ARRL

ARRL Propagation Bulletin ARLP015 (1997)

SB PROP @ ARL $ARLP015
ARLP015 Propagation de KT7H

ZCZC AP15
QST de W1AW
Propagation Forecast Bulletin 15  ARLP015
From Tad Cook, KT7H
Seattle, WA  April 11, 1997
To all radio amateurs

SB PROP ARL ARLP015
ARLP015 Propagation de KT7H

Solar activity was up last week.  Flux went as high as 80, and then
on Monday morning there was a big eruption on the Sun that ejected a
large amount of matter toward earth.  It was originally thought that
perhaps this might cause a big disturbance here on Wednesday, but
effects weren't really felt until Thursday.  As this was being
written Friday morning UTC, the K index was 7 at the 0300z and 0600z
readings.

''The eruption seemed to blow open a hole in the Sun's corona,'' said
Dr. Barbara Thompson, a SOHO scientist.

Images of this eruption taken by the SOHO satellite can be seen at
the following web site:
http://pao.gsfc.nasa.gov/gsfc/newsroom/flash/flash.htm

Watch for solar flux to drop soon to the low seventies, but then
jump back to 80 by the end of the month.

Sunspot Numbers for April 3 through 9 were 46, 36, 36, 28, 16, 27
and 30 with a mean of 31.3.  10.7 cm flux was 78.8, 78.5, 80.2,
78.1, 76.8, 76.1 and 78.1, with a mean of 78.1, and estimated
planetary A indices were 7, 12, 8, 11, 7, 4, and 5, with a mean of
7.7.

The JA CW DX Contest is this weekend, and since the object is to
work Japanese stations, here are some path projections to Japan:

From Seattle check 80 meters from 0930 to 1330z, 40 meters from 0830
to 1500z, 20 meters from 2100 to 0000z and 0300 to 0700z, and 15
meters for marginal conditions from 2230 to 0000z.

From Los Angeles check 80 meters from 0900 to 1400z, 40 meters from
0800 to 1430z, 20 meters from 0200 to 0800z, 15 meters from 2230 to
0300z.

From Salt Lake City check 80 meters from 0930 to 1300z, 40 meters
from 0830 to 1400z, 20 meters from 2030 to 0700z and 15 meters for
marginal conditions from 2200 to 0200z.

From Chicago check 80 meters from 0930 to 1100z, 40 meters from 1000
to 1200z, and 20 meters from 2100 to 0000z.

From Atlanta check 80 meters from 0930 to 1100z, 40 meters from 0930
to 1130z, and 20 meters around 1330z and 0300z.

From Cleveland check 80 meters from 0930 to 1030z, 40 meters from
0900 to 1130z, and 20 meters from 2100 to 2300z.

From Dallas check 80 meters from 0930 to 1200z, 40 meters from 0830
to 1300z, and 20 meters from 0330 to 0600z, and 15 meters for
marginal conditions from 2230 to 0130z and 0330 to 0600z.
NNNN
/EX