ARRL Propagation Bulletin ARLP043 (2007)

ARLP043 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 43  ARLP043
From Tad Cook, K7RA
Seattle, WA  October 19, 2007
To all radio amateurs 

ARLP043 Propagation de K7RA

Our Sun is still blank.  The past week has shown no sunspots, and we
will probably see more of nothing.  Geomagnetic conditions have been
very quiet, which means lower absorption of HF radio signals and
lower noise.  But this will become more active in the near future
due to a returning solar wind.  The planetary A index for October
19-26 is predicted to be 15, 12, 8, 5, 8, 18, 20 and 25.  Things
should settle down during the CQ World Wide DX Phone Contest next

Geophysical Institute Prague predicts unsettled conditions for
October 19-21, quiet to unsettled October 22, quiet conditions
October 23, and unsettled to active October 24-25.

We continue to receive reports from surprised hams that are getting
15 and 10 meter propagation that they don't expect at the bottom of
the solar cycle.

Brian Edward, N2MF of Jamesville, New York worked 3B7C at 1218z on
10 meter CW on September 22.  Brian wrote, "This strikes me as
unusual because I'm quite north, in Syracuse NY.  I haven't heard
much on 10 meters in years.  It was relatively early in our morning,
0818 am.  Although Europe was posting them on the DX internet spots,
no other stateside was in there.  They were quite strong at this
location, I worked them first call.  I believe this was a single day
occurrence, heard them shortly after on 12 meters, but unfortunately
I'm lacking a good antenna on that band."

One thing that definitely helped Brian were his antennas, which you
can see on  He has two 7-element 10 meter
Yagis, one aimed on Europe and the top one at 80 feet is rotatable.

Rodney Vorndam, K9ROD of Rye, Colorado mentioned he hasn't heard any
15 meter openings in a while, but on October 13-14 he worked Spain,
Honduras, Haiti and Virgin Islands on that band.

Steve Doty, KA9OKH of Evansville, Indiana said over the past week,
October 11-18, he has had strong signals from East Asia on the low
end of 20 meter CW.  Steve hasn't heard Asia in a long time, but
even with this extended period of no sunspots the signals out of
Japan and Korea were as high as 20 db over S9.

Last week's Propagation Forecast Bulletin ARLP042 mentioned a
problem a reader had running W6ELprop under Microsoft's Vista
operating system.  There is an easy fix.  Our reader's problem was
probably with a security feature in Vista, and the solution is to
right-click the W6ELprop installation file W6ELPropInst270.exe from
Windows Explorer, then select the Run as Administrator option.

We also received a helpful tip from Rex Lint, K1HI of Merrimack, New
Hampshire.  Vista isn't compatible with the Help file in W6ELprop,
which has an .hlp extension.  To fix this, there is a free patch
from Microsoft, described at,

We should mention Kangaroo Tabor Software, which produces several
very useful propagation tools.  These are shareware which is not
totally free, but the trial versions don't cost anything, and are
fully functional.  Check their web site at,  Jim Tabor, KU5S is the author, and he has
several distinctive and quite useful propagation software tools

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 web page 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 October 11 through 17 were 0, 0, 0, 0, 0, 0 and
0 with a mean of 0.  10.7 cm flux was 68.8, 68.6, 67.6, 67.1, 67.2,
67.1, and 67.4 with a mean of 67.7. Estimated planetary A indices
were 1, 4, 2, 5, 2, 2 and 1 with a mean of 2.4. Estimated
mid-latitude A indices were 0, 3, 2, 3, 1, 1 and 0, with a mean of