SB PROP @ ARL $ARLP049 ARLP049 Propagation de K7RA ZCZC AP49 QST de W1AW Propagation Forecast Bulletin 49 ARLP049 From Tad Cook, K7RA Seattle, WA November 30, 2009 To all radio amateurs SB PROP ARL ARLP049 ARLP049 Propagation de K7RA This is a follow-up to last Wednesday's pre-Thanksgiving Propagation Forecast Bulletin ARLP048. It was a little early to provide the complete Thursday through Wednesday sunspot, solar flux, and A index that normally appears in Friday's bulletin, so we are including it here at the bottom of this bulletin. The next bulletin will be out four days from now. Our exciting period of nearly daily sunspot activity ended with the first spotless day on November 23, and the Sun has been blank since then. A look at the STEREO image at http://stereo.gsfc.nasa.gov/ shows a bright active area perhaps five days over the eastern horizon, but we don't know if that will give us sunspots or not. As the two STEREO craft move further from earth, the visual gap on the Sun's far side is gradually closing, and we look forward to the time in 2011 when all of the Sun will be visible from STEREO and earth. Currently the gap is about 14.3%. You can calculate the approximate percentage of the Sun in that dark spot by using the "Where is STEREO?" link on the STEREO home page, which takes you to http://stereo-ssc.nascom.nasa.gov/where.shtml. Check the "Separation angle A with B" stat at the bottom, subtract that number from 180, divide the result by 360, then multiple that result by 100 to get a percentage figure. You can check future dates by clicking on the "STEREO Orbit Tool" link, taking you to http://stereo-ssc.nascom.nasa.gov/where/. When you check February 1, 2010 at 0000 UTC it yields a separation angle of 135.197 degrees. Subtracted from 180 degrees, this yields 44.803, divide that by 360, then multiply by 100, and you get approximately 12.45% remaining on the dark side. October 1, 2010 yields 5.58%, and January 1, 2011 just 1.26% in the dark. Check the arithmetic! WorldRadio Online posts a new issue on the twentieth of each month, and each has a column on propagation by Carl Luetzelschwab, K9LA. You can download it at, http://www.cq-amateur-radio.com/WorldRadio.html and read Carl's article on "The Impact of Deep Solar Minimum on 160m Propagation." Carl's column begins on page 28 of the current December issue. The January 2010 issue should appear online on December 20. Past bulletins mentioned the incredible WSPR mode for weak signal communication. Doug Hawkins, W3HH of Ocala, Florida was using WSPR mode on November 18 on 30 meters, and copied AA1A in Marshfield, Massachusetts -- 1,105 miles away. Not unusual, except that AA1A was running only 10 microwatts! Doug points out that this signal is 20 dB below 1 mW. Doug says that several other stations have copied AA1A, but so far this is the longest distance record. Doug thought the distance was about 900 miles, but I looked up the address for each station at the top of the ARRL web page at http://www.arrl.org/, then plugged the addresses into a computer atlas to find the exact latitude and longitude coordinates, then used W6ELprop to calculate the distance, which turned out to be over 20 percent further than Doug's estimate. If you would like to make a comment or have a tip for our readers, email the author at, k7ra@arrl.net. For more information concerning radio propagation, see the ARRL Technical Information Service web page at, 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. An archive of past propagation bulletins is at http://www.arrl.org/w1aw/prop/. Monthly propagation charts between four USA regions and twelve overseas locations are at http://www.arrl.org/qst/propcharts/. Instructions for starting or ending email distribution of this bulletin are at, http://www.arrl.org/w1aw.html#email. Sunspot numbers for November 19 through 25 were 30, 31, 14, 13, 0, 0, and 0 with a mean of 12.6. 10.7 cm flux was 76.7, 76.2, 75.8, 76.3, 75.7, 74.7, and 74.2 with a mean of 75.7. Estimated planetary A indices were 2, 1, 8, 4, 0, 6 and 5 with a mean of 3.7. Estimated mid-latitude A indices were 0, 2, 6, 2, 0, 3 and 4 with a mean of 2.4. NNNN /EX