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From: rjr@mgweed.UUCP (Bob Roehrig)
Newsgroups: net.ham-radio
Subject: arrl propagation forecast bulletin nr 16
Message-ID: <16710@mgweed.UUCP>
Date: Tue, 23-Apr-85 21:50:50 EST
Article-I.D.: mgweed.16710
Posted: Tue Apr 23 21:50:50 1985
Date-Received: Sat, 27-Apr-85 00:32:08 EST
Organization: AT&T Consumer Products - Montgomery Illinois
Lines: 42


qst de k9eui
hr propagation forecast bulletin nr 16  from arrl headquarters
newington ct   april 21, 1985
to all radio amateurs bt

the area of the sun responsible for the march solar  flux  peak
of  80  is  back  with us again.  the flux had been down to its
cycle 21 low of 69 on april 16, but was back up to  72  on  the
20th.   a sizable spot group about 3 days in from the east limb
of the sun showed marked eruptive  activity  intermittently  on
saturday  and continuously through sunday afternoon.  the solar
flux jumped five points to 77 on the 21st, as propagation  went
from  bad  to worse until it began to stabilize again late that
day. with the wwv k index peaking at an almost  unheard  of  8,
reception   of   their   propagation   bulletins  was  all  but
impossible, for the first time in our  7  years  of  part  time
florida living.

such near or total blackouts in the  5  to  20  mhz  range  are
likely when the solar flux rises suddenly.  more communications
difficulty is likely when charged particles from the  eruptions
enter  the  earths  atmosphere,  some  18 to 36 hours after the
event itself.  this is likely to bring  auroral  conditions  in
the higher latitudes on monday or tuesday, and generally poorer
propagation on all but  transequatorial  circuits.   there  may
even be an enhancement on north south paths on 50 and 28 mhz at
such times. if we are to have any good te work on 50  mhz  this
spring it should come this week.

there is ordinarily a period of exceptional propagation on  all
dx  frequencies, as a major disturbance clears up.  no accurate
prediction can be made for this event.  the best indication  is
a  drop  in  the  wwv  k index, given as part of their bulletin
transmitted at 18 minutes past each hour.  a downward trend  is
the thing to watch for, particularly when the k index gets down
to 2 or lower.

the period april 28 to may 2 is likely to bring  at  least  one
medium  level disturbance.  this could be followed by our first
sporadic e skip of the season, on 50 mhz    ar