ARRL

ARRL Propagation Bulletin ARLP011 (2006)

SB PROP @ ARL $ARLP011
ARLP011 Propagation de K7RA

ZCZC AP11
QST de W1AW  
Propagation Forecast Bulletin 11  ARLP011
From Tad Cook, K7RA
Seattle, WA  March 17, 2006
To all radio amateurs 

SB PROP ARL ARLP011
ARLP011 Propagation de K7RA

The recent big news regarding projections for a huge solar cycle
number 24 brings in more mail daily. All of us want to see lots of
exciting space weather over the next decade, but not everyone is
convinced. While I wouldn't count him among dissenters, Jon Jones,
N0JK sent in this article from a year ago (several readers mentioned
this) which predicts a very small cycle 24, and also claims to use a
successful prediction method. Read it and weep (or not) at
http://www.spacew.com/news/05Mar2005/index.php.

Several people wrote in this week about enjoying the quiet
conditions. Without many sunspots, the MUF is low, but there is less
noise and absorption.

Mike Schatzberg, W2AJI writes, "The low solar activity seems to have
produced some exceptional conditions on 20 meters within the last
week. The band has been most reliable all day long here in western
NC."

He continues, "Propagation is marked by very low atmospheric noise.
Weaker stations are easily pulled out, provided QRM permitting. I am
working great numbers of QRP stations, worldwide. Although we all
are hoping for the beginning of the new cycle and greatly improved
propagation, I do well remember the QRM that accompanies great
propagation. Things don't really seem nearly so poor as in the
bottom of other cycles which I have experienced. Maybe it's much
better equipment and antenna systems than in years gone by."

I suspect Mike's better antenna system may help. Check out the 5
element 20 meter Yagi at,
http://home.earthlink.net/~cherokeehillfarm/id2.html.

Mike also writes, "Early morning contacts include strong European
propagation, which continues well into the later afternoon. Signal
reports of well over S9 are common, from both sides. Propagation
into India, and Southeast Asia is quite good in the early morning
times also. Regular contact is found with Jakarta, Indonesia also."

He goes on to say, "Later afternoon, the long path opens to the
South Pacific, with unbelievable VK propagation. Yesterday's
contacts, including VK3OK, VK2ZF and many others, produced reports
of from 20 to 25 DB over S9 in both directions. The band goes
longer, short path to the Pacific about 2 to 3 hours after dark.
KH7F has his usual S9 signal here at my location. South America
remains strong for most of the evening."

Orrin Brand, K9KEJ is using a ground-mounted vertical antenna on 20
meters with no radials. He writes, "Late mornings in the Chicago
area have been rather unusual of late. I'm able to hear and work
Africa, Eastern Europe and VK land, all in a matter of minutes on 20
meters. European signals run anywhere from S7 to 10/9, while East
and West African stations run a solid S9. The VKs and ZLs go
anywhere from S5 to S8--all on the vertical."

Average daily sunspot numbers and solar flux values were down just
slightly this week when compared to last, and the geomagnetic
indexes were up just a bit. We only saw one day of 0 sunspot count,
and there weren't any really stormy days with high geomagnetic K and
A indices.

The prediction for the next few days is a solar flux value of 75,
and in fact that continues in Thursday's prediction from the U.S.
Air Force for the next 45 days. They also predict Sunday, March 19
to be a day of geomagnetic activity, with a planetary A index
projected to reach 20. The five day projection for planetary A index
from March 17-21 is 8, 8, 20, 15 and 12. This slightly higher
activity is based on what was occurring in the area that will be
facing us this weekend, looking back to February 19-22, when the
planetary A index was 6, 20, 17 and 12.

This projection for geomagnetic activity seems shared this week by
Geophysical Institute Prague, which projects quiet conditions for
March 17, 22 and 23, quiet to unsettled for March 18, unsettled for
March 20 and 21, and unsettled to active on March 19.

If you would like to make a comment or have a tip for our readers,
email the author at, k7ra@arrl.net.

For more information concerning radio propagation and an explanation
of the numbers used in this bulletin see the ARRL Technical
Information Service propagation page at,
http://www.arrl.org/tis/info/propagation.html. An archive of past
propagation bulletins is found at, http://www.arrl.org/w1aw/prop/.

Sunspot numbers for March 9 through 15 were 12, 12, 0, 18, 14, 34
and 22 with a mean of 16. 10.7 cm flux was 72.9, 72.2, 74, 73.2,
72.6, 73.6, and 74.2, with a mean of 73.2. Estimated planetary A
indices were 4, 12, 12, 6, 3, 4 and 7 with a mean of 6.9. Estimated
mid-latitude A indices were 3, 9, 9, 3, 2, 2 and 6, with a mean of
4.9.
NNNN
/EX