[SFDXA] ARLP038 Propagation de K7RA

[WILLIAM MARX]

> 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 17, 2021
> To all radio amateurs 
> 
> SB PROP ARL ARLP038
> ARLP038 Propagation de K7RA
> 
> On this reporting week, September 9-15, sunspot numbers started
> strong at 124 but ended at 0. Average daily sunspot numbers went
> from 64.6 to 58.3. Average daily solar flux declined from 92.9 to
> 87.4.
> 
> Geomagnetic indicators remained moderate, with last week's average
> daily planetary A index unchanged at 7, and average daily middle
> latitude A index changed from 7.7 to 6.9.
> 
> Predicted solar flux is much lower than last week's bulletin
> reported. Solar flux is predicted at 75 on September 17-23, 76 on
> September 24-26, 78, 80 and 82 on September 27-29, 86 on September
> 30 through October 10, 82 on October 11-12, 80 on October 13, 78 on
> October 14-17, and 76 on October 18-23. Solar flux is expected to
> rise to 89 by the end of October.
> 
> Predicted planetary A index is 15 on September 17-18, 8 on September
> 19-20, then 5 and 8 on September 21-22, 5 on September 23 through
> October 3, then 8 and 12 on October 4-5, and 5 on October 6-17, 8 on
> October 18, and 5 on October 19 through the end of the month.
> 
> Geomagnetic activity forecast for the period September 17 to October
> 12, 2021 from F.K. Janda, OK1HH:
> 
> "Geomagnetic field will be:
> quiet on: September 19, 29-30, October 9-10,
> quiet to unsettled on: September 20, 28, October 1, 4, 7, 12,
> quiet to active on: September 17-18, 22-23, 25-27, October 3, 8, 11,
> unsettled to active on: September 21, 24, October (2,) 5-6,
> Active to disturbed: Nothing predicted.
> 
> "Solar wind will intensify on October 11.
> 
> "Remarks:
> - Parenthesis means lower probability of activity enhancement.
> - The confusing situation mentioned two weeks ago, together
>  with the variable configuration of active areas and coronal
>  holes, was a sign of the subsequent increase in solar activity."
> 
> Marty, KB0QZ in Tulsa was tuning 10 meters at noon on Sunday,
> September 12 and heard no signals, not even any propagation beacons.
> He called CQ on 28.040 MHz CW and received a 599 report from LU4HK,
> who was also S9. The path distance was 5,094 miles. He continued to
> tune the band and call CQ through the afternoon with nothing else
> heard.
> 
> Page down in this article, https://bit.ly/3Ch98XD, "Nevada County
> Captures: Glorious sunrise" and page down for a great solar image in
> a local California newspaper.
> 
> Go to your favorite search engine and enter this text:
> 
> mdpi: sunspot number and photon flux data
> 
> An interesting PDF is available for download.
> 
> At 2000 UTC on September 13 I (K7RA) called CQ on 15 meters with FT8
> from my station in Seattle at CN87uq using a marginal end fed wire
> antenna, about .72 wavelength long, partially indoors.
> 
> Typically I would see the map at pskreporter.info light up with many
> stations reporting my signal. But at that time only one station,
> WA1SXK in North Carolina (EM95lf) heard me, reporting -19 dB, and
> this continued through many attempts.
> 
> I switched to 17 meters and saw typical reports from stations in the
> Midwest and East coast, 1500-2400 miles out.
> 
> Checked for flare activity and anything else unusual, but saw
> nothing. But solar flux and sunspot numbers were declining, after
> reaching a high several days earlier. Perhaps the MUF for this path
> at that time was below 15 meters.
> 
> If you would like to make a comment or have a tip for our readers,
> please email the author at, k7ra at arrl.net .
> 
> For more information concerning shortwave radio propagation, see
> http://www.arrl.org/propagation and 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/.
> 
> Instructions for starting or ending email distribution of ARRL
> bulletins are at http://arrl.org/bulletins .
> 
> Sunspot numbers for September 9 through 15, 2021 were 124, 99, 93,
> 47, 32, 13, and 0, with a mean of 58.3. 10.7 cm flux was 99.7, 96.3,
> 91.8, 87.7, 83.3, 78.1, and 75.2, with a mean of 87.4. Estimated
> planetary A indices were 6, 9, 7, 6, 9, 6, and 6, with a mean of 7.
> Middle latitude A index was 7, 9, 8, 6, 7, 5, and 6, with a mean of
> 6.9.
> NNNN
> /EX