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ARRL Propagation Bulletin ARLP052 (1999)

ARLP052 Propagation de K7VVV

QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7VVV
Seattle, WA  December 23, 1999
To all radio amateurs 

ARLP052 Propagation de K7VVV

HF radio conditions improved over the past week, with solar flux and
sunspot numbers higher than the previous period, and geomagnetic
indices more stable.  Average planetary A index declined from 9.7 to
3.7, and average solar flux was up over 40 points.  This is a happy
combination, because often higher solar indices are coupled with
less stable geomagnetic conditions.  Look for solar flux to remain
around 200 for Thursday and Friday of this week, and slip just below
200 on Christmas day.  Planetary A indices are predicted at 7 for
all three days.

Beyond this weekend look for solar flux to decline to around 150 by
the end of the year, rising above 160 after the first week in
January.  Solar flux should top 200 again by the middle of next
month.  Look for unstable geomagnetic conditions returning around
December 31 through January 2.

If you missed the Talk of the Nation program Science Friday on
December 17 on National Public Radio, you will want to hear it over
the web.  Check the NPR archive at
or after this week check the archives at and look for the
December 17 program.  The first hour featured Victor Pizzo and
Howard Singer, two scientists from the NOAA Space Environment Center
in Boulder, Colorado.  They made many interesting comments about the
current solar cycle and gave some great explanations concerning
various space weather facts of interest to hams.

Merry Christmas from Seattle, where your bulletin author is
performing in his seventeenth season as the grandfather in Pacific
Northwest Ballet's production of The Nutcracker.  Next week's
bulletin ARLP053 will mark the end of the 9th year of writing these
bulletins, after taking over from the late W1HDQ in early 1991.
There should be a review of the solar numbers for this cycle in the
first bulletin of the new year.  You can always write with questions
or comments to

Sunspot numbers for December 16 through 22 were 146, 179, 190, 154,
149, 129 and 130 with a mean of 153.9. 10.7 cm flux was 194, 200.7,
205.5, 206.9, 209.2, 217.2 and 201.7, with a mean of 205, and
estimated planetary A indices were 5, 5, 5, 4, 3, 2 and 2, with a
mean of 3.7.

Path projections this time around are for Christmas day from
Charlotte, North Carolina.

To Europe, 80 meters 2100-1000z (best 0030-0700z), 40 meters
1930-1130z (best 2300-0730z), 30 meters 1800-0900z and 1100- 1400z,
20 meters 1130-2230z, 17 meters 2130-2100z, 15 meters 1230-2030z, 12
meters 1300-1930z, 10 meters 1330-1900z.

To Southern Africa, 80 meters 2130-0430z (best around 0000z and
0330z), 40 meters 2100-0500z (best 2230-0300z), 30 meters
2030-0530z, 20 meters 1900-0030z and around 0600z, 17 meters
1700-2330z, 15 meters 1200-2300z (best later in the period), 12
meters 1200-2200z, 10 meters 1230-2130z.

To South America, 80 meters 2300-0930z (best 0200-0800z), 40 meters
2230-1030z, 30 meters 2200-1100z (best 2330-0900z), 20 meters
1930-0800z and 1130-1230z, 17 meters 1130-0200z (best later in the
period), 15 meters 1200-0030z, 12 meters 1230- 0000z, 10 meters

To the Caribbean, 80 meters 2130-1230z, 40 meters all hours, best
2300-1030z, weakest 1530-1800z, 30 meters open all hours except
around 0930z, best 2300-0300z and 0530-0800z, 20 meters 1130-0030z,
17 meters 1200-0000z, 15 meters 1230-2300z, 12 meters 1300-2230z, 10
meters 1330-2130z.

To Australia, 80 meters 0930-1300z, 40 meters 0900-1400z, 30 meters
0830-1430z, 20 meters 1300-1530z, 17 meters 1330-1730z, 15 meters
1400-1830z, 12 meters 1430-1930z, 10 meters 1500-1730z and

To Japan, 80 meters 0630-1300z, 40 meters 0530-1400z, 30 meters
0430-1500z and 2200-2300z, 20 meters 0330-0930z and 2030- 0130z, 17
meters 2100-0130z, 15 meters 2130-0030z, 12 meters 2130-2300z, 10
meters 2200-2300z.


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