SB PROP @ ARL $ARLP019   
   ARLP019 Propagation de K7RA   
      
   ZCZC AP19   
   QST de W1AW     
   Propagation Forecast Bulletin 19  ARLP019   
   From Tad Cook, K7RA   
   Seattle, WA  May 11, 2012   
   To all radio amateurs    
      
   SB PROP ARL ARLP019   
   ARLP019 Propagation de K7RA   
      
   Average daily solar flux for the past week rose slightly, 116.2 to   
   119, but average daily sunspot numbers declined more than 14 points   
   (about 13%) to 92.6.   
      
   Predicted solar flux for the near term is quite a bit higher than   
   the average for the past week. Solar flux on May 11-18 is 130, and   
   then it drops sharply to 110 on May 19-22, 115 on May 23-25, 110 on   
   May 26, 105 on May 27-31, 110 on June 1-2, and 115 on June 3-10.   
      
   Predicted planetary A index is 12 on May 11-12, 10 on May 13, 5 on   
   May 14-18, 8 and 10 on May 19-20, 15 on May 21-23, 8 on May 24, 5 on   
   May 25 through June 4, 12 on June 5-6, 18, 10 and 5 on June 7-9, 8   
   on June 10-11, then 5, 8, 5, 8 and 10 on June 12-16, and 15 on June   
   17-19.   
      
   Right now sunspot group 1476 has been producing a lot of activity,   
   and could give us an X-Class solar flare. It is currently pointed   
   straight at Earth, at the center of the visible solar disk.  This   
   sunspot is the subject of news reports lately, including,   
   http://www.abcactionnews.com/dpp/news/science_tech/sun-spot-ar14   
   6-setting-sight   
   s-on-earth-solar-flares-and-aurora-borealis-possible-this-week   
      
   http://www.usnews.com/news/articles/2012/05/10/video-monster-sunspot-emerges   
      
   If you like your solar news with dramatic music, don't miss these   
   videos:   
      
   http://www.youtube.com/watch?v=vL1hTcIq9vI   
      
   http://www.youtube.com/watch?v=mO9I1J3yVm0   
      
   This week you can compare the tables in the Preliminary Report and   
   Forecast at http://www.swpc.noaa.gov/weekly/pdf/prf1914.pdf and the   
   earlier version at http://www.swpc.noaa.gov/weekly/pdf/prf1910.pdf   
   and see the slight decline in estimated and predicted smoothed   
   sunspot numbers for October 2011 through October 2012.  These   
   smoothed numbers are averaged over a whole year, so a current number   
   would be an average made up of half predicted numbers and half   
   actual sunspot numbers for the past half-year.   
      
   David Gerns, K1LD of Plaistow, New Hampshire sent a link to a   
   remarkable article on the "Carrington Event of 1859, the Great   
   Auroral Storm."   
      
   Read it at   
   http://arstechnica.com/science/2012/05/1859s-great-auroral-storm   
   he-week-the-sun   
   -touched-the-earth/,   
   and note the exchange between the two telegraphers in which they   
   observed better performance of the telegraph system by disconnecting   
   their batteries, and just using the induced currents from the   
   aurora!   
      
   I also was not aware that recordings were made from magnetometers   
   150 years ago, such as the one shown in the article.  Also note that   
   at the end of the piece is a link   
   (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/2005021015   
   _2005210155.pdf   
   )   
   to a collection of eyewitness reports of this event.   
      
   Josep, EA3AKY of Catalunya Spain wrote on May 4: "I'm a 6 meter DXer   
   and appreciate very much your information. This band is not easy and   
   sometimes surprises me. In spite of this low Sun activity, today I   
   worked OA4TT at 1810 UTC at 10029 Km. Signal on CW was 519-529 with   
   some flutter and quick QSB. Jack has worked several other EAs and   
   CTs. After Jack, I worked UR7FM/MM in field IG28. Propagation to   
   Jack was sporadic-E (EA8 and CS3 were in at same time) linking to F2   
   /TEP layer."   
      
   Fred Honnold, KH7Y of Ocean View, Hawaii wrote: "We still are having   
   openings just about every evening from 0500 to 0800 UTC to   
   DU7/PA0HIP with very good signals most of the time peaking S9+10.  I   
   was lucky and worked 9M0L on April 21, 2012. They were into KH6 for   
   over 2 hours with their beacon, thanks to Dave N2NL was able to   
   alert them on 10 meters to man their six meter station and look   
   towards KH6.  I am not sure if any other KH6 stations worked them.   
   Also on April 21 worked YN2N, 9M6XRO, DU7/PA0HIP all with big   
   signals 30+ over S9.   
      
   "Last night I worked KG6DX, BV2DQ, was copied by Han, JE1BMJ 519,   
   and I was hearing KH0/W3STX but could not get their attention.  So   
   the six meter band is alive and well out here."   
      
   Tom McGuire, W0VPI of Davenport, Iowa asked about a website that   
   would show him real time MUF, or Maximum Usable Frequency. The   
   problem is there is no single MUF value, as it varies according to   
   the path, or the location of the two endpoints.   
      
   I mentioned that he could estimate MUF using W6ELprop, available at   
   http://www.qsl.net/w6elprop/.  MUF programs are written to use the   
   predicted smoothed sunspot number for the month.  Apparently they   
   aren't any more accurate if you use the current daily sunspot   
   number, but one compromise might be to average the sunspot number   
   over the past few days.   
      
   For the day that I was using in my example, the average sunspot   
   number would be 99. I calculated that at 2200 UTC on that day the   
   MUF would be about 21.7 MHz between my place in Seattle and W0VPI in   
   Davenport.   
      
   I continued, "Interesting that throughout the day and night, the MUF   
   doesn't vary much.  The lowest it goes at 3:00 AM my time (1000 UTC)   
   is 15.1 MHz, so 20 meters is always open between us. 17 meters looks   
   like the best band between us at the moment.   
      
   "You can see how location dependent MUF is by entering the default   
   location for Brazil, PY. The MUF is above 28 MHz from your place   
   from 1530-2200 UTC, all day long."   
      
   To look at real time conditions, you could use   
   http://wsprnet.org/drupal/wsprnet/map.  Note that you can customize   
   it by band.   
      
   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://myplace.frontier.com/~k9la/.   
      
   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 May 3 through 9 were 107, 101, 88, 104, 79, 90,   
   and 79, with a mean of 92.6. 10.7 cm flux was 114, 114, 116, 117.3,   
   121.7, 122.8 and 127.3, with a mean of 119. Estimated planetary A   
   indices were 8, 4, 4, 5, 4, 9, and 24, with a mean of 8.3. Estimated   
   mid-latitude A indices were 9, 4, 4, 5, 4, 8, and 19, with a mean of   
   7.6.   
   NNNN   
   /EX   
      
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   Providing   emergency   communications  assistance  to  your   
   neighbors and community isn't just a good thing to do,  it's   
   the first and foremost activity recognized in the U.s. rules   
   governing amateur radio in 47 CFR section 97.1. IF you enjoy   
   amateur  radio  remember  that  this  is  an  obligation you   
   tacitly agreed to when you acquired your license.   
      
      
      
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