TZUTC: -0500   
   MSGID: 467.fidonet-ls_arrl@1:2320/33 28cd03c5   
   PID: Synchronet 3.20a-Win32 master/52fa4b0ea May 18 2023 MSC 1929   
   TID: SBBSecho 3.20-Win32 master/52fa4b0ea May 18 2023 MSC 1929   
   BBSID: TBOLT   
   CHRS: ASCII 1   
      
   SB PROP @ ARL $ARLP020   
   ARLP020 Propagation de K7RA   
      
   ZCZC AP20   
   QST de W1AW     
   Propagation Forecast Bulletin 20  ARLP020   
   From Tad Cook, K7RA   
   Seattle, WA  May 19, 2023   
   To all radio amateurs    
      
   SB PROP ARL ARLP020   
   ARLP020 Propagation de K7RA   
      
   This reporting week, May 11-17, average daily sunspot number was   
   nearly the same as last week, 118.6 compared to 119.3, only   
   marginally lower.   
      
   But average daily solar flux dropped from 167.8 to 143.2.   
      
   Geomagnetic indicators were quieter, both planetary and middle   
   latitude A index at 9.6. Last week the two numbers were 15.1 and   
   11.9, respectively.   
      
   What is the outlook for the next few weeks?   
      
   10.7 cm solar flux is forecast to have a peak of 165 on June 8.   
      
   The predicted numbers are 145 on May 19, 140 on May 20-21, 135 on   
   May 22-24, 140 on May 25-26, 145 on May 27, 155 on May 28-30, 160 on   
   May 31 and June 1, 155 on June 2-3, 160 on June 4-7, then 165, 160,   
   150, 145, and 150 on June 8-12, then 155 on June 13-17, 150 on June   
   18, 145 on June 19-21, 140 and 145 on June 22-23, and 155 on June   
   24-26 then 160 on June 27-28.   
      
   Predicted planetary A index is 5, 8, 12, 15 and 5 on May 19-23, 12   
   on May 24-25, 15 on May 26, 10 on May 27-28, 8 on May 29, 5 on May   
   30 through June 1, then 16, 12, 16 and 12 on June 2-5, 8 on June   
   6-8, then 5 on June 9-18, 12 and 20 on June 19-20, 15 on June 21-22,   
   10 on June 23-24, 8 on June 25, and 5 on June 26-28.   
      
   These numbers are updated daily here:   
      
   https://services.swpc.noaa.gov/text/45-day-ap-forecast.txt   
      
   Thanks to reader David Moore for this:   
      
   "How 1,000 undergraduates helped solve an enduring mystery about the   
   Sun:   
      
   "https://www.sciencedaily.com/releases/2023/05/230509122026.htm   
      
   "For three years at the height of the COVID-19 pandemic, a group of   
   students spent an estimated 56,000 hours analyzing the behavior of   
   hundreds of solar flares. Their results could help astrophysicists   
   understand how the Sun's corona reaches temperatures of millions of   
   degrees Fahrenheit."   
      
   Weekly Commentary on the Sun, the Magnetosphere, and the Earth's   
   Ionosphere - May 18, 2023, from F.K. Janda, OK1HH.   
      
   "On May 12, we expected a CME impact from the flare on the evening   
   of May 9. It was indeed registered - at 0635 UTC the geomagnetic   
   storm began. However, it was weaker than expected, of G1 class.   
      
   "On 13 May at 1915 UTC, an unexpected CME impact followed for a   
   change, which again triggered another G1 class geomagnetic storm.   
      
   "On 16 May, we expected another smaller CME. The particle cloud has   
   been slowly approaching Earth since the magnetic filament eruption   
   in the southern hemisphere of the Sun on 12 May.   
      
   "The next solar flare on May 16, with a maximum at 1643 UTC, was   
   M9.6 class. It came from a sunspot group still hiding behind the   
   southeastern limb of the Sun. In fact, it may have been an X flare,   
   partially obscured by the solar horizon. Yet it caused the strong   
   Dellinger effect (shortwave fade) over North America. After the   
   sunspot group came out on the solar disk, we could observe it as AR   
   3310. It's about three times wider than Earth, and its magnetic   
   configuration promises more flares.   
      
   "Not only was solar flare activity quite high, but the Sun was   
   hurling so many CMEs into space that hardly a day went by without   
   one hitting Earth. Therefore, the frequency of geomagnetic storms   
   was also higher, followed by frequent deterioration of shortwave   
   propagation conditions. In summary, the 25th solar cycle continues   
   to evolve nicely."   
      
   Frank, VO1HP sent this from St. Johns, Newfoundland:   
      
   "On May 12 1957-2113 UTC, there was a strong 6M Es opening into mid   
   South America. Logged 20 stations using FT8. No CW or SSB heard.   
   Stations worked at VO1HP remote station: LU3CQ, CE3SX, 2SV, LI7DUE,   
   9AEA, 9DO, 1FAM, 8EX, CX3VB, PP5BK, LU2DPW, CX1VH, PU3AMB, CX6VM,   
   LU3FAP, XQ3SK, XQ3MCC, CE3VRT, 3SOC, and LU5FF.   
      
   "Antenna 4el Yagi at 35ft overlooking ocean. K3 + PR6, KPA500   
   KAT500. Other VO1s seen: VO1CH, VO1SIX, and VO1AW."   
      
   On April 24, Rocky Riggs, W6RJK in Truckee, California wrote:   
      
   "I was not very active until recently when I was introduced to POTA.   
   The park I frequent the most would typically give me 40-60 contacts   
   in a 2 hour period.   
      
   "On Monday, April 24th, I went to the same park, and in 30+ minutes   
   had no contacts and couldn't hear anyone either. I later found out   
   that the solar storm was causing most of our radio problems. Until   
   then, I had never considered much about solar flares, or how the Sun   
   influences radio propagation. Now, finally, I'm trying to learn as   
   much as I can. The K7RA Solar Update in the ARRL Newsletter is   
   FANTASTIC and will be my source going forward to help me learn and   
   understand.   
      
   "Here's my question.  Is there a 'real time' place where I can go to   
   determine if a particular band has good propagation (I typically use   
   20m and 40m)?   
      
   "You know, like before I go out and get all set up and it's a 'goose   
   egg.'"   
      
   As I first reported in Propagation Forecast Bulletin ARLP017, I told   
   him that a very useful tool (to use) is to check real time   
   geomagnetic indices with this:   
      
   https://www.swpc.noaa.gov/products/planetary-k-index   
      
   Nice quiet conditions show a planetary A index at 1 or 2, unsettled   
   conditions at 3, then above 3 conditions are disturbed. The scale is   
   logarithmic, so each point in either direction is important.   
      
   Another approach is to use pskreporter at   
   https://www.pskreporter.info/pskmap.html which is handy if you live   
   in a grid square that has many active hams, or a nearby grid that is   
   more populated.   
      
   You can check FT8 activity on any band. There is also a "Country of   
   Callsign" selection so you can check activity across your nation of   
   choice. Recently when I have raised nobody on 10 meter FT8 this   
   option showed no activity here in the Pacific Northwest but plenty   
   of 10 meter activity in the southeast United States.   
      
   Here is a new video from Dr. Tamitha Skov, WX6SWW:   
      
   https://youtu.be/xSQYjH6D_YA   
      
   NASA sunspot picture:   
      
   https://bit.ly/458DrPw   
      
   A video of a recent eruption:   
      
   https://www.youtube.com/watch?v=Rm7M5pqjCgY   
      
   Here are articles about Radio Blackout:   
      
   https://bit.ly/434c5bw   
      
   https://bit.ly/3pWId2e   
      
   https://bit.ly/45hXTxh   
      
   https://bit.ly/3MEkCwa   
      
   NASA warning of a Solar Storm threat:   
      
   https://bit.ly/3pSK4p2   
      
   Send your tips, reports, observations, questions and comments to   
   k7ra@arrl.net. When reporting observations, don't forget to tell us   
   which mode you were operating.   
      
   For more information concerning shortwave radio propagation, see   
   http://www.arrl.org/propagation and the ARRL Technical Information   
   Service at http://arrl.org/propagation-of-rf-signals . For an   
   explanation of 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/ .   
      
   Instructions for starting or ending email distribution of ARRL   
   bulletins are at http://arrl.org/bulletins .   
      
   Sunspot numbers for May 11 through 17, 2023 were 152, 134, 120, 109,   
   103, 106, and 106, with a mean of 118.6. 10.7 cm flux was 163.4,   
   149.1, 143.8, 139.7, 134.5, 134.3, and 137.9, with a mean of 143.2.   
   Estimated planetary A indices were 9, 19, 13, 8, 6, 8, and 4, with a   
   mean of 9.6. Middle latitude A index was 10, 15, 12, 9, 6, 10, and   
   5, with a mean of 9.6.   
   NNNN   
   /EX   
   --- SBBSecho 3.20-Win32   
    * Origin: The Thunderbolt BBS - Little Rock, Arkansas (1:2320/33)   
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