SB PROP @ ARL $ARLP014<br />ARLP014 Propagation de K7RA<br /><br />ZCZC AP14<br />QST de W1AW <br />Propagation Forecast Bulletin 14 ARLP014<br />>From Tad Cook, K7RA<br />Seattle, WA April 4, 2003<br />To all radio amateurs <br /><br />SB PROP ARL ARLP014<br />ARLP014 Propagation de K7RA<br /><br />Unsettled geomagnetic conditions continued, with the average daily<br />planetary A index increasing over the previous week. Only one day<br />was mildly unsettled, April 1, with the planetary A index at 12.<br />All other days of the week were more active. But the K index dropped<br />all the way from 5 to 1 over the first six hours of that UTC day.<br />(The daily A index is calculated from the K index, taken every three<br />hours. A UTC day is the 24 hours after 0000z.) K index at 5 is very<br />stormy, and if continued through a whole day would result in an A<br />index of 48. You can see the relationship between K and A indices at<br />http://www.ngdc.noaa.gov/stp/GEOMAG/kp_ap.html.<br /><br />The predicted planetary A index for Friday through Monday, April 7<br />is 10, 12, 12 and 15. Geomagnetic conditions are expected to be<br />active again April 10-15, with the rougher conditions toward the end<br />of that period. The author has been operating mostly 17-meter HF<br />mobile lately, and not getting on the air when the mid-latitude K<br />index has been 4 or higher as reported by WWV. The K index is<br />updated every three hours, and a convenient way to check it is to<br />call 303-497-3235. Another way to check (other than listening to WWV<br />at 18 minutes or WWVH at 45 minutes past the hour) is to point your<br />web browser toward ftp://ftp.sel.noaa.gov/pub/latest/wwv.txt.<br /><br />Solar flux is expected to drift down below 150 over the next few<br />days, and may go to a low around 110 from April 17-21. It is not<br />expected to dip below 100 as it did last month. This week average<br />daily sunspot numbers rose nearly 108 points and average daily solar<br />flux rose 52 points, when compared to the previous week.<br /><br />We are currently in springtime propagation. As the days lengthen,<br />80-meter propagation will fade and worldwide 20-meter propagation<br />will extend into the night. The sunspot count is still high enough<br />that 10 and 12-meters should remain promising, much better this year<br />than next spring.<br /><br />Another quarter year has passed, and a daily average of sunspot<br />numbers and solar flux with tell us about the trend of the solar<br />cycle. The average daily sunspot number for the first quarter of<br />this year was 120.3. The average for the previous eight quarters was<br />147.3, 164.8, 170.4, 198.1, 178.3, 165.3, 193.5 and 152.7. We<br />haven't seen a quarter with an average daily solar flux as low as<br />120.3 since the first quarter of 1999, when it was 96.1.<br /><br />The average daily solar flux for the first quarter of this year was<br />134.3. The average daily flux values for the previous eight quarters<br />was 164.4, 166.7, 175.5, 219.1, 203.9, 156.4, 178.1 and 164.2. A<br />quarterly flux value as low as 134.3 hasn't been seen since the<br />third quarter of 1998, when it was 129.2. We are definitely on the<br />other side of the current cycle and heading down. The rough thing<br />for HF operators is that sunspot counts are lower as geomagnetic<br />disturbances seem more frequent.<br /><br />Of course unsettled and active geomagnetic conditions aren't bad for<br />everyone. Tom, K4SUS of Miami is positively glowing about making<br />6-meter Worked All States on Sunday, March 30. He worked K6MIO in<br />Hilo, Hawaii on SSB at 2211z, a distance of a little over 4,700<br />miles from Tom's QTH in southwest Miami. Tom uses a home made<br />4-element quad inside his HF quad antenna at 65 feet. The path was<br />via backscatter skewed southwest of the direct path.<br /><br />He said this is one of the greatest highlights of his 6-meter<br />operation over 40 years, with 108 DXCC countries worked and 102<br />confirmed. On the day he worked Hawaii, the planetary K index<br />indicated disturbed conditions, with numbers as high as 4 and 5.<br /><br />Tom says 6-meters is open most afternoons and evenings via<br />trans-equatorial propagation to South America with many 6-meter<br />signals at S9-plus.<br /><br />Sunspot numbers for March 27 through April 2 were 156, 189, 155,<br />176, 165, 161, and 189, with a mean of 170.1. 10.7 cm flux was<br />141.1, 146.9, 155.1, 154.5, 160.1, 153, and 157.5, with a mean of<br />152.6. Estimated planetary A indices were 27, 24, 27, 26, 31, 12,<br />and 20, with a mean of 23.9.<br />NNNN<br />/EX