ZCZC AP06
QST de W1AW
Propagation Forecast Bulletin 6 ARLP006
From Tad Cook, K7VVV
Seattle, WA February 5, 1999
To all radio amateurs
SB PROP ARL ARLP006
ARLP006 Propagation de K7VVV
The geomagnetic field has been very stable over the past week, with many periods when all of the planetary, Boulder and even high- latitude K indices were zero. Average planetary A indices, which are based on the 3-hour K index over 24 hours, were down five points to 4.4. At the beginning of this month, the Boulder K index was zero for 24 hours, resulting in an A index of zero for February 1.
Unfortunately, we not only saw low geomagnetic activity, but declining solar activity as well. The daily sunspot number on Saturday was only 29, and it has not been that low since October 4 when it was 21. Low activity like this means poorer conditions on higher frequencies. A southern California ham that the author spoke with on 17 meters this week mentioned that solar activity has been too low to enable many openings on 10 and 12 meters.
Since January has passed, it is time to review some monthly averages. The average daily solar flux for January was 142.4. This is a drop of almost eight points from December, which was 150.1. It is still a higher average solar flux than any month other than December, 1998 in the current solar cycle.
For the near term look for better conditions and a rising solar flux. Predicted flux values for Friday through Sunday are 110, 115 and 115, and the predicted planetary A index for those days is 10, 8 and 8. Beyond this weekend expect flux values to rise to around 120 by February 9, 130 by February 11, 140 on the 12th, 150 on the 13th, and remain around 160 from the 14th through the 16th. Look for unsettled to active geomagnetic conditions around February 9-11.
There is good news from the SOHO mission this week. SOHO is the sun observing satellite that brought us so much great data and solar images last year until problems began to develop in June. This week some new software was tried which allows SOHO to ignore the broken gyroscopes which were the source of its problems, and instead track stars to determine position. Three spinning wheels now keep SOHO oriented, and on Tuesday the craft returned to a position where it is pointing toward the sun. Check the latest on SOHO at http://sohowww.nascom.nasa.gov. The first new images are at http://sci.esa.int/soho/.
In VHF news, Fernando Garcia, a TV DXer in Monterrey, Mexico reported that last month was the best January for tropospheric propagation that he has seen in his eight seasons of observation. On January 10 with a Sony television and a dish he copied UHF television signals from Georgia, and Georgia and Florida signals two days later. There were a total of eight days where he observed signals over 1000 miles away, with signals from Tennessee and Alabama as well as the ones mentioned above.
Sunspot Numbers for January 28 through February 3 were 37, 33, 29, 59, 36, 47 and 42 with a mean of 40.4. 10.7 cm flux was 118.8, 177.7, 118, 114.8, 118, 110.9 and 108.8, with a mean of 123.9, and estimated planetary A indices were 7, 7, 5, 3, 2, 2 and 5, with a mean of 4.4.