ARRL

ARRL Propagation Bulletin ARLP041 (2001)

SB PROP @ ARL $ARLP041
ARLP041 Propagation de K7VVV

ZCZC AP41
QST de W1AW  
Propagation Forecast Bulletin 41  ARLP041
From Tad Cook, K7VVV
Seattle, WA  October 5, 2001
To all radio amateurs 

SB PROP ARL ARLP041
ARLP041 Propagation de K7VVV

Solar flux and sunspot numbers were lower this week. This is no
surprise, because the flux had reached a new high for this solar
cycle during the previous week. Average daily sunspot numbers
dropped over 45 points and solar flux was down over 25 points.
Indicators that did not drop were those tied to geomagnetic
stability. The average daily planetary A index increased by 16
points to 29.6. The most active days were Monday through Wednesday,
when the planetary A index was 50, 43 and 53. The planetary K index
reached a high of 7 on Wednesday, indicating a geomagnetic storm.
For higher latitudes the peak day for geomagnetic activity was
Tuesday, when Alaska's College A index was 82, and the College K
index reached 8.

The geomagnetic activity was caused by a series of solar wind
disturbances. In addition to absorption of HF signals over high
latitude paths, there were some impressive aurora displays. Check
http://spaceweather.com/aurora/gallery_01oct01.html for some
dramatic photos.

Current predictions project solar flux decreasing to 185 on Friday,
then increasing to 190 on Saturday and 195 on Sunday and Monday.
Geomagnetic indices should be quiet to unsettled. The next peak in
solar flux is projected around October 22 or 23. Flux values are
expected to rise above 200 after October 14 and above 250 after
October 19.

September 30 ended the third quarter of 2001. Now it is time to look
at quarterly averages for sunspot numbers and solar flux. The
numbers begin with the first quarter of 1999 and end with the third
quarter of 2001. Average daily sunspot numbers were 96.1, 147.2,
137.9, 163.1, 168.9, 190.8, 187.4, 145, 147.3, 164.8 and 170.4.
Average daily solar flux was 136.7, 145, 157.6, 175.2, 180.5, 182.9,
181.9, 173.3, 164.4, 166.7 and 175.5. Even after the recent record
shattering daily solar flux for the current cycle, it still appears
that solar flux had a broad peak throughout the first nine months of
last year. But this year the trend was up, with higher average daily
numbers in each quarter for both solar flux and sunspot numbers.

The monthly averages of daily numbers over the past few months show
a steady rise in activity. Average daily sunspot numbers for July,
August and September were 124.6, 159.4 and 229.1, and average daily
solar flux was 131.3, 163.1 and 233.8.

The 2001 Oceania DX SSB Contest is this weekend. Here are some path
projections.

From Boston to Australia, 80 meters 0900-1100z, 40 meters
0830-1230z, 20 meters 0700-0800 and 1200-1430z, 15 meters
1400-1600z, 10 meters 2100-2330z. To New Zealand, 80 meters
0630-1130z, 40 meters 0530-1200z, 20 meters 0430-1300z, 15 meters
0100-0300 and 1630-1700z, 10 meters 1800-0100z.

From New York City to Australia, 80 meters 0900-1200z, 40 meters
0830-1230z, 20 meters 0700-0800 and 1130-1430z, 15 meters
1330-1600z, 10 meters 2100-0000z. To New Zealand, 80 meters
0630-1100z, 40 meters 0530-1200z, 20 meters 0430-1300z, 15 meters
0100-0330z, 10 meters 1800-0130z.

From Philadelphia to Australia, 80 meters 0900-1200z, 40 meters
0830-1230z, 20 meters 0700-1430z, 15 meters 1330-1600z, 10 meters
possibly 2030-0100z. To New Zealand, 80 meters 0630-1130z, 40 meters
0530-1200z, 20 meters 0400-1330z, 15 meters 0100-0330z, 10 meters
1800-0130z.

From Richmond, Virginia to Australia, 80 meters 0900-1200z, 40
meters 0900-1230z, 20 meters 0700-1400z, 15 meters 1300-1530z, 10
meters possibly 2100-0130z. To New Zealand, 80 meters 0630-1100z, 40
meters 0530-1200z, 20 meters 0400-1300z, 15 meters 0100-0500z, 10
meters 1800-0200z.

From Atlanta to Australia, 80 meters 0900-1200z, 40 meters
0830-1300z, 20 meters 0700-1430z, 15 meters 1330-1500z and possibly
0300-0400z, 10 meters possibly 2130-0130z. To New Zealand, 80 meters
0600-1200z, 40 meters 0530-1230z, 20 meters 0400-1330z, 15 meters
0100-0830z, 10 meters 2200-0300z.

From Miami to Australia, 80 meters 0830-1130z, 40 meters 0830-
1230z, 20 meters 0630-1330z, 15 meters 0430-0930 and 1230-1400z, 10
meters 0130-0300z. To New Zealand, 80 meters 0600-1130z, 40 meters
0600-1200z, 20 meters 0400-1300z, 15 meters 0100-0930z, 10 meters
1830-0630z.

From Cleveland to Australia, 80 meters 0900-1230z, 40 meters
0830-1300z, 20 meters 0700-1430z, 15 meters 1400-1530z, 10 meters
possibly 2130-0030z. To New Zealand, 80 meters 0630-1130z, 40 meters
0530-1230z, 20 meters 0400-1400z, 15 meters 0100-0330z, 10 meters
1800-0200z.

From Chicago to Australia, 80 meters 0900-1230z, 40 meters
0900-1330z, 20 meters 0700-1500z, 15 meters 1400-1530z, 10 meters
possibly 2100-0100z. To New Zealand, 80 meters 0600-1230z, 40 meters
0530-1300z, 20 meters 0400-1400z, 15 meters 0100-0400z, 10 meters
1830-0200z.

From Kansas City to Australia, 80 meters 0900-1300z, 40 meters
0830-1330z, 20 meters 0700-1500z, 15 meters 1430-1530 and 0430z, 10
meters possibly 2100-0200z. To New Zealand, 80 meters 0600-1230z, 40
meters 0600-1300z, 20 meters 0400-1430z, 15 meters 0130-0430 and
around 1700z, 10 meters 1830-0230z.

From Dallas to Australia, 80 meters 0900-1300z, 40 meters
0800-1330z, 20 meters 0700-1500z, 15 meters 1400-1530 and
0500-0930z, 10 meters 2030-0400z. To New Zealand, 80 meters
0600-1230z, 40 meters 0600-1300z, 20 meters 0400-1430z, 15 meters
0130-0930z, 10 meters 1830-0400z.

From Denver to Australia, 80 meters 0900-1330z, 40 meters
0830-1400z, 20 meters 0700-1530z, 15 meters 1500-1600 and
0500-0600z, 10 meters 2030-0400z. To New Zealand, 80 meters
0630-1330z, 40 meters 0600-1330z, 20 meters 0430-1500z, 15 meters
0130-0500z, 10 meters 1900-0300z.

From Salt Lake City to Australia, 80 meters 0900-1400z, 40 meters
0830-1430z, 20 meters 0700-1630z, 15 meters 1530-1630 and
0430-0600z, 10 meters 2100-0400z. To New Zealand, 80 meters
0630-1330z, 40 meters 0600-1400z, 20 meters 0430-1530z, 15 meters
0230-0530z, 10 meters 1900-0330z.

From Seattle to Australia, 80 meters 0930-1500z, 40 meters
0900-1600z, 20 meters 0700-1700z, 15 meters 0430-0630z, 10 meters
2100-0430z. To New Zealand, 80 meters 0630-1430z, 40 meters
0600-1500z, 20 meters 0430-1630z, 15 meters 0300-0530z, 10 meters
1900-0330z.

From California to Australia, 80 meters 0830-1430z, 40 meters
0830-1530z, 20 meters 0700-1630z, 15 meters around 1530z, 2000z and
0400-0630z, 10 meters 2100-0430z. To New Zealand, 80 meters
0600-1430z, 40 meters 0530-1500z, 20 meters 0400-1600z, 15 meters
0130-1200 and 1700-1830z, 10 meters 1800-0600z.

Sunspot numbers for September 27 through October 3 were 279, 234,
233, 230, 289, 236 and 196 with a mean of 242.4. 10.7 cm flux was
269.5, 284.5, 239.5, 235.8, 216.5, 200.9 and 191.7, with a mean of
234.1, and estimated planetary A indices were 10, 13, 21, 17, 50, 43
and 53 with a mean of 29.6.
NNNN
/EX