ARRL

ARRL Propagation Bulletin ARLP023 (1999)

SB PROP @ ARL $ARLP023
ARLP023 Propagation de K7VVV

ZCZC AP23
QST de W1AW  
Propagation Forecast Bulletin 23  ARLP023
From Tad Cook, K7VVV
Seattle, WA  June 4, 1999
To all radio amateurs 

SB PROP ARL ARLP023
ARLP023 Propagation de K7VVV

Sunspot counts and solar flux rose this past week, with the average
daily sunspot number up nearly 46 points and flux values up nearly
19 points, compared to the previous week.  The big day was
Wednesday, when the sunspot number was 214, a big jump.

Contesters were elated when the poor conditions predicted for last
weekend's WPX contest did not materialize.  A coronal mass ejection
sent charged particles our way, but they missed the earth, and
conditions were excellent last weekend.  Instead of a high A index,
the planetary A index for Saturday and Sunday was only six and five,
and the mid-latitude numbers, which affect most of the readers of
this bulletin, were even better at three and three.  In the
mid-latitudes, there were many periods when the K index was zero,
which is very stable.

Expect more good conditions this weekend, with the Friday through
Monday solar flux predicted at 175, 170 and 170, and the planetary A
index at 8, 7 and 7.

Beyond the weekend look for solar flux to drift down to 150 by June
10, bottom out around 140 from June 18-20, then rise to 165 toward
the end of June.  Unsettled geomagnetic conditions could return on
June 9, with active conditions June 14, and unsettled to active
conditions around June 21.

Earlier in the week there were several wire service stories about
the predicted peak of solar cycle 23 next year, and how solar flares
could disrupt various communication systems and even the power grid.
One article quoted Richard Altrock of the Air Force Research
Laboratory in Sunspot, New Mexico, saying that this cycle should
peak between January and April of next year.  He also said that the
number of sunspots at the peak should roughly equal the activity
during the peaks of the two previous cycles.

Sunspot Numbers for May 27 through June 2 were 154, 146, 151, 169,
157, 190 and 214 with a mean of 168.7.  10.7 cm flux was 155.2,
152.1, 148.6, 156.8, 165.4, 176 and 173.1, with a mean of 161, and
estimated planetary A indices were 10, 9, 6, 5, 4, 8 and 11, with a
mean of 7.6.

Here is the path projection for this weekend, which is from Chicago,
Illinois.  Next week the paths will originate from Dallas, Texas,
and should follow the same pattern recently established.  The only
exceptions will be the bulletins prior to ARRL Field Day and ARRL
Sweepstakes, when the paths will all be domestic only.

To Europe, 80 meters 0100-0430z, 40 meters 2330-0600z, 30 meters
2200-0900z, 20 meters all hours, best 0130-0430z, weakest 1430-
1600z, 17 meters all hours, best 0200-0330z, weakest 1030-1130z, 15
meters all hours, weakest 0600-1030z, 12 meters possibly open at any
time, but best bet around 1400z and again 1730-1800z, 10 meters may
open, but strongest bet is around 0130-0330z.

To Southern Africa, 80 meters 0100-0430z, 40 meters 0030-0500z, 30
meters 2300-0530z, 20 meters 2100-0700z, 17 meters 1800-0200z and
0500-1000z, 15 meters 0530-0130z, with best bets around 1030, 1900
and 0100z, 12 and 10 meters possibly in the morning hours.

To the Caribbean, 80 meters 0000-1000z, 40 meters 2230-1200z, 30
meters all hours, best 0130-0900z, weakest 1600-1800z, 20 meters all
hours, strongest 0200-0900z, weakest 1530-1830z, 17 meters
2100-1300z, strongest 0030-0930z, 15 meters all hours, best 0100-
0530z, weakest 1500-1900z, 12 meters best 1200-0430z, 10 meters
could open any time, but best bets are around 1330z and 1530-1630z,
worst chances around 0430-0830z.

To South America, 80 meters 0100-1000z, 40 meters 0000-1030z, 30
meters 2300-1100z, 20 meters all hours, best 0130-0930z, weakest
1530-1800z, 17 meters all hours, best 0130-0800z, weakest 1530-
1800z, 15 meters 1100-0700z, strongest 0030-0400z, 12 meters
possibly 1200-0000z and 0130-0430z, 10 meters possibly 1330-1400z
and 1600-1700z.

To Australia, 80 meters 0700-1100z, 40 meters 0600-1200z, 30 meters
0530-1230z, 20 meters 0400-1330z, 17 meters 0130-0830z, 15 meters
0000-0700z, 12 and 10 meters best chance around 0300.

To Japan, 40 meters around 1030z, 30 meters 0830-1230z, 20 meters
0600-1500z, peaking 0930-1130z, 17 meters all hours, best 1000-
1200z, weakest 2130-0000z, 15 meters all hours, best 0730-0930z and
1130-1230z, weakest 2200-2300z, 12 meters could open any time, best
bet around 1600z, 0430z or 0700z, 10 meters perhaps around 0630z or
1730-2130z.
NNNN
/EX