SB PROP @ ARL $ARLP030   
   ARLP030 Propagation de K7RA   
      
   ZCZC AP30   
   QST de W1AW     
   Propagation Forecast Bulletin 30  ARLP030   
   From Tad Cook, K7RA   
   Seattle, WA  July 29, 2011   
   To all radio amateurs    
      
   SB PROP ARL ARLP030   
   ARLP030 Propagation de K7RA   
      
   Sunspot activity dipped over this past week, but now is on its way   
   back up.   
       
   On July 20, five sunspot groups were visible, but on July 21, only   
   groups 1251, 1254 and 1259 remained.  On July 24, new sunspot group   
   1260 appeared, and the next day 1251 disappeared.  On July 26 groups   
   1254 and 1259 went away, and new sunspot group 1261 arrived.  The   
   next day another new group, 1262 appeared, and on July 28 two new   
   sunspot groups, 1263 and 1264 appeared.  On July 28 the total area   
   of visible sunspots was greater than it has been since the end of   
   May.   
       
   Average daily sunspot numbers for the week July 21-27 declined   
   nearly 47 points, a little over 50 percent, to 45.6.  Average daily   
   solar flux declined over 6 points to 91.8.   
       
   The latest forecast has been revised upward for solar activity   
   higher than was reported in this week's ARRL Letter.  The forecast   
   shows predicted solar flux at 110 on July 29 through August 4, 100   
   on August 5, 95 on August 6-7, 98 on August 8, and 100 on August   
   9-16.  It also shows planetary A index at 5 on July 29-30, 12 on   
   July 31 through August 1, 7 on August 2, 5 on August 3-4 followed by   
   12 again on August 5-7, and 8 on August 8-11.   
       
   Geophysical Institute Prague predicts quiet conditions on July 29,   
   quiet to unsettled July 30, unsettled July 31 and August 1, then   
   quiet to unsettled August 2 and quiet again on August 3-4.   
       
   Kent Reinke, KL1V reports some interesting VHF propagation on   
   Thursday, July 28.  He writes: "I live in Valdez, Alaska, and today   
   I had a very strange opening while I was driving home from Dawson   
   City Yukon.  I was 30 miles northwest of Tok Alaska on the 'Top of   
   the world highway' and while trying to pick up a local FM station   
   from Tok I was surprised to hear several stations and they were full   
   quieting with slow fade and after listening to them a few minutes I   
   found out they were all from Edmonton Alberta, which is a distance   
   of about 1235 miles.  There are several mountain ranges between   
   where I was and Edmonton.  The stations sounded like I was in   
   downtown Edmonton between the fades.  I only had my 2 meter radio   
   with a mag mount antenna but I did try a few calls on 146.52 simplex   
   but no one heard me.  The opening lasted 45 minutes and I was not   
   sure if it was ducting or sporadic E.  Next time I will have the 6   
   meter along".   
       
   Thanks, Kent.  Very interesting.   
       
   Bear Carson, AC7HI lives in Spokane in eastern Washington State and   
   wrote to ask about a "blackout" of radio signals he noticed   
   recently.  I sent his message to Randy Crews, W7TJ, who lives about   
   8 miles southeast of AC7HI.  Randy had these comments:   
       
   "You know if I could pick one month out of the year that I believe   
   is the worst for propagation in the Pacific Northwest, it would be   
   July.  Not so much QRN/Static, but flat East/West Propagation and   
   high summer D-layer absorption.   
       
   There have been exceptions over the years, however July seems to   
   always be the low point of the Summer.  Recently I noticed that all   
   HF propagation has really been down in the past few days even in   
   spite of increasing solar flux and sunspots plus a quiet geomagnetic   
   field, low dynamic pressure and solar wind plus magnetic field   
   oriented north, and small auroral ovals.   
       
   The big reason I can see is high X-ray flux, which will negate all   
   the propagation positives just mentioned.  What I noticed was 4   
   months of just stellar propagation starting in mid February of this   
   year and going until about mid June.   
       
   Recently two DXpeditions, ST0R and VK9HR have been extremely   
   difficult to copy.  The VK9 Group is on an island surrounded by salt   
   water and compared to the T31A group in April from Canton Island,   
   their signal on all bands has really been marginal.  With the recent   
   increase of solar flux they should be S-9 all the time.  So I would   
   attribute things to the lower solar flux vs. what we observed this   
   last spring, high D level absorption, and very high levels of X Ray   
   Flux.  I believe that in spite of all the satellites, scientific   
   equipment etc, propagation is still immensely complex".   
       
   Thanks, Randy!   
       
   Often we get email from non-hams who heard some piece of   
   contemporary folklore about threats to Earth from giant solar flares   
   or mysterious planets.  A recent article on Space.com covers this   
   well.  Thanks to N7SO for this.  Read it at   
   http://i.space.com/12194-comet-elenin-planet-nibiru-doomsday-2012.html.   
        
   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 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 July 21 through 27 were 56, 54, 41, 46, 38, 30,   
   and 54, with a mean of 45.6.  10.7 cm flux was 96, 92.4, 88.2, 86.2,   
   87, 93.5, and 99.3, with a mean of 91.8.  Estimated planetary A   
   indices were 12, 10, 8, 4, 12, 5, and 4, with a mean of 7.9.   
   Estimated mid-latitude A indices were 10, 10, 6, 3, 10, 5, and 2,   
   with a mean of 6.6.   
   NNNN   
   /EX   
      
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