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ARRL Propagation Bulletin ARLP050 (1999)

ARLP050 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 50  ARLP050
From Tad Cook, K7VVV
Seattle, WA  December 9, 1999
To all radio amateurs 

ARLP050 Propagation de K7VVV

This bulletin presents solar data for the past three weeks.  The
November 18-24 data from Propagation Forecast Bulletin ARLP048 is
presented again, because of an error in the November 24 sunspot
number and resulting error in the weekly average, as noted in
Propagation Forecast Bulletin ARLP049.  The November 25 through
December 1 data was not available last week, so it is presented
here, along with the most recent December 2-8 data.

If you are trying to load this automatically into the WA4TTK solar
graphing software, do each week one at a time, editing the other two
weeks out of the bulletin so that the software can grab the data in
the familiar format.  If you would like to try the graphing
software, which is free, you can download it from Scott Craig's web
site at

The general trend in sunspots and solar flux has been down for the
past few weeks, but conditions are turning around.  For the ARRL 10
Meter contest this weekend expect a rising solar flux on Friday
through Sunday of 165, 175 and 185, and a moderate planetary A index
of 10, 10 and 12.  Beyond the weekend the solar flux is expected to
peak above 200 next week, and then drop below 190 around December
20.  Geomagnetic conditions should be stable for the next couple of

Sunspot numbers for November 18 through 24 were 194, 234, 225, 200,
179, 157 and 157 with a mean of 192.3. 10.7 cm flux was 217.9, 210,
204.3, 210.1, 192, 185.6 and 186.7, with a mean of 200.9, and
estimated planetary A indices were 12, 12, 9, 10, 10, 15 and 19,
with a mean of 12.4.

Sunspot numbers for November 25 through December 1 were 147, 143,
187, 173, 101, 127 and 119 with a mean of 142.4. 10.7 cm flux was
183.7, 172.2, 169, 174.8, 163.9, 162.7 and 165, with a mean of
170.2, and estimated planetary A indices were 18, 4, 3, 7, 4, 8 and
4, with a mean of 6.9.

Sunspot numbers for December 2 through 8 were 156, 107, 78, 78, 80,
76 and 116 with a mean of 98.7. 10.7 cm flux was 165.5, 151.8,
147.5, 142.7, 142.8, 153.3 and 150.1, with a mean of 150.5, and
estimated planetary A indices were 4, 13, 28, 18, 19, 14 and 13,
with a mean of 15.6.

Path projections for this weekend are devoted to the ARRL 10 Meter

From the USA West Coast to the center of the continental USA, 10
meters should be open 1700-2300z.  To the East Coast, 1700-2100z.
To Europe, 1630-1830z, to Southern Africa, 1600-2330z, to South
America, 1500-0130z, to the Caribbean, 1530-2300z, to Australia,
2030-0330z, to Japan, 2200-0200z, to Alaska, 1800-0100z, and to
Hawaii, 1830-0030z.

From the center of the continental USA to the East Coast, 10 meters
should be open 1600-2100z, to Europe, 1500-1830z, to Southern
Africa, 1400-2130z, to South America, 1430-2300z, to the Caribbean,
1530-2030z, to Australia, 2130-0100z, to Japan, 2200-0000z, to
Alaska, 2030-2230z, and to Hawaii, 1730-0030z.

From the USA East Coast 10 meters should be open to Europe 1400-
1800z, to Southern Africa, 1230-2030z, to South America, 1230-2230z,
to the Caribbean, 1330-2100z, to Australia, 1500- 1630 and
2030-2300z, to Japan, 2200z, to Alaska, 1930-2130z and to Hawaii,

From Japan, 10 meters should be open to Europe 0730-0900z, to
Southern Africa, 0400-1100z, to South America, 2130-0730z, to the
Caribbean around 2200z, to Australia, 2130-1730z, to Alaska,
2230-0330z, to Hawaii, 2100-0600z.


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