 24 sunspot, but not too encouraging, considering how brief and weak it appeared. There are no predictions for new sunspots, but these events tend to occur suddenly. In this bulletin we have been tracking our own flavor of smoothed sunspot number, one based on a shorter period of data (three months instead of one year that the official smoothed sunspot graphs are based upon), perhaps revealing trends earlier. But the trend goes down again. Now that February has passed, we can take sunspot data from December 1 through February 28 to calculate a three month average, centered on January. The total daily sunspot numbers for that period was 208, divide that by 90 days, and the result is 2.3. Here are the numbers for the recent past, updated through last month: Jan 07 22.7 Just as Cycle 23 had a double-peak, we are perhaps observing a double bottom, centered on August 2008 and early 2009, or with the second minimum perhaps some time in the near future. We won't know it until it has passed, but it sure feels like a minimum at the moment. The lack of sunspots has been gaining attention outside of the usual scientific, amateur astronomer and amateur radio circles, and with so many people commenting on it who have no familiarity whatsoever with solar cycles and sunspots, we are bound to see poor judgment passed on as settled fact. For years, non-scientists (I am one too) have occasionally attempted to correlate sunspot trends with everything from social unrest, cardboard box production, and stock market averages, to climate and hem lengths, with no success. Or, at least the conclusions were not reproducible. A year ago, some of us witnessed up close the resulting flap when a daily financial news organ grossly misquoted an astrophysicist, claiming he had predicted decades of few if any sunspots, accompanied by endless winter. Even though the scientist denied ever saying those things, the story seemed to develop a life of its own, a sort of social virus that spread widely very quickly, nearly impossible to correct. As a long time fan of contemporary folklore, I thought it might be interesting to track this particular meme, so I used a popular search engine feature in which I registered a particular string (the word sunspot, in this case), and every day it sent me a summary of every new use of this word found on web sites, in blogs, Usenet newsgroups, and newspapers, along with links to these articles. One of the common mistakes I found involved the difference between number of sunspots and sunspot numbers. For instance, the sunspot number is 11 if there is a single sunspot, and 23 if there are three sunspots in two groups. So someone looks at old sunspot records, sees a sunspot number of 150 for a certain day, and assumes that the appearance of 150 simultaneous sunspots in a single day is a common occurrence. Or they might take a look at a graph of smoothed sunspot numbers, such as the one at http://www.swpc.noaa.gov/ What they don't know is that every point on the graph is based on the average of a year of sunspot data, and is placed in the middle of that year. So for any points within the past six months, up to half are based on predicted data. So if NOAA predicts sunspot numbers to rise in the future, it is normal to see the graph rising when in fact the sunspot numbers have not yet increased. Some of the erroneous accounts have pushed some sort of conspiracy theory, claiming that "the government" doesn't want us to know how rare recent sunspots have become. Sometimes a letter to the editor of a newspaper, or a blog remark, will state without attribution to any source, that the sunspot number for a certain month was only 3. They probably heard somewhere that there were only three sunspots making an appearance one month, when the actual average daily sunspot number for the month was several times that. On April 20, 2007 in Propagation Forecast Bulletin ARLP017 we told you about Jeff Lackey, K8CQ of St. Simon's Island, Georgia (see http://www.arrl.org/w1aw/prop/2007- The antenna used his rain gutters and downspouts, and you can see a diagram of the antenna in the March 2009 issue of CQ Magazine, on page 52. Included are a nice photo of Jeff, and another of the tuning arrangement, which uses an automatic antenna tuner at the base of the antenna. The article says that Jeff has now worked 220 "DX entities" in 37 zones, less than two years later, and Jeff told us on Thursday that the total is now 243/38, with 87 countries on 80 meters. Jeff says the gutter antenna is a tricky tune on 160 meters, but there he has worked 34 states, 3 provinces and 7 countries. Asram Chou, BV2WM of Taiwan is translating this weekly bulletin into Chinese and posting it on the web at, http://tw.myblog.yahoo.com/bv2wm-tw/ and http://bv2wmtpe.blogspot.com/. I used Google Language Services at http://www.google.com/language_tools?hl=en to translate it back to English, and was interested to see that even with the automatic translation it was pretty close to the original. Bob King, K7OFT of Seattle, Washington sent in an interesting link to a December 2008 conference where multiple papers on the start of Cycle 24 are stored. See it at, http://sprg.ssl.berkeley.edu/RHESSI/napa2008/pts.php. For anyone in Seattle this Thursday afternoon, March 12 at 3:30 PM is a presentation at University of Washington's Johnson Hall in room 102 about probing the Earth's ionosphere with lightning. See the program schedule on the web at, http://www.geophys.washington.edu/web/ess/ This weekend is the ARRL International SSB DX Contest. We can assume conditions will include no sunspots and very stable geomagnetic conditions. NOAA and USAF predict a planetary A index at 5 for March 6-12, and Geophysical Institute Prague predicts quiet conditions, March 6-12. If you would like to make a comment or have a tip for our readers, email the author at, k7ra@arrl.net. For more information concerning radio propagation, see the ARRL Technical Information Service web page at, http://www.arrl.org/tis/info/propagation.html. For a detailed explanation of the numbers used in this bulletin see, http://www.arrl.org/tis/info/k9la-prop.html. An archive of past propagation bulletins is at, http://www.arrl.org/w1aw/prop/. Monthly propagation charts between four USA regions and twelve overseas locations are at, http://www.arrl.org/qst/propcharts/. Instructions for starting or ending email distribution of this bulletin are at http://www.arrl.org/w1aw.html#email. Sunspot numbers for February 26 through March 4 were 12, 0, 0, 0, 0, 0, and 0 with a mean of 1.7. 10.7 cm flux was 69.9, 68.9, 70.6, 69.4, 69.2, 69.1, and 69.7 with a mean of 69.5. Estimated planetary A indices were 2, 8, 5, 3, 2, 5 and 7 with a mean of 4.6. Estimated mid-latitude A indices were 2, 7, 4, 2, 0, 5 and 5 with a mean of 3.6.
Source: The American Radio Relay League • All propagation
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