[net.ham-radio] arrl propagation forecast bulletin nr 44

rjr@mgweed.UUCP (Bob Roehrig) (11/06/85)

qst de k9eui
hr propagation forecast bulletin nr 44  from arrl headquarters
newington ct  november 4, 1985
to all radio amateurs bt

for several months solar activity has  been  lower  than  might
have  been  expected  at  this point only about nine years into
solar  cycle  21.   at  the  middle  of  october  there  was  a
remarkable  reversal of this trend.  the first sunspot activity
of any consequence since last july appeared on the east limb of
the  sun  october  15.   in  a  few days it produced solar flux
readings of 95 on october 22 and 23, and a run above 75 for  12
consecutive  days. the most recent 75 had been logged on august
11.

this rise could not have come at a better time, as we are  just
entering  the prime dx season for the northern hemisphere.  the
second half of october saw 21 mhz open over much of the  world,
and  24  and  28 mhz were more active than at anytime this past
year.  though the solar flux was back down to 70, both  21  and
28  mhz  were  fairly productive in the recent arrl sweepstakes
and cq ww dx contests.

judging by the shape of our october solar flux curve, there  is
a fairly good chance for another surge beginning about november
11, when the same area of the sun  will  be  facing  the  earth
again.  this could begin as early as november 6, as there was a
small bulge in the flux curve beginning october 9.

as this bulletin was being prepared, we were at the peak  of  a
strong  geomagnetic  disturbance.  this should be giving way to
improved  propagation  november  4  to  6.   mildly   disturbed
conditions may be with us much of the time through november 19.
the best overall time of the entire fall should be november  20
to  28,  with  the  muf  the  highest  at the beginning of that
period.

american sunspot numbers for october 24 through 30 were between
0 and 53 with a mean of 11  ar