[SFDXA] ARLP027 Propagation de K7RA

[Bill]

> SB PROP @ ARL $ARLP027
> ARLP027 Propagation de K7RA
> 
> ZCZC AP27
> QST de W1AW  
> Propagation Forecast Bulletin 27  ARLP027
> From Tad Cook, K7RA
> Seattle, WA  July 7, 2023
> To all radio amateurs 
> 
> SB PROP ARL ARLP027
> ARLP027 Propagation de K7RA
> 
> The average daily sunspot number for June, 2023 was the highest in
> 21 years, according to Spaceweather.com.
> 
> From a July 3 email alert from Spaceweather.com:
> 
> "SUNSPOT COUNTS HIT A 21-YEAR HIGH:  It's official:  The average
> sunspot number in June 2023 hit a 21-year high.  Solar Cycle 25 has
> shot past its predecessor, Solar Cycle 24, and may be on pace to
> rival some of the stronger cycles of the 20th century."
> 
> Could we see another Cycle 19, the biggest in recorded history, even
> back before the birth of radio?
> 
> Not too long ago, we heard that this cycle should peak in summer
> 2025.  Later that was revised to 2024.  Now I am seeing occasional
> references to a cycle peak at the end of this year.
> 
> From my own records, average daily sunspot numbers for April through
> June 2023 were 93.7, 125.8 and 143.9, a nice upward trend.
> 
> Some popular news outlets seem confused by the difference between
> sunspot number and number of sunspots, and have quoted another
> higher average.
> 
> Here is the difference.  If they are just counting the total number
> of sunspots for the month, this is far different from average daily
> sunspot numbers.  The sunspot number is somewhat subjective, but it
> gets ten points for each sunspot group, and one point for each
> sunspot in those groups.
> 
> But I stand by my numbers.  They are all from NOAA and appear at the
> end of each bulletin.
> 
> But they may be referencing International Sunspot Number, which may
> be different from the SESC numbers from NOAA.
> 
> Here is an example of confusing sunspot numbers with number of
> sunspots:  https://bit.ly/3NCQCAl
> 
> This one is also confusing, saying there were 163.4 sunspots in
> June.  https://bit.ly/3PMu6Ym
> 
> But what does this mean?  It could be either 163 or 164 sunspots,
> but not a fractional number, unless it expresses an average.  The
> minimum sunspot number is 11.  This would be one sunspot group
> containing one spot.  They are always whole, not fractional
> integers.
> 
> There was one new sunspot region (group) on June 30, three more on
> July 1, one more on July 2, another on July 4, and one more on July
> 5.
> 
> Sunspot and solar flux data again this week did not track together.
> Average daily sunspot number declined from 170 to 126.1, while
> average daily solar flux rose slightly from 160.3 to 164.5.
> 
> Geomagnetic indicators were lower, with average daily planetary A
> index declining from 10.7 to 7.3, and middle latitude averages from
> 9.9 to 8.
> 
> Predicted solar flux is 155 on July 7, 150 on July 8 to 10, then 155
> on July 11, 160 on July 12 to 13, 175 on July 14 to 18, 170 on July
> 19 to 21, 160 on July 22 and 23, 155 on July 24 and 25, 160 on July
> 26 and 27, 165 on July 28 and 29, then 170, 170 and 165 on July 30
> through August 1, 155 on August 2 to 6, then 160, 165 and 170 on
> August 7 to 9, and 175 on August 10 to 14.
> 
> Predicted planetary A index is 5, 12 and 8 on July 7 to 9, 5 on July
> 10 and 11, then 20 and 30 on July 12 and 13, 8 on July 14 to 22, 5
> on July 23 to 30, 8 on July 31 through August 1, then 5 on August 2
> to 4, 12 and 8 on August 5 and 6, then 5, 20 and 30 on August 7 to
> 9, and 8 on August 10 to 18.
> 
> Note those big numbers are about one solar rotation apart, which is
> about 27.5 days.
> 
> Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
> Ionosphere for July 6, 2023 from F. K. Janda, OK1HH.
> 
> When the current 25th solar cycle began in December 2019, solar
> astronomers thought it would be a weak cycle similar to its
> immediate predecessor, solar cycle 24.  But now we have a twenty-one
> year peak.  And we expect a continued increase for about two more
> years.
> 
> The misfortune is that ongoing global changes are reducing the
> ionization rate of the ionosphere.  Yet the current conditions for
> shortwave or decameter wave propagation do not match the amount of
> solar activity - they are worse.
> 
> But that's not all.  Not only is solar cycle 25 likely to rival some
> of the more powerful cycles of the 20th century, but we're likely to
> see even more powerful solar flares and magnetic storms.  History
> repeats itself cyclically, and we need only think of the great
> Halloween storm of 2003, including the strongest solar flare ever
> recorded in X-ray (X45).
> 
> The giant sunspot group AR3354 (only about four times smaller than
> the giant sunspot group of early September 1859) made its last
> appearance on July 2 with an X-class flare.  Two days later it
> eclipsed.
> 
> We won't lose the source of the stronger flares, however - the
> growing AR3359, with its Beta-Gamma magnetic configuration, crossed
> the central meridian toward active western longitudes on July 6 and
> will continue to grow.  With its predicted higher activity, we could
> see an increase in the Earth's magnetic field activity as early as
> the middle of next week.
> 
> Tamitha Skov, from July 1.  https://youtu.be/HR8mm30oxOQ
> 
> Blackout  http://bit.ly/46tTRT8  https://bit.ly/3rhbjdz
> 
> Stormy weekend?  https://bit.ly/3pDrT6R
> 
> Send your tips, reports, observations, questions and comments to
> k7ra at 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 .
> 
> Also, check this article from September, 2002 QST:
> 
> https://www.arrl.org/files/file/Technology/tis/info/pdf/0209038.pdf
> 
> 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 June 29 through July 5, 2023 were 112, 187, 119,
> 126, 117, 121, and 101, with a mean of 126.1.  10.7 cm flux was
> 162.2, 158.6, 165.5, 170.2, 173.2, 167.2, and 154.6, with a mean of
> 164.5.  Estimated planetary A indices were 17, 8, 5, 5, 5, 4, and 7,
> with a mean of 7.3.  Middle latitude A index was 13, 8, 6, 8, 7, 5,
> and 9, with a mean of 8.
> NNNN
> /EX