ARRL

ARRL Propagation Bulletin ARLP020 (1998)

SB PROP @ ARL $ARLP020
ARLP020 Propagation de K7VVV

ZCZC AP20
QST de W1AW
Propagation Forecast Bulletin 20  ARLP020
From Tad Cook, K7VVV
Seattle, WA  May 15, 1998
To all radio amateurs

SB PROP ARL ARLP020
ARLP020 Propagation de K7VVV

Conditions certainly calmed down this week.  Not only were solar
flux and sunspot numbers off, but the most disturbed day, May 8,
only had a planetary A index of 20.

W9JJ wrote to remind us that during recent geomagnetic storms that
wiped out HF there were many interesting periods of propagation on
VHF due to auroral activity.  He also passed along some late word
from WB2WPA in Florida about 2 meter signals from South Dakota and
Minnesota, and also a report from N0JK about 2 meter exchanges
between the Midwest and Cuba,

For the next few days no geomagnetic disruptions are forecast, with
A indexes over the weekend around five.  The solar flux for Friday
through Sunday is expected to be 115, 115 and 110.

Solar flux may dip below 100 around May 18 or 19, and we could have
geomagnetic disturbances around May 22 to 24.  May 23 should see
solar flux above 110 again and above 120 around May 25 and peaking
just below 130 by the end of the month.

Sunspot Numbers for May 7 through 13 were 82, 81, 56, 61, 72, 90 and
90 with a mean of 76.  10.7 cm flux was 123.3, 118, 110.7, 107.2,
108, 112.1 and 116.6, with a mean of 113.7, and estimated planetary
A indices were 13, 20, 12, 11, 13, 19, and 6, with a mean of 13.4.
NNNN
/EX