SB PROP @ ARRL $ARLP017
ARLP017 Propagation DE KT7H
QST DE W1AW
Propagation Forecast Bulletin 17  ARLP017
From Tad Cook, KT7H
Seattle, WA  April 30, 1993
To All Radio Amateurs

Last week in ARLP016 a rising flux was forecast for the week,
peaking around 150 at the end of April.  During the week the rising
trend reversed, with a solar flux of 107 for April 29, the day this
bulletin was written.  One later forecast is for the flux to rise to
around 145 around May 4 or 5, and then drop to 105 around May 12 or
13, before rising again toward the end of May.  Another forecast
shows the next peak around May 5 at only 120 instead of 145.
A possible geomagnetic storm may visit us around May 2, and some
disturbed conditions, although less so, may prevail around May 10
and 18.

According to NOAA's Space Environment Center we are in the 77th
month of solar cycle 22.  The 10.7 cm flux maximum was in June, 1989
at 213.1, and there was another peak at 207.7 in July 1991.  This
gave us an unusual double peak of solar activity.  We are in the
declining part of this cycle, where the chance of major flares is
less, but recurring coronal holes are more common.  This results in
more cyclical monthly geomagnetic activity.

The current forecast suggests the minimum of the current cycle will
occur in 1996.  The upcoming cycle 23 is expected to be larger than
average, but somewhat shorter in duration, with a 10 year life.

Sunspot Numbers from April 22 to 28 were 134, 154, 174, 124, 81, 91
and 62, with a mean of 117.1.  10.7 cm flux was 117.1, 121.5, 128.8,
124.6, 123.3, 118.0 and 113.6, with a mean of 121.

The projection for this week is from Vancouver, BC Canada to
Brazil.

80 meters should be open from 0230z to 1000z, peaking from 0530z to
0900z.  40 meters should be open from 0130z to 1030z, peaking from
0330z to 0930z.  30 meters should be open from 0000z to 1100z,
peaking from 0230z to 1000z.  20 meters should be open from 2230z to
1200z, with the best times from 0100z to 0900z.  17 meters should be
best from 2300z to 0630z, and 15 meters from 2130z to 0130z.  12 and
10 meters should be marginal over this path.
/EX