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The K7RA Solar Update

09/18/2009

The STEREO mission (Solar TErrestrial RElations Observatory) Web site shows a new display, where the Sun is visible via an animated image that rotates to show the whole Sun. The small portion on the Sun's far side -- which is not yet visible to the spacecraft -- is shown as a dark area. Currently (early Friday, September 18) the animation shows an emerging bright spot, just beyond the direct view from Earth.

The zero degree meridian represents the area closest to Earth, appearing in the center of the solar disk as viewed from Earth. The two 90 degree meridians represent the eastern and western horizon, and of course the 180 degree meridian is directly opposite Earth's view. A full rotation of the Sun relative to Earth takes slightly less than four weeks. The bright spot appears around 120 degrees -- or 30 degrees short of the eastern limb -- and may represent a new sunspot group. This would be a wonderful event coinciding with the autumnal equinox, the first day of fall, which starts next Tuesday afternoon (September 22) in North America. Helioseismic readings also show an active region in that area, at 30 degrees south latitude. Go here to see the current position of the two craft relative to Earth. Eventually, they will be 180 degrees relative to each other and 90 degrees relative to Earth.

Sunspot numbers for September 10 through 16 were 0, 0, 0, 0, 0, 0 and 0 with a mean of 0. The 10.7 cm flux was 69.3, 69.3, 69, 69.1, 69, 69.2 and 68.8 with a mean of 69.1. The estimated planetary A indices were 2, 4, 4, 6, 5, 5 and 6 with a mean of 4.6. The estimated mid-latitude A indices were 2, 2, 1, 4, 4, 4 and 5 with a mean of 3.1. Thursday's prediction shows solar flux values at 70 beginning tomorrow, September 19, and continuing through September 24, then rising to 72 September 25-28. We haven't reported a weekly solar flux average above 70 in this bulletin since May 19, and prior to that there were only four more weeks above 70 in 2009. These predictions are from NOAA and the US Air Force, who also predict a planetary A index of 8 for September 18, and only 5 from September 19 to more than a month after. Geophysical Institute Prague also predicts nothing but quiet geomagnetic conditions for September 18-24.

Steve Jones, N6SJ, of Woodside, California, hopes to work FT5GA, the Glorioso DXpedition. Glorioso is northwest of Madagascar in the Indian Ocean at approximately 11.5 degrees south latitude, and 47.33 degrees east longitude. The expedition is expected to be on the air until October 5, and you can check here to see who is currently working them.

From California this weekend, Steve's best bet may be 20 meters from 2100-2330 UTC, and possibly 1600-1700 UTC with lower signals. If we get some sunspot activity next week, for the following weekend 20 meters looks good 1430-1930 UTC, and then 2100-0000 UTC. Fifteen meters with no sunspots looks bad for this weekend, but on the following weekend, if there is more solar activity, 1900-2130 UTC looks possible. Seventeen meters looks very good that following weekend (September 26) from 1630-2300 UTC. For September 19, 40 meters is possible 0130-0300 UTC, and the following weekend 2330-0330 UTC, again assuming some solar activity in the days prior.

If you live in the Southeast United States, based on projections from Atlanta, your chances look much better than from the West Coast. On both weekends from Atlanta, 40 meters looks good 2230-0230 UTC, and 20 meters on this weekend 1930-2300 UTC, lasting an hour later on the next weekend. Fifteen meters looks promising, assuming some sunspots, 1530-1900 UTC on the next weekend.

From Ohio, 20 meters looks good both weekends 1900-2300 UTC, and 40 meters 2200-0330 UTC.

Bobby Raymer, N2BR, of Cookeville, Tennessee, says he enjoys working distant stations despite lack of solar activity. Running 100 W into a vertical dipole, he usually has better luck with CW than phone. On 17 meters on September 9, he worked OJ0B on CW on Market Reef, and on September 11 using SSB, he worked St Helena Island. He said he works more stations outside the USA than stateside.

Dennis Reagin, W7KB, of Vail, Arizona, was running 10 W SSB into a portable vertical antenna on September 6 and enjoyed JA0JHA, getting an S8 report, XE1REM who said he was 10 dB over S9, and DL8OBQ/PJ2 in Netherlands Antilles who gave him an S6 report. He notes he is having fun and working distant stations with no sunspots, low power, patience and persistence.

Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears in The ARRL Letter. Check here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.

 



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