SB PROP @ ARL $ARLP027<br />ARLP027 Propagation de K7RA<br /><br />ZCZC AP27<br />QST de W1AW <br />Propagation Forecast Bulletin 27 ARLP027<br />>From Tad Cook, K7RA<br />Seattle, WA July 7, 2006<br />To all radio amateurs <br /><br />SB PROP ARL ARLP027<br />ARLP027 Propagation de K7RA<br /><br />Solar activity was up this week. Average daily sunspot numbers rose<br />nearly 22 points from last week's average to 35.6. Average solar<br />flux rose as well, 11 points from 75.7 to 86.7. The (moderately)<br />active geomagnetic day this week was July 5, with a planetary A<br />index of 19, and the college A index from the magnetometer near<br />Fairbanks at 28.<br /><br />The increased geomagnetic activity was due to a high-speed solar<br />wind stream from a coronal hole on the sun beginning July 4. Earth<br />was vulnerable due to a south-pointing interplanetary magnetic field<br />(IMF). When the IMF points north, Earth is less vulnerable. The<br />IMF is again pointing south on July 7. The next increase in<br />geomagnetic activity is predicted for July 9. The current<br />prediction for the planetary A index for July 7-10 is 8, 10, 25 and<br />18. Solar flux for those days is predicted at about 85.<br /><br />When the solar wind stream hit earlier this week, a radio burst from<br />giant sunspot 898 was recorded by Thomas Ashcraft of Lamy, New<br />Mexico at 1743z on July 5. He used receivers tuned to just above 17<br />meters and just above 15 meters to produce a binaural audio<br />recording best appreciated with stereo headphones. Listen to it at<br />
http://www.heliotown.com/Radio_Sun_Introduction.html. Thanks to Don<br />Mayhall, N5DM for the tip.<br /><br />We received more notes on 6 meters and Field Day. Bill Baker, W5GT<br />reports that his club entry from W5NOR in Oklahoma used a rotatable<br />dipole on six and made 109 contacts over June 24-25. Bill Van<br />Alstyne, W5WVO of Rio Rancho, New Mexico writes of six meters on<br />Field Day, ''Saturday evening saw some really nice double-hop into<br />the east (NY, PA, MD, VA mostly), plus the usual single-hop path to<br />the mid-way point (MO, IA, IL). Signal strength on the east coast<br />stations was very good, in some cases as good as the Midwest<br />stations. Worked a new grid square (FM09) in the WV panhandle, a<br />club FD effort that decided to activate this somewhat rare grid as<br />well as work the contest. Sunday morning featured a long, strong,<br />and fairly broad opening into the Midwest -- MO, IA, IL, IN. WI, MN,<br />and others. Only sporadic east coast contacts, mostly in FL''. Bill<br />is looking forward to the CQ World Wide VHF Contest, July 15-16.<br /><br />Eric Hall, K9GY of Lansing, Illinois reminds us to operate the IARU<br />contest this weekend and specifically work operators in the World<br />Radiosport Team Championship 2006, which this time around is held in<br />Florianopolis, Brazil. You can follow the progress of the teams via<br />an online scoreboard. Check
http://www.wrtc2006.com/release55.html.<br /><br />If you want to work the teams in Brazil, propagation to South<br />America from the Northern Hemisphere should be good this weekend.<br />>From California, best times should be 80 meters around 0330z and<br />0530-0900z, 40 meters 0330-1000z, 20 meters 0100-0700z, and 15<br />meters 1700z-0530z, with the best bet around 2330-0430z. Although<br />not a sure bet, check for 10-meter openings 2000-0500z.<br /><br />>From Chicago, 80 meters looks best 0330-0900z, 40 meters 0130-0930z,<br />and 20 meters 2230-0530z. 15 meters does not look promising, but<br />your best bet is 2100-0400z.<br /><br />>From Dallas, 80 meters looks good 0230-0930z, 40 meters 0100-1000z,<br />20 meters 2230-0530z, 15 meters 1700-0200z, and perhaps 10 meters,<br />best chances 1800-0400z, with stronger signals toward the end of<br />that period.<br /><br />>From Philadelphia, 80 meters looks good 0200-0830z, 40 meters<br />0000-0730z, 20 meters 2200-0530z, and perhaps 15 meters from<br />2100-0300z.<br /><br />You can work out paths from your own location using the method<br />outlined in earlier bulletin ARLP014.<br /><br />Read it at
http://www.arrl.org/w1aw/prop/2006-arlp014.html.<br /><br />Of course, for the IARU contest, you work stations all over the<br />world, not just in Brazil. See the IARU HF World Championship rules<br />on the ARRL web site at<br />
http://www.arrl.org/contests/rules/2006/iaru.html.<br /><br />The end of June brings to a close the second quarter of 2006. This<br />is a good time to review average quarterly and monthly sunspot and<br />solar flux numbers. It's a good way to spot trends.<br /><br />>From the first quarter of 2003 through the second quarter of 2006,<br />the average daily sunspot number was 120.3, 107.3, 110.2, 99.2,<br />72.9, 71.3, 69.3, 61, 46.1, 55.7, 58, 36, 18.1 and 39.7.<br /><br />The average daily solar flux for the same period was 134.3, 124.2,<br />120.8, 137.4, 111.1, 99.5, 111, 104.8, 96.4, 93.1, 93.6, 84.5, 78.5<br />and 82.1.<br /><br />Three-month averages should be a bit smoother than one-month<br />averages, and from the numbers above you might think we already hit<br />bottom on the solar cycle and began a rebound. Although activity is<br />low, we haven't seen the weeks of zero sunspots that we experienced<br />about a decade ago during the last solar minimum. Also, look at the<br />monthly numbers below. Although there was a slight uptick in<br />sunspot numbers and solar flux for the last quarter, the monthly<br />numbers for the three months that make up this last quarter show an<br />orderly decline.<br /><br />The average daily sunspot numbers for the months May 2005 through<br />June 2006 were 65.4, 59.8, 68.7, 65.6, 39.2, 13, 32.2, 62.6, 26.7,<br />5.3, 21.3, 55.2, 39.6 and 24.4. Average daily solar flux for the<br />same months was 99.5 , 93.7, 96.5, 92.4, 91.9, 76.6, 86.3, 90.8,<br />83.4, 76.5, 75.5, 88.9, 80.9 and 76.5.<br /><br />We now have a new forecast from NOAA Space Environment Center for<br />the bottom of this solar cycle, and compared to the forecast of the<br />past few years, it puts the bottom just slightly further out than<br />the forecast of a few years ago, which is all we had until this<br />week.<br /><br />You can see it in the charts in the back of the July 4 Preliminary<br />Report and Forecast, at<br />
http://www.sec.noaa.gov/weekly/pdf/prf1609.pdf. Note on pages 9 and<br />10 that the table of predicted smoothed sunspot numbers put the<br />minimum in January 2007, or it may be more realistic to characterize<br />it as occurring between December 2006 and May 2007. The projection<br />running just one week earlier, at<br />
http://www.sec.noaa.gov/weekly/pdf/prf1608.pdf is the same one that<br />has been out for several years. Note the minimum sunspot numbers at<br />December 2006 and January 2007. Similar numbers for the smoothed<br />solar flux, which in last week's table show a minimum from December<br />2006 through April 2007, while this week's forecast shows January<br />through April 2007. Not much difference, but a slight shift out<br />into 2007, and the first update to this forecast in years.<br /><br />If you would like to make a comment or have a tip for our readers,<br />email the author at, []k7ra@arrl.net.[/]<br /><br />For more information concerning radio propagation, see the ARRL<br />Technical Information Service at<br />
http://www.arrl.org/tis/info/propagation.html. For a detailed<br />explanation of the numbers used in this bulletin, see<br />
http://www.arrl.org/tis/info/k9la-prop.html. An archive of past<br />propagation bulletins is at
http://www.arrl.org/w1aw/prop/ .<br /><br />Sunspot numbers for June 29 through July 5 were 35, 38, 36, 34, 38,<br />40 and 28 with a mean of 35.6. 10.7 cm flux was 85.5, 86.1, 85.5,<br />87.1, 85.9, 92, and 84.7, with a mean of 86.7. Estimated planetary A<br />indices were 12, 8, 5, 2, 4, 13 and 19 with a mean of 9. Estimated<br />mid-latitude A indices were 8, 7, 3, 1, 2, 11 and 18, with a mean of<br />7.1.<br />NNNN<br />/EX
