[SFDXA] ARLP035 Propagation de K7RA

[Bmarx@bellsouth.net]

> SB PROP @ ARL $ARLP035
> ARLP035 Propagation de K7RA
> 
> ZCZC AP35
> QST de W1AW  
> Propagation Forecast Bulletin 35  ARLP035
> From Tad Cook, K7RA
> Seattle, WA  August 30, 2019
> To all radio amateurs 
> 
> SB PROP ARL ARLP035
> ARLP035 Propagation de K7RA
> 
> The current stretch of spotless days is now over three weeks,
> according to http://www.spaceweather.com. The continuing quiet seems
> eerie. For this past reporting week, Thursday through Wednesday, the
> average daily solar flux (10.7 GHz radiation recorded in Penticton,
> British Columbia, which roughly tracks with sunspot activity) was
> only 66. I couldn't recall when the weekly average reported in this
> bulletin was last that low, and couldn't find any report during the
> past year with such low activity.
> 
> I did an inspection of the numbers and had to go back to the Fall of
> 2007 to find average solar flux in that range. In 2007 we reported
> an average of 66.5 in propagation forecast bulletin number 40:
> 
> http://www.arrl.org/w1aw-bulletins-archive/ARLP040/2007
> 
> Can anyone else find solar flux that low or lower in past bulletins?
> We have them online going back to 1995:
> 
> http://arrl.org/w1aw-bulletins-archive-propagation
> 
> If anyone has copies of propagation bulletins prior to 1995, I would
> love to see them. I began writing the bulletin in March 1991. Before
> that, W1HDQ was the author. I recall copying the bulletin as a
> teenager in 1966 using CW but have not found anyone who knows when
> the bulletin began. I should have asked W1HDQ before he became a
> silent key.
> 
> Predicted solar flux for the next 45 days is 66 on August 30 through
> September 6, 67 on September 7-11, 68 on September 12-15, 67 on
> September 16 through October 8, and 68 again on October 9-12, then
> 67 on October 13.
> 
> Predicted planetary A index is 8, 20, 34, 16 and 8 on August 30
> through September 3, 5 on September 4-5, 8 on September 6-7, 5 on
> September 8-21, then 10, 15 and 8 on September 22-24, 5 on September
> 25-27, then 35, 18 and 10 on September 28-30, 5 on October 1-2, 10
> and 8 on October 3-4, and 5 on October 5-13.
> 
> Note that the predicted planetary A index is 34 on September 1,
> which according to W3LPL and the ARRL Letter is the 160th
> anniversary of the infamous Carrington Event.
> 
> https://en.wikipedia.org/wiki/Solar_storm_of_1859
> 
> https://arxiv.org/abs/1908.10326
> 
> Http://www.spaceweather.com reported a large recurring coronal hole
> facing Earth, and they expect the effects to be felt this Sunday,
> September 1. A planetary A index value of 35 is predicted for the
> next solar rotation, on September 28.
> 
> Geomagnetic activity forecast for the period August 30 to September
> 26, 2019 from OK1HH.
> 
> "Geomagnetic field will be
> Quiet on: September 10-11, 20-21, (25-26)
> Quiet to unsettled on: August 30, September 3-5, 7-8, 13, 17, 22, 24
> Quiet to active on: August 31, September 6, 9, 12, 14-16, 18-19, 23
> Unsettled to active on: September 2
> Active to disturbed: September 1
> 
> "Solar wind will intensify on August (30)-31, September 1 (-2), (4-6)
> Parenthesis means lower probability of activity enhancement."
> 
> If you would like to make a comment or have a tip for our readers,
> email the author at, k7ra at 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
> 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 22 through 28, 2019 were 0, 0, 0, 0, 0,
> 0, and 0, with a mean of 0. 10.7 cm flux was 65.7, 66.5, 66.3, 66,
> 65.8, 66.1, and 65.9, with a mean of 66. Estimated planetary A
> indices were 6, 4, 5, 4, 6, 10, and 5, with a mean of 5.7. Middle
> latitude A index was 7, 4, 5, 5, 6, 10, and 5, with a mean of 6.
> NNNN
> /EX