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ARRL Propagation Bulletin ARLP050 (2007)

ARLP050 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 50  ARLP050
From Tad Cook, K7RA
Seattle, WA  November 30, 2007
To all radio amateurs 

ARLP050 Propagation de K7RA

Sunspots appeared over several days in the past week.  November
24-27 had daily sunspot numbers of 15, 12 and 11.  Otherwise, the
Sun has been blank.  In the previous reporting period, November
15-21, there were only two days with sunspots, and the daily sunspot
numbers on both days were 13.  The result is the average daily
sunspot number from the previous reporting period to the current
(November 22-28) reporting period rose from 3.7 to 5.4.

There were no days with geomagnetic storms, and geomagnetic
conditions should be quiet over the near term.  The next recurring
solar wind stream is expected December 17.  Expect more weeks of no
sunspots, with occasional appearances for a few days at a time.  The
U.S. Air Force predicts a planetary A index of 5 for the next ten
days.  For the week, Geophysical Institute Prague predicts quiet
geomagnetic conditions for today, November 30, quiet to unsettled
December 1, and back to quiet conditions for December 2-6.

This weekend is the ARRL 160 Meter Contest, which begins today at
2200z.  This is a CW only contest, and you can study the rules at,

Check out a resource for 160 meter propagation in the Northern
Hemisphere at,  This is
from the same folks who publish the Proplab-Pro HF Radio Propagation
Laboratory software.  They say version 3.0 is radically updated, and
will be released this week, on Monday, December 3.  Unlike W6ELprop
and some other propagation software, this one is not free, and in
fact is likely the most expensive propagation software that hams
will run across.  But it looks like a powerful program.

Another one that is quite powerful is ACE-HF, with info at,  ACE stands for "Animated Communications
Effectiveness," and it was originally developed for the military by
a non-ham, who was able to obtain licensing for it upon retirement.
Tomas Hood, NW7US, who writes the monthly propagation column for CQ
Magazine has a page devoted to it on his personal web site at,

There were more reports of interesting 10 meter propagation.  In the
CQ World Wide DX Contest on November 25, Doug Charette, W5GA of
Wagoner, Oklahoma reported that he worked V51AS in Namibia around
1700z.  Doug uses a very modest commercial multiband vertical
antenna, and heard the African station at S-5.  He was surprised
that he didn't hear many South American stations on 10 meters in the

Also in the contest, Phil Finkle, K6EID of Marietta, Georgia worked
6W1RW (Senegal) on 10 meters at 1409z on Saturday.  On the same band
on Sunday around 1630z he worked V51AS, D4C (Cape Verde) and 3X5A
(Guinea).  Walt Knodle, W7TTE of Bend, Oregon heard V51AS very
clearly on Sunday morning on 10 meters (he didn't say what time),
but the opening only lasted about three minutes.  Around the same
time he heard LW5EE in Argentina, which also disappeared shortly.

Fabrizio Valdirosa, an Italian shortwave listener in Rome, reports
he also observed the 12 meter opening on November 21 reported in our
extra post-Thanksgiving Propagation Forecast Bulletin ARLP049.
Fabrizio reported that this was the first time he's heard Mozambique
on 12 meters, and could hear C91R working North American stations.
He wrote, "This opening happened just at the onset of some
geomagnetic activity, as I have seen other times.  When the Kp index
starts to go up, we have good openings on the higher bands, usually
from Europe to Africa and South America."

If you would like to make a comment or have a tip for our readers,
email the author at,

For more information concerning radio propagation, see the ARRL
Technical Information Service at, For a detailed
explanation of the numbers used in this bulletin see, An archive of past
propagation bulletins is at, Monthly
propagation charts between four USA regions and twelve overseas
locations are at,

Sunspot numbers for November 22 through 28 were 0, 0, 15, 12, 11, 0
and 0 with a mean of 5.4.  10.7 cm flux was 69.7, 70, 71.3, 70.7,
71.5, 71.4, and 71.2 with a mean of 70.8.  Estimated planetary A
indices were 13, 10, 12, 11, 8, 4 and 3 with a mean of 8.7.
Estimated mid-latitude A indices were 6, 8, 8, 8, 6, 5 and 3, with a
mean of 6.3.


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