[SFDXA] ARLP033 Propagation de K7RA

[Bill Marx]

> 

> SB PROP @ ARL $ARLP033
> ARLP033 Propagation de K7RA
> 
> ZCZC AP34
> QST de W1AW  
> Propagation Forecast Bulletin 33  ARLP033
> From Tad Cook, K7RA
> Seattle, WA  August 17, 2012
> To all radio amateurs 
> 
> SB PROP ARL ARLP033
> ARLP033 Propagation de K7RA
> 
> There was a big drop in solar activity over the past week, with the
> average daily sunspot numbers declining nearly 42 points to 77.6,
> and average daily solar flux down 20 points to 114.7.
> 
> Solar flux has dropped below 100, where it is expected to remain
> through August 22. NOAA/USAF predicted solar flux on August 16 and
> 17 at 100, but it was actually 98.3 on August 16. The prediction for
> August 18 is 95, then 90 on August 19-22, then 100, 120 and 130 on
> August 23-25, then 135 on August 26-29. It is expected to drop below
> 100 again on September 12-15. This is almost exactly the forecast
> that was in the ARRL Letter on Thursday, with the August 23-24
> sunspot numbers dropped by five points on each day.
> 
> Predicted planetary A index is 10 on August 17, 14 on August 18, 12
> on August 19-20, then 8 on August 21, 5 on August 22-23, 8 on August
> 24-25, 12 on August 26, followed by 5 on August 27 through September
> 7, then 8 on September 8-10, and 5 on September 11-14. This is
> identical to the forecast in Thursday's ARRL Letter.
> 
> The weekly prediction of geomagnetic indicators from OK1HH says to
> watch for quiet to unsettled conditions August 17-20, mostly quiet
> August 21, quiet on August 22-24, quiet to active August 25-26,
> mostly quiet August 27-28, active to disturbed August 29-30, and
> quiet again on August 31 through September 1.
> 
> Many readers have commented that the short term view of the solar
> cycle has a recent peak around Fall 2011, yet predictions still
> focus on Spring 2013 for the peak of Cycle 24.
> 
> It is interesting to look back over the past two solar rotations,
> which is 55 days, and see an average compared with the same 55 days
> last year, June 23 through August 16.  The average daily sunspot
> numbers for those dates in 2009-2012 are 3.3, 26.5, 61.2, and 91.6.
> If we want to look at last Fall's peak we can cherry pick the data,
> and chose the 55 day period of November 7 through December 31, 2011.
> The average daily sunspot number then was 119.3, about 30% higher
> than current values.
> 
> This week N7QR, Russ Mickiewicz, of Portland, Oregon (and later
> reader David Moore, and others) sent information on a new method for
> predicting solar flares, by tracking decay rates in gamma radiation
> from radioactive elements. Read about it at
> http://phys.org/news/2012-08-solar-flares-advance.html.
> 
> Randy Crews, W7TJ of Spokane, Washington offered some opinions on
> future solar activity and propagation.  He writes, "Reading K9LA's
> excellent article in QST this past July, the graph on the cover
> pretty well confirms the good HF propagation bestowed on DXers for
> now, and if one 'connects the dots' the HF propagation following the
> years after the peak (sometime in 2013) will be considerably
> different from what we all have experienced in the past 30+ years.
> Cycles 21, 22 and 23 were good strong normal sunspot cycles. As we
> all can conclude from the numerous forecasts, Cycle 24 will be a
> very low one. There will be much lower highs to drop from once the
> decline begins, and the low point of Cycle 24 will occur much
> sooner, unlike the many years of previous cycles where solar
> activity declined from solar flux values of 200+. Carl is right.
> Enjoy and make the most of propagation now. Once the cycle turns,
> everyone will be surprised at the swiftness of the decline of high
> band propagation."
> 
> George Kutcher, K3GWK of Jenkinsburg, Georgia mentioned that "There
> is a simple sunspot data app for the iPhone, iPad and iPod Touch.
> The app is called 'Sunspot' by AMI Mobile.  There is a cost for the
> app.  'Sunspot' is a simple application to display 3-hour WWV space
> weather and NOAA sunspot data on your iPhone, etc. Data is
> updateable on demand, as well as current trending from the previous
> data set."
> 
> Brendan Wahl, WA7HL of Bisbee, Arizona likes the N0HR Propfire
> program for the Firefox web browser. It displays the geophysical and
> solar data that WWV transmits at 18 minutes after each hour, and can
> also display sunspot number. You can get it for free at,
> http://www.n0hr.com/Propfire.htm.
> 
> N0AX reports that DX Sherlock has a new URL at,
> http://www.dxmaps.com/.
> 
> Turns out our Sun is not perfectly round. Check it out at
> http://www.cbsnews.com/8301-205_162-57494899/the-suns-strange-shape-revealed/.
> 
> 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 the
> 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. Find more good
> information and tutorials on propagation at
> http://myplace.frontier.com/~k9la/.
> 
> 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 9 through 15 were 124, 105, 98, 76, 62,
> 46, and 32, with a mean of 77.6. 10.7 cm flux was 131.2, 125.4,
> 119.7, 112.3, 108.1, 105.8, and 100.7, with a mean of 114.7.
> Estimated planetary A indices were 6, 4, 4, 7, 9, 7, and 6, with a
> mean of 6.1. Estimated mid-latitude A indices were 7, 4, 5, 7, 8, 7,
> and 7 with a mean of 6.4.
> NNNN
> /EX