SB PROP @ ARL $ARLP051   
   ARLP051 Propagation de K7RA   
      
   ZCZC AP51   
   QST de W1AW   
   Propagation Forecast Bulletin 51  ARLP051   
   > From Tad Cook, K7RA   
   Seattle, WA  December 13, 2013   
   To all radio amateurs   
      
   SB PROP ARL ARLP051   
   ARLP051 Propagation de K7RA   
      
   Solar indicators rose over the past week, for both solar flux and   
   sunspot numbers. The highest were on Tuesday, December 10 when the   
   sunspot number was 169 and solar flux 175.2. In an otherwise quiet   
   week the planetary A index reached 26 on Sunday, December 8, sparked   
   by a strong solar wind surging from a coronal hole. We could see a   
   repeat this weekend. Geomagnetic activity during the ARRL 10 Meter   
   Contest this weekend should be more active than contesters would   
   prefer, with predicted planetary A index values of 20 and 15 on   
   Saturday and Sunday.   
      
   NOAA said Thursday night that the geomagnetic field may be anywhere   
   from quiet to minor storm levels this weekend.   
      
   For the past six 10-Meter Contests, geomagnetic conditions have been   
   very quiet. But in 2006 the contest (always the second full weekend   
   in December) fell right between two very active periods. The 2006   
   contest was held on December 9-10, and checking the record at   
   http://www.swpc.noaa.gov/ftpdir/indices/old_indices/2006_DGD.txt we   
   see the planetary A index on those dates was 7 and 14. But just   
   prior on December 6 the A index was 28, and 25 on December 7-8.   
   Following the contest that year the planetary A index on December   
   11-15 was 15, 26, 5, 63 and 104. The last two figures indicate a   
   major geomagnetic storm. Lucky it didn't hit earlier, but the   
   contest weekend was still feeling the effects of the higher activity   
   in the days before. Reports included much trans-equatorial   
   propagation. North-South propagation across the equator is not   
   enhanced during periods of high geo-activity, but rather that is   
   often the only propagation path available.   
      
   Compared to the previous seven days, over December 5-11 the average   
   daily sunspot number rose from 102.9 to 122.1, and average daily   
   solar flux increased from 132.9 to 162.4.   
      
   The predicted values in the 45-day outlook for solar flux took a   
   substantial leap on December 8.  For example, on December 7 the   
   predicted average solar flux for December 10-15 was 141, and on   
   December 8 the projected average for the same period was 170. The   
   predicted values for the following 45 days increased across the   
   board, but have since scaled back somewhat.   
      
   The latest prediction has solar flux at 165 on December 13, 160 on   
   December 14-15, 155 on December 16-18, 150 on December 19-20, 172 on   
   December 21-22, 175 on December 23-25, 172 on December 26, 170 on   
   December 27-29, 165 on December 30, and 160 on December 31 through   
   January 2, 2014. After dipping to 150 on January 4, solar flux is   
   expected to rise to a short term peak of 172 on January 7-8.   
      
   Predicted planetary A index is 12, 20 and 15 on December 13-15, then   
   5 on December 16-25, then 12, 10 and 8 on December 26-28, 5 on   
   December 29 through January 2, 2014, then 10, 20, 15, 10 and 8 on   
   January 3-7.   
      
   OK1HH believes the geomagnetic field will be quiet December 13-14,   
   mostly quiet December 15, quiet to unsettled December 16, quiet   
   December 17-18, quiet to unsettled December 19, quiet December   
   20-24, mostly quiet December 25, quiet to unsettled December 26,   
   quiet to active December 27, quiet December 28, mostly quiet   
   December 29, and quiet on December 30-31.   
      
   Predicted solar flux shows this weekend's 10 Meter Contest should   
   have the highest solar flux and sunspot numbers since the 2002   
   contest. Conditions may be similar to the 1999 contest, when solar   
   flux and sunspot numbers were about the same as now. This was before   
   the peak of the last solar cycle, cycle 23.   
      
   To test this out and see where conditions are compared to previous   
   ten meter contests, I averaged sunspot numbers and solar flux since   
   1997 for the contest weekend including the Friday before.   
      
   From 1997 through 2012, the average solar flux on the second full   
   weekend in December was 90.6, 143.5, 160.9, 139.9, 224.2, 185.3,   
   89.1, 88.4, 91.2, 92.8, 87.5, 69.8, 74, 88.2, 139.3, and 100.6. For   
   Friday through Saturday this weekend the average of predicted flux   
   values is 161.7, very close to what it was in 1999, and as you can   
   see, stronger than any contest weekend after 2002.   
      
   Over the same period using the same method, average sunspot numbers   
   were 66.7, 153.3, 120.3, 70.7, 201.3, 202.3, 41.3, 27, 55.7, 22.7,   
   34, 4.7, 13, 27, 103 and 32.7. We don't have a source for predicted   
   daily sunspot numbers, but the average reported at the end of this   
   bulletin was 122.1.  This is also stronger than any contest weekend   
   since 2002.   
      
   Note that in 2008 the average sunspot number on the second weekend   
   in December was only 4.7.  This may seem strange, because the arcane   
   method used for determining sunspot number produces no non-zero   
   sunspot numbers below 11. But on that Friday through Sunday period,   
   over the three days sunspot numbers were 14, 0 and 0. That produces   
   an arithmetic average of 4.667, or 4.7.   
      
   You can find information on the ARRL 10 Meter Contest at   
   http://www.arrl.org/10-meter.   
      
   I used past ARRL Propagation Bulletins from the archive at   
   http://arrl.org/w1aw-bulletins-archive-propagation as a source for   
   data on past 10 Meter contests. While browsing, in ARLP050 in 2010 I   
   found an interesting resource that I had forgotten about at   
   http://www.helioviewer.org/ .  With this tool you can set up a movie   
   of recent or past solar images, and have them continually animated   
   at a variety of rates and representing a time period of your   
   choosing.   
      
   I also ran into a bulletin by Tony, G4CJC concerning 10 meter DX and   
   propagation news from Europe at   
   http://www.southgatearc.org/bands/10metres/december2013/december   
   12.htm#.Uqls0- JC2UU   
   .   
      
   Jon Jones, N0JK writes The World Above 50 MHz column in QST, and   
   sent this note:   
      
   "The Winter 6 meter Es season is underway.   
      
   Tuesday Dec. 10 -  6 meters was open before sunrise (1230 UTC) from   
   KS, NE to Florida, and strong Es from W1 to Florida.   
      
   Geminids meteor shower to peak this weekend."   
      
   That's right, and the meteor shower should enhance 10 meter   
   propagation, because of all those ionized meteor trails. In fact,   
   the story goes that the second weekend in December was picked for   
   the 10 meter contest because it coincides, with some variation year   
   to year, with the Geminids shower.   
      
   Max White, M0VNG sent along an article about threats from massive   
   solar events. Read it at at http://www.colorado.edu/news/release   
   /2013/12/09/cu-boulder-scientist-2012-sola r-storm-points-need-society-prepare   
   .   
      
      
   Ray Soifer, W2RS of Green Valley, Arizona wrote: "Interesting to   
   read about Larry, W0OGH's experience with VU7AG. Mine was very   
   similar. I am 113 miles south of Larry's QTH and worked VU7AG on 20   
   CW a minute before he did. I too noticed the auroral flutter on the   
   VU7's signal. Most of their times and frequencies seemed to favor   
   Europe and the eastern half of North America so it was good to have   
   this opening.   
      
   On 20 CW I have 600 watts to a Hy-Gain AV620 vertical mounted on a   
   10-foot pipe. It isn't a 4- element monobander but it does pretty   
   well on DX paths due to its fairly low radiation angle."   
      
   Funny. My word processing program did not like the word "monobander"   
   above, and suggested "mindbender" as the correct spelling.   
      
   For more information concerning radio propagation, see the ARRL   
   Technical Information Service 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. More good   
   information and tutorials on propagation are at http://k9la.us/.   
      
   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 December 5 through 11 were 103, 105, 104, 83,   
   125, 169, and 166, with a mean of 122.1. 10.7 cm flux was 149.6,   
   150.5, 156.9, 165.5, 168.1, 175.2, and 170.8, with a mean of 162.4.   
   Estimated planetary A indices were 5, 4, 6, 26, 5, 5, and 4, with a   
   mean of 7.9.  Estimated mid-latitude A indices were 4, 3, 4, 14, 2,   
   3, and 2, with a mean of 4.6.   
   NNNN   
   /EX   
      
      
      
   )\/(ark   
      
   Not only is the Universe stranger than we think, it is stranger than we can   
   think. - Werner Heisenberg   
      
   --- FMail/Win32 1.60   
    * Origin:  (1:3634/12.71)