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 23, 2010   
   To all radio amateurs    
      
   SB PROP ARL ARLP051   
   ARLP051 Propagation de K7RA   
      
   This bulletin is posting nearly a day early, because ARRL   
   Headquarters is closed on December 24.  Next week the bulletin will   
   also be out late Thursday instead of the usual Friday distribution,   
   as ARRL is closed on December 31.  There is no ARRL Letter until   
   January 6, 2011.   
      
   Sunspots disappeared this week.  Five days with no spots is the   
   longest since May 9-19, 2010, when we saw 11 days in a row in which   
   the Sun was spotless.  Since then there has only been the occasional   
   day or two that was spot-free. April 2010 saw 13 consecutive days   
   with no spots, followed by one day in which the sunspot number was   
   12 (indicating the emergence of a sunspot group with two spots),   
   only to be followed by another spotless day, April 29.   
      
   As this bulletin is being written early Thursday, December 23, there   
   may be a spot emerging right in the center of our Sun, when viewed   
   from Earth.  It is visible as a white area when viewing the image   
   from the STEREO mission at http://stereo.gsfc.nasa.gov, although   
   this image just shows magnetically active areas in a lighter shade,   
   which does not always correspond to areas with sunspots.  Viewing   
   the rest of the image out to the eastern horizon (left side, on   
   solar images) shows no dramatic activity.  Unfortunately, the Solar   
   Dynamics Observatory Joint Science Operations Center has experienced   
   a disk controller failure, and until it can be replaced, the latest   
   image they have is from December 19.  There is a recent H-Alpha   
   image at http://www.solarmonitor.org.   
      
   With no spots for five days, the average daily sunspot number for   
   December 16-22 dropped nearly 23 points to 4.9.  Average daily solar   
   flux declined 8 points, or a little over 9%, to 80.1.   
      
   The noon reading at the Penticton observatory showed the solar flux   
   rose today to 80.1, precisely the arithmetic average listed below   
   for the prior seven days.  Although still pretty weak, solar flux   
   hasn't been this high since last weekend, on Sunday, December 19.   
      
   NOAA/USAF sees a low solar flux of 78 until December 26-27, when   
   they predict a flux value of 80, then 82 for December 28-29, 84 on   
   December 30, and 90 on December 31 and January 1.  They also show   
   low geomagnetic activity with a daily A index of 5, except for   
   December 25, with an index value of 7.  They show the A index going   
   back to 5 until the third week in January 2011.   
      
   Geophysical Institute Prague always has a more detailed outlook on   
   geomagnetic activity, and they show quiet conditions for December   
   24, quiet to unsettled December 25, quiet December 26, quiet to   
   unsettled December 27, and unsettled December 28-29.   
      
   For some, a dead quiet A index with no sunspots might be ideal for   
   the Winter Solstice, which was on December 21 at 2338z in the   
   Northern Hemisphere.  Long nights with low seasonal noise from   
   lightning signal good conditions on 80 and 160 meters, and with   
   quiet geomagnetic conditions, even better.   
      
   Chris Scibelli, NU1O lives in grid square FN32rb in Longmeadow,   
   Massachusetts. On 10 meters he runs 100 watts into a 3 element beam   
   at 55 feet.  He sent us a message after reading about the December   
   14 E-skip opening on 6 meters in the last bulletin.  Chris writes,   
   "On December 13 after the 10 meter contest ended we had about a 4   
   1/2 hour E-skip opening to GA, TN, NC, and VA.  Most of the guys   
   were running ground mounted verticals with 100 watts. I went QRT at   
   0500z as I put in a full 36 hours in the contest and that was enough   
   radio for a weekend.  I don't know if there was any relation to what   
   you wrote about but what was ironic was we did not have decent E   
   layer openings during the contest. Most of the states I worked at   
   the normal E layer distance were extremely weak -- about an S1. I   
   did have an opening to the West Coast on both the 11th and 12th but   
   signals weren't very strong, either. Toward the end of the contest   
   on Sunday I had a great opening to LU and PY. Most were 59 to 59   
   plus."   
      
   Brett DeWitt, W0BLD lives in Southwest Missouri, near Springfield,   
   and says that he worked a lot of E-skip on 6 meter SSB to both the   
   east and west coasts on December 13.  He runs 100 watts to a 3   
   element Yagi at 25 feet, and you can see a log of his contacts by   
   querying the DX Sherlock database at   
   http://www.vhfdx.info/spots/index.php. He wrote, "The opening lasted   
   for several hours. I try to log MOST of my VHF QSOs on the   
   vhfdx.info site. Worked QSOs from Myrtle Beach SC to Los Angeles CA.   
   Some contacts I worked a couple different times over several hours   
   apart.  Florida mainly came in first for a couple hours along with   
   SC, VA, GA, MS and AL. Then later in the opening NM, AZ, CA started   
   booming in here with CO in and out. I think I was able to work one   
   Colorado station. There were also openings several days after the   
   13th. The band was real good for about a week. I started out in the   
   afternoon and the band was open till I think 9pm or so if I recall   
   correctly."   
      
   To see Brett's contacts at http://www.vhfdx.info/spots/index.php   
   most of the settings can be left at default values, but select 50   
   MHz, reported from 12 December 2010 to 18 December 2010, containing   
   the callsign W0BLD, and set the maximum number of returned QSOs to   
   100 or greater.   
      
   Note that in the returned listings, you can click on any of the   
   callsigns, then click on the maps link to see where their grid   
   locator is.  Or you can click on the grid locator, and see all of   
   the stations reporting from that same locator.   
      
   Merry Christmas from K7RA.   
      
   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 December 16 through 22 were 23, 11, 0, 0, 0, 0,   
   and 0, with a mean of 4.9. 10.7 cm flux was 84.1, 81.6, 80.5, 80.9,   
   77.9, 77.9 and 77.7 with a mean of 80.1. Estimated planetary A   
   indices were 5, 3, 2, 1, 8, 1 and 0 with a mean of 2.9. Estimated   
   mid-latitude A indices were 4, 2, 2, 2, 6, 1 and 1 with a mean of   
   2.6.   
   NNNN   
   /EX   
      
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