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ARRL Propagation Bulletin ARLP020 (2001)

ARLP020 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 20  ARLP020
From Tad Cook, K7VVV
Seattle, WA  May 11, 2001
To all radio amateurs 

ARLP020 Propagation de K7VVV

As sunspots fade from view, solar flux and sunspot numbers are down.
Average sunspot numbers for the week declined by nearly 45 points,
and average solar flux was off by over 40 points. A and K indices
went high this week, indicating a minor geomagnetic storm on May 9
and 10. This began on May 8 when the earth entered a high speed
solar wind stream. The interplanetary magnetic field, which is
another name for the sun's enormous magnetic field, turned south on
May 9. This rendered the earth's magnetosphere vulnerable to gusts
of solar wind.

Active geomagnetic conditions are fading, and should become
unsettled on May 11 and 12, with planetary A indices of 15 and 12,
dropping to around 10 on May 13 and 14. Contesters should see fairly
good conditions for the CQ-M Contest this weekend. Solar flux is
expected to stay near 135 for the next few days, then rise above 150
after May 17 and above 175 after May 19.

Currently we are moving from spring toward summer propagation
conditions. 10 meters is not as viable as it was in late March, and
as longer daylight hours in the northern hemisphere heat the
ionosphere, the ionosphere thins and the MUF is lower during
daylight hours. 15 meters can still be quite good, especially into
areas that are dark, and as the days become longer, night time
openings on 20 meters will become more common.

For the CQ-M International DX Contest this weekend, we have some
path projections to several targets in the former Soviet Union,
including Asiatic Russia (UA0), European Russia (UA1), and Ukraine

From the East Coast of the United States (centered on Charlotte,
North Carolina), to UA0, 20 meters 0400-1300z. To UA1, 80 meters
0100-0130z, 40 meters 0000-0300z, 20 meters 2100-0630z, 15 meters
possibly 1200-2300z. To UR, 80 meters 0030-0230z, 40 meters
2330-0400z, 20 meters 2100-0630z, 15 meters possibly 1200-2300z.

From the center of the 48 contiguous United States (centered on
Kansas) to UA0, 40 meters 0900-1130z, 20 meters 0100- 0530z, 15
meters possibly 1900-0500z. To UA1, 40 meters around 0200z, 20
meters 2300-0630z, 15 meters 1800-2000z. To UR, 40 meters
0100-0330z, 20 meters 2200-0700z, 15 meters 1700-2300z.

From Central California to UA0, 80 meters 0930-1230z, 40 meters
0730-1400z, 20 meters open all hours, strongest 0730-1430z, weakest
around 1600z and 1930 to 0100z, 15 meters 2100-0800z. To UA1, 20
meters 0130-0900z, 15 meters 1700-1900z. To UR, 20 meters
0000-0730z, 15 meters 0500-0600z and 1600-2200z. 10 meter opening
possible around 1700z or 1900-2030z.

Sunspot numbers for May 3 through 9 were 157, 186, 151, 120, 103, 88
and 98 with a mean of 129. 10.7 cm flux was 172.3, 175.6, 160.6,
155, 138.3, 128.7 and 129.4, with a mean of 151.4, and estimated
planetary A indices were 7, 9, 5, 7, 17, 14 and 32 with a mean of


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