SB PROP @ ARL $ARLP012   
   ARLP012 Propagation de K7RA   
      
   ZCZC AP12   
   QST de W1AW     
   Propagation Forecast Bulletin 12  ARLP012   
   From Tad Cook, K7RA   
   Seattle, WA  March 25, 2011   
   To all radio amateurs    
      
   SB PROP ARL ARLP012   
   ARLP012 Propagation de K7RA   
      
   All solar indicators were lower again for the second consecutive   
   week.  Average daily sunspot numbers declined over 28 points from   
   the week before to 40.9, and average daily solar flux was off over   
   18 points to 94.8.   
      
   But looking at solar images from the STEREO mission at   
   http://stereo.gsfc.nasa.gov we can see a great deal of activity   
   about to rotate toward us over the Sun's eastern horizon.  The whole   
   "back" side of our Sun looks very busy.   
      
   The March 24 NOAA forecast for solar flux and planetary A index sees   
   solar flux for March 25 to April 3 at 110, 115, 120, 125, 125, 130,   
   130, 130, 120 and 115.  Planetary A index for the same period is   
   predicted at 5 for March 25-29, 7 on March 30-31, and 5 on April   
   1-3.   
      
   This indicates improving HF propagation for the near term, with   
   geomagnetic indicators unsettled only very slightly compared to   
   recent very quiet conditions.  Conditions should be good for the CQ   
   World Wide WPX SSB Contest this weekend, and there is a useful web   
   site devoted to this contest at http://www.cqwpx.com.   
      
   Geophysical Institute Prague has a forecast for geomagnetic   
   conditions quite different from NOAA, predicting quiet conditions   
   for March 25-27, unsettled to active on March 28, unsettled March   
   29-30, and quiet to unsettled March 31.   
      
   Carl Luetzelschwab, K9LA pointed out that the nanoTesla values for   
   each level of K index mentioned in last week's bulletin are actually   
   for the Boulder, Colorado magnetometer, and the values are different   
   for each observatory.  He has a good description of how this all   
   works at his web site,   
   http://mysite.ncnetwork.net/k9la/Where_Do_the_K_and_A_Index_Come_From.pdf.   
      
   Jeff Hartley, N8II of Shepherdstown, West Virginia sent in a report   
   last Saturday, March 19.  He wrote, "Despite the decline in solar   
   activity 12 meters has been consistently open to Europe every   
   weekday this week including some Russians, Latvia, and Lithuania. As   
   the flux has dropped off, the band has been opening later. The band   
   was wide open to Europe at 1230Z Monday (March 14), Thursday and   
   Friday (March 17-18) were good from about 1445Z to past 1600Z. 15   
   meters has been consistently good to Russia with loud signals (RL3A   
   S9+20-30dB) and even central Asia including UK6, UK8, and UN3M (S9)   
   worked 2 days and I even caught HS0ZDS on Wednesday right over the   
   pole. The low K indexes seem more important than the high flux for   
   anything close to the pole, no big surprise. VU4PB had a good signal   
   Thursday (March 17) on 17 meters from 1300-1500Z and quite a few USA   
   stations, including me, were getting thru the European pile for a   
   new one."   
      
   NASA has a video at http://www.youtube.com/watch?v=aTBgHd8exI4   
   explaining the very low sunspot activity over the past few years.   
      
   MIT Technology Review at   
   http://www.technologyreview.com/blog/arxiv/26568 has an article   
   about the double-peak of many sunspot cycles.   
      
   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://arrl.org/propagation-of-rf-signals. For an explanation of the   
   numbers used in this bulletin, see   
   http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past   
   propagation bulletins is at   
   http://arrl.org/w1aw-bulletins-archive-propagation. Find more good   
   information and tutorials on propagation at   
   http://mysite.ncnetwork.net/k9la/index.html.   
      
   Monthly propagation charts between four USA regions and twelve   
   overseas locations are at http://arrl.org/propagation.   
      
   Instructions for starting or ending email distribution of ARRL   
   bulletins are at http://arrl.org/bulletins.   
      
   Sunspot numbers for March 17 through 23 were 45, 35, 48, 47, 34, 31,   
   and 46, with a mean of 40.9. 10.7 cm flux was 90.1, 87.6, 88.8, 92,   
   101, 99.8, and 104.6, with a mean of 94.8. Estimated planetary A   
   indices were 3, 2, 4, 4, 4, 6, and 10, with a mean of 4.7. Estimated   
   mid-latitude A indices were 2, 2, 2, 4, 4, 5, and 9, with a mean of   
   4.   
   NNNN   
   /EX   
      
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