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ARRL Propagation Bulletin ARLP005 (2010)

ARLP005 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 5  ARLP005
From Tad Cook, K7RA
Seattle, WA  February 5, 2010
To all radio amateurs 

ARLP005 Propagation de K7RA

As soon as sunspot 1041 went over the horizon at the end of January,
sunspot 1043 emerged, high in our Sun's northern hemisphere.
Average daily sunspot number this week fell over 13 points to 14.6,
and average daily solar flux declined nearly 7 points to 75.
Geomagnetic activity was up, and the average daily planetary A index
rose 2 points to 5.1.

Average daily sunspot number for January was 21.3, and the 3-month
trailing average, centered on December, was approximately 15.2.
Like last month, the average for the month greater than the 3-month
average centered on the previous month is a good trend.

The difference between the monthly average sunspot number and the
trailing 3-month average has been positive since September.  The
difference for November, December and January was 0.6, 5.5 and 6.2.

For 2009, the 3-month average centered on January through December
resolved to two digits beyond the decimal point was 2.19, 2.02,
1.49, 2.01, 4.23, 5.2, 4, 4, 4.64, 7.1, 10.16 and 15.15.

Predicted planetary A index for February 5-9 is 5, 10, 12, 12 and 5.
Predicted solar flux for those same days is 80, 82, 85, 88 and 90.
Geophysical Institute Prague sees quiet conditions February 5,
active February 6, quiet to unsettled February 7, quiet February 8,
active February 9, quiet to unsettled February 10-11.

We received an interesting report recently from Peter Thulesen,
OX3XR in Greenland.  He writes:

"During the last 2 days on Tuesday February 2 and Wednesday February
3 we have in Nuuk observed shortwave conditions quite different from
what we normally are used to.

"On around 21 UTC Jan/OX3DB was listening to very weak PSK signals
on 20m from a VK5 station. Suddenly the signals were very strong for
a short period where Jan worked the VK5 station. Thereafter the VK5
stations signals disappeared. Jan was not able to find out if the
VK5 station signals were short-path or long-path.

"Later around 2200 to 0000 UTC quite heavy aurora activity was
observed over Nuuk, westcoast Greenland. On February 3 around 0100
UTC the aurora observed from Nuuk area had changed from few rather
strong green bands to a wide area with weak green 'clouds' covering
the sky overhead from south west to north east.

"This evening the aurora situation was the same as observed
yesterday evening. The K-index shown on NOAA site is quite low here late
Wednesday evening and the aurora oval activity shows low activity
(activity level on or below 1). When the aurora and K index are that
low I wonder what causes the bad conditions observed here in Nuuk.

"On both days we have experienced the shortwave bands have been
closing down very quick within few minutes around 22-23 UTC."

Carl Luetzelschwab, K9LA sent in the following item.

"A really neat picture showed up at on
February 2, 2010 (you can view the February 2 report in the
'archives' link at the top right of the referenced web site).

"It's an image from the US military's DMSP-18 weather satellite.
DMSP stands for Defense Meteorological Satellite program. The
picture shows a thin intense band of aurora north of Norway at 1817
UTC on February 1.

"Why does the auroral oval image (called a pmap) indicate lots of
orange, but the DMSP picture only shows a thin intense band? The
reason is the auroral oval image simply indicates where visible
aurora can occur based on the energy and flux of the electrons
measured during the satellite pass.

"The auroral oval image is not a real-time picture of what's going
on - it's one of ten canned pictures correlated to the ten activity

"So don't assume an orange or red auroral oval is full of
ionization. As the DMSP picture and the auroral oval image suggest,
the intense auroral bands generally occur at the equatorward edge of
the auroral oval.

For more on what's happening in the auroral oval, visit"

Thanks, Carl!

Doc Kelly, K4WY of the NASA Space Operations Mission Directorate
sent a link to information on the new
Solar Dynamics Observatory, set to launch Tuesday, February 9, 2010
around 1530z from Florida.

Whitham Reeve of Anchorage, Alaska operates a magnetometer, and sent
a printout showing recent geomagnetic activity.  You can observe his
magnetometer in action at,

Jon Jones, N0JK of Kansas says 6 meters really opened up on February
1, with openings all over the eastern U.S. and the southeast.

Jon reports: "Big 6 Meter E-skip opening January 31 and February 1.
After a long dry spell, 6 Meters opened up with a bang on the last
day of January.

"Noted Es spots on DX Summit from 1630 UTC on for stations along the
Atlantic seaboard. Long duration opening, over 8 hours continuous
for some along the east coast. C6AGN just spotted by K4ZOO at 0050
UTC Feb. 1.

"Es stayed east of Kansas most of the day until late Sunday
afternoon. Around 2340 UTC Florida and the Carolinas begin coming
in. The eastern stations that poked through had large pileups of 4s,
5s, and 0s calling them.

"Worked from Wichita on 6M:

"January 31

"2349  KA4YMY  50.145  North Carolina EM95  5x9++  large pileup on

"February 1

"0013  N2XQM  50.130  Virginia EM26 "rare grid"  5x9++  said a
"hornet's nest of a pileup!"

"Some foreign DX spotted - C6AGN and C6AMN among others. Heard C6AGN
on 50.118 MHz ~ 2355 UTC Jan. 31. Nice opening for February 1!"

John sent a long list of calls heard.  The next day, he reported:

"After getting off work at 7:30 pm CST (0130 UTC Feb 2) I worked the
following from Topeka, KS from the hospital parking garage roof.

"Feb 2  6 Meters

"0145  KA2FWN  FN22 0149  KE1LI  FN41 0156  N2LID  FN12

"5/8 wave 2M mag. mount whip, FT-897.  All were loud.

"While driving back to Wichita copied KA2LIM FN12 ragchewing for
quite a while. Also heard AI1C FN34 work N0LL. Had a partial QSO
with K2MPE FN13, just after he answered me, my whip fell off the
car. Had freezing fog and the ice built up on the whip until it got
too heavy and off it went. It was dangling off the car by the coax
with the tip dragging on the road. I pulled off the turnpike and put
it away."

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

Instructions for starting or ending email distribution of this
bulletin are at

Sunspot numbers for January 28 through February 3 were 13, 12, 25,
14, 16, 11, and 11 with a mean of 14.6. 10.7 cm flux was 76.3, 73.3,
75, 75.3, 75.3, 75.2, and 74.4 with a mean of 75. Estimated
planetary A indices were 3, 2, 4, 3, 6, 9 and 9 with a mean of 5.1.
Estimated mid-latitude A indices were 2, 0, 3, 3, 7, 7 and 7 with a
mean of 4.1.


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