ARRL

ARRL Propagation Bulletin ARLP010 (2001)

SB PROP @ ARL $ARLP010
ARLP010 Propagation de K7VVV

ZCZC AP10
QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7VVV
Seattle, WA  March 9, 2001
To all radio amateurs 

SB PROP ARL ARLP010
ARLP010 Propagation de K7VVV

Although the week's sunspot numbers and solar flux began low, they
rose steadily, with the average sunspot number up over 8 points and
average solar flux up over 10. Last Thursday, 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
nineteen 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
10:00 AM and a 2:00 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, over a ten-
point difference, seems somewhat 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 (like 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.

This week we will attempt another path projection, this time from
Austin, Texas to the rest of the world.

To Western Europe, 80 meters 0000-0730z, 40 meters 2330-0830z, 30
meters 2230-1000z, 20 meters all hours, best 2200-0630z, weakest
1400-1830z, 17 meters 1300-2230z, 15 meters 1330-2130z, 12 meters
1430-2000z, 10 meters 1530-1900z.

To Eastern Europe, 80 meters 0030-0530z, 40 meters 2330-0630z, 30
meters 2300-0730z, 20 meters 2200-0700z, 17 meters 1230-1600z and
2030-2130z, 15 meters 1330-2000z, 12 meters 1430-1900z, 10 meters
1530-1800z.

To Central Asia, 40 meters 0030-0130z, 30 meters 0000-0200z, 20
meters 2330-0230z, 17 meters 2130-0330z, 15 meters 0130-0300z and
1400-1830z, 12 meters 1500-1600z.

To Southern Africa, 80 meters 0000-0500z, 40 meters 2330-0500z, 30
meters 2300-0530z, 20 meters 2230-0600z, 17 meters 2130-0300z and
0430-0700z, 15 meters 1930-0200z, 12 meters 1800-2330z, 10 meters
1800-2230z.

To the Caribbean, 80 meters 2330-1200z (best 0300-1000z), 40 meters
2200-1300z (best 0100-1030z), 30 meters open all hours, best
0030-1030z, weakest 1530-1930z, 20 meters open all hours, best
0030-1100z, weakest 1630-1830z, 17 meters open all hours, best
0000-0900z, weakest 1600-1930z, 15 meters 1200-0300z, 12 meters
1230-0200z, 10 meters 1300-0030z.

To South America, 80 meters 0030-1000z, 40 meters 0000-1030z, 30
meters 2330-1130z, 20 meters 2200-1230z, 17 meters 2100-0800z and
1230-1400z, 15 meters 1300-1500z and 1830-0330z, 12 meters
1330-0230z, 10 meters 1400-0100z.

To the South Pacific, 80 meters 0530-1330z, 40 meters 0430-1400z, 30
meters 0400-1430z, 20 meters 0330-1500z, 17 meters 0230-1100z and
1330-1500z, 15 meters 1700-0900z and around 1400z, 12 meters
1700-0500z, 10 meters 1730-0400z.

To Australia, 80 meters 0900-1330z, 40 meters 0900-1400z, 30 meters
0800-1430z, 20 meters 0730-1500z, 17 meters 0700-1130z and
1330-1500z, 15 meters 0700-0800z.

To Japan, 80 meters 0800-1330z, 40 meters 0730-1330z, 30 meters
0700-1430z, 20 meters 0600-1530z, 17 meters 1400-1600z, 2230-2330z
and 0530-0700z, 15 meters 2000-0430z, 12 Meters 2030-0330z, 10
meters 2100-0230z.

To Hawaii, 80 meters 0400-1330z, 40 meters 0300-1430z, 30 meters
0230-1500z, 20 meters 0030-1700z, 17 meters open all hours,
strongest 0500-0930z, weakest 1930-2200z and 1200-1500z, 15 meters
1600-0500z, 12 meters 1630-0400z, 10 meters 1700-0300z.

Sunspot numbers for March 1 through 7 were 59, 77, 138, 157, 143,
131 and 102 with a mean of 115.3. 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, and
estimated planetary A indices were 5, 8, 14, 17, 18, 6 and 7 with a
mean of 10.7.
NNNN
/EX