ARRL

ARRL Propagation Bulletin ARLP031 (1997)

SB PROP @ ARL $ARLP031
ARLP031 Propagation de K7VVV

ZCZC AP31
QST de W1AW
Propagation Forecast Bulletin 31  ARLP031
From Tad Cook, K7VVV
Seattle, WA  August 1, 1997
To all radio amateurs

SB PROP ARL ARLP031
ARLP031 Propagation de K7VVV

Solar flux has been settling down from last week, but several
coronal holes have moved into position, and are probably the cause
of geomagnetic upset on earth along with rising K and A indices.  A
coronal mass ejection on July 30 is a likely suspect as well.  Look
for marginal conditions this weekend as a result.

Watch for a return of the recent activity about 28 days later.
Based on recent activity, solar flux is expected to stay around the
low seventies.

Look for good conditions after the A and K indexes quiet down.  For
an updated reading tune to WWV at 18 minutes after the hour, with
new K indices at 0318, 0618, 0918, 1218, 1518, 1818 and 2418 UTC.  K
indices below three mean stable conditions, and above three they do
not.  You can also get the latest WWV forecast over the phone by
calling (303) 497-3235.

Sunspot Numbers for July 24 through 30 were 44, 65, 58, 53, 26, 24
and 12 with a mean of 40.3.  10.7 cm flux was 78.7, 80.4, 76.6,
74.5, 74.2, 72.7 and 71, with a mean of 75.4, and estimated
planetary A indices were 10, 5, 4, 6, 5, 3, and 7, with a mean of
5.7.
NNNN
/EX