‰ Now 18 WPM transition file follows ‰

Finally this week a sunspot group appeared, and this time there was
about three weeks since the last group disappeared.  The first
spotless day after sunspot group 1008s last appearance was Tuesday,
November 18 and the last spotless day before group 1009 emerged was
Tuesday, December 9.  As expected, this was another Cycle 24 group,
emerging far south of our Suns equator.  This weekend is the ARRL 10
meter contest, and it would be great to have enough sunspots to
drive the MUF, Maximum Usable Frequency, above 28 MHz, but that
doesnt seem likely, as group 1009 is near the western limb of the
visible solar disk.  What level of solar activity would we need in
order to see the MUF above 28 MHz?  That varies according to the
locations of the two stations trying to communicate, the season, and
the time of day.  For example, if the date is December 13, the path
from Cleveland, Ohio to Dallas, Texas is likely to briefly have an
MUF at 28R0 MHz around 1730z, if the average sunspot number was at
least 105 for several days.  In our example, if the average sunspot
number for several days was 125, the three hour period from 1700 to
2000z would have an MUF above 28 MHz, and the 1730 to 1800z period
would likely have the best signals.  If we calculate the path from
Boston to Atlanta for the same date, instead of 105, the average
sunspot number for several days should be at least 131 to reach an
MUF of 28R0 MHz.  But dont expect 10 meters to be unusable this
weekend.  An MUF above 28 MHz is desirable for very reliable
communications, but perhaps sporadic E skip will offer surprises.
Summer sporadic E is more intense, but this time of year we should
see some sporadic E.  A few weeks ago Vic Woodling, WB4SLM of
Centerville, Georgia wrote about an experience on 30 meters in the
middle of the day, copying strong European stations, and also 5R8IC
working into Europe from Madagascar, but with weaker signals on Vics
end.  This was at 1630z, and when Vic came back to the radio at
1830z, they were even stronger.  Although in Vics experience this is
uncommon, a check with a propagation program for 30 meters on
November 22 with zero sunspots between Georgia and England shows
propagation closely matching his report.  At 1630z it shows the
relative signal level at 15 db, and then at 1830z it jumps to 29 db.
But if he looks further east to the Czech Republic, the signals stay
around the level that they would be for England at 1630z, all
through the same period.  Ed Clulow, N7TL of Portland, Oregon
commented on 75 meter conditions during the SSB Sweepstakes Contest,
which was November 15 to 17.  He uses an inverted vee dipole, and
said after dabbling in contests for several decades, he has never
seen propagation like it was on Saturday evening, and said it
sounded more like 20 meters.  He worked Midwest and East Coast
stations with ease, snagging them on the first or second call.
Sunspot numbers were 0, 0, 0, 0, 0, 0, and 13 with a mean of 1R9.
10R7 cm flux was 69R6, 68R8, 69R1, 69, 68R5, 68R7, and 70R8 with a
mean of 69R2.  Estimated planetary A indices were 6, 10, 7, 6, 5, 0
and 2 with a mean of 5R1.  Estimated mid latitude A indices were 4,
7, 14, 6, 1, 1 and 2 with a mean of 5‚

‰ End of 18 WPM transition file ‰