SB PROP @ ARL $ARLP015<br />ARLP015 Propagation de K7VVV<br /><br />ZCZC AP15<br />QST de W1AW <br />Propagation Forecast Bulletin 15 ARLP015<br />>From Tad Cook, K7VVV<br />Seattle, WA April 12, 2002<br />To all radio amateurs <br /><br />SB PROP ARL ARLP015<br />ARLP015 Propagation de K7VVV<br /><br />Sunspot numbers and solar flux rose again this week. Average daily<br />sunspot numbers for April 4-10 were up nearly 40 points, and average<br />daily solar flux rose by over 11 points, when compared with the<br />seven-day period ending April 3. Solar flux is expected to decline<br />over the short term, to below 190 after this weekend, and below 180<br />after next Wednesday. There is a chance of geomagnetic unrest this<br />weekend due to a solar flare and coronal mass ejection on April 10<br />at 1230 UTC. This wasn't aimed exactly at earth, so the effects are<br />a little hard to predict, but Thursday morning's forecast from the<br />U.S. Air Force has the planetary A index at 12 on Friday, 15 on<br />Saturday and 20 on Sunday.<br /><br />We got mail this week via k7vvv@arrl.net. N2YQZ wrote from<br />Eastern New York to comment that over the past few weeks he has<br />noticed more frequent dead times on 10 meters, particularly around<br />sunrise.<br /><br />N0JK reported that on April 6, K4SUS in Florida worked Japan, Taiwan<br />and China on six meters, all via long path. N0JK also worked LU1YBB<br />in Argentina around 1904 UTC on April 3 from Kansas via F2 layer<br />propagation on six meters. He reports that more seasonal north-<br />south propagation on six meters is noted around this time of year,<br />particularly from the southern tier of the United States. He says<br />that peak times are around early afternoon.<br /><br />KD2FT wrote to say he reads this bulletin via email, and plans to<br />take an extended cruise in his boat this fall. He wants to get<br />basic solar flux and geomagnetic alerts via HF radio. Best to tune<br />into WWV at 18 minutes after each hour, or WWVH at 45 minutes past<br />the hour. WWVH is on Kauai in Hawaii, and broadcasts on 2.5, 5, 10<br />and 15 MHz. WWV is in Fort Collins, Colorado, and is on 2.5, 5, 10,<br />15 and 20 MHz. Of course the precise time service from these<br />stations is also useful if you need to set an old style ship's<br />chronometer.<br /><br />N0YD wants to know, in a nutshell, how the numbers reported in this<br />bulletin will affect propagation. He would like to know if<br />conditions will get better or worse, or when we can expect radio<br />blackouts.<br /><br />A good place to look for an explanation is K9LA's piece at<br />
http://www.arrl.org/tis/info/k9la-prop.html, but N0YD would like a<br />shorter summary of the upcoming week in each bulletin. Well,<br />basically on HF we like to see lots of sunspots (or high solar flux)<br />and very low geomagnetic activity, as reported in K and A indices.<br />This past week had very low geomagnetic activity, so that was good.<br />The fact that solar flux was higher over the past week is generally<br />good, although it really takes a big movement in the numbers to have<br />a noticeable effect. There is a possibility for higher geomagnetic<br />activity this weekend, and that might be bad for high frequency<br />propagation, partly because of increased absorption. But it could<br />be good for VHF in terms of auroral propagation, where you can<br />bounce your VHF signals off of an aurora by aiming your antenna<br />north. Solar flux is expected to be slightly lower next week, but<br />not enough to make a big difference.<br /><br />10, 15 and 20 meters will be the focus this weekend for the Japan<br />International HF CW DX Contest. Stations outside of Japan will<br />score points by working Japanese stations. Here are a few path<br />projections for this weekend from various locations. Those that are<br />polar paths to Japan could have a rough time if the K index is above<br />3.<br /><br />>From Boston, MA, try 20 meters 0500-0630, 0830-1600, 2000-0130 UTC,<br />15 meters 1300-1430, 2000-0130 UTC, 10 meters possibly 1200-1400,<br />2000-0200 UTC. This is a polar path.<br /><br />>From New York City, 20 meters 0500-0630, 0930-1600 UTC, 15 meters<br />1300-1430, 2000-0200 UTC, 10 meters possibly 1200-1400 or 2000-0230<br />UTC. This is a polar path.<br /><br />>From Toronto, Ontario/Buffalo, New York, 20 meters 0500-0630, 1000-<br />1630 UTC, 15 meters around 1400 and 2000-0230 UTC, 10 meters<br />possibly 1230-1400 or 2000-0300 UTC. This is a polar path.<br /><br />>From Cleveland, OH, 20 meters 0500-0630, 0800, 1000-1630 UTC, 15<br />meters 1300-1430, 1930-0300 UTC, 10 meters possibly 1300-1400 or<br />1930-0200 UTC. This is a polar path.<br /><br />>From Atlanta, 20 meters 0500-0800, 1030-1530 UTC, 15 meters 1300-<br />1430, 1930-0500 UTC, 10 meters possibly 1300-1400 or 1930-0400 UTC,<br />and within the last period, very good possibility around 2030-0030<br />UTC, especially at 2200 UTC. This is a polar path.<br /><br />>From Miami, 20 meters 0600-0730, 1000-1400 UTC, 15 meters 1200-1400,<br />2000-0500 UTC, 10 meters good around 2130-2300 and possible as early<br />as 2000 or as late as 0400 UTC, or possibly 1230-1400 UTC. This is<br />a polar path.<br /><br />>From the geographic center of the contiguous 48 United States, 20<br />meters 0430-0830, 1200-1630 UTC, 15 meters possibly 1330-1500 UTC<br />and probably 1930-0530 UTC, 10 meters 2030-0200 UTC.<br /><br />>From Dallas, Texas 20 meters 0430-0900, 1130-1630 UTC, 15 meters<br />1330-1430, 1930-0600 UTC, 10 meters very good 2030-0130 UTC.<br /><br />>From Salt Lake City, 20 meters 0230-0930, 1300-1600 UTC, 15 meters<br />1930-0600 UTC, 10 meters 2000-0300 UTC.<br /><br />>From Omaha, Nebraska, 20 meters 0500-0830, 1200-1630 UTC, 15 meters<br />1400-1500, 1930-0500 UTC, 10 meters 2000-0100 UTC.<br /><br />>From Denver, 20 meters 0300-0900, 1230-1600, 1800-1900 UTC, 15<br />meters 1430 UTC, 1930-0600 UTC, 10 meters 2100-0200 UTC.<br /><br />>From Los Angeles, 20 meters 0230-1030, 1230-1630 UTC, 1800-2000 UTC,<br />15 meters 1400-1500, 1930-0800 UTC, 10 meters excellent 2130-0200,<br />opening as early as 2000 to as late as 0730 UTC.<br /><br />>From the San Francisco Bay Area, 20 meters 0230-1030, 1330-2030 UTC,<br />15 meters 2000-0730 UTC, 10 meters 2100-0200 UTC.<br /><br />>From Seattle, 20 meters 0130-0930, 1430-2200 UTC, 15 meters 2000-<br />0530 UTC, 10 meters possibly 2030-0430 UTC.<br /><br />>From Edmonton, Alberta, 20 meters 0300-0930, 1330-1730, 1830-2100<br />UTC, 15 meters 2030-0300 UTC, 10 meters possibly 2100-0400 UTC.<br />This is a polar path.<br /><br />>From Alaska (between Anchorage and Fairbanks) 20 meters 1600-1230<br />UTC, 15 meters 2000-0730 UTC, 10 meters possibly 2000-0800 UTC.<br />This is a polar path.<br /><br />>From Hawaii, 20 meters open all the time, best 0830-1700 UTC,<br />weakest 2300-0200 UTC, 15 meters 1900-1230 UTC, strongest signals<br />0900-1200 UTC, 10 meters excellent conditions 2100-1100 UTC, with<br />strongest signals toward the end of the period.<br /><br />Sunspot numbers for April 4 through 10 were 176, 200, 234, 227, 245,<br />212 and 220 with a mean of 216.3. 10.7 cm flux was 216.2, 217.4,<br />206.3, 207.9, 206.2, 205 and 194.3, with a mean of 207.6, and<br />estimated planetary A indices were 8, 6, 5, 7, 5, 6 and 7 with a<br />mean of 6.3.<br />NNNN<br />/EX
