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ARRL Propagation Bulletin ARLP021 (1998)

ARLP021 Propagation de K7VVV

Propagation Forecast Bulletin 21  ARLP021
From Tad Cook, K7VVV
Seattle, WA  May 22, 1998
To all radio amateurs

ARLP021 Propagation de K7VVV

First thing to report this week is that geomagnetic or space weather
conditions probably had nothing to do with the failure of the Galaxy
4 satellite.

Geomagnetic indices have settled over the last two weeks.  Solar
flux and sunspot numbers have also been generally down, but last
week the average sunspot number was up about ten points while the
average solar flux was off almost six points.

Until the end of the month the solar flux should rise, past 120 by
May 25, and then up to 128 around May 29 and 30.  Solar flux should
drop down below 120 around June 2 or 3, below 110 around June 6, and
below 100 after June 13.  Look for unsettled conditions around May
23, and May 30 through June 2.  Stable conditions are forecast
around June 11 and 12.

20 meters is still the best HF band for DX, with daily worldwide
openings.  The South Pacific is strong into Seattle on that band
late into the night.  The ionosphere thins as the days lengthen,
which means that Maximum Usable Frequency (MUF) during the daylight
hours will gradually lower.

On the VHF front, W1LP from Massachusetts reported good 6 meter
openings into W3, W4, W0, New Brunswick and Cuba around a week ago.
W1JJM reported EA7 and CT3 signals on 6 meters into Rhode Island on
May 14, along with more contacts from the Northeast into the
Southeast and the Caribbean on 2 meters.  W9JJ reported a 432 MHz
Delaware to Florida QSO.

Sunspot Numbers for May 14 through 20 were 94, 101, 92, 89, 92, 77
and 58 with a mean of 86.1.  10.7 cm flux was 117.2, 116, 117.7,
110, 102.2, 99.7 and 91.9, with a mean of 107.8, and estimated
planetary A indices were 5, 8, 12, 9, 11, 8, and 9, with a mean of


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