ARRL

ARRL Propagation Bulletin ARLP016 (1997)

SB PROP @ ARL $ARLP016
ARLP016 Propagation de KT7H

ZCZC AP16
QST de W1AW
Propagation Forecast Bulletin 16  ARLP016
From Tad Cook, KT7H
Seattle, WA  April 18, 1997
To all radio amateurs

SB PROP ARL ARLP016
ARLP016 Propagation de KT7H

Average solar flux was down a little with sunspot numbers up a bit
over the past week.  The most significant event was the delayed
reaction to the big solar mass ejection, which drove the Planetary A
index to 38 and K index up to 7 on April 11.

Over the next few days watch for a retreat in the solar flux from
the high seventies down to the low seventies until the end of the
first week in May, when it will start creeping up to the eighties
again.  Solar flux is expected to be above 80 by May 10.  Look for
geomagnetic disturbances to appear again around April 24 and 25.
All of this forecast is based upon activity seen during the last
solar rotation, and of course new activity could appear at any time.

Sunspot Numbers for April 10 through 16 were 47, 31, 30, 34, 45, 39
and 33 with a mean of 37.  10.7 cm flux was 77.6, 77.1, 76.4, 78.8,
77.4, 78.7 and 75, with a mean of 77.3, and estimated planetary A
indices were 10, 38, 9, 8, 4, 4, and 12, with a mean of 12.1.
NNNN
/EX