[SFDXA] ARLP041 Propagation de K7RA

Fri Oct 9 15:06:40 EDT 2015

> SB PROP @ ARL $ARLP041
> ARLP041 Propagation de K7RA
> 
> ZCZC AP41
> QST de W1AW  
> Propagation Forecast Bulletin 41  ARLP041
> From Tad Cook, K7RA
> Seattle, WA  October 9, 2015
> To all radio amateurs 
> 
> SB PROP ARL ARLP041
> ARLP041 Propagation de K7RA
> 
> Sunspot numbers and solar flux softened over the past week, with
> average daily sunspot numbers declining from 120.9 to just 37, and
> average daily solar flux down from 122.7 to 93.8. These numbers
> compare the October 1-7 activity against the previous seven days.
> 
> Average planetary A index was way up, from 5.1 to 24.3. The
> planetary A index reading of 77 on Wednesday was a big factor in the
> high average. That is a huge number, indicating a strong geomagnetic
> storm.
> 
> Predicted solar flux for the near term is 80 on October 9-10, 85 on
> October 11, 90 on October 12, 95 on October 13-14, 100 on October
> 15-16, 130 on October 17-18, 125 on October 19, 120 on October
> 20-25, 115 on October 26, 110 on October 27 and 100 on October
> 28-29.
> 
> Solar flux is predicted to decline to 85 on November 1-3, then rise
> to 130 on November 12-14.
> 
> Predicted planetary A index is 27 on October 9, 12 on October 10-11,
> 20 and 15 on October 12-13, 12 on October 14-15, then 10, 12, 8, 10
> and 12 on October 16-20, followed by 8 on October 21-27, then 10, 12
> and 10 on October 28-30, 12 on October 31 to November 1, then 8, 12
> and 15 on November 2-4, then 20, 18 and 12 on November 5-7, and 8 on
> November 8-11.
> 
> A geomagnetic forecast comes to us from Tomas Bayer of the Budkov
> Geomagnetic Observatory in South Bohemia (Czech Republic):
> 
> "Currently, active conditions should continue after the storm
> yesterday (at the Budkov observatory, the seventh K-index reading on
> October 8 has reached 6). The first three days of the forecast week
> (October 10-12), we expect at the Budkov observatory at most
> unsettled conditions.  After day 4 (October 13), geomagnetic
> conditions should turn to quiet, nevertheless, an isolated active
> episode is possible. Day 5 (October 14), we expect at most unsettled
> conditions, the rest of forecast week should be at most quiet with a
> short active episode."
> 
> We also have a weekly geomagnetic forecast from F.K. Janda, OK1HH of
> the Czech Propagation Interest Group. He expects the geomagnetic
> field will be active to disturbed October 9-10, quiet to active
> October 11, quiet to unsettled October 12, quiet to active October
> 13, quiet to unsettled October 14-15, quiet to active October 16-17,
> mostly quiet October 18-19, quiet to active October 20, mostly quiet
> October 21, quiet to unsettled October 22, quiet on October 23-24,
> quiet to unsettled October 25, quiet on October 26, mostly quiet
> October 27, quiet to unsettled October 28-29, quiet to active
> October 30, quiet to unsettled October 31, quiet to active November
> 1, and active to disturbed on November 2-4.
> 
> He expects increased solar wind on October 9-10, 16-17, 19-20 and
> November 2-4.
> 
> John Van Dalen, N7AME of Everett, Washington wrote, "My read of the
> last week have been disgusting to say the least. The East Coast
> seems to be enjoying some propagation as does South America and the
> lower 48. But it appears that Washington State is in a real slump
> unless I have a radio problems or all three antenna have gone bad."
> 
> Yes, the high levels of geomagnetic disturbance this week have had a
> disruptive effect on HF propagation. John reminds us of a useful
> tool for propagation work, the online version of VOACAP:
> 
> http://www.voacap.com/prediction.html
> 
> It's easy to use and works great. The predicted mean sunspot number
> for the month is already entered, so all you need are the two
> endpoints of the path you want to look at.
> 
> Jon Jones, N0JK in Kansas reports a nice 6 meter opening during all
> the geomagnetic upset:
> 
> "A surprise 6 meter F2 opening occurred the afternoon of October 7
> between the Caribbean, Central America and Gulf Coast and Midwest
> states.
> 
> "The solar flux was only 83, but the Boulder K index went to 7
> causing a class G3 geomagnetic storm.
> 
> "Aurora was spotted in northern W9 and W0 at 1900z.
> 
> "Around 1925z FG8OJ was spotted to south Texas along with VP2ETE.
> 
> "I was on the radio at 1940z. TI3/W7RI popped up 59++ on 50.110 MHz
> and in my log at 1941z. Scott, TI3/W7RI worked many stations over
> the next 25 minutes. Other TI stations active included TI5XP and
> WA8NJR/TI5. The TI stations worked W8, W9 and W0 along with the Gulf
> Coast states. This was one hop F2. By 2005z the TI - Midwest opening
> was over. A brief but intense opening.  Stations further south heard
> the OA4TT/b for another hour or so."
> 
> Thanks, Jon!
> 
> 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. More good
> information and tutorials on propagation are at http://k9la.us/.
> 
> My own archives of the NOAA/USAF daily 45 day forecast for solar
> flux and planetary A index are in downloadable spreadsheet format at
> http://bit.ly/1VOqf9B and http://bit.ly/1DcpaC5 .
> 
> Click on "Download this file" to download the archive, and ignore
> the security warning about file format. Pop-up blockers may suppress
> the download.
> 
> 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 October 1 through 7 were 73, 58, 47, 18, 15, 24,
> and 24, with a mean of 37. 10.7 cm flux was 119.7, 107.4, 96.9,
> 88.3, 82.6, 81.4, and 80.5, with a mean of 93.8. Estimated planetary
> A indices were 11, 14, 11, 20, 18, 19, and 77, with a mean of 24.3.
> Estimated mid-latitude A indices were 8, 9, 10, 16, 12, 11, and 44,
> with a mean of 15.7.
> NNNN
> /EX