SB PROP @ ARL $ARLP016   
   ARLP016 Propagation de K7RA   
      
   ZCZC AP16   
   QST de W1AW   
   Propagation Forecast Bulletin 16  ARLP016   
   > From Tad Cook, K7RA   
   Seattle, WA  April 17, 2014   
   To all radio amateurs   
      
   SB PROP ARL ARLP016   
   ARLP016 Propagation de K7RA   
      
   ARRL headquarters is closed for Good Friday on April 18, so the   
   bulletin comes to you a day early.   
      
   After a few days in the doldrums on April 8-13 with sunspot numbers   
   in the double digits, solar activity made a strong recovery over the   
   following three days, with daily sunspot numbers of 105, 149 and   
   245. Sunspot numbers have reached this level several times in the   
   past 12 months. On February 28, 2014 the daily sunspot number   
   reached 279, it was 245 on January 6, and back on November 15-17,   
   2013 it was 272, 213 and 282.   
      
   The average daily sunspot number was actually down this week   
   compared to last, dropping from 129.3 to 118.4. Average daily solar   
   flux was higher, rising from 142.2 to 149.1. There was one   
   geomagnetically active day, when the planetary A index reached 25 on   
   April 12. This was caused by a solar wind stream.   
      
   Predictions for solar flux made a big leap yesterday, when it was   
   predicted to be 190 on April 17-19, 185, 180 and 175 on April 20-22,   
   170 on April 23-24, 140 on April 25-27, 130 on April 28-29, 125 on   
   April 30, 120 on May 1-2, 125 on May 3-5 then peaking at just 145 on   
   May 12-19.   
      
   Predicted planetary A index is 8 on April 17-18, 5 on April 19 to   
   May 10, 8 on May 11-12, then 5 for the remaining days of the 45-day   
   forecast period.   
      
   On April 12, OK1HH predicted the geomagnetic field to be quiet to   
   active on April 17, quiet April 18, mostly quiet April 19-20, quiet   
   to active April 21, quiet to unsettled April 22, mostly quiet April   
   23, quiet April 24, mostly quiet April 25-26, quiet April 27, mostly   
   quiet April 28, quiet April 29, mostly quiet April 30, quiet May   
   1-2, mostly quiet May 3, quiet to unsettled May 4, quiet May 5,   
   quiet to unsettled May 6, and quiet on May 7-8.   
      
   For the first time in many years, WWV again is transmitting on 25   
   MHz, on an experimental basis. A week ago David Crawford, KF4VXJ of   
   Raleigh, North Carolina reported hearing the 25 MHz signal on April   
   10 at 2118 UTC with some fading, with signal strength varying from   
   S5-S8. He included this in a reception report to WWV, along with   
   readings at 10, 15 and 20 MHz (2.5 and 5 MHz signals were   
   inaudible).   
      
   He got this reply: "Thanks for your email, and your reception report   
   of the WWV experimental broadcast at 25 MHz.   
      
   "WWV first began broadcasting on 25 MHz in 1946, but the broadcast   
   was suspended in 1977. Due to listener interest and changes in   
   broadcasting technology, NIST is pleased to be able to provide this   
   service on a limited basis once again. At present, the broadcast is   
   carried on a base-fed broadband monopole antenna. All normal WWV   
   frequencies operate on a center-fed half-wave dipole antenna, with a   
   dedicated backup transmitter that will come online automatically   
   should the main transmitter fail. The 25 MHz broadcast does not have   
   this capability at this time. Please note that the experimental 25   
   MHz broadcast may be interrupted without notice at any time.   
      
   "For the latest status in the 25 MHz broadcast, refer to the NIST   
   Radio Station WWV web site.   
      
   "http://www.nist.gov/pml/div688/grp40/wwv.cfm ."   
      
   Well that's it for this week. There were no other reports from   
   readers.   
      
   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. 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 April 10 through 16 were 78, 83, 74, 95, 105,   
   149, and 245, with a mean of 118.4. 10.7 cm flux was 136.7, 137.6,   
   135.9, 137.1, 150.3, 161.9, and 183.9, with a mean of 149.1.   
   Estimated planetary A indices were 3, 8, 25, 16, 8, 6, and 5, with a   
   mean of 10.1. Estimated mid-latitude A indices were 4, 7, 16, 13, 7,   
   5, and 5, with a mean of 8.1.   
   NNNN   
   /EX   
      
      
   )\/(ark   
      
   One of the great tragedies of life is the murder of a beautiful theory by a   
   gang of brutal facts. --Benjamin Franklin   
      
   --- FMail/Win32 1.60   
    * Origin:  (1:3634/12.71)