ARRL

ARRL Propagation Bulletin ARLP021 (1999)

SB PROP @ ARL $ARLP021
ARLP021 Propagation de K7VVV

ZCZC AP21
QST de W1AW  
Propagation Forecast Bulletin 21  ARLP021
From Tad Cook, K7VVV
Seattle, WA  May 21, 1999
To all radio amateurs 

SB PROP ARL ARLP021
ARLP021 Propagation de K7VVV

Solar flux and sunspot numbers dropped this week, with average flux
values off over 18 points and average sunspot numbers down over 33
points.  May 13 and 18 were disturbed days, with planetary A indices
over 20.  The planetary K index reached 5 on both days, and on May
13 the high latitude K index was 7, with the high latitude A index
at 46.  This higher number reflects the high latitude and polar
region's greater vulnerability to solar flares and proton events.

Solar flux peaked for the week at 152.2 on Sunday, and is expected
to be 140 for the next few days.  The planetary A index for Friday
through Sunday is expected to be 8, 8 and 10.  Flux is expected to
reach 145 on May 27, and 150 by June 2, peaking around 170 on June
5.  Look for geomagnetic disturbances due to coronal hole effects on
May 26-29, with the worst conditions on the first two days of that
period.

In VHF news, W7XU and N0QJM in South Dakota both worked KH7R in
Hawaii on 6 meters on May 17 around 0400z.

Readers who tried last week to reach the website
http://www.nwra.com/nwra/spawx/tiros.html mentioned in Propagation
Bulletin ARLP020 probably were unsuccessful, because nwra.com had
some problems.  You are encouraged to try again this week.

Sunspot Numbers for May 13 through 19 were 118, 126, 167, 151, 148,
129 and 120 with a mean of 137.  10.7 cm flux was 147.3, 144.2,
143.6, 152.2, 145.3, 140.6 and 142.4, with a mean of 145.1, and
estimated planetary A indices were 24, 9, 9, 6, 5, 23 and 10, with a
mean of 12.3.

The path projection for this week is from Atlanta, Georgia.

To Western Europe, 80 meters 0030-0500z, 40 meters 2330-0600z, 30
meters 2200-0900z, 20 meters all hours, with best signals 0100-0400z
and weakest 1600-1700z, 17 meters 2000-2100z.

To Eastern Europe, 80 meters 0100-0200z, 40 meters 0000-0330z, 30
meters 2300-0500z, 20 meters all hours, with best signals 0030-0300z
and weakest 1300-1600z, 17 meters all hours, best signals 0030 and
again 0300-0330z, 15 meters possibly 1800-2230z and 0330-0400z,

To Southern Africa, 80 meters 0000-0500z, 40 meters 2330-0530z, 30
meters 2230-0600z, 20 meters 2000-0200z and 0500-0800z, 17 meters
0530-0800z and 1730-0130z, 15 meters 0530-1000z and 1730-0130z, 12
meters possibly 1530-2330z.

To the Caribbean, 80 meters 2330-1030z (best 0230-0900z), 40 meters
2100-1300z (best 0100-0900z), 30 meters open all hours, best
0100-0900z, weakest 1600-1800z, 20 meters open all hours, best
0100-0930z, weakest 1300-1530z, 17 meters open all hours, best
0100-0500z, 15 meters 1230-0400z, 12 meters possibly 1630-1800z.

To South America, 80 meters 0000-1000z, 40 meters 2330-1030z, 30
meters 2200-1130z, 20 meters open all hours, best 0030-0800z,
weakest 1630-1730z, 17 meters 1100-0500z, 15 meters 1230-0430z, 12
meters possibly 1430-0430z.

To Australia, 80 meters 0630-1100z, 40 meters 0600-1200z, 30 meters
0500-1230z, 20 meters 0300-1330z, 17 meters 0100-0800z, 15 meters
2100-0700z, 12 meters 2100-0500z, 10 meters possibly 2100-0430z.

To Japan, 40 meters 0930-1100z, 30 meters 0800-1200z, 20 meters
0500-1500z, 17 meters 1030-0630z, 15 meters possibly 1830-0530z.
NNNN
/EX