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 Previous: Vintage AM Radio at Dayton |  Next: NAB Hosts ARRL Beltway Hams |
SEATTLE, WA, Mar 9, 2001--Although the week's sunspot numbers and solar flux began low, they rose steadily, with the average sunspot number up more than eight points and average solar flux up more than ten. Thursday, March 1, the beginning of the reporting week, the sunspot number was a very low 59. December 10, 2000 was the last day with a reported sunspot number as low as this, when it was 58. Prior to that, the previous low was around September 11 and 12, 2000, when it was 27 and 38. To find another date with a sunspot number as low, one would have to look on the other side of the solar cycle peak, way back to October 2, 1999, when it was 47.
Current activity is a far cry from last summer, when daily sunspot numbers were routinely 200 or more, or even 300, or on July 20 over 400.
Solar flux rose from a low of 129.7 last Friday, then jumped nearly 19 points in a single day to 176.6 on Wednesday. The official daily solar flux is always the noon reading, but there is also a 10 AM and a 2 PM reading (at local time for the observatory in Penticton, British Columbia). On that day the early reading was 164.8, and the late one was 165.5, so the noon reading, a more than 10-point difference, seems somewhat of an anomaly. Solar flux has not been this high since January 13, when it was 184.3.
Solar flux is predicted at 170 for Friday and Saturday, March 9 and 10, and 165 for Sunday and Monday. Current best projections show flux values hanging around 160 for March 13-23, then dropping to 135 around March 28 or 29.
NASA's Spaceweather.com reports that the flux of solar X-rays has increased several-fold since Monday, because hot gasses trapped by magnetic fields above several sunspots are glowing with high-energy radiation. M-class solar flares could erupt from regions 9368 and 9371 over the next day. Currently quiet geomagnetic conditions are forecast, but the planetary A index could rise to 15, indicating unsettled conditions on Sunday. For an explanation of the different classes of solar flares, look at http://spaceweather.com/glossary/flareclasses.html .
While the solar cycle appears to have peaked last year, we are still at a high point in the cycle, and headed toward typical spring HF conditions, when overall propagation is best (as in the fall equinox). These times are when sunlight is maximized in both the northern and southern hemispheres, and propagation between the two is best.
Sunspot numbers for March 1 through 7 were 59, 77, 138, 157, 143, 131 and 102, with a mean of 115.3. The 10.7-cm flux was 131.4, 129.7, 139.6, 141, 155.8, 157.8 and 176.6, with a mean of 147.4. Estimated planetary A indices were 5, 8, 14, 17, 18, 6 and 7, with a mean of 10.7.
This week we will attempt another path projection, this time from Austin, Texas to the rest of the world.
To Western Europe, 80 meters 0000-0730 UTC, 40 meters 2330-0830 UTC, 30 meters 2230-1000 UTC, 20 meters all hours, best 2200-0630 UTC, weakest 1400-1830 UTC, 17 meters 1300-2230 UTC, 15 meters 1330-2130 UTC, 12 meters 1430-2000 UTC, 10 meters 1530-1900 UTC.
To Eastern Europe, 80 meters 0030-0530 UTC, 40 meters 2330-0630 UTC, 30 meters 2300-0730 UTC, 20 meters 2200-0700 UTC, 17 meters 1230-1600 UTC and 2030-2130 UTC, 15 meters 1330-2000 UTC, 12 meters 1430-1900 UTC, 10 meters 1530-1800 UTC.
To Central Asia, 40 meters 0030-0130 UTC, 30 meters 0000-0200 UTC, 20 meters 2330-0230 UTC, 17 meters 2130-0330 UTC, 15 meters 0130-0300 UTC and 1400-1830 UTC, 12 meters 1500-1600 UTC.
To Southern Africa, 80 meters 0000-0500 UTC, 40 meters 2330-0500 UTC, 30 meters 2300-0530 UTC, 20 meters 2230-0600 UTC, 17 meters 2130-0300 UTC and 0430-0700 UTC, 15 meters 1930-0200 UTC, 12 meters 1800-2330 UTC, 10 meters 1800-2230 UTC.
To the Caribbean, 80 meters 2330-1200 UTC (best 0300-1000 UTC), 40 meters 2200-1300 UTC (best 0100-1030 UTC), 30 meters open all hours, best 0030-1030 UTC, weakest 1530-1930 UTC, 20 meters open all hours, best 0030-1100 UTC, weakest 1630-1830 UTC, 17 meters open all hours, best 0000-0900 UTC, weakest 1600-1930 UTC, 15 meters 1200-0300 UTC, 12 meters 1230-0200 UTC, 10 meters 1300-0030 UTC.
To South America, 80 meters 0030-1000 UTC, 40 meters 0000-1030 UTC, 30 meters 2330-1130 UTC, 20 meters 2200-1230 UTC, 17 meters 2100-0800 UTC and 1230-1400 UTC, 15 meters 1300-1500 UTC and 1830-0330 UTC, 12 meters 1330-0230 UTC, 10 meters 1400-0100 UTC.
To the South Pacific, 80 meters 0530-1330 UTC, 40 meters 0430-1400 UTC, 30 meters 0400-1430 UTC, 20 meters 0330-1500 UTC, 17 meters 0230-1100 UTC and 1330-1500 UTC, 15 meters 1700-0900 UTC and around 1400 UTC, 12 meters 1700-0500 UTC, 10 meters 1730-0400 UTC.
To Australia, 80 meters 0900-1330 UTC, 40 meters 0900-1400 UTC, 30 meters 0800-1430 UTC, 20 meters 0730-1500 UTC, 17 meters 0700-1130 UTC and 1330-1500 UTC, 15 meters 0700-0800 UTC.
To Japan, 80 meters 0800-1330 UTC, 40 meters 0730-1330 UTC, 30 meters 0700-1430 UTC, 20 meters 0600-1530 UTC, 17 meters 1400-1600 UTC, 2230-2330 UTC and 0530-0700 UTC, 15 meters 2000-0430 UTC, 12 Meters 2030-0330 UTC, 10 meters 2100-0230 UTC.
To Hawaii, 80 meters 0400-1330 UTC, 40 meters 0300-1430 UTC, 30 meters 0230-1500 UTC, 20 meters 0030-1700 UTC, 17 meters open all hours, strongest 0500-0930 UTC, weakest 1930-2200 UTC and 1200-1500 UTC, 15 meters 1600-0500 UTC, 12 meters 1630-0400 UTC, 10 meters 1700-0300 UTC.
Amateur solar observer Tad Cook, K7VVV Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version also appears in The ARRL Letter. Readers may contact the author via k7vvv@arrl.net.
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