Propagation Forecast Bulletin #10 de K7RA:

ZCZC AP10
QST de W1AW
Propagation Forecast Bulletin 10 ARLP010
>From Tad Cook, K7RA
Seattle, WA March 12, 2010
To all radio amateurs

SB PROP ARL ARLP010
ARLP010 Propagation de K7RA

We experienced a bit of a scare this week when four days went by with no sunspots. That's right -- for the first time in three months we saw more than a single day with a sunspot number of zero, and that last period was back during November 23 through December 8. Until March 6, there were just three days since then with no sunspots, each a bit less than two weeks apart, December 25, January 6, and January 19.

On Wednesday, sunspot group 1054 emerged in the northeastern quadrant of the visible solar disc, and just south of the center of the field another sunspot group appeared on Thursday, number 1055. This brought the sunspot number from 12 on Wednesday to 31 on Thursday, March 11. The total area covered by sunspots increased 14 times from Wednesday to Thursday.

The STEREO mission (see http://stereo.gsfc.nasa.gov/) shows a possible third sunspot group possibly appearing over the horizon in a few days. As of 0300z on March 13, 88.23% of the Sun can be observed by STEREO, and two weeks later the coverage will expand to about 88.42%. 90% coverage should be achieved on June 18 around 2323-2335z. The 45 day forecast for solar flux has been shifting over the past few days.

On March 9, it predicted solar flux for March 12-22 at 78, falling to 75 after March 23. On March 10 it shifted to 84 on March 12, 86 March 13-18, then 78 on March 19-22. On March 11, the latest available for this bulletin, it changed to 85 for March 12-15, 83 on March 16, 81 on March 17, and 80 on March 18-19. For the latest forecast, check http://www.swpc.noaa.gov/ftpmenu/forecasts/45DF.html. The new daily forecast appears some time after 2100z each day.

Current planetary A index prediction from the same source shows the value at 5 on March 12-13 and 7 on March 14-15, then back to 5. Geophysical Institute Prague says watch for quiet conditions March 12-13, quiet to unsettled March 14-15, unsettled March 16, and back to quiet for March 17-18.

David Moore, a shortwave listener in Morro Bay, California regularly sends us articles of interest to readers. About ten days ago he sent us this article, http://www.astronomynow.com/news/n1003/02solar/ from "Astronomy Now" about a project at the Royal Observatory Greenwich involving the public in an effort to analyze solar data. Don Kalinowski, NJ2E of Cary, North Carolina also sent a link to this project, called "Solar Stormwatch," at http://solarstormwatch.com/.

Their idea is that there is too much data for the scientists to observe, so they hope to use a recently popular concept called "crowdsourcing" in which large numbers of people can expand the observatory's capabilities. This definitely sounds like a fascinating endeavor for many of our readers.

Lots of reports received about good conditions for the ARRL International SSB DX Contest last weekend. Andy Gudas, N7TP of Amaragosa Valley, Nevada worked all continents in a half hour on 40 meters with 100 watts and a simple wire antenna, an inverted Vee.

His log:

07:56  VK3IO  Australia   Oceania 
08:07  ZX2B   Brazil   South America 
08:10  4A2S   Mexico   North America 
08:15  CR2X   Azores   Europe 
08:21  D4C    Cape Verde  Africa 
08:25  JA1ELY Japan   Asia
 

Scott Bidstrup, TI3/W7RI sent a link ( http://tinyurl.com/ygzg6rv) to an interesting article in "Science News" about predicting sunspot minima by studying magnetic flows.

Jon Jones, N0JK in Kansas noted E-skip a bit early for the normal season. On March 9 at 2320z he worked K2EK, from EL88 in Florida, and around 90 minutes later, at 0052z on March 10 he worked AC5O from EL49 in Louisiana. Jon was in his car, but using a 5/8 wave 2 meter whip. Jon notes that March normally has the lowest occurrence of E-skip of any month of the year. He also reported that W0WOI in Iowa heard the TI2NA beacon in Costa Rica about 0115z that day. Mike Schaffer, KA3JAW in EL87 (Tampa, Florida) reports receiving TV signals from Central America around the same time. Around 2300z he heard YNTC, TV2 in Nicaragua. The strongest signals were around 2325z, and gradually faded away around 0025z.

Bob Alsaker, N7HJL in Phoenix, Arizona wrote, "I received my first license in 1960 (Novice WV6NTQ) and have been active most of the 50 years since then (except for my 'vacation' in Viet Nam) Back then working all around the world was expected, even with modest equipment (50 Watts or less), and minimal antennas (ground mounted verticals with no radials!). The past few months have been a real joy again, after what has seemed like an eternity with no sunspots and no DX."

"The recent ARRL CW DX contest was once again a blast! Over fifty countries with 9 new ones added to my DXCC. For all the hams licensed in the past decade, get ready for some real fun, especially if you like working DX. Us OTs remember!"

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 web page at, http://www.arrl.org/tis/info/propagation.html. For a detailed explanation of the numbers used in this bulletin, see http://www.arrl.org/tis/info/k9la-prop.html. An archive of past propagation bulletins is at http://www.arrl.org/w1aw/prop/.

Monthly propagation charts between four USA regions and twelve overseas locations are at http://www.arrl.org/qst/propcharts/.

Sunspot numbers for March 4 through 10 were 40, 35, 0, 0, 0, 0, and 12 with a mean of 12.4. 10.7 cm flux was 81.3, 79.5, 78.3, 76.6, 76.3, 77.9, and 80.3 with a mean of 78.6. Estimated planetary A indices were 6, 2, 3, 4, 3, 2 and 7 with a mean of 3.9. Estimated mid-latitude A indices were 4, 1, 3, 3, 1, 2 and 6 with a mean of 2.9.
NNNN
/EX

Source: W1AW Bulletin via the ARRL.

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