> > > 425 DX NEWS MAGAZINE < < <The latest issue (June 2006) is now available at www.425dxn.org/monthly/ _____________________________________________________________________________ SB PROP ARL ARLP031 ARLP031 Propagation de K7RA Last Friday, July 28, a high speed solar wind stream hit earth, and created a geomagnetic disturbance that drove the planetary and mid-latitude A index up to 29 and 26, respectively. This actually began in the early hours of Friday UTC, which was Thursday afternoon and early evening in North America. Both mid-latitude and planetary K index rose to six. If you noticed some periods of high absorption, or when the only propagation seemed to occur north to south, that would be why. Now we are moving slowly toward the fall equinox, and HF radio conditions tend to get better when the hours of light and darkness are equal between the northern and southern hemispheres. This week we saw the average daily sunspot number rise over five points to 20. We will see little variations like this as the solar cycle declines toward its minimum next year. Solar activity still seems too high to be at the bottom though. A glance at graphs of smoothed sunspot numbers shows we are still experiencing more sunspots than the minimum back in 1996. Check the graph at <http://wm7d.net/hamradio/solar/historical.shtml>http://wm7d.net/hamradio/solar/historical.shtml on the very bottom of the page, and <http://www.sec.noaa.gov/weekly/pdf/prf1613.pdf>http://www.sec.noaa.gov/weekly/pdf/prf1613.pdf on page 9. Further down on page 9, you can see that the prediction for the smoothed sunspot number for August 2006 is the same as for August of next year, and the minimum is somewhere in between. That means according to this graph, a year from now the new solar cycle will be bouncing back from the minimum, and rising past the point where we are now. The smoothed numbers are averaged over many months (I think this graph uses a moving six-month average) to help us see past the ''noise'' of daily variations. This graph shows a minimum in January 2007, only five months from now, with a smoothed sunspot number of five. July is over, so we can look at some monthly averages of sunspot numbers and solar flux. The average daily sunspot numbers for the months July 2005 through July 2006 were 68.7, 65.6, 39.2, 13, 32.2, 62.6, 26.7, 5.3, 21.3, 55.2, 39.6, 24.4 and 22.6. Average daily solar flux for the same months was 96.5, 92.4 , 91.9, 76.6, 86.3, 90.8, 83.4, 76.5, 75.5, 88.9, 80.9, 76.5 and 75.8. Over the past week I've been playing with the excellent HF radio propagation software, ACE-HF Pro, written by Richard Buckner. ACE is an acronym: Animated Communications Effectiveness, and it was originally written for VLF communication with submarines. This program is really a treat. ACE-HF Pro is based on software that Buckner wrote for military and commercial clients while at Collins Radio, and it uses the VOACAP engine. He has a new version 2.05 out, which is much more Windows-friendly than earlier versions. With it, you can produce colorful graphs that make it easy to visualize propagation over time and space, and users can even animate the results to produce a movie of signal coverage over time. Unlike other propagation programs I've used, it also makes 160-meter predictions, and attempts to predict sporadic-E skip. Tomas Hood, NW7US, who writes the monthly Propagation column for CQ Magazine, did some detailed reviews of ACE-HF in the May and July issues. He also has reviews online at <http://hfradio.org/ace-hf/>http://hfradio.org/ace-hf/ . Among the interesting and unusual features is the ability to factor antenna radiation patterns into the calculations of propagation paths. David Mays, W8UI of St. Marys, West Virginia sent some big beacon lists for HF and six meters, put together by G3USF. See them at <http://www.keele.ac.uk/depts/por/28.htm>http://www.keele.ac.uk/depts/por/28.htm and <http://www.keele.ac.uk/depts/por/50.htm>http://www.keele.ac.uk/depts/por/50.htm. Also, Bruce Brackin, N5SIX of Brandon, Mississippi commented on Larry Godek, W0OGH and his wish for a database of 10-meter repeaters searchable by frequency, all across North America, rather than lists sorted by state. This would help him identify the location of 10 meter repeaters when they appear. David recommends getting the ARRL TravelPlus CD, then exporting the data to a CVS file and sorting it in a spreadsheet program. If you would like to make a comment or have a tip for our readers, email the author at, k7raarrl.net. For more information concerning radio propagation, see the ARRL Technical Information Service at <http://www.arrl.org/tis/info/propagation.html>http://www.arrl.org/tis/info/propagation.html. For a detailed explanation of the numbers used in this bulletin, see <http://www.arrl.org/tis/info/k9la-prop.html>http://www.arrl.org/tis/info/k9la-prop.html. An archive of past propagation bulletins is at <http://www.arrl.org/w1aw/prop/>http://www.arrl.org/w1aw/prop/ . Sunspot numbers for July 27 through August 2 were 23, 17, 19, 23, 25, 11 and 22 with a mean of 20. 10.7 cm flux was 74.4, 72.6, 73, 73.9, 72.4, 72.8, and 72.1, with a mean of 73. Estimated planetary A indices were 9, 29, 5, 5, 12, 12 and 10 with a mean of 11.7. Estimated mid-latitude A indices were 5, 26, 3, 3, 11, 9 and 7, with a mean of 9.1. ,-~~-.___. / | ' \ ( ) 0 \_/-, ,----' ==== // / \-'~; /~~~(O) / __/~| / | =( _____| (_________| ______________________________ Mauro Pregliasco, I1JQJ 425 DX News Editor e-mail: [EMAIL PROTECTED] http://www.425dxn.org <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><> >>> 425 DX NEWS - NEW SEARCH TOOL <<< Leonardo Lastrucci, IZ5FSA has developed a software which allows to query the 425 DX News Archive maintained on www.ariscandicci.it from the PacketCluster. The command is SH/425 [text], where [text] should be replaced with a callsign, a IOTA Reference number, Island name, Antarctica Base, Lighthouse, etc. ---------------------------------------------------------- Archives http://www.mail-archive.com/dx-news@njdxa.org THE DXR is sponsored by the North Jersey DX Association. 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