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ARRL Propagation Bulletin ARLP049 (1997)

ARLP049 Propagation de K7VVV

Propagation Forecast Bulletin 49  ARLP049
From Tad Cook, K7VVV
Seattle, WA  December 5, 1997
To all radio amateurs

ARLP049 Propagation de K7VVV

HF conditions were good over the past week, with geomagnetic indices
very stable.  Most periods had a K index of zero or one, which is
very quiet.  Quiet conditions would be very good for the 160 meter
contest this weekend, but geomagnetic indices may be up just
slightly.  Currently the Boulder A index is forecast to be eight on
both Saturday and Sunday, which indicates slightly more geomagnetic
activity than we have seen recently.

Solar flux was up, with the average for the week increasing by over
13 points compared to the week previous.  Average solar flux for the
past 90 days increased by another point this week to 94, and the
flux was well above this level on every day, which is a nice upward
trend.  Speaking of upward trends, both the average solar flux and
the average sunspot number for the same period one year ago were
over 30 points lower.

Watch for solar flux to drop a bit below 100 over the next few days,
then rise above 100 again a few days before Christmas and above 110
a day or two after the holiday.  Geomagnetic conditions might become
a bit unsettled around December 19 or 20.  Predicted solar flux for
December 5 to 7 is 105, 103 and 101.

Sunspot Numbers for November 27 through December 3 were 44, 40, 48,
56, 73, 54 and 54 with a mean of 52.7.  10.7 cm flux was 111.1,
116.3, 112.1, 112.4, 117, 112.2 and 112.2, with a mean of 113.3, and
estimated planetary A indices were 2, 2, 2, 4, 3, 3, and 6, with a
mean of 3.1.


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