Saturday, December 01, 2007
ARLP050 Propagation de K7RA
Sunspots appeared over several days in the past week. November 24-27 had daily sunspot numbers of 15, 12 and 11. Otherwise, the Sun has been blank. In the previous reporting period, November 15-21, there were only two days with sunspots, and the daily sunspot numbers on both days were 13. The result is the average daily sunspot number from the previous reporting period to the current (November 22-28) reporting period rose from 3.7 to 5.4.
There were no days with geomagnetic storms, and geomagnetic conditions should be quiet over the near term. The next recurring solar wind stream is expected December 17. Expect more weeks of no sunspots, with occasional appearances for a few days at a time. The U.S. Air Force predicts a planetary A index of 5 for the next ten days. For the week, Geophysical Institute Prague predicts quiet geomagnetic conditions for today, November 30, quiet to unsettled December 1, and back to quiet conditions for December 2-6.
This weekend is the ARRL 160 Meter Contest, which begins today at 2200z. This is a CW only contest, and you can study the rules at, http://www.arrl.org/contests/rules/2007/160-meters.html.
Check out a resource for 160 meter propagation in the Northern Hemisphere at, http://solar.spacew.com/www/160pred.html. This is from the same folks who publish the Proplab-Pro HF Radio Propagation Laboratory software. They say version 3.0 is radically updated, and will be released this week, on Monday, December 3. Unlike W6ELprop and some other propagation software, this one is not free, and in fact is likely the most expensive propagation software that hams will run across. But it looks like a powerful program.
Another one that is quite powerful is ACE-HF, with info at, http://acehf.com. ACE stands for "Animated Communications Effectiveness," and it was originally developed for the military by a non-ham, who was able to obtain licensing for it upon retirement. Tomas Hood, NW7US, who writes the monthly propagation column for CQ Magazine has a page devoted to it on his personal web site at, http://hfradio.org/ace-hf.
There were more reports of interesting 10 meter propagation. In the CQ World Wide DX Contest on November 25, Doug Charette, W5GA of Wagoner, Oklahoma reported that he worked V51AS in Namibia around 1700z. Doug uses a very modest commercial multiband vertical antenna, and heard the African station at S-5. He was surprised that he didn't hear many South American stations on 10 meters in the contest.
Also in the contest, Phil Finkle, K6EID of Marietta, Georgia worked 6W1RW (Senegal) on 10 meters at 1409z on Saturday. On the same band on Sunday around 1630z he worked V51AS, D4C (Cape Verde) and 3X5A (Guinea). Walt Knodle, W7TTE of Bend, Oregon heard V51AS very clearly on Sunday morning on 10 meters (he didn't say what time), but the opening only lasted about three minutes. Around the same time he heard LW5EE in Argentina, which also disappeared shortly.
Fabrizio Valdirosa, an Italian shortwave listener in Rome, reports he also observed the 12 meter opening on November 21 reported in our extra post-Thanksgiving Propagation Forecast Bulletin ARLP049. Fabrizio reported that this was the first time he's heard Mozambique on 12 meters, and could hear C91R working North American stations. He wrote, "This opening happened just at the onset of some geomagnetic activity, as I have seen other times. When the Kp index starts to go up, we have good openings on the higher bands, usually from Europe to Africa and South America."
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For more information concerning radio propagation, see the ARRL Technical Information Service 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 November 22 through 28 were 0, 0, 15, 12, 11, 0 and 0 with a mean of 5.4. 10.7 cm flux was 69.7, 70, 71.3, 70.7, 71.5, 71.4, and 71.2 with a mean of 70.8. Estimated planetary A indices were 13, 10, 12, 11, 8, 4 and 3 with a mean of 8.7. Estimated mid-latitude A indices were 6, 8, 8, 8, 6, 5 and 3, with a mean of 6.3.