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ARRL Propagation Bulletin ARLP042 (2009)

ARLP042 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 42  ARLP042
From Tad Cook, K7RA
Seattle, WA  October 16, 2009
To all radio amateurs 

ARLP042 Propagation de K7RA

No sunspots appeared this week, although there were hopeful signs. reported on October 11 that a new sunspot was
''struggling to emerge'', but it faded quickly, and the sun has been
blank since then.

We got a nice response from Dr. Joseph B. Gurman, Project Scientist
on the NASA Solar Terrestrial Relations Observatory, or STEREO (see regarding observing sunspots on the
far side of the sun.

''Those bright spots are indicators of magnetic activity, which may
or may not be associated with sunspot groups.  Joe wrote, ''The
bright areas you see, called 'plage' (pronounced 'plahj') in the
solar physics business (thanks to some solar astronomer of yore who
thought they looked like white-sand beaches, 'plage' being French
for beach), represent areas higher in the solar atmosphere than the
visible surface of the Sun where (1) magnetic fields are stronger
than in their surroundings, and (2) material has been heated to
higher temperatures than in their surroundings''.

''The two appear to go together, somewhat paradoxically when one
considers that only a few hundred km lower in the atmosphere,
sunspots are cooler than the surrounding photosphere. Plage is a
feature of both active regions with sunspots (''sunspot regions'') and
active regions without visible spots. Indeed, in the coronal extreme
ultraviolet (EUV) lines (Fe IX, X; Fe XII; Fe XV) in which the
STEREO images are obtained, we call anything of a certain size and
that bright that persists for hours to weeks an active region,
regardless of whether NOAA has assigned it a number''.

''If there are no spots, it may be 'old plage' from a region whose
spots have disappeared, a new region that will eventually produce
spots, or a modest active region that never shows more than tiny
''pores'' (spots without penumbrae), that are sometimes very difficult
to see from the ground''.

We also heard from William Thompson of NASA Goddard Space Flight
Center in Greenbelt, Maryland, who wrote ''No, we can tell if there's
an active region or not, but we can't determine from the EUVI data
alone whether that active region will have a sunspot''.

Dr. Gurman also mentioned checking magnetic maps of the sun from the
ground based GONG network (Global Oscillation Network Group) at, and animations of solar magnetic
activity at
What I currently see using these tools is very little magnetic

Robert Brock, K9OSC of Fridley, Minnesota expressed some frustration
trying to install the free propagation prediction program W6ELprop
on a PC running Microsoft Vista.  This suggestion ran in this
bulletin back in 2007, and the key is to be sure you are logged in
to the PC as Administrator, then from Windows Explorer right-click
the installation file, and from the drop-down menu select ''Run as
Administrator''.  This is just an annoyance caused by security
features in the operating system.  I haven't tried Windows 7, which
is due to be released this week, but probably similar steps will be
needed.  You can download W6ELprop from  Information on running W6ELprop is at

In April and May bulletins ARLP017 and ARLP018 mentioned WSPRnet,
the Weak Signal Propagation Reporter Network, which looks to be a
promising tool for looking at HF propagation.  The October 2009
issue of CQ Magazine has an interesting interview with Nobel
Laureate Dr. Joe Taylor, K1JT, the developer of WSPRnet and other
weak signal signaling methods.  You can read it online at  

Also, Steve Nichols, G0KYA gave a talk on WSPR at the recent Radio
Society of Great Britain convention.  You can download his excellent
PowerPoint presentation from

If you don't have PowerPoint, which is part of the Microsoft Office suite, 
you can download a free PowerPoint viewer from

After recent items in this bulletin about VHF propagation and fog
banks, Len Halvorsen, WA2AMW wrote: ''The comments from Alan, KI6HPO,
reminded me of an article I read many years ago about a VHF/UHF
Propagation Enthusiast in Hawaii, who would search for (Tropo?)
Propagation Ducts to the mainland by driving up the side of the
volcano (the access road to the observatory telescopes) and stopping
at various altitudes to test for existing propagation conditions to
the west coast. He would often find paths to the mainland that were
open only from within a narrow band of altitude on the side of the
volcano. Above and below that band the propagation corridor did not
exist, nor was it accessible from his mobile/portable equipment''.

Carson Haring, AC0BU of Corydon, Iowa says he was surprised to see
VHF fog propagation a subject of discussion, because he assumed it
was common knowledge.  ''Here in southern Iowa, where I work removing
trees under the power lines from before the sun rises, I very often
have assumed that fog influences propagation on 2 meters. Many
summer mornings from the time we get to the work site until the fog
burns off, (maybe 9 or 10 am) I can reliably use 2 meters for long
distance QSOs from my bucket truck mobile''.

Also commenting on KI6HPO was Jug, WA6MBZ of Santa Barbara,
California, who wrote, ''Until he died, we had an American who had
been an AT&T employee who retired the moved to San
Quentin, Mexico, about 250 miles below the US-Mexican border''.

''Every year for many years during the summer months etc, he would
come on the Santa Barbara repeater on 146.790 MHz.  He knew when the
signal level was right and therefore when he could get into our
repeater with a usable signal''.

''Our repeater is located on a hill near the beach called the Mesa.
It is at about 400 feet above sea level.  He could not get into our
other repeaters that were located up at about 4,000 feet''.

''He was a very friendly guy and we used to talk to him for hours on
end.  I don't think any of our group ever asked him if he could get
into other repeaters along the coast of Southern California''.

Thanks, Jug.

Also coming in this week were 6 meter sporadic-E reports.  Jon
Jones, N0JK reported from Kansas on Saturday, October 11 that he saw
double-hop e-skip on 6 meters to beacons in Costa Rica, Bahamas and
Florida.  That same evening, which was October 12 at 0200z he worked
WA4GPM in FN11 and N2LID in FN12 on 6 meters.  On 10 meter CW on
October 11, 2217-2236z he heard TX4SPA working N0RR, N4KG, KF6JOQ,
W6QE, K1ZZI, KT4MM and W7DO.

For this week expect more of the same quiet geomagnetic conditions.
Geophysical Institute Prague expects quiet to unsettled conditions
today, October 16, then quiet conditions October 17-22.  NOAA and
USAF predict planetary A index today of 7, then back down to 5 for
the foreseeable future.  They expect solar flux to be up to 72 today
through October 30.

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

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

Sunspot numbers for October 8 through 14 were 0, 0, 0, 0, 0, 0, and
0 with a mean of 0.  10.7 cm flux was 68.8, 69.2, 70, 70.4, 70.1,
69.8, and 70.9 with a mean of 69.9.  Estimated planetary A indices
were 2, 3, 2, 6, 2, 2 and 2 with a mean of 2.7.  Estimated
mid-latitude A indices were 1, 1, 0, 7, 1, 2 and 0 with a mean of


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