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1993-03-20
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(3078) Fri 19 Mar 93 2:01
By: Tad Cook
To: All
Re: ARRL Propagation Bulletin #11
St:
------------------------------------------------------------
SB PROP @ ARRL $ARLP011
ARLP011 Propagation DE KT7H
QST DE W1AW
Propagation Forecast Bulletin 11 ARLP011
From Tad Cook, KT7H
Seattle, WA March 19, 1993
To All Radio Amateurs
We are now in month 79 of the current solar cycle 22.
Recent projections from NOAA show a continued drop in the solar flux
over the next few months, and then starting in August, a modest rise
in activity, peaking in April, 1994. This is followed by a decline
in activity until we reach the bottom of the solar cycle around
early 1997. But given the brief rise in activity, conditions should
be better from this summer until November, 1994, when solar flux is
back down around the levels for the current month.
There was plenty of flare activity to disrupt HF communications last
week. The worst days were March 11 and 15, when the Planetary
A Index was 32 and 54. Over the next few days there may be some
disturbances from Solar Region 7448, which has grown in complexity
on Thursday. Coronal holes should be in position to launch more
disturbances around March 21 and 27, and April 4 and 12.
We have just passed the Spring Equinox, which makes this a great
season for HF communications.
WWV reported solar flux of 161 for March 12, but this appears to be
flare enhanced. The number shown below for that date uses the 1700Z
measurement of 151.1, in order to exclude the effect of the flare.
Sunspot Numbers from March 11 to 17 were 111, 108, 88, 66, 82, 84
and 82, with a mean of 88.7. 10.7 cm flux was 150, 151.1, 141.5,
136, 131.4, 121.7 and 123.6, with a mean of 136.4.
The propagation projection for this week is from Hawaii to Germany.
80 meter propagation should be limited, with a brief opening around
0500 to 0600 UTC. 40 meters should be best from 0400 to 0800 UTC,
peaking around 0530. 30 meters should be open from 0330 to 1300
UTC, and again from 1430 to 1700 UTC, with the best times from 0430
to 0730 UTC. 20 meters looks best from 0630 to 1800 UTC, and 17
meters from 1700 to 1930 UTC, and around 0800 UTC. 15 meters should
have some openings on most days from 1730 to 1930 UTC, with the best
path around 1800 UTC. 12 meters looks marginal, but could have some
openings on some days around 1800 to 1900 UTC. The prognosis for 10
meters from Hawaii to Europe does not look good, although on some
days there may be an opening for a few hours after the European
sunset.
/EX
--- Opus-CBCS 1.73a
* Origin: The Brier Patch *HST/DS* (206) 743-9452 (1:343/5.0)
SEEN-BY: 11/2 13/13 101/1 109/25 114/5 123/19 124/1 2107 4115 4210
SEEN-BY: 124/5118 5125 6108 6119 7001 7007 7009 7012 7014 8002
SEEN-BY: 153/752 203/23 209/209 280/1 390/1 393/101 396/1 15