The K7RA Solar Update


This is an early bulletin for the Thanksgiving holiday, as ARRL is closed on Friday, the regular day for release of this bulletin. We plan another brief regular propagation bulletin on Monday, December 1 that will contain the propagation numbers for November 20-26 in the regular format that normally appears at the end of the bulletin. On Friday, December 5, the propagation bulletin will be back on regular schedule, at least into spring 2009.

We had our last glimpse of sunspot group 1008 as it was about to slip over our Sun's western horizon on November 18. No sunspots have emerged since then, but it seems a reasonable assumption that we will see more Solar Cycle 24 spots, but we do not know when. There is a prediction from USAF/NOAA that shows solar flux rising to 70 on December 8-9. This is just tracking a possible reappearance of the region that birthed sunspot group 1007 that we saw in the Sun's southern hemisphere from October 30 through November 6.

Tonight ,high latitude regions may see some aurora caused by another solar wind stream from a coronal hole. But that same USAF/NOAA forecast mentioned earlier shows a planetary A index of just 12 for today, dropping to 8 on Thursday, then 5 (a very quiet level) until December 4-6 when they expect a planetary A index of 8, 15 and 10. The planetary A index is calculated with data from a collection of mid-latitude and higher magnetometers around the world, and 12 is a drop from Tuesday's (November 25) planetary A index of 17, when aurora was observed in Polar Regions.

Recently, geomagnetic conditions have been very, very quiet, as mentioned in the last bulletin. Check this site out and note the abundance of zeroes for both A and K index for two weeks through November 24, with the exception of November 16.

Milan Cerny, OK3AA, of the Czech Republic, is QSL manager for Josef Archman, ET3JA, in Addis Ababa, Ethiopia. Milan says that Josef is on 20 meters PSK sporadically from 0600-1600 UTC. With no sunspots, stations in the northeastern United States and southeastern Canada should have a good shot during the last couple of hours in that period on 20 meters.

Australian and New Zealand stations my find a workable path with stronger signals into Australia starting around 1200 UTC, and to New Zealand an hour later. Stations in and around India should see excellent signals until 1200 UTC. Milan should see excellent conditions over the whole 0600-1600 UTC period, with strongest signals at the beginning and end of that period. Weakest signals should be around 0800-1100 UTC.

In last week's bulletin, we mentioned Jim Borowski's, K9TF, of West Allis, Wisconsin, request for information on propagation prediction software for the Apple Macintosh. David Olsen, VK4FOLO (not a typographical error!) suggested DX Toolbox from Black Cat Systems; this works with both Mac and PC. If you click on the screenshots link at the bottom of the page, you can see some of the prediction screens, including the maps that show propagation conditions in all directions from your location, varying by the hour. It isn't free software, but you can download a trial version. David also has his own Web site devoted to his ham station at, and if you back up on that URL to delete everything to the right of .com, you can see what else David does in the Australian Outback.

Stew, N7NRA, mentioned that recent Mac models with Intel processors can run Windows in a separate partition, allowing the user to run W6ELprop or other programs for the PC.

Joe Large, W6CQZ, of Alameda, California in San Francisco's East Bay, also likes DX Toolbox, and points out that the Mac Ham Radio Software site has references to Amateur Radio software for Mac users.

Look for more reader comments concerning recent propagation and those 6 and 10 meter antennas this coming Monday, December 1. Have a happy Thanksgiving!

Amateur solar observer Tad Cook, K7RA, of Seattle, Washington, provides this weekly report on solar conditions and propagation. This report also is available via W1AW every Friday, and an abbreviated version appears in The ARRL Letter. Check here for a detailed explanation of the numbers used in this bulletin. An archive of past propagation bulletins can be found here. You can find monthly propagation charts between four USA regions and 12 overseas locations here. Readers may contact the author via e-mail.