SB PROP @ ARL $ARLP038   
   ARLP038 Propagation de K7RA   
      
   ZCZC AP38   
   QST de W1AW   
   Propagation Forecast Bulletin 38  ARLP038   
   > From Tad Cook, K7RA   
   Seattle, WA  September 19, 2014   
   To all radio amateurs   
      
   SB PROP ARL ARLP038   
   ARLP038 Propagation de K7RA   
      
   On September 11 and 12 two powerful CMEs hit Earth, producing a G3   
   class geomagnetic storm. The result was a planetary A index of 44 on   
   Friday, and during the final three hours of the UTC day (2:00 PM to   
   5:00 PM PDT) the planetary K index reached 7, which is very high.   
      
   Overall solar activity is down, with the average daily sunspot   
   number declining from 152 to 124.9 in the latest reporting period   
   (September 11-17). Average daily solar flux dropped from 155.8 to   
   139.8.   
      
   Predicted flux values have declined as well. As an example, the   
   daily 45 day forecast for solar flux on September 21 was 120 on   
   August 6-10, 125 on August 11-17, 135 on August 18 through September   
   7, 150 on September 8-12, 130 on September 13, 120 on September   
   14-15 and 115 on every day since.   
      
   Predicted solar flux is 120 on September 19, 115 on September 20-21,   
   110 on September 22-25, 115 on September 26, 120 on September 27-28,   
   130 on September 29, 135 on September 30 and October 1, 140 on   
   October 2, 145 on October 3-5, 150 on October 6-7, 145 on October   
   8-9. and 140 on October 10-12. Flux values then dip to 125 on   
   October 17, rise again slightly, then go down to 115 on October   
   21-23. After that solar flux values are expected to rise again,   
   perhaps to 150 by early November.   
      
   Predicted planetary A index is 5 on September 19-25, 15 on September   
   26-27, 12 on September 28-29, 10 on September 30, 5 on October 1-2,   
   8 on October 3-4, 5 on October 5, 10 on October 6-7, then quieting   
   down to 5 on October 8-11, then rising to 8, 10 and 8 on October   
   12-14, and quieting down to 5 again on October 15-21. The next   
   really active period is predicted to have a planetary A index of 20   
   on October 22.   
      
   Petr Kolman, OK1MGW of the Czech Propagation Interest Group believes   
   geomagnetic conditions should be quiet to unsettled on September   
   19-20, quiet on September 21, active to disturbed September 22-23   
   (although he is uncertain about this), quiet to unsettled September   
   24-26, quiet to active September 27-28, quiet to unsettled September   
   29 through October 3, quiet to active October 4-5, mostly quiet   
   October 6-9, quiet October 10-12. mostly quiet October 13-14, and   
   quiet to unsettled October 15.   
      
   Petr expects an increase in solar wind on September 22-23 (although   
   he is less than certain about this, just as in the geomagnetic   
   prediction for those two days), and also on September 26-29 and   
   October 3-4.   
      
   The Autumnal Equinox is just a short time away, in the early hours   
   of September 23 at 0229 UTC. This is Monday night in North America.   
   The equinox portends improved worldwide communications on the HF   
   bands. As an example, modeling propagation using W6ELprop and a   
   modest solar flux of 120, 20 meter signals between California and   
   Japan on the equinox run about 6 dB hotter in the early evening on   
   the West Coast than they would a month earlier.   
      
   Rich Zwirko, K1HTV of Amissville, Virginia (FM18ap) sent this report   
   about recent activity in the ARRL September VHF Contest last weekend   
   (September 13-15):   
      
   "The Wednesday, September 10 CME and X1.6 solar flare resulted in an   
   aurora which occurred on Friday evening, Sept. 12. Unfortunately,   
   this was the day before the ARRL VHF Contest. I managed to work   
   W1AW/1 and a couple of VEs on 6 meter CW via the buzz mode. On 2   
   meters I worked W9EWZ (EN52) and heard W9ZIH (EN51) and K9MRI (EN72)   
   via the auroral curtain. During the VHF contest, the first sign of   
   Es occurred just before 2030Z Saturday. A number of Florida stations   
   were worked plus stations in Cuba (CO3VR and CO3JA) and Mexico   
   (XE3/K5ENS). Just before 2200Z our Es opening to the south coupled   
   into the Florida-to-South America TEP. This resulted in K1HTV QSOs   
   with two LU stations in GF05 (LU9AEA and LU6DRV) and two stations in   
   GF15 (CX2TQ and CX9AU). By 2220Z Saturday the Es and TEP had   
   disappeared.   
      
   "As September VHF contests go, I would rate the overall conditions   
   to be above what is normally expected in the inland Mid-Atlantic   
   region. Normally the Summer Es conditions have gone, but the   
   Saturday Es opening, coupling to the TEP resulted in some   
   interesting QSOs.   
      
   "73, Rich - K1HTV"   
      
   Thanks, Rich!   
      
   I'll clarify a couple of terms, for readers who might be new. When   
   Rich refers to "Es" he is talking about E-layer propagation, which   
   can appear sporadically and propagate signals at 10, 6 and 2 meters   
   during certain seasons of the year, such as summer and again and   
   less often in December. Long distance HF propagation relies on the   
   higher and more predictable F-layer of the ionosphere.   
      
   TEP refers to Trans-Equatorial Propagation, or propagation in an   
   approximate north/south path across the equator. When we have a big   
   solar flare and geomagnetic storm such as the one last week,   
   sometimes on HF TEP is the only available propagation mode.   
      
   "Buzz mode" refers to auroral propagation, in which VHF stations aim   
   their antennas north toward the Aurora Borealis. The reflected   
   signals are distorted, hence the reference to "buzz."   
      
   Wikipedia has a pretty good description of sporadic-E propagation at   
   http://en.wikipedia.org/wiki/Sporadic_E_propagation , and K9LA has a   
   treatise on TEP at http://k9la.us/Trans-Equatorial_Propagation.pdf .   
      
   As mentioned every week at the end of this bulletin, K9LA has a   
   great web site devoted to propagation at http://k9la.us/ .   
      
   Http://www.spaceweather.com reports "No geomagnetic storm was in the   
   forecast for September 19, but a storm occurred anyway. Sky watchers   
   around the Arctic Circle saw the midnight sky turn green as   
   magnetometers registered an unexpected G1-class disturbance between   
   0300 and 0600 UTC. The source of the display was a fluctuation in   
   the interplanetary magnetic field (IMF). During the early hours of   
   September 19 the IMF tipped south, opening a crack in our planet's   
   magnetosphere. Solar wind poured in to fuel the storm."   
      
   The planetary K index was 4 at 0300 UTC and 5 at 0600 UTC. NOAA   
   forecasters estimated a 20% chance of more polar geomagnetic storms   
   overnight. See http://www.swpc.noaa.gov/ftpdir/latest/DGD.txt .   
      
   Dennis Condron, K0LGI of Marion, Iowa posted his observations about   
   last week's big flare, and you can read it here:   
      
   https://groups.google.com/forum/?fromgroups#!topic/radiometeors/cKA0M9bokRM   
      
   Dave Sublette, K4TO of Winchester, Kentucky pointed out that the   
   report from N0JK in last week's bulletin never mentioned what band   
   he was talking about. Later, after putting the bulletin to bed I   
   received an email from N0JK to let me know it was 6 meters.   
      
   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 September 11 through 17 were 164, 157, 165, 120,   
   92, 85, and 91, with a mean of 124.9. 10.7 cm flux was 151.4, 152,   
   145.1, 139.3, 132.9, 133, and 125, with a mean of 139.8. Estimated   
   planetary A indices were 12, 44, 13, 3, 3, 7, and 6, with a mean of   
   12.6. Estimated mid-latitude A indices were 16, 35, 13, 3, 2, 7, and   
   4, with a mean of 11.4.   
   NNNN   
   /EX   
      
      
   )\/(ark   
      
   If you think it's expensive to hire a professional to do the job, wait until   
   you hire an amateur.   
      
   --- FMail/Win32 1.60   
    * Origin:  (1:3634/12.71)