ARRL

ARRL Propagation Bulletin ARLP048 (1997)

SB PROP @ ARL $ARLP048
ARLP048 Propagation de K7VVV

ZCZC AP48
QST de W1AW
Propagation Forecast Bulletin 48  ARLP048
From Tad Cook, K7VVV
Seattle, WA  November 27, 1997
To all radio amateurs

SB PROP ARL ARLP048
ARLP048 Propagation de K7VVV

Over the past week we experienced mostly good conditions, with the
exception of last weekend.  The Planetary A Index, an indicator of
geomagnetic instability, rose to 45 and 60, and the Planetary K
index rose as high as seven on both days.  This indicated a major to
severe geomagnetic storm, which began after 0900 UTC on November 22
and continued until about 1500 UTC the next day.

Solar flux rose over the week.  The average solar flux for the
previous 90 days rose two more points to 93, and the daily solar
flux values were above the 90 day average on all days except last
Thursday.  Average solar flux for the week was up about six points
over the previous week.

For the contest weekend, expect excellent conditions.  Barring some
unforeseen solar flare, the geomagnetic indices are expected to
remain low.  The 10.7 cm solar flux should keep rising.  The three
daily flux measurements for Wednesday at Penticton were 106.3, 108.1
and 109.2, and over the next few days the best guess places the flux
around 110 on Thursday and 115 on Friday and Saturday.

Solar activity may begin falling off after December 2, with flux
values dropping below 100 by December 8 and back up over 100 by
December 22.  Judging from activity during the previous solar
rotation, disturbed periods will probably center around December 3
and December 19 and 20.

Sunspot Numbers for November 20 through 26 were 57, 52, 62, 70, 61,
58 and 43 with a mean of 57.6.  10.7 cm flux was 88.7, 95.9, 100.2,
99.8, 103.3, 102.1 and 108.1, with a mean of 99.7, and estimated
planetary A indices were 2, 2, 45, 60, 7, 3, and 2, with a mean of
17.3.

Here are some path projections for the contest weekend.

From the Eastern USA:

To Western Europe, check 80 meters from 2000-0930 UTC (strongest
signals 0000-0700 UTC), 40 meters 1830-1230 UTC (best signals 2200-
0800 UTC, unstable around 0900 UTC), 20 meters 1230-1930 UTC (best
signals early in the day), 15 meters 1400-1730 UTC, and 10 meters
1530-1700 UTC.

To Southern Africa, check 80 meters 2100-0430 UTC (best signals
0000-0300 UTC), 40 meters 2030-0500 UTC (best signals 2200-0330
UTC), 20 meters 1530-2200 UTC (best signals late in the period), 15
meters 1230-2000 UTC (best signals late in the period) and good 10
meter conditions 1330-1800 UTC.

To South America, check 80 meters 2230-0930 UTC (best signals 0030-
0830 UTC), 40 meters 2200-1030 UTC, 20 meters 1200-2300 UTC (best
signals late in the day), 15 meters 1300-2100 UTC, and 10 meters
1500-1830 UTC.

To the Caribbean, check 80 meters 2030-1230 UTC (best signals 0000-
1000 UTC), 40 meters around the clock (weakest 1500-1800 UTC,
strongest 2230-1000 UTC), 20 meters 1200-2300 UTC (best signals late
in the day), 15 meters 1300-2030 UTC, and 10 meters with strong
signals 1430-1830 UTC.

To the South Pacific, check 80 meters 0500-1300 UTC, 40 meters
0400-1330 UTC, 20 meters 1300-1500 UTC, 1630-1830 UTC and again
around 0100 UTC, 15 meters 1700-2200 UTC and 10 meters 1800-2030
UTC.

To East Asia, check 80 meters 0630-1300 UTC (best signals 0800-1130
UTC), 40 meters 0500-1500 UTC, and again around 2130 UTC (best
signals 0800-1200 UTC), 20 meters 2030-2230 UTC and a small chance
of a 15 meter opening 2100-2200 UTC.

From the Western USA:

To Western Europe, check 80 meters 2330-1100 UTC (strongest signals
0300-0700 UTC) 40 meters 2130-1600 UTC (best signals 0100-0730 UTC),
20 meters 1500-1800 UTC, 15 meters around 1600-1700 UTC and perhaps
a 10 meter opening around 1700 UTC.

To Southern Africa, check 80 meters 0000-0400 UTC, 40 meters 2300-
0500 UTC, 20 meters 1600-0100 UTC (best signals late in the day), 15
meters 1530-2230 UTC and 10 meters 1700-1900 UTC.

To South America, check 80 meters 0030-1000 UTC (best signals 0330-
0800 UTC), 40 meters 0000-1030 UTC (best signals 0130-0830 UTC), 20
meters around local sunrise and 2000-0930 UTC (with weak periods
around 0400 and 0700 UTC), 15 meters 1500-0030 UTC (best signals
late in the day) and 10 meters with good conditions all day from
local sunrise to an hour before local sunset (1530-2330 UTC).

To the Caribbean, check 80 meters 2330-1200 UTC (best signals 0300-
1000 UTC), 40 meters 2230-1330 UTC (best signals 0100-1030 UTC), 20
meters 1500-0030 UTC (stronger signals late in the day), 15 meters
1500-2200 UTC, and 10 meters 1600-2030 UTC with strong signals.

To the South Pacific, check 80 meters 0500-1530 UTC, 40 meters
0400-1600 UTC, 20 meters 1630-0330 UTC (with best signals early and
late in the period), 15 meters 1730-0230 UTC and 10 meters 1830-
0030 UTC.

To East Asia, check 80 meters 0630-1630 UTC (best signals 0930-1430
UTC), 40 meters 0500-1800 UTC (best signals 0800-1430 UTC), 20
meters 2100-0200 UTC, 15 meters 2130-0100 UTC and 10 meters 2200-
0015 UTC, with best conditions around 2300 UTC.
NNNN
/EX