SB PROP @ ARL $ARLP010 ARLP010 Propagation de K7RA ZCZC AP10 QST de W1AW Propagation Forecast Bulletin 10 ARLP010 >From Tad Cook, K7RA Seattle, WA March 7, 2008 To all radio amateurs
SB PROP ARL ARLP010 ARLP010 Propagation de K7RA Following five days of no sunspots, we saw one (number 984) on March 5 and 6, but it is fading off the west limb of the earth-facing portion of the Sun. Solar activity is still very low. Last week we reported, in error, that an opening on 6 meters extended to VP6DX. The openings were actually on 10 meters. Last week saw a geomagnetic disturbance on February 28 and 29, caused by solar wind streams from a coronal hole. The far north saw dramatic aurora displays, and the planetary A index on the last two days of the month were 22 and 27. At the start of every month we've been calculating a new average based on the previous three months of sunspots. This seems like it may be a way to spot solar minimum in less time than looking at 12-month smoothed numbers. May 06 39.7 Jun 06 28.9 Jul 06 23.3 Aug 06 23.5 Sep 06 21.2 Oct 06 24.1 Nov 06 23.1 Dec 06 27.3 Jan 07 22.7 Feb 07 18.5 Mar 07 11.2 Apr 07 12.2 May 07 15.8 Jun 07 18.7 Jul 07 15.4 Aug 07 10.2 Sep 07 5.4 Oct 07 3 Nov 07 6.9 Dec 07 8.1 Jan 08 8.4 January 2008 is the new figure, because it is a three-month average, and January is the middle-month, now that we can average all the sunspot numbers for December, January and February. The numbers still seem to suggest a possible sunspot minimum last October. For the next week NOAA and the US Air Force predict a planetary A index of 5, 15, 15, 10, 10, 15, 10 for March 7-13. Geophysical Institute Prague predicts unsettled to active conditions March 7, active geomagnetic conditions March 8, and unsettled conditions March 9-13. Peter Morrison, EI9ES advises that he likes IonoProbe, a utility program from Afreet Software that sits in your computer system tray and monitors sunspot numbers, solar flux, and geomagnetic indices. The tool was written by VE3ENA, and you can download it from http://www.dxatlas.com/. Also at that site are other interesting and useful programs, including Morse Runner, a CW contest simulator that reminds me of the old Doctor DX program produced years ago for the C-64. Using it seems almost like being on the air. Spring Equinox, always a good time for propagation, is less than two weeks away. Let's hope for sunspots to go with it. If you would like to make a comment or have a tip for our readers, email the author at, [EMAIL PROTECTED] 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 February 28 through March 5 were 12, 0, 0, 0, 0, 0, and 13 with a mean of 3.6. 10.7 cm flux was 70, 69.8, 68.6, 69.2, 68.4, 68.3, and 69.3 with a mean of 69.1. Estimated planetary A indices were 22, 27, 19, 8, 5, 4 and 8 with a mean of 13.3. Estimated mid-latitude A indices were 17, 18, 13, 8, 4, 3 and 7, with a mean of 10. NNNN /EX ---------------------------------------------------------- Archives http://www.mail-archive.com/dx-news@njdxa.org THE DXR is sponsored by the North Jersey DX Association. Please visit our website: http://www.njdxa.org/index.php To subscribe/unsubscribe, please send request to [EMAIL PROTECTED] and allow a few hours for acknowledgement ----------------------------------------------------------
