ARRL

ARRL Propagation Bulletin ARLP007 (2012)

SB PROP @ ARL $ARLP007
ARLP007 Propagation de K7RA

ZCZC AP07
QST de W1AW  
Propagation Forecast Bulletin 7  ARLP007
From Tad Cook, K7RA
Seattle, WA  February 17, 2012
To all radio amateurs 

SB PROP ARL ARLP007
ARLP007 Propagation de K7RA

We are over half way through the winter season, and today, February
17 is 58 days after the winter solstice.  Propagation should improve
as we approach the vernal equinox on March 20, which is just 32 days
from now.
 
Solar activity is still in the temporary doldrums, with sunspot
numbers below 100.  But the weekly average of daily sunspot numbers
rose this week by over 15 points to 55.6.
 
There was a geomagnetic storm on Wednesday, February 15 (UTC).
Early in the UTC day (Tuesday night in North America) the planetary
K index went to 5, and planetary A index was 22.  The College A
index in Fairbanks was estimated at 46, which is quite high.  The
disturbance was probably from a CME a few days earlier.  Aurora in
North America was seen as far south as Minnesota.
 
The latest forecast has solar flux about 65 points lower than last
month's prediction for the ARRL International CW DX Contest this
weekend.  Latest predicted flux values are 105 on February 17-18,
100 on February 19, 110 on February 20-21, 115 on February 22-26,
110 on February 27-29, and 105 on March 1-3.  The predicted flux
values go back to 115 on March 14-16 and again on March 20-24.
Predicted planetary A index for February 17-19 is 5, 8, and 8, then
5 on February 20 through March 1.
 
This just in, the latest sunspot cycle prediction from NASA, and it
doesn't look good: http://solarscience.msfc.nasa.gov/predict.shtml.
 
Two weeks ago NASA released a revised prediction stating the cycle
should peak in late 2013 at a smoothed sunspot number of 96.  The
latest outlook estimates a peak in early 2013 at 63, about 35
percent lower than the prediction from two weeks ago.  We hope it
isn't true.
 
Tom Little, WA9BOT is in EM57 in West Frankfort, Illinois.  He
reports:  "On Wednesday, January 25, 2012, I heard a couple of 6
meter QSOs.  While I heard no call signs, I was able to determine
the stations were in New Mexico and Florida.  They were using 50.165
MHz.  I heard another QSO at 50.150 MHz, but could not pick up a
call sign as what I heard was only one side of the QSO.
  
I am new to 6 meters.  Just recently put up a 5 element beam.  I am
waiting for a good opening."
 
Thanks, Tom.
 
N5TM, Dan Bates lives in Katy, Texas, and wrote:  "ZL1RS was loud
into south Texas on 50.105 starting around 0230 on February 8, and
lasted for about an hour.  I personally worked Bob three times,
twice on CW and once on SSB.  He also worked WD5IYT, and many
others... At times he was S9."  That's loud!
 
Jon Jones, N0JK writes:  "FK8CP had an extensive opening on 50 MHz
to the Midwest February 12.  States hearing/working Remi included
AR, CA, IA, IL, IN, KS, MI, MO, MS NE, OH, OK, and TX.  This was an
Es link to TEP opening.  FK8CP peaked up to 5x9 in KS and OH between
0200-0220 UTC February 13."
 
In last week's bulletin there was a URL linking to an old newspaper
article which blamed a plane crash on solar activity.
Unfortunately, the ampersands in this long URL were dropped in the
email version, and on the copy in the bulletin archive listed toward
the end of this bulletin, so the link did not work.  Try this one:
http://www.arrl.org/news/the-k7ra-solar-update-204. The link is in
the last paragraph of the bulletin.
 
Another article on solar activity appeared in the popular press this
week.  See http://raleightelegram.com/20120216846.
 
Of course, not all articles about solar activity in the popular
press are accurate.  Leave it to Britain's Fleet Street tabloids to
make normal solar activity sound like the end of the world.  Of
course, the sun is massive and the amount of energy involved in
solar events is huge, but check the headline for this article:
http://www.dailymail.co.uk/sciencetech/article-2100082/.  You'll
note that these journalists reserve the right side of paper for the
really substantial news.
 
Note they get their information from the Spaceweather website, but
check the archive at http://spaceweather.com/ in the upper right
corner, dialing back to February 11.  Yes, the sunspot doubled in
size, twice actually.

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, see the ARRL
Technical Information Service at
http://arrl.org/propagation-of-rf-signals.  For an explanation of
the numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere.  An archive of
past propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation.  Find more good
information and tutorials on propagation at
http://myplace.frontier.com/~k9la/.
 
Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.
 
Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.
 
Sunspot numbers for February 9 through 15 were 33, 51, 62, 80, 59,
64, and 40, with a mean of 55.6. 10.7 cm flux was 99.2, 110.8,
112.3, 110.4, 108.4, 107.4, and 104.6, with a mean of 107.6.
Estimated planetary A indices were 4, 4, 4, 4, 8, 10, and 22, with a
mean of 8. Estimated mid-latitude A indices were 4, 4, 3, 3, 7, 8,
and 18, with a mean of 6.7.
NNNN
/EX