SB PROP @ ARRL $ARLP052
ARLP052 Propagation DE KT7H
QST DE W1AW
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, KT7H
Seattle, WA  December 31, 1993
To All Radio Amateurs

Solar activity took a large unexpected jump last week, averaging
more than 34 points better than the week prior.  The greatest solar
flux was on December 27, reaching 140.4, the highest since May 30,
1993 when it was 140.  Prior to that, the last time the flux was
higher was on April 8, 1993 when it was 143.1

The best part of this event for radio amateurs was that there was no
increase in geomagnetic disturbances.  In fact, the A and K indices
were very quiet.  There has been a forecast for a recurring coronal
hole to wreak havoc around the last day of the year, but as of this
writing, it has not appeared.

Perhaps the big rise in activity is part of the moderate increase in
flux that was forecast for this Fall and Winter season, before the
solar cycle continues it's retreat toward a probable minimum in
about 3 years.  1993 has been a year of declining solar activity,
and this should continue through 1994, 1995, and the following year.
The latest long term forecast shows average monthly flux values
rising about five to fifteen points until April 1994, and then
dropping to about ten points lower than the current level by the end
of 1994.

As we begin the new year, look for typical winter conditions with 80
and 160 meters benefitting from low noise levels and long nights.
40 meters should be a good DX band starting around sundown, and the
higher bands during the daytime.

In January the flux should reach a minimum around the 17th or 18th,
dipping below 100, and then rise back to the current higher levels
around the end of the month.

Sunspot Numbers from December 23 through 29 were 70, 117, 120, 92,
107, 108 and 112, with a mean of 103.7.  10.7 cm flux was 105,
111.2, 119.1, 125, 140.4, 133.6 and 128.7, with a mean of 123.3

Beginning this week the sample path projections will take a slightly
more cautious approach to when band openings begin.  It is difficult
to make these forecasts for all levels of amateur radio stations,
given the wide range of antennas and station environments.  There
will now also be weightings used to make the forecast, particularly
on the lower frequencies to account for average low band antennas at
most stations.

The projection this week is from West Suffield, Connecticut to
Germany.

Look for 80 and 75 meters to open after 2030z, peak from 2330z to
0630z, and end after 0900z.  40 meters looks good from 1900z to
0800z or 1000z, peaking around 2130z to 0730z, which is the period
that darkness prevails over both ends of the path.  Check 30 meters
from 1230z until 1900z, and again around 0330z to 0500z.  20 meters
also looks good from 1230z to 1900z, with the peak periods at the
beginning and the end of the opening.  17 meters should be usable
from 1330z to 1730z, and 15 meters from 1430z to 1700z.  12 meters
has some possibility of openings on some days from 1500z to 1630z.
10 meters does not look promising, but on some days there may be
openings around 1600z.
/EX