Subj : ARRL Propagation Bulletin To : All From : Daryl Stout Date : Mon Sep 04 2017 09:53 am SB PROP @ ARL $ARLP035 ARLP035 Propagation de K7RA ZCZC AP35 QST de W1AW Propagation Forecast Bulletin 35 ARLP035 From Tad Cook, K7RA Seattle, WA September 1, 2017 To all radio amateurs SB PROP ARL ARLP035 ARLP035 Propagation de K7RA A new video from Dr. Skov: https://youtu.be/qvjfFpRMQpY Average daily sunspot numbers and solar flux declined this week (August 24 to 30). Average daily sunspot number went from 39.9 to 33.3, while average daily solar flux declined to 81.2 from 84.6. Average planetary A index declined from 23.1 to 7.1, and average mid-latitude A index went from 18.6 to 7.4. The latest forecast shows planetary A index at 24, 16, 12 and 8 on September 1 to 4, 5 on September 5 and 6 then 8, 10 and 8 on September 7 to 9, 5 on September 10 to 12, 25 on September 13, 30 on September 14 and 15, then 25 and 12 on September 16 and 17, 8 on September 18 and 19, 5 on September 20 to 22, 10 on September 23 and 24, then 8, 15, 25, 18, 15 and 8 on September 25 to 30, then 5 on October 1 to 4, 10 and 8 on October 5 and 6, 5 on October 7 to 9, 25 on October 10, 30 on October 11 and 12, then 25, 12 and 8 on October 13 to 15. Predicted solar flux is 92 on September 1 and 2, 91 on September 3, 90 on September 4 to 7, 80 on September 8, 85 on September 9 to 14, 88 on September 15 to 18, 85 on September 19 and 20, then 82 and 80 on September 21 and 22, and 78 on September 23 to 25, 77 and 75 on September 26 and 27, 74 on September 28 and 29, 72 on September 30 through October 3, 75 and 80 on October 4 and 5, 85 on October 6 to 11 and 88 on October 12 and 15. Geomagnetic activity forecast for the period September 1 to 27, 2017 from OK1HH. "Geomagnetic field will be: Quiet on September 10 and 11, 20 and 21 Mostly quiet on September 4 to 6, 23, 26 Quiet to unsettled September 3, 8 and 9, 19, 22, 27 Quiet to active on September 2, 7, 12, 16 and 17, 24 Active to disturbed on September 1, 13 to 15, 18, 25 Remark: Parenthesis means lower probability of activity enhancement and/or lower reliability of prediction." For more information concerning radio propagation, see 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/. 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 August 24 to 30, 2017 were 43, 39, 35, 22, 17, 35, and 42, with a mean of 33.3. 10.7 cm flux was 78.8, 80.8, 77.5, 78.2, 81.6, 84.3, and 86.9, with a mean of 81.2. Estimated planetary A indices were 11, 5, 5, 10, 4, 10, and 5, with a mean of 7.1. Estimated mid-latitude A indices were 16, 7, 5, 6, 3, 10, and 5, with a mean of 7.4. NNNN /EX --- þ Synchronet þ The Thunderbolt BBS - wx1der.dyndns.org .