SB PROP @ ARL $ARLP008   
   ARLP008 Propagation de K7RA   
      
   ZCZC AP08   
   QST de W1AW     
   Propagation Forecast Bulletin 8  ARLP008   
   From Tad Cook, K7RA   
   Seattle, WA  February 25, 2011   
   To all radio amateurs    
      
   SB PROP ARL ARLP008   
   ARLP008 Propagation de K7RA   
      
   The average solar flux was nearly unchanged this week, up just 0.3   
   point to 103.8, while the average daily sunspot number was down 4.9   
   points to 65. Sunspot groups 1161 and 1162 -- which brought so much   
   activity last week -- have now rotated across our Sun's western   
   horizon, but new sunspot group 1163 has now emerged over the eastern   
   limb.  For Thursday, February 24, we saw a sunspot number of 23. The   
   solar flux was 88.9, planetary A index was 3 and the mid-latitude A   
   index was 0.   
      
   The outlook from NOAA/USAF shows 90, 88 and 88 for February 25-27,   
   then 86 on February 28 through March 4, 95 on March 5, 100 on March   
   6-8, 105 on March 9 and rising to 110 on March 10-15. The predicted   
   planetary A index for February 25-March 2 is 7, 8, 8, 15, 12 and 8,   
   then 5 on March 3-6, and 7, 8, 8, 7 and 5 on March 7-11. Geophysical   
   Institute Prague expects quiet to unsettled conditions for February   
   25-26 and quiet conditions on February 27 through March 3.   
      
   The predicted geomagnetic storm just prior to last weekend's DX   
   contest did not persist, lasting only half a day through February   
   18. It was triggered by a flare on February 15. Bob Marston, K6TR,   
   sent a link to a high definition video of the flare, as seen through   
   the Solar Dynamics Observatory. It can be viewed on YouTube at,   
   http://www.youtube.com/watch?v=IJViaJ_kgZ0.   
      
   Note that you can select resolution of the image by clicking on the   
   360p on the lower right and can run it as high as 720p. It takes   
   some time to load, varying dependent on your Internet connection   
   speed. Best to just let it load, then run it again to actually watch   
   it.   
      
   Dean Straw, N6BV, observed last Friday that the "latest solar wind   
   sequences show that the Bz field was strongly north-directed (rather   
   than south-directed) from 05 to 10 UTC Feb 18, so we probably dodged   
   the big bullet for this ARRL DX CW weekend." He is referring to an   
   element of the IMF, or interplanetary magnetic field. When Bz points   
   south, our planet is vulnerable to flares and resulting solar wind,   
   but when Bz points north, we tend to be protected.   
      
   Carl Luetzelschwab, K9LA, has an interesting and informative column   
   on 10 meter sporadic-E propagation in the current issue of   
   WorldRadio Online. Carl mentions downloading N6BV's presentation on   
   sporadic-E titled, "HF Propagation and Sporadic-E, A Case Study:   
   WRTC 2010."   
      
   Bill Collins, KB1MSJ, of Boylston, Massachusetts, is excited about   
   openings on 10 meters. He wrote: "On Friday, February 18, there was   
   a 10 meter band opening here on the East Coast. I was able to talk   
   to Aruba, Brazil and El Salvador, all with only 25 W of power on a   
   homebrew 10 meter antenna. I have been waiting for this to happen   
   for years, as I only have my Tech license (working on General) and   
   have an old 10 meter radio".   
      
   Elwood Downey, WB0OEW, of Tucson, Arizona, wrote: "Just wanted to   
   mention you seem to have missed the highest actual 10.7 cm flux   
   reported from Penticton for all of last week. On February 13 at   
   1800, it was 125.7. The value you report for February 13 -- 106.8 --   
   was reported two hours later at 2000. Normally I wouldn't bother to   
   mention it, but this was higher than any value you reported for the   
   entire week and is something for the record books."   
      
   Yes, I saw that, but only the local noon number is the "official"   
   number for the day. Elwood is talking about the numbers as they are   
   reported directly from Penticton. Note that there are three readings   
   per day, and the local noon number is at 2000. NOAA rounds off the   
   solar flux noon reading to the nearest whole number, and reports it   
   at, http://www.swpc.noaa.gov/ftpdir/indices/DSD.txt.  I do like to   
   look at the morning and afternoon numbers though to try to spot   
   trends.   
      
   Sometimes NOAA will report a lower value for the day than the noon   
   reading at Penticton. This is if the receiver at Penticton was   
   overloaded, and the value is regarded as anomalous. But I don't have   
   any way of knowing when that receiver is overloaded. My only clue is   
   when NOAA reports a lower value.   
      
   In Propagation Forecast Bulletin ARLP006 we mentioned Joan Feynman   
   and erroneously reported that she is physicist Richard Feynman's   
   daughter, when in fact she is his sister. Thanks to Walt Knodle,   
   W7VS, Michael A. Gottlieb and Gregory Andracke, W2BEE, for the   
   correction. Greg is a filmmaker and mentioned that he met Richard   
   Feynman while working on a documentary with Bill Moyers on the 45   
   year anniversary of the atomic bomb. Michael A. Gottlieb (who is not   
   a ham) runs a website devoted to The Feynman Lectures on Physics. He   
   also published the book Feynman's Tips on Physics: A Problem-Solving   
   Supplement to the Feynman Lectures on Physics. He works in the   
   Caltech Physics Department and is editor of two editions of the   
   Feynman Lectures on Physics.   
      
   Another correction, this time from last week's bulletin, we mistyped   
   Bob Marston's call sign (K6TR) as K6TW. We got a nice note about   
   this from Tim Goodrich of Torrance, California, the proud owner of   
   new vanity call K6TW, which he has held for just one month.   
      
   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 February 17-23 were 51, 101, 79, 103, 60, 34 and   
   27, with a mean of 65. The 10.7 cm flux was 110.9, 124.8, 109.4,   
   104.6, 96.7, 90.9 and 89.3, with a mean of 103.8. The estimated   
   planetary A indices were 2, 17, 5, 7, 7, 1 and 4, with a mean of   
   6.1. The estimated mid-latitude A indices were 5, 15, 3, 6, 7, 1 and   
   1, with a mean of 5.4.   
   NNNN   
   /EX   
      
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   Gentlemens' agreements ratified by IARU regions 1 and 2 have   
   designated a global "center of activity" frequency  in  each   
   of  the  international  hf  bands.  THese are similar to the   
   concept for weak signal calling and other center of activity   
   frequencies.  Three of these have been ratified worldwide.   
      
   THese  center of activity frequencies are where stations can   
   go to render or obtain emergency assistance.   
      
   WHen casually operating or  contesting  on  hf  please  make   
   yourself  aware  of  these  frequencies,  and give them some   
   space. Remember that often stations with emergency needs are   
   not  those  utilizing  high  gain antennas and maximum legal   
   power.   
      
   TO find out more, visit 14300.net or IARU web resources.   
      
      
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