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ARRL Propagation Bulletin ARLP010 (1999)

ARLP010 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 10  ARLP010
From Tad Cook, K7VVV
Seattle, WA  March 5, 1999
To all radio amateurs 

ARLP010 Propagation de K7VVV

Average sunspot numbers for the past week were up when compared to
the previous week, while average solar flux was down.  How could
this be?  If you look at a graph of the two indices at or,
you can see that a recent minimum followed by a rise in solar flux
lagged sunspot numbers.  So the minimum solar flux of 115.1 occurred
during the past week, while the minimum sunspot number of 38 was
during the previous week.

Geomagnetic conditions have been active, with A indices in the
double-digits over most of the past week.  The worst day was Monday,
when the planetary A index was 33 and the K index was four or five
for most of the day.  This is generally bad for HF, but often
provides interesting VHF propagation.  N5JHV received television
signals from New Zealand, and V73AT was hearing California Highway
Patrol around 42 MHz on Monday.

For the ARRL International DX Phone Contest this weekend, look for
improving conditions with a rising solar flux of 150, 158 and 165
for Friday through Sunday.  Geomagnetic conditions should settle
down, indicated by a falling planetary A index of 18, 15 and 9 for
those same days.  The first day of the contest may be a little
rough, with geomagnetic conditions possibly unsettled to active.

After the weekend expect the solar flux to peak near 200 around
March 13, then drop below 170 five days later, then down to 130 on
March 21, and 120 from March 23 until the end of the month.  Days
with possible unsettled to active geomagnetic conditions are March
10 and 11 and 27 and 28.

A couple of readers mentioned that the JA7SSB URL in ARLP009 was
wrong because ip was written instead of jp.  It should be

Sunspot Numbers for February 25 through March 3 were 66, 70, 93,
145, 127, 143 and 148 with a mean of 113.1.  10.7 cm flux was 119.5,
115.6, 115.1, 123, 120.2, 129.9 and 137, with a mean of 122.9, and
estimated planetary A indices were 7, 3, 5, 14, 33, 18 and 15, with
a mean of 13.6.

Here are some path predictions for this weekend from New York City:

To Western Europe, try 80 meters 2200-0730z, 40 meters 2030-0930z,
30 meters open around the clock, with the worst times 0830-1030z and
1400- 1800z, and strongest signals 2300-0600z.  Check 20 meters
1200- 0100z, 17 meters 1200-2130z, 15 meters 1300-2100z, 12 meters
1500-1930z, and possibly 10 meters, 1600-1900z.

To South Africa, 80 meters 2230-0400z, 40 meters 2200-0500z, 30
meters 2100-0530z, 20 meters 1830-0500z, 17 meters 1600-0030z, 15
meters 1100-2330z, 12 meters 1200-2230z, and 10 meters 1300-2100z.

To the Caribbean, 80 meters 2230-1130z, 40 meters open all hours,
best 2330- 1000z, worst 1430-1930z, 30 meters open all hours, best
2300-1030z, weakest 1530-1800z, 20 meters open all hours, best
2330-0800z, weakest 1600-1730z, 17 meters 1130-0130z, 15 meters
1200-0030z, 12 meters 1230-2330z, and 10 meters 1330-2130z.

To South America, 80 meters 2300-0930z, 40 meters 2230-1030z, 30
meters 2200-1100z, 20 meters open all hours, best 2330-0800z,
weakest 1500-1800z, 17 meters 1130- 0130z, 15 meters 1200-0030z, 12
meters 1230-2300z, and 10 meters 1330-2130z.

To South Pacific, 80 meters 0515-1215z, 40 meters 0500-1230z, 30
meters 0415-1330z, 20 meters 0230-1500z, 17 meters 1300-1500z,
1630-1900z and 0030-0300z, 15 meters 1330-1430z and 1700-0200z, 12
meters 1700-0100z and 10 meters 1730-2300z.

To Australia, 80 meters 0800-1200z, 40 meters 0730-1230z, 30 meters
0700-1330z, 20 meters 0530-1500z, 17 meters 1300-1430z, 15 meters
0000-0230z, 12 meters 2000-0130z, and 10 meters 2100-0000z.

To Japan, 80 meters 0830-1145z, 40 meters 0800-1245z, 30 meters
0630-1345z, 20 meters 1300- 0130z and around 0530z, 17 meters
2030-0030z, 15 meters 2100-2300z, and 12 meters around 2130z.

To Central Asia, 80 meters 2230-0130z, 40 meters 2200-0145z, 30
meters 2030-0245z, 20 meters 1130-0400z, 17 meters 1300-2200z, 15
meters 1400-1600z, and 12 meters around 1500-1530z.


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