[SFDXA] ARLP031 Propagation de K7RA

[Bill]

> SB PROP @ ARL $ARLP031
> ARLP031 Propagation de K7RA
> 
> ZCZC AP31
> QST de W1AW  
> Propagation Forecast Bulletin 31  ARLP031
> From Tad Cook, K7RA
> Seattle, WA  July 31, 2020
> To all radio amateurs 
> 
> SB PROP ARL ARLP031
> ARLP031 Propagation de K7RA
> 
> Finally, sunspots have returned!  There are currently two sunspots
> visible, both from new solar cycle 25.  The daily sunspot number was
> 11 on July 21 to 27, then rose to 22 on July 28 to 30.
> 
> Recently we have noticed an improvement in propagation due to
> seasonal sporadic-E activity.
> 
> Average daily sunspot numbers rose from 3.1 to 14.1 this week, and
> average daily solar flux changed from 69.1 to 71.1.
> 
> Total sunspot area covered 80 millionths of the solar disc on July
> 21, 120 millionths on July 22 to 26, and the coverage on the
> following four days was 70, 50, 85 and 110.
> 
> Geomagnetic indicators were a bit more active, with average daily
> planetary A index rising from 3.9 to 6.7, while average daily
> mid-latitude indicators rose from 4.3 to 8.7.
> 
> Predicted solar flux is 72 on July 31 through August 2, 70 on August
> 3 to 7, 68 on August 8 to 22, 69 on August 23 to 28, and 68 on
> August 29 through September 13.
> 
> Predicted planetary A index is 5 on July 31, then 8 and 10 on August
> 1 and 2, 5 on August 3 to 23, 8 on August 24 and 25, and 5 on August
> 26 through September 13.
> 
> Geomagnetic activity forecast for the period July 31 to August 26,
> 2020 from F. K. Janda, OK1HH.
> 
> "Geomagnetic field will be 
> Quiet on: August 4 to 7, 15 to 19, 22 to 26 
> Quiet to unsettled on: July 31, August 2 and 3, (8,) 9, 11, (12 to
> 14,) 20
> Quiet to active on: (August 1, 10, 21) 
> Unsettled to active on: not expected 
> Active to disturbed: not expected 
> 
> Solar wind will intensify on: August 1 to 3 (-4, 11 to 15,) 20 and
> 21, (22 to 25)
> 
> - Parenthesis means lower probability of activity enhancement. 
> - The predictability of changes remains lower, this time thanks to
> new active regions on the Sun."
> 
> K7DWI has interesting details on his blog about using cheap SDR
> dongles for studying VHF openings:
> 
> https://bit.ly/315dRdP
> 
> Thanks to Howard Lester, N7SO for this article on solar flares:
> 
> https://www.cfa.harvard.edu/news/2020-15
> 
> And thanks to regular contributor David Moore for this:
> 
> https://www.sciencedaily.com/releases/2020/07/200727145826.htm
> 
> The latest from Tamitha Skov, WX6SWW:
> 
> https://www.youtube.com/watch?v=vifDrXHwwsE
> 
> It looks like her entry on QRZ.com was recently updated and
> expanded:
> 
> https://www.qrz.com/db/wx6sww
> 
> For more information concerning 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/.
> 
> 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 July 23 through 29, 2020 were 11, 11, 11, 11,
> 11, 22, and 22, with a mean of 14.1.  10.7 cm flux was 70.3, 69.5,
> 70.4, 71.4, 71.4, 71.8, and 72.6, with a mean of 71.1.  Estimated
> planetary A indices were 4, 11, 15, 3, 4, 5, and 5, with a mean of
> 6.7.  Middle latitude A index was 4, 13, 27, 3, 5, 5, and 4, with a
> mean of 8.7.
> NNNN
> /EX